presumed Bicknell's Thrush nocturnal flight calls
Fig.2. Florida May 6, 1989 (WRE).
Chuck-will's-widow calling in the background.
Fig.3. Florida May 6, 1989 (WRE).
Chuck-will's-widow calling in the background.
Fig.4. Florida May 14, 1991 (WRE).
Fig.5. Florida May 14, 1991 (WRE).
Fig.6. New Jersey May 25, 1998 (MO).
Nocturnal flight call sequences:
1. Florida May 14, 1991 (WRE). Two presumed Bicknell's Thrushes calling in nocturnal migration amidst many warblers (mostly Common Yellowthroat) and cricket noise.
2. New Jersey September 23, 2001 (MO). Mixed nocturnal flight calls from presumed Bicknell's (higher-pitched calls) and Gray-cheeked (lower-pitched calls) Thrushes and several warblers. In the sequence, the first two calls are Gray-cheeked, the third is Bicknell's, the fourth is Gray-cheeked, the fifth is Bicknell's, the sixth is Gray-cheeked, the seventh is an overlapping call of Gray-cheeked and Bicknell's (see Fig.7 below), and the eighth is Gray-cheeked.
Fig.7. New Jersey September 23, 2001 (MO).
Presumed Gray-cheeked (lower) and Bicknell's (upper) Thrush night flight calls from example 2.
Calls occur nearly simultaneously.