Henslow's Sparrow Ammodramus henslowii
Flight call description A long, descending "tseewd" with a sweet, waxwing-like trill.
Fig.1. New York July 25, 1995 (WRE).
Perched bird.
Similar species Most similar to White-throated Sparrow but typically longer, more clearly and uniformly trilled, and more descending. Cedar Waxwing's call superficially similar but much longer and more monotone. See descending seeps.
Behavior Nocturnal migrant. Gives flight call while perched during the day, particularly around dawn and dusk, and presumably during nocturnal migration.
Spectrographic description Measured calls (N=4) were 197 (193-211.9) mS in duration and in the 6.8-9.6 (6.9-9.5) kHz frequency range. The frequency track was double-banded and descending. The separation between bands ranged from 760-900 kHz. Calls from New York State contained 1-3 modulations with a spacing of 55 (46-67) mS and a depth of around 1 kHz. The modulations were complex in that the humps contained two small peaks. A call from Maryland had similar duration and frequency parameters, but its modulation was erratic. The first third of the call had tight modulations with a spacing of 12.8 mS between humps, while the last two-thirds had more widely-spaced, irregular modulations with a spacing of 44.7 mS between humps and an additional squiggle near the peak of each hump.