Contents
Genetic and Phenotypic Differentiation in a Wood Warbler (genus Dendroica) Hybrid Zone
George F. Barrowclough
Feeding Territories of Brown Skuas (catharacta Lonnbergi)
Wayne Trivelpiece, Ronald G. Butler, and Nicholas J. Volkman
Fecundity of the Brown-headed Cowbird in Southern Ontario
D. M. Scott and C. Davison Ankney
Changes in Nutrient Reserves and Diet of Breeding Brown-headed Cowbirds
C. Davison Ankney and D. M. Scott
A Comparative Analysis of the Bill Markings of Whistling and Bewick's Swans and Out-of-range Occurrences of the Two Taxa
Mary E. Evans and William J. L. Sladen
Notes and News
The Auk
Effect of Season on the Energetics, Body Composition, and Cage Activity of the Field Sparrow
John B. Olson and S. Charles Kendeigh
Growth of Nestling Ipswich Sparrows in Relation to Season, Habitat, Brood Size, and Parental Age
Howard A. Ross
Territory Size Differences in Relation to Reproductive Stage and Type of Intruder in Herring Gulls (larus Argentatus)
Joanna Burger
Offspring Reduction in Macaroni and Rockhopper Penguins
Anthony J. Williams
Feeding Ecology of the Barn Owl in Central Chile and Southern Spain: a Comparative Study
Carlos M. Herrera and Fabian M. Jaksic
Postnatal Development of Leach's Storm-petrel
Robert E. Ricklefs, Susan White, and John Cullen
Differential Perch Site Selection by Color Morphs of the Red-tailed Hawk (buteo Jamaicensis)
Charles R. Preston
Hummingbird Foraging Behavior at Malvaviscus Arboreus Var Drummondii
Mary Wissink George
Energetics of Two Wintering Raptors
James R. Koplin, Michael W. Collopy, Albert R. Bammann, and Howard Levenson
Crown Color and Dominance in the White-crowned Sparrow
John Parsons and Luis F. Baptista
The Insulation in Nests of Selected North American Songbirds
Carol Skowron and Michael Kern
Apostatic Selection and Kleptoparasitism in the Parasitic Jaeger: a Comment
Bridget L. Furness and Robert W. Furness
Geographic Variation in Leach's Storm-petrel
David G. Ainley
Kin Selection in Rio Grande Turkeys: a Critical Assessment
David F. Balph, George S. Innis, and Martha Hatch Balph
Simultaneous Doubly Labeled Water (3 Hh 18 O) and Time-budget Estimates of Daily Energy Expenditure in Phainopepla Nitens
Wesley W. Weathers and Kenneth A. Nagy
Index to Volume 97
The Auk
Covers
Front Matter
The Auk
Back Matter
The Auk
Short Communications
Copulatory Behavior of the American Bittern
Paul A. Johnsgard
Group Foraging by Mockingbirds in a Florida Strangler Fig
Peter G. Merritt
Avian Time Budgets and Distance to Cover
Thomas Caraco, Steven Martindale, and H. Ronald Pulliam
Forced Copulation in Captive Mallards I Fertilization of Eggs
Jeffrey T. Burns, Kimberly M. Cheng, and Frank Mckinney
Sexual Development during Winter in Male American Woodcock
Thomas H. Roberts
Feather Pigmentation and Abrasion: Test of a Hypothesis
George F. Barrowclough and Fred C. Sibley
A New Race of Atlapetes Leucopterus, with Comments on Widespread Albinism in a L Dresseri (taczanowski)
John W. Fitzpatrick
Cleaning/feeding Symbiosis Between Birds and Reptiles of the Gal
Keith A. Christian
First Description of the Eggs of the White-winged Guan, Penelope Albipennis, with Notes on Its Nest
Morris D. Williams
Wind Direction and the Species Composition of Autumn Tv Tower Kills in Northwest Florida
Robert L. Crawford
Differential Utilization of Prey Resources by Great Horned Owls and Barn Owls in Central Chile
Fabian M. Jaksic
Food-niche Relationships Between Chilean Eagles and Red-backed Buzzards in Central Chile
Roberto P. Schlatter
Stones: an Important Incubation Stimulus for Gulls and Terns
Malcolm C. Coulter
Rediscovery of the Rufous-faced Crake (laterallus Xenopterus)
Philip Myers and Rick L. Hansen
First Record of the Gadwall from the Philippines
Robert S. Kennedy and Edward C. Dickinson