2025-07-28 カリフォルニア大学サンタバーバラ校(UCSB)
Known for their distinctive singing, Eastern Whip-poor-wills’ nocturnal nature and expert camouflage make them easier to hear than to see. (Megan Gray)
<関連情報>
- https://www.uri.edu/news/2025/07/novel-discoveries-about-eastern-whip-poor-will-nesting-and-chick-growth/
- https://www.tandfonline.com/doi/full/10.1080/15594491.2025.2475272
東部のホイップ・プール・ウィル(Antrostomus vociferus)の巣作り生態学:巣作りを行う成鳥の行動とヒナの成長 Eastern Whip-poor-will (Antrostomus vociferus) nesting ecology: behavior of nesting adults and chick growth
Liam S. Corcoran,Megan E. Gray & Scott R. McWilliams
The Wilson Journal of Ornithology Published: 12 May 2025
DOI:https://doi.org/10.1080/15594491.2025.2475272
ABSTRACT
Eastern Whip-poor-will (Antrostomus vociferus) populations have declined precipitously since 1970, yet key aspects of their breeding biology remain understudied compared to other aerial insectivores. We used trail cameras to monitor 14 whip-poor-will nests during May–August 2023 in Rhode Island, USA. We estimated sex-specific incubation constancy (number of minutes per day on the nest) and observed behavioral interactions of adults with the nest, between paired males and females, between adults and chicks, and between adults and predators during the incubation and chick rearing stages. Additionally, we quantified chick growth trajectories (n = 12) for nine morphometric measurements, and growth rates for the four most informative measurements. Females spent 92 ± 2% of the 24 h period incubating, while males only assisted with incubation 4 ± 4% of the time. Paired males and females displayed a rarely documented courtship-like behavior at the nest. We also observed incubating females singing the male song, an anti-predator defensive behavior, and a slug (Gastropoda) as a predator of an egg. We provide the first published estimates of chick growth for the species and generated predictions of chick size that estimated chick age to a range of 1–2 days based on four measures (mass, tarsus length, humerus length, and wing chord). Whip-poor-will growth rates were like those of similar sized nightjars (Fiery-necked Nightjar Caprimulgus pectoralis and Common Pauraque Nyctidromus albicollis) and other aerial insectivores (flycatchers, Tyrannidae; sw allows, Hirundinidae). Our growth models provide a baseline for assessing the effects of habitat quality on whip-poor-will chick growth, and a valuable tool for estimating nesting phenology and enhancing survival analyses through precise age-specific survival estimates.
