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El Niño – Effects on Birds and Birding

Now more than ever, birders are able to practice their interest with in increased sense of how the weather influences the movements of birds. Whether this is reading dopplar and wind speed charts to predict landfall of migrating passerines, or following hurricanes and tropical storms for waifs, or tying influxes of vagrants to storm systems crossing the continent, it’s quite heady to think of the information increasingly at our fingertips. But weather is still a mysterious in many ways, and no weather-related phenomenon is surrounded by more mystery than the famed El Niño – Southern Oscillation (ENSO).

Maybe it’s the effect it has on Pacific seabirds. Maybe it’s because it was celebrated in Mark Obmascik’s The Big Year as the driver of dozens of Asian vagrants to Attu. What most of us know about El Niño, the abnormal and seemingly cyclical period of prolonged warm water in the eastern Pacific that spins off unusual weather events on the west coast of the Americas, is that the aberrant water temperature and the weather it creates causes birds to move around around in important ways. Birders are often the recipients of such largess in the form of scattered vagrants and exciting birds. For instance, the El Niño believed to be forming in the eastern Pacific now in the summer of 2014 may have been the agent of a potential ABA Area first in southern California. And, of course, there was the aforementioned 1998 Attu invasion celebrated in myth and legend, also presumably El Niño driven, though for reasons that are less clear.

What we do know about El Niño is that the abnormally warm weather does odd things to bird populations. Not only related to vagrancy, but also potentially making it more difficult for Neotropic migrants to find food on land and for communal nesting seabirds to find high quality food along the shore. Occasionally this shortfall manifests itself in dramatic fashion, as it has this week in Peru and Chile.

El Nino

Dead and dying seabirds in Arica, Chile/June 2014. The birds are likely starving in response to changes in fish abundance related to the formation of an El Niño event. photo by Ronny Peredo

Alvaro Jaramillo reports to Seabird News as follows:

Thousands of dead seabirds washing up on shore. Preliminary reports from Peru (June press release from IMARPE – Inst. Del Mar del Peru) include over 6000 dead or dying seabirds, mainly in the last two weeks of June. The report mentions that 80% are Peruvian Boobies, 10% Guanay Cormorant, and 4% Blue-footed Booby, and 4% Peruvian Pelicans. Reported cause of death is starvation. Ronny send me photos of dozens of corpses on Arica beaches, and also photos of dead Blue-footed Booby. The latter is of particular importance as Blue-foot is a rare species in northern Chile, not an annually observed species. This suggests that birds are not only succumbing, but they are moving south in search for food. I gather that Ronny and people in Arica have counted several thousand dead seabirds on their beaches.

This seems like a massive amount of die off, given that in theory the warm water ENSO event is merely developing at this point. If the birds are a sign, this may indeed be a big one that is coming.

The occasional ENSO event is the sort of thing populations of birds have been dealing with for millennia, but one of the side effects of climate change in the South Pacific is predicted to be an increase in the regularity of these events. This would potentially have some long-term effects on these communcal nesting species, and many of those we hope to see end up in the ABA Area in the near future.

That doesn’t mean we shouldn’t be excited about the bounty this potentially huge phenomenon could push towards our own backyards in coming months. The unexpected is one of the most wonderful aspects of birding, and after all, the reason a bird like a Nazca Booby is turning up in the ABA Area is because boobies are powerful flyers and capable of responding to periodic food shortages with impressive feats. But do be aware of the toll the event has on those birds in its epicenter, and be conscientious of the stress many of these birds are under.

Thanks to Alvaro Jaramillo for his help in preparing this post

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