U.S. Department of Agriculture: Animal and Plant Health Inspection Service

 

Date of this Version

2017

Citation

Volume 119, 2017, pp. 787–799

Comments

Copyright 2017 American Ornithological Society.

This document is a U.S. government work and is not subject to copyright in the United States.

DOI: 10.1650/CONDOR-16-234.1

Abstract

Winter distribution and resource use of animals is driven by myriad interacting biotic and abiotic factors. Urban areas provide sanctuaries from hunting for game animals and may have thermal benefits during winter through reduced thermoregulatory costs. We deployed cellular GPS transmitters affixed to neck collars of 41 Canada Geese (Branta canadensis) in the Greater Chicago Metropolitan Area (GCMA) of northeastern Illinois, USA, to determine habitat selection and survival during autumn and winter. Canada Geese selected green spaces (59.8%) in greater proportion than available (14%), but they also regularly used industrial urban habitats such as rooftops and rail yards (11.3%), which has not been previously reported. Use of green spaces (-55.8%) decreased and use of industrial urban (+11.4%), riverine (+23.8%), and deep-water habitats (+140.7%) increased as temperatures dropped below the lower critical temperature for Canada Geese (i.e. the temperature at which increased thermoregulatory costs are incurred to maintain core body temperature). Most Canada Geese (85%) remained within the GCMA throughout winter, and none made foraging flights to agricultural fields within or outside of the urban area. Seasonal survival was considerably greater (S¼ 1.0) for geese that remained within the GCMA than those that left (S¼ 0.48) during winter. High survival, use of nontraditional habitats (e.g., green spaces, rooftops, and rail yards), and avoidance of agricultural fields suggests Canada Geese may be minimizing risk rather than maximizing energy intake by using urban areas during winter. Future research should focus on the thermoregulatory and movement strategies employed by geese to survive in urban areas where food resources may be limited. Further, researchers interested in discouraging geese should evaluate their response to harassment when temperatures are below the lower critical temperature.

La distribuci ´on invernal y el uso de recursos de los animales esta´n impulsados por un conjunto numeroso de factores bi ´ oticos y abi ´ oticos interactuantes. Las a´reas urbanas brindan santuarios sin cacer´ıa para los animales de caza y pueden tener beneficios clima´ticos durante el invierno mediante la reducci ´on de costos de termorregulaci ´ on. Colocamos transmisores GPS de celular fijados en el cuello por medio de collares a 41 individuos de Branta canadensis en el Gran A´ rea Metropolitana de Chicago (GAMC) del noroeste de Illinois, EEUU para determinar la seleccio´n de ha´bitat y la supervivencia durante oto ˜no e invierno. La especie seleccion ´o espacios verdes (59.8%) en mayor proporci ´on que los disponibles (14%), pero tambi´en us ´o regularmente ha´bitats urbanos industriales como techos y descampados del ferrocarril (11.3%), lo que no ha sido reportado con anterioridad. El uso de espacios verdes (-55.8%) disminuy ´o y el uso de ha´bitats industriales urbanos, (+11.4%), fluviales (+23.8%) y de aguas profundas (+140.7%) aument´o a medida que las temperaturas cayeron por debajo de la temperatura cr´ıtica inferior para B. canadensis (i.e. la temperatura a la cual se incurren en mayores costos de termorregulaci ´on para mantener la temperatura corporal central). La mayor´ıa de los individuos de B. canadensis (85%) permaneci ´o dentro del GAMC a lo largo del invierno y ninguno realiz ´o vuelos de forrajeo a campos agr´ıcolas dentro o fuera del a´rea urbana. La supervivencia estacional fue considerablemente mayor (S ¼ 1.0) para los individuos que permanecieron dentro del GAMC que paro los que se fueron (S ¼ 0.48) durante el invierno. La alta supervivencia, el uso de ha´bitats no tradicionales (e.g., espacios verdes, techos y descampados del ferrocarril) y la elusi ´on de los campos agr´ıcolas sugiere que B. canadensis puede estar minimizando los riesgos ma´s que

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