ABA Blog

Certainty, Experts, and Confirmation

A couple of friends and I were birding around Jamaica Bay in New York a few years ago. We came upon a couple of people, a man and a woman, looking out over the water and discussing a bird perched in plain view, but a bit distantly, out in the marsh. They didn't seem to be birders (judging by their lack of optics), but one of them suggested it could be an Osprey. I took a look with my binoculars, easily saw the relevant field marks due to the benefit of magnification, and assured them that yes, it's an Osprey. The woman replied "Could be" as they were walking away.

Could be?! How could she doubt someone with expensive binoculars and birding experience? I had confirmed that it was in fact an Osprey, there was no doubt necessary, we now knew it was an Osprey, didn't we? In this post, I want to discuss how we confirm identifications, what we mean by expert, and how we ever know we are right. It is a treacherous subject, as birding reputations are built on accuracy and perceived infallibility, but I think it is a necessary discussion that may reveal a lot about the community of birders and our interpretations of other people's birding abilities.

What kind of hawk is this? Larger pictures available here. Read more about this bird below.

More recently, I found a hawk on our property. We haven't had a lot of raptors on our farm, not even migrants. I've been hoping for more buteos, and as soon as I saw this bird I knew it was a new species for us. However, I also knew it was going to be a tough ID. It seemed to be a young hawk, smaller than a Red-tail, perched on a dead branch in the morning fog. I immediately had it down to two species: Red-shouldered or Broad-winged. But which one? I quickly digibinned a few pictures, taking breaks to look more carefully with my binocular. I really wanted to see the top of the wings, so I decided to walk around the row of pine trees beside me and have a better angle on the bird's back. I quickly but quietly moved around the pines, and of course the bird was gone. Fortunately I had the pictures, and headed indoors to clinch an ID.

I started with reference books, but didn't find a definitive answer. I only saw the bird from the front, and young Red- shoulders and Broad-wings can be really similar from that angle. I was leaning toward Broad-wing (it was around the peak of their migration through the east), but I certainly wasn't leaning very strongly. I decided to seek outside help, get some other views on the matter. I emailed pictures to some of my birding friends and to the Ohio-Birds email list. One of my first responses was from the list, someone I didn't know. His name was John Blakeman, and he introduced himself: "Blake, I'm a master falconer and raptor biologist. The bird is a red-tailed hawk, clearly. But I'm not so sure it's an immature. Did you see the brown tail? The tail here looks too short for an immature. Immie RTs have tails about an inch longer than adults. But no doubt, a red-tail. --John Blakeman."

I panicked for a second. Wait, was this a Red-tail? Did I just jeopardize my birding reputation by asking for ID help on the most commonly seen hawk in the country? I went back to the pictures, and quickly assured myself that it indeed wasn't a Red-tail. How did I know? Well...it didn't look like one to me. I started to receive other replies; Haans Petruschke said, "...Looks like a Red-Shouldered Hawk. Others may say something else based upon plumage, but the eye structure and shape is pure Red-shouldered." Then another reply, "Immature Red Shouldered Hawk. (For what it's worth, raptors are my specialty.)" This last was another reply trying to convey the idea of knowledge and experience. Not confirmation necessarily, but just trying to indicate that they weren't some random person who started birding yesterday; they had time and experience and background with this subject. A couple of my birding friends agreed with Red-shouldered, but then a couple said Broad-wing, and then a couple more from the email list also said Broad-wing, so I was faced with a split vote. I really wanted to add this bird to our property list, so what to do?

I joined the ID-Frontiers email list to post a message about this bird. I included a link to the pictures, hoping to gain some insight from those on the 'frontiers of identification.' I knew that there were a few people on the Ohio-Birds email list who also subscribed to ID-Frontiers, but I hadn't heard an opinion from them. Based on the split vote, I thought that moving it up to a higher court was acceptable. But what do I mean by acceptable? Aren't birders available to help others, would anyone judge you for asking a stupid question? I mentioned to my wife I was thinking about emailing Sibley to get his opinion. She was incredulous: can you just email Sibley? I felt like it was an identification question that was worthy of expert advice; I'm not a new birder sending out a fuzzy picture of an obvious Brown Pelican. I have some idea what I'm talking about and didn't know what this hawk was, and other people couldn't agree, so I didn't think I'd be wasting anyone's time. I knew many respected birders were on ID-Frontiers, and I would get some good feedback. I received three responses; the one I weighted highest came from Bill Clark, co-author of the Peterson Field Guide to Hawks of North America. He said it was a Broad-winged, and I took that as the final answer.

I emailed the Ohio-Birds list, saying I'd accepted the expert testimony from ID-Frontiers (all in favor of Broad-wing). Case closed. John Blakemen replied, "Blake, You are certainly welcome to assign the ID of the hawk photo to a Broadwinged. But all of the Broadwings I've ever dealt with have distinct but subtle horizontal patterns on the breast, not the vertical ones on your provided photo...Redtails (except in the vary rare melanistic specimens) always have the central, upper breast lighter than the belly band or flanks of the upper breast (chest area), exactly as on your photo of your bird. Red-shouldereds and Broadwings have evenly hued coloration and evenly-patterned upper breasts. But the lack of horizontal patterning on the upper or middle breast negates a Broadwing for me, and the presence of a less-patterned, slightly lighter central area on the upper breast marks the bird as a Red-tail for me. I've trapped, banded, and rehabbed many dozens of Buteos in 40 yrs of working with these birds. John A. Blakeman".

I quickly did an internet search for John Blakeman. Who is this guy? Does he really have the credentials that he claims? I quickly found that yes, indeed he does. He has many years of hands-on experience with these birds. How do I decide which expert to believe, which claims to consider valid, how do I confirm an identification when it isn't clear-cut? The bird is gone, there is no way to get it back. We can't collect further evidence to make a final determination. What if everyone I consulted said it was a Broad-wing? What if they all said it was a Red-tail? Would I listen to the majority, or choose voices here and there? Maybe this bird was a hybrid, or a ghost (I mean a literal ghost, not one of the two species we sometimes call 'gray ghosts')?

My point is, we often have no way to be certain of our identifications. We see a bird, we put a name on it, and it flies away. We don't know whether we were right or wrong. Even if we move it to a higher authority, we can't know for sure if they were right or wrong. One of the people who corresponded with me suggested I try whatbird.com; the site includes a forum where people will help you identify birds. Many people post pictures, hoping to find someone knowledgeable to determine the bird's identity. Many times the responses say something like, "Chipping Sparrow. Confirmed." That is supposed to mean that the person doing the confirming knows what the species is, and they know that they are right. But how do any of us ever know that for sure?

When I decided to write this post, I emailed all of the participants in the discussion and asked whether it would be okay to use their names and responses. A couple were reticent at first, they wanted to check what they had said to me before having it thrust upon a larger birding audience. Why is that?

