Alternate reproductive strategies in the California gull

Evolutionary Ecology
By:  and 



We analysed 6 years of reproduction data for 176 California gulls (Larus californicus) surviving from 1980 to 1988. Using a statistical model adapted from Rao's (1958) and Tucker's (1966) generalized growth curve analysis, we reconstructed the reproductive patterns of gulls aged from 0 to 26 years. Individuals were highly consistent in following one of two patterns of reproduction. In a primary pattern employed by most gulls, individuals skipped breeding less frequently and laid larger clutches as they aged. Clutch size increased to a plateau and remained at high levels throughout remaining life. In an alternate pattern employed by a smaller subset of the sample, clutch size also increased to a plateau. However, as a result of frequent skipping of breeding and smaller clutches, this plateau was considerably lower compared to that of gulls adopting the primary reproductive pattern. Data on fledging success from 1980 and 1984 were consistent with the finding of two reproductive patterns. Gulls adopting the alternate reproductive pattern produce fewer offspring per breeding attempt but survive longer than gulls adopting the primary pattern. The frequency of gulls employing the alternate pattern will increase with age relative to gulls employing the primary pattern. The alternate pattern, and not senescence, may explain why several cross-sectional studies on seabirds report declines among the oldest breeders in measures of clutch size, egg mass, hatching success, and fledging success.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Alternate reproductive strategies in the California gull
Series title Evolutionary Ecology
DOI 10.1007/BF02270965
Volume 6
Issue 4
Year Published 1992
Language English
Publisher Springer
Contributing office(s) National Wetlands Research Center, Wetland and Aquatic Research Center
Description 15 p.
First page 279
Last page 295
Country United States
State Wyoming
Other Geospatial Bamforth Lake