It’s no secret that there are those among us in the birding community with sharper eyes and sharper ears that others. One only has to spend a morning on a group walk to realize that. Some of it is the benefit of experience, to be sure, but some of it is simple variation among human senses. What I hear may be different than what you hear, and I may be able to see farther, sharper, than others, and not as far and sharp as some. Short of some sort of cybernetic birding equalizer, we’re all in different boats.
We’re also destined to see our senses wain as we age, an unfortunate fact of life. In birding, this means that those with the greatest acquired experience often find themselves struggling with age just as their ability and availability reaches its zenith. It’s an irony known to many.
But what does it mean for the data collected by birders, the numbers critical to determining population trends among breeding birds? According to a recent study published in Ecology and Evolution – and written up at National Geographic Daily News – based on work with the Ontario’s Breeding Bird Atlas, there’s a difference. Volunteer birders older than 50 were less proficient at detecting a number of bird species than volunteers under the age of 40.
[T]he aging process tends to knock out our ability to hear high-pitched sounds, and most songbirds are detected by hearing their song rather than seeing them flit through the trees.
But—contrary to expectations—the songs produced by the 13 problematic species did not cluster at the higher-pitched end of the spectrum. Some of the species, like the yellow-bellied flycatcher, sing relatively low-pitched songs.
“I was surprised that the results were not as strong for hearing loss as we might have expected,” said Robert Farmer, the lead author of the study, published in the June issue of the journal Ecology and Evolution.
“There is an aging effect but it’s not restricted to birds that sing at [pitches] associated with hearing loss,” continued Farmer, who did this research while he was a doctoral student at Dalhousie University in Halifax, Canada.
Of course this is all not to say that experience isn’t also a critical aspect of bird survey work, or that the results find a marked enough difference among differently aged volunteers. The distinction is, as admitted by the researcher, subtle, and when you’re looking for skilled birders to man a variety of routes and projects across the continent and the world, such subtle effects are the least of your worries.
The quote from ornithologist John Faaborg at the end of the article does say it all, “With all the other [potential] sources of error, maybe it’s not that big of a deal having a bunch of old men doing these surveys.”