Bicknell's Thrush Catharus bicknelli
Flight call description A high, raspy, descending "vzeer" or "pzeeer".
Fig.1. New Hampshire June 27, 1994 (MO).
Perched bird on the breeding grounds with Swainson's Thrush singing in the background.
Examples Nocturnal
Diurnal calling sequence:
1. New Hampshire June 27, 1994 (MO). Perched bird on the breeding grounds with Winter Wren and Swainson's Thrush singing in the background.
Similar species Very similar to Gray-cheeked Thrush but typically higher and more evenly descending (less downward-arched). May be some overlap but extremes are distinctive. See Veery and thrush-like calls.
Behavior Primarily a nocturnal migrant. Likely engages in some diurnal onward spring migration in the southern Atlantic coast region. Not known to occur in redetermined migration though presumed to do so rarely based on the behavior of other Catharus Thrushes. In the mid-Atlantic coast region, this redetermined migration behavior apparently occurs to some degree prior to sunrise coinciding with a characteristic early-dawn period of increased nocturnal flight call activity. Along the east coast of Florida, no early dawn period of increased nocturnal flight call activity has been documented in spring migration. Flight calls are commonly given in nocturnal migration. Perched birds may give flight calls at any time during the day, but they do so particularly around dawn and dusk.
Discussion See Evans (1994) and Ball (1952).