Immigration and recruitment in an urban white-winged dove breeding colony

Abstract

Dove population management necessitates estimates of vital rates for use in mechanistic models used to evaluate and predict population responses to environmental variation and/or alternative harvest scenarios. Estimating recruitment (number of juveniles per adult) is complicated because a compendium of factors drives production in doves. Whitewinged doves Zenaida asiatica exhibit a fairly unique breeding strategy wherein they commonly return to the same breeding area and reproduce in large breeding aggregations (i.e., colonies). We used an open-population capture-recapture model to estimate annual immigration and in situ recruitment of white-winged doves breeding in an urban colony during 2009 and 2010. We captured 5,101 unique white-winged doves in 2009 (2,894 after hatch year, 2,207 hatch year) and 3,502 unique white-winged doves in 2010 (3,106 after hatch year, 486 hatch year). Immigration of adults into the breeding colony peaked during late April and early May, with in situ recruitment occurring during a 6-wk period from 19 June to 30 July. Our results predicted that <90% of all hatch-year individuals had entered the local population by 1 August. The Jolly-Seber model used allows white-winged dove recruitment values to be estimated directly (rather than as a conglomerate of multiple parameters), separates immigration from in situ recruitment within a season, and can be useful for monitoring recruitment and evaluating alternative recruitment indices for future use in harvest management-planning actions.