Contents
Two Sibling Species of Tyrannus (tyrannidae)
Melvin A. Traylor Jr.
The Annual Cycle of Body Composition of Canada Geese with Special Reference to Control of Reproduction
Dennis G. Raveling
Notes and News
The Auk
Bioenergetics of Molt in the Chaffinch (fringilla Coelebs)
Victor R. Dolnik and Valery M. Gavrilov
Competitive Interactions and Adaptive Strategies of American Redstarts and Least Flycatchers in a Northern Hardwoods Forest
Thomas W. Sherry
Differential Effects of Chick Vocalizations and Bill-pecking on Parental Behavior in the Ring-billed Gull
Don E. Miller and Michael R. Conover
Age-specific Changes in the Major Body Components and Caloric Values of Growing Wood Ducks
Deborah L. Clay, I. Lehr Brisbin Jr., and Kenneth A. Youngstrom
Relative Heart Size in Alaskan Tetraonidae
Robert B. Weeden
Selection of Prey by Size in Screech Owls
Carl D. Marti and Janet G. Hogue
Distribution and Spatial Patterning of Flamingos in the Andean Altiplano
Stuart H. Hurlbert and James O. Keith
Male Characteristics and Pairing Success in Red-winged Blackbirds
William A. Searcy
Effects of Human Disturbance on Breeding of Black-crowned Night Herons
Jacqueline Tremblay and Laurence N. Ellison
Effect of Prey on Predator: Voles and Harriers
Frances Hamerstrom
Structure and Dynamics of Interspecific Flocks in a Neotropical Mid-elevation Forest
George V. N. Powell
Ecological Correlates of Monogamy in Tundra-breeding Savannah Sparrows
Patrick J. Weatherhead
In Memoriam: Hoyes Lloyd
C. H. D. Clarke
Variability of Egg Size and Composition in the Great White Pelican (pelecanus Onocrotalus)
P. J. Jones
Two Winter Breeding Records for the Harris' Hawk
David H. Ellis and Wayne H. Whaley
Reverse Mounting in the Painted Bunting
Charles F. Thompson and Scott M. Lanyon
Foraging Behavior of Male and Female Nuttall Woodpeckers
J. Mark Jenkins
The Incubation Period of the Yellow Rail
R. D. Elliot and R. I. G. Morrison
Geographic Variation in the Bell Calls of the Blue Jay (cyanocitta Cristata)
Howard G. Kramer and Nicholas S. Thompson
The Paint-billed Crake in Guyana
David R. Osborne and Steven R. Beissinger
Covers
Front Matter
The Auk
Back Matter
The Auk