Contents
Hybridization Between Gulls (larus Glaucescens and L Occidentalis) in the Pacific Northwest
Wayne Hoffman, John A. Wiens, and J. Michael Scott
Nutrient Reserves and Reproductive Performance of Female Lesser Snow Geese
C. Davison Ankney and Charles D. Macinnes
Cooperative Breeding Behavior in the White-browed Sparrow Weaver
Nicholas E. Collias and Elsie C. Collias
Parent-offspring Interactions in Zebra Finches
Robert E. Muller and Douglas G. Smith
On the Breeding Distribution Pattern of European Migrant Birds: Macarthur's Theme Reexamined
Carlos M. Herrera
Effects of Human Disturbance on Breeding of Double-crested Cormorants
Laurence N. Ellison and Lynn Cleary
Distribution and Abundance Patterns of the Palila on Mauna Kea, Hawaii
Charles Van Riper III, J. Michael Scott, and David M. Woodside
Notes and News
The Auk
Origin and Evolution of the Eastern House Finch Population
John W. Aldrich and John S. Weske
Hybridization in Calypte Hummingbirds
Shirley Wells, Richard A. Bradley, and Luis F. Baptista
Pre-roosting Flight of the Clark's Nutcracker
Diana F. Tomback
Audibility Thresholds of the Blue Jay
Steven M. Cohen, William C. Stebbins, and David B. Moody
Authors' Response
David L. Lyon
Comment: Interspecific Territoriality in Hummingbirds
Bertram G. Murray Jr.
The Development of Shell-cracking Behavior in Herring Gulls
Agnar Ingolfsson and Bruce T. Estrella
Reproductive Ecology of the Sage Thrasher (oreoscoptes Montanus) on the Snake River Plain in South-central Idaho
Timothy D. Reynolds and Terrell D. Rich
Mice as a Source of Egg Loss among Ground-nesting Birds
Stephen J. Maxson and Lewis W. Oring
Fratricide and Cannibalism in Swainson's Hawk
Wayne R. Pilz and Linda K. Seibert
Land Birds in the Stomachs of Tiger Sharks Galeocerdo Cuvieri (peron and Lesueur)
Jon W. Dodrill and R. Grant Gilmore
Foraging Success in Three Age Classes of Glaucous-winged Gulls
William A. Searcy
Sexual Chase in Purple Martins
Charles R. Brown
Snowy Egret in the Strait of Magellan
Nathaniel T. Wheelwright
Undependable Breeding Conditions in the Red Phalarope
Harold F. Mayfield
Metabolic Heat Production in the Chukar Partridge
M. L. Laudenslager and H. T. Hammel
A Probable First North American Record of the Greater Antillean Race of Black-whiskered Vireo
Henry M. Stevenson
Stomach Contents of Clark's Nutcrackers Collected in Western Montana
Mervin Giuntoli and L. Richard Mewaldt
Observations and Reinterpretation of Kingfisher-raptor Interactions
Ronald E. Kirby and Mark R. Fuller
Acoustical Properties of the Swoop-and-soar Call of the Ring-billed Gull
Michael R. Conover and Don E. Miller
Interspecific Vocal Imitation in White-eyed Vireos
Curtis S. Adkisson and Richard N. Conner
Two Successive Male Eastern Bluebirds Tending the Same Nest
Benedict C. Pinkowski
Effects of Interspecific Dominance among Egrets Commensally Following Roseate Spoonbills
James K. Russell
Osprey Trapped by Water Chestnut
Jeff Connor
A Jabiru (jabiru Mycteria) Specimen from Texas
Keith A. Arnold
Covers
Front Matter
The Auk
Back Matter
The Auk