It is partly because birding credibility is fragile; there are people who think they are good at identifying birds, very willing to share their expertise, but who in fact lack those skills. People who are well-known in birding circles or make their living from birding-related enterprises are justifiably concerned about being lumped in with these other 'bad birders.' Unfortunately, this often keeps them quiet when a difficult identification arises. Sometimes the best identification is 'I Don't Know', but we don't usually want to admit that fact. Even worse is proposing an incorrect identification. This has the obvious side effect of stifling discourse and preventing knowledge from being shared. I was impressed when Birding began running photo quizzes where different birders explained their identification and how they got there. This prevented a consensus view from clouding perception and coloring judgment. Sometimes the experts differed, and I don't think there is anything wrong with that. Maybe there was no right answer (hybrids...or ghosts).

My point with this post is not to decide what kind of hawk is in the pictures, or decide which birders are better than others. I wanted to point out that we perceive different levels of birding expertise, and there are people and organizations we are more likely to believe. It isn't always clear why we choose to believe some people over others, or how we pick which 'experts' to consult. The next time you are out birding and run across someone grossly misinformed about the identification of a bird, feel free to do your best to correct their obvious error. Just remember, they may be trying to do the same thing for you.

Been Banding Lately?

Last weekend I had the pleasure of visiting an educational bird banding station run by the Rocky Mountain Bird Observatory at Barr Lake State Park, just northeast of Denver.  Meredith McBurney and her team of volunteers do a fantastic job of engaging school groups, bird club trips, individual birders, and passers-by (the banding table is along a popular hiking trail.)  Meredith is amazing at explaining what's going on with each bird to anyone from pre-schoolers to folks with decades of serious birding under their belts.  Birds in hand catalyze discussions ranging from the esoteric to expressions of delight and amazement.  During my visit I compared and contrasted subtle Dusky vs. Hammond's Flycatcher features and pondered why silent fall "Western" Flycatchers in Colorado should be left at that instead of putting Cordilleran or Pacific-slope tags on them.  But equally cool topics included shared retinal wonderment at the vivid azure hues on a Blue Jay or amazement at the impossibly tiny bundle of migratory energy wrapped up in a MacGillivray's Warbler.

Birders of all ages & experience levels have much to learn at a bird banding station.

I've been to many banding stations throughout my birding life and always come away knowing more than I did before the visit.  My last trip also reminded me that bird banding is also a potentially good hook for beginners.  As a follow-up to the outstanding Pledge 2 Fledge initiative, perhaps you'd consider bringing a new birder to a banding station near you!  

Seeing what Peter Pyle says about determinging age & sex of Townsend's Warblers.

One last detailed look at a Townsend's Warbler before it continues on its way towards warmer climes for the winter.

Kids who mind their P's and Q's might even get to help release a bird like this MacGillivray's Warbler.

Studying in-hand nuances of birds like this Cassin's Vireo can help birders get a grip on tricky field IDs such as separating species within the Solitary Vireo complex.

 

Why Is Sound So Hard?

One of the skills most birders use is the ability to recognize birds by the sounds they make. In most bird groups (seabirds being an obvious exception), each species (and sometimes subspecies or regional variations or even individuals) can be recognized by the sounds that it makes. If you've spent much time around serious birders, you've probably heard names mentioned, people who are extraordinarily good at recognizing the sounds birds make. If you've ever spent a fall migration morning on top of Cape May's Higbee Dike, you have probably witnessed some of these amazing events of bird ID, as experienced birders are able to pick out a flight call to identify a bird that most people didn't even realize was around. I used to work with someone who could identify birds in her sleep...she would use certain species as an alarm clock to know when to wake up in the morning. Let me make it clear right now, I am not one of those people.

I find identifying birds by sound to be extremely difficult. I don't know why, maybe it is because I am more of a visual learner. Regardless of the reason, keeping a bird song in my head is often almost impossible. It was probably after about 5 years of birding that I started being able to recognize anything other than the most common bird songs. Northern Cardinals were my default answer: no matter which species was singing, there was about a 75% chance that I would think it was a cardinal. There were times that I felt like I was doing better, but then I would hear a Carolina Wren and say to myself "Oh, a cardinal." That happened often enough that I knew not to trust my sound IDs, that they were always suspect. I'm starting to get better now (after about 12 years of pretty serious birding, including field work on birds in multiple states and countries), but it still falls apart sometimes. I'll be happily birding along, and then I'll hear a song. I'll recognize it, but not quite know to whom it belongs. In fact, it happened this morning. As background, about 10 years ago my friend Tom and I were birding in Ohio near Lake Erie. We were both still learning at the time, and there was a bird sitting up in a tree singing. It just kept singing, over and over again. We were having a tough time getting a look at it, and listened to the song, without knowing its identity, for nearly half an hour. It finally moved enough for us to get a good look at it, and we realized it was a Warbling Vireo. As we walked away, Tom said "Well, at least we'll never forget that song." I had no recollection of the song. This morning, I was tracking down migrants at one of my usual birding spots. There was a song I kept hearing, a real sing-songy song, repeated many times. I looked and followed and looked and finally got my binocular on it. Warbling Vireo. After all of these years, a relatively common bird with a distinct song continues to confuse me.

The reason I've mentioned these things is to encourage those birders who have a tough time with bird song. It is not easy for everyone, and most of us will never be as good as the experts. However, the more you work at it (spending time in the field listening, reviewing CDs, or perhaps using some of the new song-teaching software), the better you'll be. Don't expect to recognize every bird song every time, and try not to be frustrated when you get one wrong. There are a lot of us who have troubles. Stick with it, it will get better.

On Avian Subspecies: Buyer Beware? - Part 4

By Steve N.G. Howell

Part 1 is here

Part 2 is here

Part 3 is here

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Part 4

Subspecies and the Birder: Variation and Probability

            Putting names to birds, especially at the level below species, is often about probability. Few subspecies are so well defined that 100% of individuals can be identified with confidence in the hand, let alone in the field. If we accept the 75% rule, this means that up to 25% of individuals - 1 in 4 birds we see - may not be diagnosable. Of course, many of these 25% may well look like the other 75%, but this doesn't have to be the case.

            In 1948, A. L. Rand discussed the problems of how one determines whether an atypical bird in an area is from another population or simply reflects variation within the regular population of that area. As far as the birder goes, it's all a matter of probability, of educated guesswork. Examples Rand discussed include Spruce Grouse, where females of one subspecies are typically grayish toned, whereas those of another are reddish toned. The average differences are not in dispute, but if you found a reddish female far into the range of the grayish subspecies, would it be a vagrant or local variation? Given that grouse don't move much, the probability favors local variation.

            The breeding subspecies of American Robins in the Newfoundland region (nigrideus) is typically blacker above than eastern mainland breeders (nominate migratorius). But individuals resembling nigrideus have been found breeding west to Manitoba. Are these vagrant nigrideus or simply variants of migratorius? We don't know, we can't know - at least for now.

