Model of burrow selection predicts pattern of burrow switching by Leach's Storm-Petrels

Patterns of nest site selection exhibited at the scale of a population should result from initial preferences of individuals occupying nest sites as well as preferences exhibited by individuals moving between nest sites. We tested whether nest-site preferences measured at the population scale were predictive of patterns of burrow switching by Leach's Storm-Petrels (Oceanodroma leucorhoa), a long-lived seabird that nests in underground burrows. Breeding pairs generally choose from the pool of available existing burrows rather than constructing new burrows, and a portion of the burrows in a colony remains unused in any breeding season. We quantified burrow preference at a colony on Kent Island, New Brunswick, over four breeding seasons. We used a classification and regression tree analysis to build a predictive model of nest-site selection. Preferentially occupied burrows were drier, longer, had larger nest chambers, and were in areas of higher burrow density. To measure preferences during burrow switching, we tracked individuals that switched burrows, comparing characteristics of the burrows in which these birds were originally found to those they inhabited at the end of the study period. Characteristics preferred by switching individuals were a subset of those observed at the scale of the population; individuals moved to burrows that were drier, longer, and had larger nest chambers. Our results show how preferences of individuals that move between nest sites contribute to nest site preferences exhibited at the population scales commonly tested. El patrón de selección del lugar en donde anidar, exhibido a escala de una población, debe ser el resultado de preferencias individuales de organismos que ocupan lugares para anidar, e igualmente de preferencias exhibidas por individuos que cambian de lugar para anidar. Pusimos apruebas si las preferencias, medidas a escala de población, podían ser utilizadas para predecir el patrón de cambio de cavidades de parte de Oceanodroma leucorhoa, que es un ave marina que anida en cavidades bajo tierra. Las parejas usualmente seleccionan entre un grupo de cavidades disponibles, en vez de estos construir la propia, y una porción de las cavidades permanecen sin ser utilizadas a lo largo de la época de reproducción. Cuantificamos la preferencia de uso de cavidades en una colonia localizada en la Isla Kent, New Brunswick, durante cuatro temporadas reproductivas. Utilizamos una clasificación y un análisis de regresión para const