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AGE-SPECIFIC REPRODUCTION BY FEMALE LAUGHING GULLS (LARUS ATRICILLA)

Authors :
Richard A. Dolbeer
Glen E. Bernhardt
Source :
The Auk. 120:531
Publication Year :
2003
Publisher :
Oxford University Press (OUP), 2003.

Abstract

The age at which female gulls first reproduce is poorly documented. We examined plumage and reproductive organs of Laughing Gulls (Larus atricilla) collected from May–August 2000–2001 at John F. Kennedy International Airport, New York, to determine age-specific reproductive effort. Each gull was classified as one year old (hatched in previous year), two years old, or ≥3 years old on the basis of color patterns of the hood and tail feathers and fifth primary flight feather. For females, each ovary was examined to determine if post-ovulatory follicles were present. In 2000 and 2001, the first gulls with postovulatory follicles were recorded on 15 and 18 May, respectively. Overall, 54% of the 211 two-year-old female Laughing Gulls collected during June–August showed evidence of egg laying compared to 88% of the 320 gulls ≥3 years old. None of the 50 one-year-old females examined showed evidence of egg laying. Although a lower proportion of two-year-old females laid eggs compared to older gulls, we f...

Details

ISSN :
00048038
Volume :
120
Database :
OpenAIRE
Journal :
The Auk
Accession number :
edsair.doi...........5623e905170161cdf397da8bda741fd4
Full Text :
https://doi.org/10.1642/0004-8038(2003)120[0531:arbflg]2.0.co;2