Coevolution is increasingly recognized as an important process structuring geographic variation in the form of selection for many populations. Here we consider the importance of a geographic mosaic of coevolution to patterns of crossbill (Loxia) diversity in the northern boreal forests of North America. We examine the relationships between geographic variation in cone morphology, bill morpholog...

Advances in the Field Identification of North American Dowitchers TheNorth American dowitchers are superficially so similar that, up until the 1950s (Pitelka 1950), the taxonomy of dowitchers was not yet agreed upon due to difficulty in field identification; see Jaramillo et al. (1991) for a synopsis of the historical changes in taxonomy. Part of this confusion stems from seasonal variability i...

Living closely with others can provide a myriad of fitness benefits, from shared territory defense to co-operative resource acquisition. Costs of social aggregation are not absent, however, and likely influence optimal and observed groups' sizes in a social species. Here, we explored optimal group size in a joint-nesting cuckoo species (the Smooth-billed Ani, Crotophaga ani) using endocrine mar...

BACKGROUND The movement patterns of many southern African waterfowl are typified by nomadism, which is thought to be a response to unpredictable changes in resource distributions. Nomadism and the related movement choices that waterfowl make in arid environments are, however, poorly understood. Tracking multiple individuals across wide spatiotemporal gradients offers one approach to elucidating...

Mallory et al. 2004: Polar Research 23(1), 111–114 The walrus (Odobenus rosmarus) is a circumpolar pinniped that has a varied diet. Evidence from numerous studies indicates that both Pacifi c walrus (O. r. divergens Illiger) and Atlantic wal rus (O. r. rosmarus Linneaus) are top predators in some trophic webs. While the majority of their diet consists of benthic invertebrates, particularly moll...

The abundance of nineteen waterbird species was counted during traverses of the entire shorelines of 17 Rotorua lakes in the summers of 1985, 1991 and 1996, by members of the Ornithological Society of New Zealand, assisted by the Department of Conservation and the Eastern Region Fish and Game Council. Also, the locations of all individuals of NZ dabchick were mapped. The overall waterbird commu...

Vocal plasticity reflects the ability of animals to vary vocalizations according context (vocal repertoire) as well develop vocal convergence group signature) in interaction members social groups. This feature has been largely reported for oscine, psittacine and trochilid birds, but little investigated birds that present innate vocalization. The smooth-billed ani (Crotophaga ani) is a bird live...