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^ Wilson Journal 
of Ornithology 
Published by the Wilson Ornithological Society 
VOL. 124, NO. 1 March 2012 PAGES 1-198 
The Wilson Journal of Ornithology 124(1): 1-8. 2012 
THE NORTHERN BLACK SWIFT: MIGRATION PATH AND 
WINTERING AREA REVEALED 
JASON P. BEASON, 1 - 6 CAROLYN GUNN, 2 KIM M. POTTER, 3 
ROBERT A. SPARKS, 1 AND JAMES W. FOX 45 
ABSTRACT.—Winter ranges have been identified for most neotropical migrant bird species, those that spend the winter 
months in Central and South America and summer months in North America. Published accounts and specimen collections 
of the Northern Black Swift (Cypseloides niger borealis) during spring and fall migration are extremely limited and winter 
records are nonexistent. We placed light-level geolocalors on four Black Swifts in August 2009. and retrieved three a year 
later. Data from the geolocalors revealed initiation of fall migration (10 to 19 Sep 2009). arrival dales at wintering areas (28 
Sep to 12 Oct 2009), departure dales from wintering areas (9 to 20 May 2010). and return dates to breeding sites (23 May to 
IS Jun 2010) for Northern Black Swifts breeding in interior North America (Colorado. USA), Northern Black Swifts 
traveled 6,901 km from the Box Canyon breeding site and 7,025 km from Fulton Resurgence Cave to the center of the 
wintering area. The swills traveled at an average speed of 341 km/duy during the 2009 fall migration and an average speed 
ot 393 km/day during the 2010 spring migration. This is the first evidence that western Brazil is the wintering area for a 
subset of the Northern Black Swill. extending the known winter distribution of this species to South America. Received 30 
August 2011, Accepted II November 2Oil. 
Knowledge of patterns and timing of migration 
of the Northern Black Swift (Cypseloides niger 
borealis) (Frontispiece) is virtually non-existent 
and the species’ winter range is unknown. 
Published accounts and specimen collections for 
this subspecies during spring and fall migration 
south of the United Stales exist only for sites in 
'Rocky Mountain Bird Observatory P. O. Box 1232. 
Brighton, CO 80601. USA. 
’P. O. Box 791. Dolores. CO 81323. USA. 
White River National Forest. Rifle Ranger District, 
0094 County Road, 244. Rifle. CO 81650. USA. 
‘British Antarctic Survey. High Cross. Madingley Road, 
Cambridge, CB3 OFT, UK. 
Current address: Migrate Technology Ltd.. P. O. Box 
749, Coton, Cambridge. CBI 0QY, UK. 
6 Corresponding author; e-mail: jason.beason@rmbo.org 
south-central Mexico (Stiles and Negret 1994), off 
the Guatemalan coast (Davidson 1934), and off 
the southwest coast of Chiapas, Mexico (Bucha¬ 
nan and Fierstine 1964). Negret collected the first 
specimens of Northern Black Swift for South 
America in southwestern Colombia in October 
1992 and 1993. suggesting a South American 
winter destination (Stiles and Negret 1994). Fall 
specimens originally reported to be C. n. costar- 
icensis from south-central Mexico (Webster 1958) 
were subsequently identified as C. //. borealis 
(Stiles and Negret 1994). Flocks ot Black Swifts 
thought to be migrating C. />. borealis in Costa 
Rica in spring had no specimens collected for 
confirmation (Stiles and Skutch 1990). Kiff 
(1975) tentatively assigned a female swift col¬ 
lected in Costa Rica to C. n. borealis based on 
1 
