Contents
Stereoscopic Views of Three-dimensional, Rectangular Flight Paths in Descending African White-backed Vultures (gyps Africanus)
Vance A. Tucker
A Comparative Study of Cowbird Parasitism in Yellow-headed Blackbirds and Red-winged Blackbirds
Catherine P. Ortega and Alexander Cruz
The Effects of Experience and Age on the Breeding Peformance of Western Gulls
Peter Pyle, Larry B. Spear, William J. Sydeman, and David G. Ainley
Energetics of Growth and Maturation in Sympatric Passerines that Fledge at Different Ages
Patrick J. Mock, Marina Khubesrian, and Dee M. Larcheveque
Song Categories and Their Functions in the Field Sparrow (spizella Pusilla)
Douglas A. Nelson and Lisa J. Croner
Histological Basis of Age-related Changes in Iris Color in the African Pied Starling (spreo Bicolor)
Neville Sweijd and Adrian J. F. K. Craig
Mate Switching in Multibrooded House Wrens
Nancy E. Drilling and Charles F. Thompson
100 Years Ago in the Auk
The Auk
Field and Laboratory Metabolism and Thermoregulation in Dovekies (alle Alle)
Geir Wing Gabrielsen, Jan R. Taylor, Marek Konarzewski, and Fridtjof Mehlum
Salt Tolerance in American Black Ducks, Mallards, and Their F1-hybrids
Gregory G. Barnes and Thomas D. Nudds
Seasonal Patterns of Reproduction in Heathland Honeyeaters Are Not Responses to Changing Nectar Availability
Doug P. Armstrong and Graham H. Pyke
The Effect of Molting on the Gliding Performance of a Harris' Hawk (parabuteo Unicinctus)
Vance A. Tucker
Notes and News
The Auk
Variation in Resource Abundance Affects Capture Rates of Birds in Three Lowland Habitats in Costa Rica
John G. Blake and Bette A. Loiselle
Sexual Selection and Parasites in Wood-warblers
Patrick J. Weatherhead, Gordon F. Bennett, and Dave Shutler
Older Males Have Bigger Knobs: Correlates of Ornamentation in Two Species of Curassow
Richard Buchholz
In Memoriam: Robert M Mengel
Harrison B. Tordoff
In Memoriam: Konrad Lorenz, 1903-1989
Peter Marler
Editorial the Conservation Crisis
Terry Root and Peter Stacey
William Brewster Memorial Award, 1990
Fred Cooke
Covers
Front Matter
The Auk
Back Matter
The Auk
Short Communications
Sequential Polyandry in the Common Redpoll (carduelis Flammea)
Gilles Seutin, