It has been proposed that crossbills (Loxia spp.) are opportunistic breeders that time the onset of their reproductive cycle based on food availability rather than photoperiod, as is the case in most other bird species. Crossbills are able to nest throughout most of the year at middle latitudes, but the reproductive biology of these birds at high latitudes remains poorly known. A total of 469 White-winged Crossbills (Loxia leucoptera) was caught in Fairbanks, Alaska during a 2.5-yr period. Based on the proportion of juvenile birds in the sampled population, the proportion of adult females with a brood patch, and seasonal changes in adult male cloacal protuberance size, it appears that interior Alaska White-winged Crossbills breed only in spring and early summer. Timing of reproduction of crossbills breeding at high latitudes may be limited by environmental factors (potentially, ambient temperature and/or photoperiod) rather than by food availability. /// Se ha propuesto que el género Loxia es de anidantes oportunistas que ajustan el inicio de su ciclo reproductivo en la disponibilidad de alimento más que en el fotoperiodo, como es el caso en la mayoría de las especies de aves Aves de este género pueden anidar a través de la mayor parte del año en latitudes medias, pero la biologia reproductiva de estas aves en latitudes altas permanece poco conocida. Un total de 46g individuos de Loxia lecoptera se capruraron en una sola estación en Fairbanks, Alaska en un periodo de 25 años. Basandose en la proporcion de aves juveniles la población muestreada, la proporción de nembras adultas con parcho reproductivo, y de los cambios estacionarios en el tamaño de la protuberancia cloacal de los machos, parece ser que en el interior de Alaska la especie anida solo durante la primavera y el verano temprano El tiempo de reproducción de Loxia lecoptera en latitudes altas puede estar limitado por factores ambientales (potencialidad, temperatura ambiental y/o fotoperíodo) más que por disponibilidad de alimento
Published on behalf of the Association of Field Ornithologists, Journal of Field Ornithology publishes original articles that emphasize the descriptive or experimental study of birds in their natural habitats. Articles depicting general techniques, emphasizing conservation, describing life history, or assessing published studies or existing ideas are appropriate. The Journal is especially interested in field studies conducted in the Neotropics and those involving participation by nonprofessional ornithologists.
Wiley is a global provider of content and content-enabled workflow solutions in areas of scientific, technical, medical, and scholarly research; professional development; and education. Our core businesses produce scientific, technical, medical, and scholarly journals, reference works, books, database services, and advertising; professional books, subscription products, certification and training services and online applications; and education content and services including integrated online teaching and learning resources for undergraduate and graduate students and lifelong learners. Founded in 1807, John Wiley & Sons, Inc. has been a valued source of information and understanding for more than 200 years, helping people around the world meet their needs and fulfill their aspirations. Wiley has published the works of more than 450 Nobel laureates in all categories: Literature, Economics, Physiology or Medicine, Physics, Chemistry, and Peace. Wiley has partnerships with many of the world’s leading societies and publishes over 1,500 peer-reviewed journals and 1,500+ new books annually in print and online, as well as databases, major reference works and laboratory protocols in STMS subjects. With a growing open access offering, Wiley is committed to the widest possible dissemination of and access to the content we publish and supports all sustainable models of access. Our online platform, Wiley Online Library (wileyonlinelibrary.com) is one of the world’s most extensive multidisciplinary collections of online resources, covering life, health, social and physical sciences, and humanities.
This item is part of a JSTOR Collection.
For terms and use, please refer to our
Journal of Field Ornithology
© 1997 Association of Field Ornithologists