One of the most striking features of bird migration is its regularity. Most populations of birds
migrate at about the same dates, in the same directions, and for similar distances each year …

Although it is widely recognized that migration is an adaptation that allows bird populations
to exploit seasonal resources, the factors that underly the rich diversity of migration patterns …

The body mass (or fat reserves) maintained by a wintering bird can be viewed as a trade—
off between the risk of starvation and the risk of predation. This follows from the fact that fat …

This study investigates, on a continent-wide scale, which environmental factors associate
with the distributional boundaries of wintering North American avifauna. Distribution and …

Presumably since man first started foraging for animals and plants in the bush he has
realized that different organisms live in different places and that different birds are found in …

(1) Death rate of yellow-eyed juncos was highest in the first year, significantly higher than in
adults; 11% of ringed nestlings were found the following spring. Nestlings, fledglings …

We examined effects of natural and experimentally created reductions in food abundance on
the reproductive ecology of Black—throated Blue Warblers (Dendroica caerulescens). The …

An index of total vegetation volume was strongly correlated with breeding bird density at 31
sites in four separate studies conducted in southwestern shrub and desert habitats between …

The Darwin's finches on Isla Daphne Major, Galapagos, were studied between July 1975
and June 1978. Geospiza fortis and G. Scandens are residents, while G. fuliginosa and G …

Two major groups of desert granivores, ants and rodents, coexist as permanent residents of
local desert habitats in southwestern North America. At our Sonoran Desert Study site, both …