The White-Crowned Sparrow - Stability, Recruitment, and Population-Structure in the Nuttall Subspecies (1975-1980)
From Pubwiki
[edit] Author(s)
- Petrinovich, L.
- Patterson, T. L.
[edit] Journal
Auk 99.1 (1982): 1-14.
[edit] Abstract
We studied two banded populations of sedentary White-crowned Sparrows (Zonotrichia leucophrys nuttalli) over a 6-yr period. Most territory holders were identified (326 males and 286 females), all nestlings (1,052) were banded, and any unbanded birds that appeared were banded. Detailed analyses were based on only those territories that were occupied for at least 4 of the 6 yr. Of the males, 0.50 repeated as territory holders on any given year and of the females 0.35. Of those that stayed on the same territory, about onequarter of the males had the same mate as compared to about one-half of the females. If there was a shift to a new territory on the succeeding year, both males and females had new mates. Females remained on a territory significantly fewer years (1.41) than did males (1.67). Divorce occurred in 0.31 of the possible instances, and there was one case of incest. Among newly recruited territory holders, 0.17 of the male and 0.15 of the female recruits were nestlings of the area. The other recruits were post-dispersal birds: 0.14 were banded as fledglings, 0.26 as 1st-yr, brown-crowned birds, 0.32 as full-crowned adults (2 yr old or more), and 0.11 were unknown. Of the total number of nestlings banded in the course of the study 0.078 entered the breeding population. In general: (1) territory size and density are stable across years. (2) One of the study regions was more variable in terms of reproductive success than the other across years, and the mean number of years that a bird held a territory was significantly less for the variable region. (3) A nonbreeding surplus of reproductively able males and females apparently is available throughout the breeding season. These results are discussed in relation to other data available. Some speculations are made regarding the significance of these findings to questions of natal dispersal.
[edit] Complete Publication (PDF; password required)
If you would like to join MIGRATE to get access to this publication, please email us!
