Contents
Aberrant Sexual Behavior in the South African Ostrich
E. G. Franz Sauer
Operant Conditioning in the Common Crow (corvus Brachyrhynchos)
Robert W. Powell
Polyandry in the American Ja
Donald A. Jenni and Gerald Collier
Population Estimates of Breeding Birds in North Dakota
Robert E. Stewart and Harold A. Kantrud
The Breeding Biology of the Black-legged Kittiwake in Newfoundland
John Ernest Maunder and William Threlfall
The Lung and Air-sac System of the Common Grackle
Gerrit P. Kloek and Clark L. Casler
Nest Success and Age-specific Mortality in Traill's Flycatchers
Larry C. Holcomb
A New Method to Separate Immature and Adult Hummingbirds
Fernando I. Ortiz-Crespo
Effect of a Conspecific on Nest Building Location in the Zebra Finch
Katri Bruen and D. W. Dunham
A Genetic Analysis of Lesser Snow Goose Families
F. Cooke and P. J. Mirsky
Periodical Literature
The Auk
Obituaries
The Auk
Notes and News
The Auk
Index to Volume 89
The Auk
General Notes
Cowbird Parasitism on the White-crowned Sparrow and Wren-tit in the San Francisco Bay Area
Luis Felipe Baptista
Two Bird Specimens Showing Abnormalities of the Quadrate
P. J. K. Burton
Field Sparrow Uses Abandoned Nest for August Brood
Pierre N. Allaire
A New Owl from the Eocene of Wyoming
Larry D. Martin and Craig C. Black
Notes on Rare and Previously Unreported Birds from Ecuador
David W. Norton and Gustavo Orc
A Wheatear on Southeast Farallon Island, California
David A. Manuwal and T. James Lewis
Two Avian Species New to Paraguay
Lester L. Short
Winter Dormitory of the Roadrunner, Geococcyx Californicus, in West Texas
Michael Kent Rylander
Herons Leaving the Water to Defecate
Harry F. Recher and Judy A. Recher
Concerning Malacurus Obsoletus Reinhardt
Finn Salomonsen
First Record of Painted Redstart (setophaga Picta) for Canada
J. Murray Speirs and Edgerton Pegg
Covers
Front Matter
The Auk
Back Matter
The Auk