Social constraints on access to mates in a high density population of New Zealand Snipe ( Coenocorypha aucklandica )Submitted by osnz-admin on Tue, 03/15/2011 - 22:43
|Title||Social constraints on access to mates in a high density population of New Zealand Snipe ( Coenocorypha aucklandica )|
|Publication Type||Journal Article|
|Year of Publication||1999|
|Type of Article||paper|
|Keywords||Coenocorypha aucklandica, mate fidelity, migration, mortality, natal dispersal, New Zealand Snipe, philopatry, Snares Islands, territory|
A colour-banded sample of New Zealand Snipe (Coenocorypha aucklandica) was studied on the Snares Islands over six breeding seasons. Snipe reached densities of 11.5 birds/ha; they were serially monogamous, but alpha males regained their original partner and territory at the start of the following breeding season. Up to 47% of males and 30% of females were excluded from breeding each year, although they were tolerated within breeding territories. Breeding adults were highly faithful to their territories and mates regardless of previous breeding success. About 83% of adults were seen in the study area the year after banding. No males moved to different territories, and only 11% of females moved, all to adjacent territories. Less than 9% of breeders changed partners between years if their previous mate was still present.Territory area was not influenced by intruder density: in years of high population density a higher proportion of birds was excluded from breeding. Nonbreeding adults obtained a territory or mate only if a territorial bird died. Prior residence was an important factor in acquiring a territory both within and between breeding seasons. Mortality was density-dependent, and a relatively constant proportion of nonbreeding birds was assimilated into the breeding population each spring.New Zealand Snipe were faithful to their natal area; 46% of fledglings were later seen in the study area. There was no sex bias in return rates, but females tended to disperse slightly further than males. About 11% of males and 57% of females bred as 1-year-olds. Previously nonterritorial birds (beta status) gained access to territories and mates when alpha status birds were caring for chicks. No inbreeding was recorded.