Contents
Replacements" of Landbird Species on Socorro Island, Mexico"
Joseph R. Jehl and Kenneth C. Parkes
Identification of Natal Locales of Peregrine Falcons (falco Peregrinus) by Trace-element Analysis of Feathers
Jimmie R. Parrish, David T. Rogers, and F. Prescott Ward
Changes in Song Dialect Distributions and Microgeographic Variation in Song of White-crowned Sparrows (zonotrichia Leucophrys Nuttalli)
Jill M. Trainer
The Laying Cycle of Brown-headed Cowbirds: Passerine Chickens?
D. M. Scott and C. Davison Ankney
Mechanism and Ecological Significance of Sperm Storage in the Northern Fulmar with Reference to Its Occurrence in Other Birds
Scott A. Hatch
Genetic Determination of Partial Migration in the European Robin (erithacus Rubecula)
Herbert Biebach
Taxonomy, Distribution, and Evolution of Golden Plovers (pluvialis Dominica and Pluvialis Fulva)
Peter G. Connors
Additions to the Avifauna of Honduras
Mickey J. Marcus
Notes and News
The Auk
Obligate and Facultative Brood Reduction in Eagles: an Examination of Factors that Influence Fratricide
Thomas C. Edwards and Michael W. Collopy
Brown Pelican Foraging Success and Kleptoparasitism by Laughing Gulls
Gary D. Schnell, Barbara L. Woods, and Bonnie J. Ploger
Specific Status and Behavior of Cymbilaimus Sanctaemariae, the Bamboo Antshrike, from Southwestern Amazonia
Nina Pierpont and John W. Fitzpatrick
Spatial Patterns of Yearling Male Blue Grouse and Their Relation to Recruitment into the Breeding Population
Ian G. Jamieson and Fred C. Zwickel
Reproductive Performance of Female-female Pairs and Polygynous Trios of Ring-billed Gulls
Kit M. Kovacs and John P. Ryder
Effects of Experience and Body Weight on Incubation Behavior of Canada Geese
Thomas W. Aldrich and Dennis G. Raveling
Competition for Nesting Space among Peruvian Guano Birds
David Cameron Duffy
The Effect of Variable Spring Water Conditions on Mallard Reproduction
Gary L. Krapu, Albert T. Klett, and Dennis G. Jorde
Clutch Size, Reproductive Success, and Organochlorine Contaminants in Atlantic Coast Black-crowned Night-herons
Thomas W. Custer, Gary L. Hensler, and T. Earl Kaiser
Feeding-site Selection and Foraging Strategies of American Woodcock
Dale L. Rabe, Harold H. Prince, and Donald L. Beaver
Covers
Front Matter
The Auk
Back Matter
The Auk
Short Communications
Sex Ratio and Egg Sequence in Ring-billed Gulls
John P. Ryder
Mate Changes by Black-bellied Whistling Ducks
Don Delnicki
Dump Nesting in the Wood Duck Traced by Tetracycline
G. Michael Haramis, W. George Alliston, and Milo E. Richmond
Possible Cases of Infanticide by Immigrant Females in a Group-breeding Bird
Peter B. Stacey and Thomas C. Edwards
A Reinterpretation of Pamprodactyly in Swifts: a Convergent Grasping Mechanism in Vertebrates
Charles T. Collins
The Raising of a Ghost-spinus Cucullatus in Puerto Rico
Herbert A. Raffaele
A Comparison of White-bearded Manakin (manacus Manacus) Populations and Lek Systems in Suriname and Trinidad
Deanna H. Olson and Michael K. Mcdowell
Nesting of Subadult Golden Eagles in Southwestern Idaho
K. Steenhof, M. N. Kochert, and J. H. Doremus
Foraging Behavior and Success of Golden Eagles
Michael W. Collopy
Flocking in the Hook-billed Kite
Dennis R. Paulson
Tree Swallows Cross a Polygyny Threshold
Terry E. Quinney
Commentary
On the Psychology of Watching Birds: the Problem of Observer-expectancy Bias
David F. Balph and Martha Hatch Balph
Editorial
Word Processing Versus Writing
John A. Wiens