I checked a number of books to see if anyone knows where these birds spend their winters, since they definitely leave their summer breeding areas. Most field-guides donít even address the question. Experts such as Kenn Kaufman and Pete Dunne only write that the wintering grounds are not well known.
The best information I could find came from a book that I consult regularly: Neotropical Migratory Birds, Natural History, Distribution, and Population Change by Richard DeGraaf and John Rappole. The authors do a good job of presenting what is known about wintering ranges of birds that nest in North America.
Evidently the status of Black Swifts in Central America is also still poorly known. It is difficult to know for sure where the birds are nesting as opposed to only appearing as migrants. Black Swifts that nest on the islands of the Caribbean can also be confused with migrants. These birds are thought to possibly winter in Guyana on the northeast coast of South America.
Last week, I received an email from the American Birding Association, with the news that researchers have finally brought new light to this question. Several years ago they were able to attach recording devices to a number of nesting Black Swifts in Colorado. When the birds returned the following spring, several were captured again and the data retrieved.
What they found was that three individual birds traveled basically the same route, through Mexico and Central America to their wintering ground in western Brazil. The birds wandered somewhat in that general area during the winter and then flew back up the same general route to their summer home in Colorado. One more mystery at least partially solved. Of course we still donít know if Black Swifts from British Columbia, Alberta, etc. fly to the same areas for the winter. But at least itís a start and will allow researchers to learn more about the wintering areas for a species that never was a common bird and has been in decline.
Black Swifts nest in areas with rocky cliffs and canyons, and especially around and behind waterfalls. They nest in small colonies, from 5-15 pairs, and are found from sea level to 11,000 feet or more. Of the other U.S. swifts, Chimney Swifts spend their winters in South America, while White-throated Swifts winter only south to Mexico and Central America. Vauxís Swifts breed all the way to Venezuela, with our northern birds most likely wintering in Central America. We keep on learning.
Published: March 12, 2012