Black Swifts have a large breeding distribution south to Central America, east to central Colorado, north to southeast Alaska, and also in the West Indies. Despite this sizeable range, only about 210 breeding sites are known, with about half of those in Colorado. Black Swifts, which typically breed near waterfalls or sea cliffs and also nest in moist caves, are listed as a Species of Greatest Conservation Need in Colorado Division of Wildlife’s Wildlife Action Plan and a Sensitive Species by the Region 2 U.S. Forest Service. The 2010 State of the Birds Report listed the Black Swift as one of the species most vulnerable to the anticipated effects of climate change. This exposure will likely bring heightened awareness of the species to anyone involved with conservation and land management in their breeding range.

One of the great mysteries of the Black Swifts is the fact that we have had no idea where they go in the winter. In 2009, the USFS and RMBO teamed with Carolyn Gunn (a long-time Black Swift researcher in Colorado) on a project to determine the winter range of the species. To conduct this research, four light-level geo-locators to be deployed on Black Swifts were purchased from British Antarctic Survey. (Read more about these devices at www.antarctica.ac.uk/bas_research/instruments/instrument7.php). The newly developed devices offered an opportunity for the first time to track Black Swifts during their migration. The trick is that the devices need to be recovered after a complete migration has occurred to determine where the bird has been. Black Swifts were an excellent species for this research since they have very high site fidelity, but we never dreamed we would achieve the success that we did. In 2010 we recovered three of the four geolocators deployed and all three are giving us useable data! We are working on analyzing and publishing the information about the migration of the three Colorado Black Swifts, and the results of this ground-breaking research will be available soon.

Working at the End of a Rope

At the end of the 19th Century, the Black Swift was considered a locally abundant summer resident in Colorado, but breeding was not confirmed until 1949 when Owen A. Knorr found nests at Niagara Gulch and Cataract Gulch, both near Silverton. From 1949 through 1958, Knorr located approximately 80 nests at 27 sites in 10 Colorado counties. His work extended the known geographical distribution of Black Swift breeding in Colorado north to Rocky Mountain National Park and the White River Plateau and east to the eastern flanks of the Sangre de Cristo Mountains (Knorr 1961). While Knorr was discovering new Black Swift breeding sites, often by using ropes to rappel into the nesting sites, he banded swifts if possible. He even banded adult swifts at night while dangling on a rope by blinding them with his headlamp before grabbing them. After Knorr’s work, only six more colonies were discovered by others in the next 50 years.

In 1998 Rich Levad of Rocky Mountain Bird Observatory joined forces with U.S. Forest Service biologists to inventory Colorado’s Black Swifts, beginning a database of known and potential nest sites. The database now contains more than 400 entries—waterfalls, caves and other potential Black Swift nesting sites. We have conducted at least a preliminary evaluation of 369 sites. We have documented 100 sites that have been occupied by Black Swifts in at least one year. We have found 25 of Knorr’s 27 colonies, documenting continued occupancy at 23. We have not yet conducted adequate surveys at two. We also surveyed the six colonies located between Knorr’s work and ours, and these have all been occupied. Our surveys since 1998 documented an additional 69 occupied sites.

RMBO and USFS biologists in 1998 began banding nestlings at breeding sites where nests were accessible using ladders or ropes. We discovered that it was possible at two of the known breeding colonies to place mist-nets across the narrow opening to the nest sites and capture adult Black Swifts as they return in the evening. Every August since 2004, we have revisited the location where this was first attempted in Colorado – Zapata Falls in Alamosa County – and we have captured, or recaptured, at least four adult Black Swifts each year. In 2006 Kim Potter of the White River National Forest began banding adult Black Swifts using mist-nets at Fulton Resurgence Cave in the Flat Top Mountains, where in the summer of 2008 researchers recaptured a Black Swift that was banded at the same location as a nestling in 2005. This is the first time documentation in Colorado that an adult swift would return to the same breeding colony where it hatched and attempt to breed. 

More Research

Rich, the USFS and volunteer researchers also conducted research on Black Swifts while searching for nest sites throughout Colorado and New Mexico. Rich co-authored two publications which appeared in the Wilson Journal of Ornithology in 2007 and 2008. The first presents Sue Hirshman’s detailed study of 11 years of Black Swift breeding phenology and success at Box Canyon in Ouray, Colorado. The second makes public the surveys conducted by RMBO and cooperators regarding distribution, abundance and nest-site characteristics of Black Swifts in the southern Rocky Mountain region.