Chimney Swift (Chaetura pelagica) South Transient Roost Staging and Timing on the Central Chesapeake Bay Coastal Plain
ABSTRACT: For south transient Chimney Swifts (Chaetura pelagica), I define the dates for extreme arrival and departure, and mean period of peak abundance at sundown staging roost chimneys in the town of St. Michaels, Maryland, and morning migrants passing overhead along the east side of Chesapeake Bay at Tilghman Island, Maryland, 16 km (10 mi) southwest, during August-October 1969-2014. Additionally, staging roost behavior is noted at the former location. Transient staging at roost chimneys was first detected on 7 August and overhead on 19 August, while staging was last observed on 18 October and the last overhead transient seen on 21 October. The date of mean peak abundance was 23 September for staging swifts and 13 September for overhead transients. The date of mean peak abundance for transient numbers coincides closely with occurrence of the autumnal equinox suggesting this celestial event may be an important indicator in timing of south transient Chimney Swifts. Transient timing and staging behavior at roost chimneys in this study did not appear to differ appreciably from that noted in the literature.