594 REPRODUCTIVE STRATEGIES OF NORTHERN GEESE: WHY WAIT? Craig R. Ely, 1,5 Karen S. Bollinger, 1,6 Roseann V. Densmore, 1 Thomas C. Rothe, 2 Michael J. Petrula, 2 John Y. Takekawa, 3 and Dennis L. Orthmeyer 4,7 1 Alaska Science Center, U.S. Geological Survey, 1011 East Tudor Road, Anchorage, Alaska 99503, USA; 2 Alaska Department of Fish and Game, 525 West 67th Avenue, Anchorage, Alaska 99518, USA; 3 San Francisco Bay Estuary Field Station, Western Ecological Research Center, U.S. Geological Survey, 505 Azuar Drive, Vallejo, California 94592, USA; and 4 Western Ecological Research Center, U.S. Geological Survey, 6924 Tremont Road, Dixon, California 95620, USA Abstract.––Migration and reproductive strategies in waterbirds are tightly linked, with timing of arrival and onset of nesting having important consequences for reproductive success. Whether migratory waterbirds are capital or income breeders is predicated by their spring migration schedule, how long they are on breeding areas before nesting, and how adapted they are to exploiting early spring foods at northern breeding areas. However, for most species, we know liĴle about individual migration schedules, arrival times, and duration of residence on breed- ing areas before nesting. To document these relationships in a northern nesting goose, we radiotracked winter-marked Tule Greater White-fronted Geese (Anser albifrons elgasi; hereafer “Tule Geese”; n = 116) from the time of their arrival in Alaska through nesting. Tule Geese arrived on coastal feeding areas in mid-April and moved to nesting locations a week later . They initiated nests 15 days (range: 6–24 days) afer arrival, a period roughly equivalent to the duration of rapid follicle growth. Tule Geese that arrived the earliest were more likely to nest than geese that arrived later; early arrivals also spent more time on the breeding grounds and nested earlier than geese that arrived later . The length of the prenesting period was compa- rable to that of other populations of this species, but longer than for goose species that initiate rapid follicle growth before arrival on the breeding grounds. We suggest that Tule Geese nesting in more temperate climates are more likely to delay breeding to exploit local food resources than Arctic-nesting species that may be constrained by short growing seasons. Received 3 October 2005, accepted 22 May 2006. Key words: Alaska, Anser albifrons elgasi, breeding strategy , migration, prenesting ecology , Tule Greater White-fronted Goose. Estrategias Reproductivas de los Gansos del Norte: ¿Por Qué Esperar? Resumen.—La migración y las estrategias reproductivas de las aves acuáticas están íntimamente ligadas, ya que los momentos de arribo y de inicio de la nidificación tienen importantes consecuencias en el éxito reproductivo. Es posible predecir si las aves migratorias acuáticas son reproductoras de capital o de ingresos de acuerdo a (1) su esquema de migración de primavera, (2) cuánto tiempo están en las áreas reproductivas antes de nidificar y (3) cuán adaptadas están para utilizar alimentos del inicio de la primavera en las áreas reproductivas del norte. 5 E-mail: craig_ely@usgs.gov 6 Present address: U.S. Fish and Wildlife Service, 1412 Airport Way , Fairbanks, Alaska 99701, USA. 7 Present address: 16000 County Road 92C, Woodland, California 95695, USA. The Auk 124(2):594–605, 2007 © The American Ornithologists’ Union, 2007. Printed in USA. Downloaded from https://academic.oup.com/auk/article-abstract/124/2/594/5562742 by guest on 01 June 2020