Population Dynamics of Zenaida Doves in Cidra, Puerto Rico

Abstract

I collected line transect data and capture-recapture data to estimate basic demographic parameters of Zenaida doves (Zenaida aurita) in farmlands and second-growth forests in eastcentral Puerto Rico during 1990-92. Zenaida doves ar widely hunted, and data on demographic parameters are needed for population management and monitoring. Mean survival rate and mean capture rate per sampling period of hatching-year (RY; o i = 0.73, p i = 0.07) and after-hatching-year (AHY; o i = 0.75, p i = 0.06) doves did not differ (Ps > 0.10). The standard Jolly-Seber model with time-specific survival and capture rates fit the capture-recapture data (Model A in JOLLY; P > 0. 10). There was no difference between the survival and capture rates of newly versus previously captured HY and AHY birds (Ps > 0.10). Survival and capture rates varied by sampling period (Ps < 0.01 ). For AHY and HY birds combined, mean survival rate per sampling period was 0.84, and mean capture rate was 0.05. Mean population size was 1,451, and mean recruitment rate (births + immigrants was 591/sampling period. Density of Zenaida doves was 0.97-1.78/ha during 1991-92. Density of nests was 2.44/ ha during January-December 1991. 1.69 during April-June 1991, and 1.44 during April-June 1992. Line transect surveys of Zenaida doves and nests were positively correlated (P < 0.01). The number of Zenaida doves and nests was positively correlated with capture-recapture estimates of population size (P <0. 10) and number of fledglings trapped or the first time (P < 0.02). Predator abundance was negatively correlated with number of nests located on the transects (P < 0.01), number of fledglings trapped for the first time (P ≤ 0.001 ), and estimates of recruitment rate (P <. 0.05). Overall, mean daily nest survival rate was 0.98, and mean nesting success rate was 0.51; mean number of young fledged per nest was 1.31. Predation caused 88% of nest losses. Zenaida doves are well adapted for multiple brooding and extended nesting, and they are able to compensate for periods of low survival (deaths and emigration) via high recruitment rates (births + immigration).