This Savannah Sparrow shows characters of the Sable Island race princeps, often known as the Ipswich Sparrow. You might feel pretty confident that it is certainly an Ipswich Sparrow, but do you really know how much variation other subspecies show? Dare County, North Carolina, 15 February 2010. © Steve N. G. Howell.

            Another of Rand's examples involved a Red-tailed Hawk matching the characters of the western subspecies calurus, which was nesting in eastern Canada, on Prince Edward Island. This recalls the recent report of an apparent eastern Red-tailed Hawk breeding in Alaska (Sullivan 2011). But are these really examples of the western or eastern subspecies, or might they simply represent occasional throwback variation of the local subspecies? Honest answer: we don't know. Each case comes down to personal opinion and probability. This conundrum brings with it the Catch 22 problem: do we describe subspecies based on appearance, or on breeding range? Is it a western Red-tailed Hawk because it looks like one, or is it an eastern Red-tailed Hawk because it's breeding in the East?

            A pioneering study that examined the feasibility of identifying subspecies in the field came in 1957 from the Savannah River area, Georgia, courtesy of a banding study by Robert Norris and Gordon Hight on - appropriately - the Savannah Sparrow. In the first winter, specimens were collected and compared with museum series to determine which subspecies occurred at the study site; 3 paler subspecies and 2 darker subspecies were identified. The second winter, banding and field observations were made, often with baseline series of specimens on hand for comparison. The field studies ascribed 195 birds to subspecies, while a further 252 birds were considered to show characters intermediate between subspecies (and perhaps some came from undescribed or different populations). Thus only 44% of birds could be placed with a described subspecies - far less than the 75% rule would decree. But is it better to know something about 44% of a population rather than nothing about 100%?

These two Savannah Sparrows show the characters of, well, Savannah Sparrows. A critical review of plumage variation in mainland North American populations of Savannah Sparrow still needs to be undertaken. Neither of these individuals particularly resembles the local breeding birds of this area, but besides that their geographic origins and subspecific status are open to conjecture. Marin County, California, 13 October 2010. © Steve N. G. Howell.

Subspecies and the Birder: Relax, be Honest

            It is clear that the term subspecies has evolved and is still evolving. Today it appears to mean different things to different people. To some scientists it is a rigorously defined entity satisfying the 75% rule (say, Subspecies version 3.3), but to birders it still has an older meaning related to average population differences (Subspecies version 2.1). For birders, the bottom line is whether a subspecies can be distinguished in the field, and with what degree of confidence. However, until the characters of most subspecies are examined critically, we can't answer that question.

This Orange-crowned Warbler shows characters of an immature of the nominate race celata. Cameron County, Texas, 19 February 2009. © Steve N. G. Howell.

            So is there a solution? Perhaps, at least in part. One approach, sometimes used in the field and in some birding publications, is that when referring to an individual bird or a few birds, one can say that the bird shows characters of subspecies X, or of a western interior population, rather than asserting that it is of subspecies X. This seems like a reasonable and realistic way to deal with subspecies and individual birds - assuming, of course, that you know what every subspecies looks like and thus can judge from the full range of possibilities. For example, we could say "this Wilson's Warbler shows characters of the eastern race pusilla" meaning: it is likely of the race pusilla, but it might just be a dull individual of the race pileolata, or an intergrade between pileolata and pusilla. Is there something wrong with being honest rather than forcing false precision on something you can't know? Moreover, in using the term race, rather than subspecies, we are subtly but semantically shifting from the scientific to the colloquial lexicon.

            When referring to a species overall we could say: populations of wetter northern areas tend to be darker, populations of drier southern areas tend to be paler (getting as specific as we like with respect to geography). We could even say something like: northern interior races (pallescens, pallidus, albus) average larger and paler overall than southern coastal races (obscurus, nigrescens), but in the field few if any individuals can be realistically ascribed to a given subspecies.

With its richly colored lores, this Wilson's Warbler shows characters of the relatively bright western race chryseola, in which both sexes have a glossy black cap. Nayarit, Mexico, 3 January 2011. © Steve N. G. Howell.

            The concept of subspecies groups can also be useful, as advocated by Dean Amadon and Lester Short (1992) and employed, for example, by Howell and Webb (1995) and Pyle (1997, 2008), and by eBird with the Identifiable Subspecific Form (ISSF). That is, a group of described subspecies (say, northern interior birds) can usually be distinguished from another group of subspecies (southern coastal birds), but in the field any individual subspecies within either group might not be safely identified. The first-named subspecies in the group gives its name to the group. Thus we might say, these birds show characters of the pallescens (or northern interior) subspecies group. This approach, without the subspecies names, is basically what is employed in the Sibley Guide. Of course, we still have the same problem of what constitutes "distinguishable" - but here it can be gut feeling rather than putative science, and perhaps this is the best we can hope for in the foreseeable future.

            The subspecies concept undeniably has utility, and many described subspecies are likely valid. It's not all a house of cards. But the arbitrary nature with which subspecies have been defined and described, or even evaluated, makes for a very uneven playing field, one where birders might easily trip and fall over their unlaced ingenuousness. Maybe a hundred years hence we will have sufficient samples of local variation throughout the ranges of every bird species that breeds in North America, and thus be able to make more "statistically meaningful" (is that an oxymoron?) statements about geographic variation. Until then, it might be best if we as birders show the characters of humility, and acknowledge that there are things we don't know we don't know.

            I thank Catherine Hamilton, Peter Pyle, and Ted Floyd for comments on an earlier draft of this essay.

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Literature Cited

Amadon, D. 1949. The seventy-five percent rule for subspecies. Condor 51:250-258.

Amadon, D., and L. L. Short. 1992. Taxonomy of lower categories - suggested guidelines. Systematic Zoology 25:161-167.

AOU. 1957. Checklist of North American Birds, 5^th edition. AOU. Washington, D.C. AOU. 1983. Checklist of North American Birds, 6^th edition. AOU, Washington, D.C.

Ball, R. M. Jr., and J. C. Avise. 1993. Mitochondrial DNA phylogenetic differentiation among avian populations and the evolutionary significance of subspecies. Auk 109:626-636.

Banks, R. C. 1988. Geographic variation in the Yellow-billed Cuckoo. Condor 90:473-477.
Banks, R. C. 2011. Taxonomy of Greater White-fronted Geese (Aves: Anatidae). Proceedings of the Biological Society of Washington 124(3):226-233.

Benkman, C. W., J. W. Smith, P. C. Keenan, T. L. Parchman, and L. Santisteban. 2011. A new species of the Red Crossbill (Fringillidae: Loxia) from Idaho. Condor 111:169-176.

Byrkjedal, I., and D. Thompson. 1998. The Tundra Plovers. Poyser, London.

Cicero, C., and N. K. Johnson. 2006. Diagnosability of subspecies: lessons from Sage Sparrows (Amphispiza belli) for an analysis of geographic variation in birds. Auk 123:266-274.

