We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
TIMING AND LOCATION OF MORTALITY OF FLEDGLING, SUBADULT, AND ADULT CALIFORNIA GULLS.
- Authors
PUGESEK, BRUCE H.; DIEM, KENNETH L.
- Abstract
We investigated patterns of mortality during post-breeding migrations of California Gulls (Larus californicus) nesting near Laramie, Wyoming, USA. We used 151 recoveries and 647 sightings of banded and patagially-marked gulls to compare ratios of mortalities to observations of live birds (1) during four time periods (early and late fall migration, winter, and spring migration), (2) at two locations (Pacific coast and inland), and (3) among three age-classes of gulls (fledglings, 1- and 2-year-olds, and breeding-age adults). Mortality rates were higher in inland areas (35%) than in coastal areas (15%) and were dependent on season within inland areas, but not in coastal areas. Mortality in inland areas during early fall (21%) was comparable with that in coastal areas (13%) but was higher during late fall (68 vs. 13%) and spring migration (46 vs. 17%). Both fledgling (71%) and adult (64%) gulls experienced high mortality rates during late fall migration, possibly because some gulls were too weak to make their way to the Pacific coast and became trapped by poor weather conditions. Adult gulls also experienced high mortality inland during spring migration; few subadults made the costly migration to and from the breeding area. Some adults also skipped breeding and remained in coastal areas during the breeding season.
- Subjects
LARAMIE (Wyo.); WYOMING; ANIMAL mortality; CALIFORNIA gull; BIRD breeding; BIRD migration
- Publication
Wilson Journal of Ornithology, 2008, Vol 120, Issue 1, p159
- ISSN
1559-4491
- Publication type
Article
- DOI
10.1676/04-023.1