Eastern Whip-poor-will (Antrostomus vociferus)
Valencia Creek Ranch (restricted access), Aptos, Santa Cruz County, CA
29 May 2013
Joseph Morlan
Voice recording © 29 May 2013 by Joseph Morlan. All rights reserved.
Following a report from David
Suddjian and others that this species was present and vocalizing near Aptos, Robbie Fischer and I made arrangements with
Patti Bubb to visit Valencia Creek Ranch. We arrived at the gate about 7:15pm where we met Sandy Koonce. Graham
Bubb arrived and opened the gate for us. We parked by the barn and waited for others to arrive. About
20 people visited including Paul Lehman, John & Lydia Sterling, Todd and Tayla Easterla, Don Roberson and Rita Carratello, Bill Bousman,
Fritz Steurer, Earl Lebow, Janet Wessell and others. Randy Wardle guided us to a small meadow where the bird had been seen two
nights before. Nancy Collins headed further up the trail to another small meadow with a yellow tractor where
she waited with Emilie Strauss.
Shortly before 8:30pm, Emilie Strauss ran back to us signalling that the Eastern Whip-poor-will was calling
near the 2nd meadow. As soon as we arrived, the bird could be heard calling loudly from a copse of Coast Live
Oak at the far end of the small meadow. It sang repeatedly from then on, occasionally stopping and then calling
from various nearby locations. It circled below us and behind us and returned to the original area. As the light started
to fade, Paul Lehman said "It's on top of the tractor!" I looked with binoculars to see the bird perched
in the open on top of a vertical exhaust pipe. Clearly visible was the bright white collar, broken
in front by the dark throat. The collar looked like two wedge-shaped headlamps. The bird was clearly in view
for about five seconds after which it dropped down to the left fanning its tail to reveal two white patches on the corners
of the tail. About 45 minutes later the bird was seen again briefly flying overhead in a spotlight.
I recorded the voice using a Panasonic DMC-LX5 digital camera. Click on Waveform/Spectrogram image to hear sound. An additional longer recording below.
Description
The following description is based on memory:
It was a medium-sized nightjar with a clean white collar and extensive white tail-corners. The rest of the
bird appeared mottled and dusky in the dim light. While the bird was perched the white collar appeared to expand and contract rhythmically while the bird was calling. Later when the bird flew over-head I was again able to see the white corners to the relatively long tail. The
wings were strongly bowed forward (swift-like) but lacked any visible white bands such as found on nighthawks
(Chordeiles sp.). The underparts including the underwings appeared to be coarsely barred with gray. The
wings were somewhat more pointed than I expected, but not acutely pointed as in nighthawks. The head seemed relatively
large.
Discussion
Taxonomy
The two Whip-poor-will species were split from each other in the 51st
AOU Supplement (2010) and both were moved from the genus Caprimulgus to Antrostomus in
the 53rd AOU Supplement (2012).
Identification
Eastern Whip-poor-will is almost identical to Mexican Whip-poor-will. The main difference is size with the
Eastern Whip being decidedly smaller than Mexican. The two are doubtfully distinguishable in the field by appearance
unless examined carefully in the hand. However the vocalizations are significantly different. Eastern Whip has
a clearer whistled quality compared to the more rolling quality of the Mexican. Also there is a difference in
the final note. In Eastern Whip the final note descends at the end while in Mexican it is steeply rising.
See sonogram above. Reference sonograms and recordings of both species and the closely related Dusky Nightjar (Antrostomus saturatus) are available at Earbirding.com. Additional reference recordings with sonograms are available at Xeno-canto.com. Comparison with those recordings confirm that this individual's vocalizations are consistent with Eastern Whip-poor-will.
Status in California
There is one previously accepted record of this species in California, an individual captured in a mist net
14 November 1970 at Pt. Loma in San Diego County. The live bird was compared directly with specimens and determined
to be an Eastern Whip-poor-will (Craig 1971).
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