Collar, N. J. 1999. New species, high standards, and the case of Laniarius liberatus. Ibis 141:358-367.

Cramp, S., and K. E. L. Simmons (eds.). 1983. The Birds of the Western Palearctic, vol. 3. Oxford University Press.

Darwin, C. 1859. On the Origin of Species by Means of Natural Selection, or, the preservation of favoured races in the struggle for life. London.

Dickinson, J. C. 1952. Geographical variation in the red-eyed towhee of the eastern United States. Bulletin of the Museum of Comparative Zoology 107:272-352.

Engelmoer, M., and C. S. Roselaar. 1998. Geographic variation in waders. Kluwer Academic Publishers.

Franzreb, K. E., and S. A. Laymon. 1993. A reassessment of the taxonomic status of the Yellow-billed Cuckoo. Western Birds 24:17-28.

Griscom, L. 1934. The ornithology of Guerrero, Mexico. Bulletin of the Museum of Comparative Zoology 75:367-422.
Howell, S. N. G., and S. Webb. 1995. A Guide to the Birds of Mexico and Northern Central America. Oxford University Press.

Huntington, C. E. 1952. Hybridization in the purple grackle. Systematic Zoology 1:149-170.

Mayr, E. 1942. Systematics and the origin of species. Columbia University Press.

Mayr, E. 1982. Of what use are subspecies? Auk 99:593-595.

Murphy, R. C. 1952. The Manx Shearwater, Puffinus puffinus, as a species of world-wide distribution. Novitates 1586.

National Geographic Society (NGS). 2011. Field Guide to the Birds of North America, 6th edition. NGS.

Norris, R. A., and G. L. Hight Jr. 1957. Subspecific variation in winter populations of Savannah Sparrows: a study in field taxonomy. Condor 59:40-59.

Patten, M. A., and P. Unitt. 2002. Diagnosability versus mean differences of Sage Sparrow subspecies. Auk 119:26-35.

Phillips, A. R. 1986. The Known Birds of North and Middle America, part 1. Allan R. Phillips, Denver, CO.

Pyle, P. 1997. Identification Guide to North American Birds, part 1. Slate Creek Press, Bolinas, CA.

Pyle, P. 2008. Identification Guide to North American Birds, part 2. Slate Creek Press, Bolinas, CA.

Rand, A. L. 1948. Probability in subspecific identification of single specimens. Auk 65:416-432.

Rising, J. D. 2001. Geographic variation in size and shape of Savannah Sparrows (Passerculus sandwichensis). Studies in Avian Biology 23.

Rising, J. D. 2011. Genus Passerculus, pp 550-551 in Handbook of the Birds of the World, volume 16 (J. del Hoyo, A. Elliott, and D. Christie, eds.). Lynx Edicions, Barcelona.

Rohwer, S., V. G. Rohwer, A. T. Peterson, A. G. Navarro S., and P. English. 2012. Assessing migratory double breeding through complementary specimen densities and breeding records. Condor 114:1-14.

Sibley, D. A. 2000. The Sibley Guide to Birds. Knopf, New York.

Sullivan, B. L. 2012. Apparent Eastern Red-tailed Hawk (Buteo jamaicensis borealis) nesting in Alaska. North American Birds 65:390-392.

Unitt, P., and A. Rea. 1997. Taxonomy of the Brown Creeper in California. Pp. 177-185 in R. W. Dickerman (compiler), The Era of Allan R. Phillips: a Festschrift. Horizon Communications, Albuquerque, New Mexico.

Wilson, E. O., and W. L. Brown Jr. 1953. The subspecies concept and its taxonomic application. Systematic Zoology 2(3):97-111.

Winker, K. 1997. A new form of Anabacerthia variegaticeps (Furnariidae) from western Mexico. Pp. 203-208 in R. W. Dickerman (compiler), The Era of Allan R. Phllips: a Festschrift. Horizon Communications, Albuquerque, New Mexico.

Zink, R. M., and 6 co-authors. 2005. Mitochondrial DNA variation, species limits, and rapid evolution of plumage coloration and size in the Savannah Sparrow. Condor 107:21-28.

On Avian Subspecies: Buyer Beware? - Part 3

By Steve N.G. Howell

Part 1 is here

Part 2 is here

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Part 3

 Subspecies and the Birder: The Problem with Subspecies X

             Many birders I talk to seem to believe that a subspecies name refers to something that is well defined, but as we've seen this is not always the case. This belief seemingly is not limited to birders. Look at the 1957 AOU checklist and you'll see that the ranges of most subspecies are carefully described - usually with no indication that one subspecies intergrades into others; that in many areas there exist intermediates, birds unidentifiable to subspecies. For example, among all the subspecies of Savannah Sparrow listed as breeding north of Mexico, the notion of intergrading is not once mentioned! Conversely, the 1997 Pyle Guide often dismisses subspecies with phrases such as: differences are "clinal where most ranges meet." Yet it would be more surprising if differences weren't clinal where ranges met - that's sort-of implied by the concept of subspecies.

            Some field guides, notably the NGS guides, illustrate a bird and label it as subspecies X, which is not wrong, but what they may not (usually, do not) tell you is that other subspecies are, to all intents and purposes, identical in the field to subspecies X. This may mislead you to name a bird you see in the field as subspecies X because it looks most like the picture in the field guide of subspecies X. That's what we do with species, so why not with subspecies? The NGS guide introduction does not caution about this problem. Rather, we are led to believe that subspecies are discrete entities; and the new subspecies maps of the NGS 6th edition (with their neatly drawn solid lines) cement this fallacy. In a few cases, the NGS subspecies maps indicate an "intergrade zone" between subspecies, but the converse of this is the implication that all other subspecies boundaries are well-known and clean cut, which is far from the case.

Clearly a Fox Sparrow - but which subspecies? Until we have a good idea of the characters of all subspecies within a species, trying to put a subspecies name on any individual is fraught with pitfalls. Marin County, California, 21 November 2011. © Steve N. G. Howell.

            Other field guides label birds by the geographic regions in which they breed. As a birder, are the labels West Taiga, East Taiga, and Interior West more meaningful to you than the scientific names gambelii, leucophrys, and oriantha? Geographic names need not be precise but at least they do convey immediate information that can be expanded upon with text or maps; we don't have to try to remember whether the subspecies oriantha breeds in the eastern taiga zone or in the interior West. This method cuts out one step in the process of information transfer, a step that may involve learning names in an alien language, names that sometimes we can't even pronounce and certainly don't remember how to spell. In this case I'm talking about White-crowned Sparrows. The Sibley Guide (2000) notes that populations of White-crowned Sparrow intergrade where their ranges meet, whereas the NGS Guide (2011) makes no mention of intergradation - subspecies such as gambelii are portrayed as discrete entities, which is misleading at best.

            I suspect many of us know birders who believe that subspecies names have sanctity, who worship at the church of geographic variation. But, as we've seen, most subspecies remain scientifically unevaluated, which might lead us to wonder if birders are sometimes worshipping false gods.

Another Fox Sparrow - but which subspecies? Marin County, California, 3 February 2012. © Steve N. G. Howell.

Subspecies and the Birder: What Do We Really Want?

            A question we might ask at this point is: are subspecies, in and of themselves, what we as birders and field ornithologists are really interested in? Might it not be more a case of wanting to appreciate and understand geographic variation? And what better way to do this than with subspecies? Yet as we have seen, while it may seem more precise, more scientific, to throw around subspecies names, instead this may be false precision, even hubris - at least until hundreds of described subspecies are evaluated critically. In addition there are surely subspecies out there that remain to be described. Witness the recent descriptions of Gunnison Sage Grouse, a new species not even previously recognized as a subspecies, and of the more controversial South Hills Crossbill (Benkman et al. 2009), a distinct population whatever its taxonomic status. Despite illusions we may have to the contrary, the details of breeding distribution and geographic variation are not that well known for many species of North American birds.

Another Fox Sparrow - but again, which subspecies? Marin County, California, 3 October 2006. © Steve N. G. Howell.

            There are two main arenas of interest to birders when thinking of subspecies, linked perhaps to the common birding themes of listing and of finding rarities. The first is in appreciating distinct local variation, usually in resident species - perhaps because some of these isolated populations might one day be split as full species (think Florida Scrub Jay 20 years ago, or perhaps Gray-headed Chickadee 20 years hence). In this instance we know the subspecies, or at least we presume it fairly safely based on geographic range. Greater numbers of distinct subspecies tend to occur among more sedentary species, such as grouse and chickadees; gene flow is relatively limited if birds aren't highly mobile, encouraging local variations to develop. Conversely, mobile and migratory species such as warblers and flycatchers tend to have fewer subspecies.

            The second arena is in attempting to determine the provenance of vagrants, or even of regular migrants. In this second instance, we have to infer subspecies based on characters such as plumage tones, structure, perhaps voice, and anything else we can. This is where the fun - and the debate - comes in. When a western type of Fox Sparrow turns up in New England the questions start: Which subspecies is it? Where did it come from? In this and so many other cases, does it really matter if we can't distinguish 75% of a population at the subspecies level? If that Fox Sparrow falls squarely into population X, or subspecies X, then we have an answer. Cool, and percentages are irrelevant. But if this is all we want, what can we do about it?

Continue to Part 4

On Avian Subspecies: Buyer Beware? - Part 1

Editor's Note: The ABA Blog is excited to offer a four part series by renowned field ornithologist and researcher Steve N.G. Howell on the history and relevance of avian subspecific identification.  Steve is a senior international bird tour leader for WINGS and has written several books including A Guide to the Birds of Mexico and Northern Central America, Gulls of the Americas (with Jon Dunn), and the recently released and impressively received Petrels, Shearwaters, and Albatrosses of North America.  He lives near Point Reyes, California.

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Part 1

            These days, birders are more interested than ever before in subspecies, and thus taxonomy. Now that we think we can identify most birds we see to species, we want to go further down the path, to put names on the variation we see in the species around us. But how realistic is this notion? And are subspecies a useful means of describing variation?

            I'd like to look at avian taxonomy from a philosophical and historical perspective, to help explain why subspecies are such a problem in modern ornithology, and by extension, in birding. The concepts are very simple, in theory. For better or worse, however, most of us live in a world of realities, not theories, and therein lies the paradox of taxonomy: if the world were simple enough for us to understand, we'd be too simple to understand it. Like the species concept, the subspecies concept might be viewed as a Procrustean bed in which Nature will not lie quietly - but as humans we have to try and make order out of chaos, one way or another.

            Any discussion of a subject should be based on definitions, so how might we define taxonomy, species, and subspecies?

 

Definitions

            Taxonomy simply means classification, usually in reference to living things, such as avian taxonomy - the classification of birds. The units of taxonomy are taxa (singular: taxon) - for example, species and subspecies are different levels of taxa. Linked to taxonomy is nomenclature, the naming of things. It's basically human nature to put things in boxes - we are the taxonomic animal, and we need to classify things, to help make our world manageable.

            But what is a species? Basically, a species is impossible to define to everyone's satisfaction and Charles Darwin's statement of 1859 holds true today: "No one definition has as yet satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species." It's a bit like Justice Potter Stewart's famous "definition" of pornography: "I know it when I see it."

            Birders should recognize that taxonomists themselves can't agree on how to define a species. Books and countless articles have been written on speciation and species concepts, with sides taken and lines drawn between proponents of different species concepts. But while there may be an answer, for now it is unknowable, or at least indefinable. Still, as humans we need a working definition, even if it's imperfect, and here I'll use the biological species concept (or BSC). The BSC remains the foundation for the taxonomy of the American Ornithologists' Union (AOU) Committee on Classification and Nomenclature (often abbreviated by birders simply to "the AOU" or "they" - as in: "Where the %$&# did they put longspurs?").

            The classic definition of a biological species, as promoted by Ernst Mayr (1942) is basically: A population of actually or potentially interbreeding organisms, which are reproductively isolated from other such populations; the members of a species should be able to interbreed and produce fertile offspring. Within a biological species we can often distinguish variation. If this variation shows consistent patterns (beyond those associated with age and sex and season) it may be recognized by means of subspecies (often abbreviated as ssp.), which are designated formally by a trinomial, a third part of the scientific name.

            A bird's scientific species name is two-part and italicized, based on Latin, and comprises the genus name (Capitalized) and the species name (lower case). A genus can be defined simply as a group of closely related species, or of species sharing a common ancestor; it's another subjective definition, but one that lies outside the scope of this essay. For example, the Song Sparrow is known scientifically as Melospiza melodia, and shares its genus, Melospiza, with Lincoln's Sparrow and Swamp Sparrow, because these three species are considered more closely related to one another than to other sparrows. Song Sparrow populations breeding in the south arm of San Francisco Bay, California, are considered distinguishable from other populations, and are given the subspecies name pusillula, as in Melospiza melodia pusillula. Usually the population of Song Sparrow described first is given the same subspecies name as the species name, as in Melospiza melodia melodia, which is known as the nominate subspecies. This nominate designation is purely administrative, it does not imply that the subspecies melodia is any more typical than any other subspecies, or more widespread - simply that is was named first.

            A subspecies is synonymous with a race, despite the colloquial term "human race" - when really what people presumably mean is human species, of any race, creed, or color. Thus, for example, the race elegans means exactly the same as the subspecies elegans.

            But as with a species, how do we define a subspecies? Ornithology is the science of the study of birds. For something to be considered a science, certain criteria should be met. These include repeatability, whereby something can be repeated and confirmed by other researchers, using universally accepted measures that are considered unambiguous. Thus, in describing a subspecies (or species) the ideal is that anyone else can recognize it and identify it by its characters.

Subspecies or species? Based on geographic location and season, in combination with bill size and shape, we can pretty safely say this Savannah Sparrow is of the taxon sanctorum, split in Handbook of the Birds of the World as a full species, San Benito Sparrow, but elsewhere considered a well-marked insular subspecies. Isla San Benito Oeste, Baja California, Mexico, 5 July 1999. © Steve N. G. Howell.

            In 1949, Dean Amadon attempted to formalize "the 75% rule" as the standard for defining a subspecies. That is, to be recognized as a subspecies, at least 75% of a population should be distinguishable from >99% of any other population, on the basis of a defining character or set of characters. This is a purely arbitrary definition, but at least it's a definition - with numbers. Applying it is not always easy, however, and this formalized definition was proposed after the great majority of subspecies had been described. Moreover, most descriptions of avian subspecies in recent years have not used the 75% rule but instead have used the concept of detecting statistically significant mean differences between populations, not on determining the extent of overlap in characters. (Whether statistical significance is the same as biological or evolutionary significance is a minefield I’m not going to enter here!)

            The AOU website (http://www.aou.org/committees/nacc/subspecies.php; accessed 4 April 2012) notes that "subspecies should represent geographically discrete breeding populations that are diagnosable from other populations on the basis of plumage and/or measurements, but are not yet reproductively isolated. Varying levels of diagnosability have been proposed for subspecies, typically ranging from at least 75% to 95%. Because subspecies represent relatively young points along an evolutionary time scale, genetic differentiation between subspecies may not necessarily parallel phenotypic divergence. ... Described subspecies that represent points along a phenotypic continuum (cline) probably would not warrant recognition given further study."

            You'll note that this definition describes what the AOU would like subspecies to be, which is not how most subspecies were necessarily described. The AOU definition is also descriptive rather than prescriptive, and there remains no official template for describing subspecies. People do what they like, and it could be argued that avian taxonomy often falls short of science.

Several subspecies have been described for both Red Knot (front left) and Short-billed Dowitcher (front center and right) - but these subspecies are rarely separable other than in breeding plumage, and then sometimes only with the aid of complicated statistics. Yucatán, Mexico, 1 December 2010. © Steve N. G. Howell.

 

Subspecies and History

            Humans like to collect things. Back in the day, especially throughout the 1800s, wealthy noblemen in Europe maintained collections of many things, bird specimens among them. They paid people to travel the world in search of new and novel additions to their collections. With specimens in hand, numerous new species of birds were described, usually based on the physical properties of structure and color - what has been termed the morphological species concept. The heyday of this naming lay in the 1830s to 1890s, and when something was named, its scientific name - and the person who described it - were enshrined forever; there was a certain prestige attached to the process.

            As one might expect, humans being humans, there was rivalry, both personal and international, in getting names published first; Nigel Collar (1999) discusses some good examples. Single specimens with scarcely any description might be published as new taxa, and because of the rules of taxonomy, these names usually had to stay. New names might even be rushed out the next day in newspapers to cement "priority" of naming in print, rather than wait for the slower process of possible peer review and publication in respected journals or more formal outlets.

            Virtually all subspecies diagnosis was based upon examination of specimens, that is, study skins made from dead birds. Other features, by which populations may be diagnosed, such as habitat, vocalizations, and breeding season, were rarely if ever used to define subspecies, yet such factors are often used in defining species. In essence, the subspecies developed as simply a morphological unit, one that could be identified in a museum tray by virtue of measurements and plumage. Perhaps paradoxically, some species appear indistinguishable by conventional measurements or plumage differences (think storm-petrels and owls, among others), and thus in a series of specimens they would not qualify as subspecies. Yet they can be distinguished as species by vocalizations, genetics, breeding seasons, habitat, and other criteria not apparent from a study skin!

            Subspecies were most often described based on males, which in many species are more colorful than females (and thus more favored by collectors), and often more conspicuous and easier to collect, such as when singing in the breeding season. However, subspecies may also be described based on distinctive features of the female plumage or even of a seasonal plumage. For example, the three widely recognized subspecies of Short-billed Dowitcher are best separated in breeding plumage - in nonbreeding plumage they are often not distinguishable. Thus, a subspecies may not be identifiable in all ages or sexes, or at all seasons.

At least 11 subspecies of Common Yellowhthroat are recognized as occurring in North America, north of Mexico. Most are perhaps best distinguished in adult male plumage - so it is difficult (at best) to assign females and immature males, like this, to any subspecies when found outside the breeding season. Marin County, California, 31 August 2010. © Steve N. G. Howell.

            Following the publication in 1859 of Darwin's worldview-changing opus, the concept of subspecies came to have two meanings: one was as an incipient species, the other as evidence of the adaptive response of a species to local climatic conditions (Mayr 1982). With the philosophical change from a morphological to a biological species concept from the 1880s to 1920s, subspecies came to be seen as measures of geographic variation. (The present AOU definition of a subspecies, quoted earlier, indicates that this is still the case.) Scientists looked anew at all of the old "species" to see if some were simply subspecies of a more widespread and variable species. Consequently, many "species" were lost in this period: in North America alone, some 315 avian taxa that had been described as species were "lumped" - subsumed as subspecies into species that exhibited geographic variation (Mayr 1982). The formal term for this is synonymizing: when one subspecies is considered indistinguishable from another, the subspecies that was described later is a synonym of the earlier described subspecies, and is lumped with it; the earlier name takes precedence.

            As with many changes in fashion, the pendulum swung too far, and much of the indiscriminate lumping that characterized the 1900s to 1950s is now being slowly undone. For example, Murphy (1952) lumped seven former species of small shearwaters as subspecies of Manx Shearwater, which then became a species of worldwide distribution; no new data prompted this move, simply a change in philosophy. Nowadays, all seven of these taxa are split again as full species - and we have come full circle.

            Concurrent with the loss of many "species" was the description of many new subspecies, as ornithologists sought further examples of geographical variation. The resultant fad of naming subspecies saw its peak in North America from the 1890s to 1950s. Ideally, to describe a subspecies one would compare a series of fresh-plumaged specimens, of the same age and sex, with another series of the same makeup, but often this was not done. Many subspecies were distinguished based on slight differences, and rarely with adequate samples of birds in comparable plumage. For example, in 1934 Ludlow Griscom described a subspecies of Calliope Hummingbird from the species' wintering grounds in southern Mexico - on the basis of a single molting male in worn plumage!

            The 5th edition of the AOU checklist (published in 1957) was the last edition to list subspecies of North American birds, and their distributions; it doesn't tell you what the subspecies look like, however - for that you need to do a lot of digging in the literature and in specimen collections. Peter Pyle's two identification guides (1997, 2008) offer a starting point, but from his descriptions it is often difficult to infer what any given subspecies really looks like, or how easy it might be to distinguish in the field. For example, average color differences apparent in series of specimens are often expressed as "absolutes," as with Vermilion Flycatcher. For adult males, the Arizona subspecies flammeus is described as "head and breast ... red to orange-red, often with pale mottling" whereas the Texas subspecies mexicanus is "deep red, without orange or pale mottling" (Pyle 1997:242). This sounds like a fairly clear difference. Yet when Brian Sullivan, Michael O'Brien, Chris Wood, and I laid out about 20 male specimens of each subspecies at the American Museum of Natural History in New York, we found only a subtle average difference in coloration, and many specimens could not be placed confidently with one subspecies or the other based simply on plumage tones.

            Implied but not stated explicitly in the 6th edition of the AOU checklist (published in 1983) is the notion that subspecies listed in the 5th edition had been evaluated critically (AOU 1983:xiii). The 1957 AOU checklist ostensibly marked the culmination of the subspecies era in North America. Subspecies description fell from fashion in the 1960s and 1970s, and the "glamour" in taxonomy is now with descriptions of cryptic species, and with revisions of genera or of families and other higher-level groups. Meanwhile, countless books and articles list subspecies as if they were inviolate and well-defined entities with mystical powers to elucidate geographic variation and distribution patterns. But are they?

 A complete Literature Cited section will appear at the end of Part 4...

Continue to Part 2

Lovitch: How to Be a Better Birder

And that's really what it's all about, isn't it? The goal of birding, of any hobby, is expertise gratia sua, and the only reason we do it is to do it better. This slender new volume by Derek Lovitch will help almost any birder do just that.

Relatively new birders who take this book in hand may be surprised to find out just what "better" means. This is not a difficult species guide. Instead, in nine short, casually written chapters, the author introduces us to some of the tools and resources 21st-century birders have available, and shows us how to bring them to bear as we look for that next "good" bird.

After an introductory chapter advocating "whole bird and more birding," Lovitch devotes the next two to how birders can use--and acquire--a knowledge of habitat and geography. Here and throughout, he offers very helpful recommendations for books and online resources in the ancillary sciences; no excuse now not to be able to tell a syacmore from a maple. There is a whiff of an eastern bias in the habitat discussions; the extended example of wintering Empidonax flycatchers in southeastern Arizona doesn't really "work" for me. But the reminder to seek out islands of habitat, especially treed islands in seas of open country, is a salutary one wherever you are. Literal islands, peninsulas, and other geographic edges are the subject of the next chapter. 

Lovitch is at his very best in the book's central chapters, where he offers detailed instruction in reading weather forecasts for finding birds. I've "bookmarked" several meteorological websites I hadn't used before, and am eager to see whether they help me this spring. Just to show that theory begets practice, the author narrates a "case study" of a few autumn days in New Jersey, when Lovitch and his friends used the techniques described here to great advantage, birding from Garrett Mountain to Cape May. 

The book ends with a postscript about "patch birding," frequent visits to the same birding site over a long period. This is how birding used to be done, by most of us at least, and Lovitch's call to return to the practice is a welcome one. And the skills we're taught in this book will make it even more fun--and make us all better birders.

 

 

 

Howell: Petrels, Albatrosses, and Storm-Petrels of North America

Steve N.G. Howell's new photographic guide covers all the procellariids, diomedeids, hydrobatids, and oceanitids recorded in (or off) the North American continent. 

Yes, you read it right: oceanitids. The taxonomy Howell uses in Petrels, Albatrosses, and Storm-Petrels is progressive indeed, leaving the AOU's would-be canonical classification schemes in the dust. Not only do we find the southern storm-petrels assigned to their own family, Oceanitidae, but numerous novel genera and species are at least tentatively recognized. Howell treats in full 70 taxa, with comparative discussion of many more; in contrast, the AOU lists only 61 species for its area, which, unlike Howell's region of coverage, includes Hawaii. Following Howell (and Robb et al.'s marvelous Petrels Night and Day), we now have in North America, for example, three "Cory's" and six "Manx" shearwaters, two "Fea's" and two "great-winged" petrels, three "wandering" albatrosses, and three "band-rumped" and four "Leach's" storm-petrels. And before each of those numbers is to be understood a quiet "at least": many of the species, and even some of the genera, split here may well conceal other cryptic taxa deserving of species-level recognition. There may even be two "Northern" fulmars. Howell is scrupulous and admirably clear in explaining the nomenclatural "clusters" that have long made even talking about so many seabirds so difficult.

Not to mention identifying them. But even storm-petrel identification, rightly described here as "one of the most challenging frontiers in modern birding," will be made less frustrating in most cases by the wealth of carefully chosen and beautifully well presented information in this book. The (sub)species accounts are clear and thorough, with full treatment of taxonomy, status and distribution, and similar taxa; behavior, especially flight habit, is given considerable space, and Howell's descriptions here are as clear as they are evocative. Each taxon treated is illustrated with an impressive number of often dazzlingly good photos--and, perhaps even more importantly, often with some poorer images of birds at a distance, in fog, or nearly lost in a swarm of similar congeners. The captions are marvels of concise eloquence, pointing out important characters and comparing similar species, sometimes even in the same photo. 

Particularly given the abundance of information and the very large number of photographs here, the book is very well produced. I might prefer to have seen a single type face throughout, rather than a different, larger and unattractive font for the introductory material. Typos are very few and mostly insignificant. The name of the island Trinidade is inconsistently spelled, and the caption to photo 7.11 reverses the identity of the background birds. The Christmas Shearwater is Puffinus nativitatis (not -us), and the black margin to the underwing of the Hawaiian Petrel is thin (not, as claimed in Fig. 120, "thick"). The specific epithet of the Black-capped Petrel, hasitata, is probably a misspelling not of haesitata but of hastata, meaning blade-shaped, in reference to the wings. Howell's writing is as pleasingly vivid as it is informative; still, it's unusual to see the phrase "brain fart" in print, and I'm skeptical as to whether "emotional castration" is truly behind the occasional abbreviation of the name of the Light-mantled Sooty Albatross. 

As one might expect from the author of the molt volume in the Peterson Reference Guide series, the plumages of seabirds are discussed with special thoroughness here. Howell gives us eight well-illustrated pages on the topic in his introduction, then provides dates--at least tentative dates--and details in each species account. It turns out that it is precisely that molt information that permits the distinction in the field between many pairs and trios of similar species; many of Howell's photos show this very well, making this an essential tool to help readers get their eye in for their next pelagic trip. But even if you're not going down to the sea in boats, Petrels, in its sophistication of approach and exemplary detail, may well be the most useful book you read this year. 

Dunn and Alderfer: Field Guide to the Birds of North America

Few are the bird books that go through six editions in their authors' lifetimes, and fewer still those every edition of which takes another considerable step up in accuracy, completeness, and usefulness. Precious few indeed.

But here's one.

I remember well my first sight of the then-new National Geographic Field Guide, twenty-eight years ago (!), and I couldn't wait to get my own copy. I've leapt on each new edition ever since, and nearly three decades of living with the book has only affirmed my conviction that this is by far the best book of any for learning the birds of the United States and Canada. And this new, sixth edition is by far the best of this splendid guide's incarnations so far.

There's no need here to rehearse in detail the NatGeo's many advantages over even its most worthy competitors. Some of those advantages--the rich text, the emphasis on variation, the comprehensiveness even at the outermost edges of the area covered--have been present ab ovo, but they have been strengthened, and new strengths added, by the increasingly unified authorial leadership provided by Jon Dunn and Jonathan Alderfer (with Paul Lehman supplying his usual excellent maps).

The editorial history of the book is as fascinating as it has been complicated: starting in the late 1970s as a true team effort forged in sad circumstances, this guide has with each passing edition become more and more the child of one of North America's very finest field ornithologists, and each new edition should be read as approaching ever more closely to Jon Dunn's ideal conception of the field guide.

Mirroring Dunn's interests and expertise, this sixth edition adds considerably to the status and distribution information available in earlier versions of the guide. We are given population numbers for many rare taxa, and the accounts for many casual and accidental species include precise dates and locations, a great boon for the watchful seeker of repeat occurrences; quite detailed historical information is often provided for species whose ranges or abundance have changed notably. Several species still relegated to an appendix in the fifth edition have been moved into the main text, and some rarities once crowded inconspicuously among the "normal" birds of the area have now been given their own plates and more extensive texts. 

Even a few species not yet recorded in North America north of Mexico are treated: the Sulphur-bellied Flycatcher account urges careful separation of apparent vagrants from the Streaked Flycatcher, and ambitious East Coast birders are furnished with an illustration and brief identification material for the Common Scoter that is certainly lurking out there in the flocks of the (newly re-split) Black Scoter. 

A trademark of this guide since its first edition, geographic variation is accorded especially full and sophisticated treatment here. Some such information appears on the plates; the seventeen figures of the Horned Lark, for example, are larger than in the immediately preceding edition and more amply annotated (one of the very few layout errors in the book finds the label alpestris for one of the flying birds attached to a perched strigata). For other taxa, such as the Common/Holarctic/Californian/Chihuahan Ravens, significant portions of the text are devoted to introducing the complications of their geographic relationships. And for nearly 100 species that are especially complex, the maps--either those accompanying the species accounts or additional, larger maps in an appendix--indicate the breeding range and often the migration routes and wintering grounds of field-identifiable subspecies and subspecies groups. Study a few of these maps carefully, and I think you'll agree with me that no self-respecting field guide of the future will fail to imitate them. Just think what an e-guide could do with this idea, adding layer upon layer to a species' base map....

Unmatchable in so many ways, the NatGeo guide, even in this newest edition, still reveals weaknesses in its paintings. Thanks to the involvement of Jonathan Alderfer in the last couple of editions, though, the less satisfying illustrations--the troublesome legacy of the book's origins as a committee project--are slowly but surely being replaced with far better images. Something like 300 new figures were painted for this edition, by Alderfer, Killian Mullarney, David Quinn, John Schmitt, and Thomas Schultz; a quick leaf through the art credits finds many of my favorite plates and images attributed to these artists.

More noticeable, and perhaps more important, than the new figures is the new design of very many of the plates, permitting the enlargement of many birds that in previous editions were tucked into corners and margins. At the same time, the redesign has left space for sometimes extensive annotation directly on the plates themselves, an innovation with an obvious and estimable forebear. 

The sixth edition of the National Geographic Field Guide is, simply put, the one book every North American birder needs to have on the shelf. Beginners will find it attractive, easy to use, and portable; intermediate and advanced birders will refer to it again and again with profit--and with surprise at how much it can teach even the most experienced among us. 

 

 

 

I Don't Know

As birders, our goal is to find and identify birds. That is what we do when we are out in the field, driving, doing yard work, or just glancing out the window. Our overriding urge is to see and then identify birds. Fortunately for us, birds are everywhere. No matter where you go in the ABA area (and, I dare say, the entire world), there are birds to be seen. And as I mentioned in my previous post, we should always be prepared for the unexpected, as you never know what you will find, even in unlikely places. All of this put together means that seeing birds is relatively easy.

The second part, identifying, can be more difficult. We try to identify every bird we see. Sure, if a bird is too far away or if the conditions are poor (low light, back light, fog, etc.), we may admit that we aren't sure what the bird was, aside from "It was a duck" or "Definitely a small passerine". This is of course the thing to do, because we just don't have enough information to completely identify what we've seen. What I want to discuss is when we have an abundance of information: when the bird is a few feet away in good light, providing excellent views. This is when the urge to identify, to name every individual possible, can get us into trouble.

Imagine the scenario that you are birding with friends. A small bird sits up on a close perch, and you are the closest to it. You get a good long look through your binoculars, and then it disappears back into the brush. You are very confused by the bird, and aren't sure of any specific ID (and in fact you aren't quite sure what family it was in). Your friends weren't as close and didn't have the view that you did; they ask you, "What was that?" This is when it is tempting to try to make the call; we want to identify birds, and we want to be good at it. We want to know what things are, and we don't want to seem like incompetent birders. We want to say without a doubt "Female Indigo Bunting". This can be an especially powerful urge if we've spent time around birders that are better than we are, and we want to show that same ability. The last thing we want to admit is that "I don't know".

"I don't know" is one of the few identifications we can ever be completely confident about. If you say you aren't sure, you are being completely honest and are completely right. When we identify birds to species, there is always that lingering possibility that we are wrong (hybridization, mutation, environmental contamination, etc., can all cause an obvious identity to be subtly or completely incorrect). Another benefit is that saying we aren't sure shows other birders that it is okay to be uncertain, that it is okay to question what we saw. These sorts of uncertainties can lead to good outcomes. In the scenario above, imagine you call out "Indigo Bunting". Your friends may keep walking, accepting your ID. You've just lost an opportunity to perhaps learn from your birding group's collective knowledge. If you say you aren't quite sure, perhaps someone more familiar with that age/plumage/subspecies will have some helpful insights into how to identify that individual, things you can use for the future.

Alternately, perhaps you say I don't know, and your birding group takes a closer look and finds a Lazuli Bunting, a rare bird in your area. Now you've learned something and helped find a rarity. The final, and least desirable, scenario is that you make the Indigo Bunting ID, despite your uncertainties; one of your birding friends happens to come across the same bird and makes the correct ID. Now you're embarrassed about the misidentification, and perhaps miss out on a good learning opportunity because of it.

It is IMPOSSIBLE to identify every single bird every time. Admitting that you aren't sure is always okay. It doesn't mean you are a bad birder, just that you are honest. Birders at every level make mistakes. Saying "I don't know" is never a mistake.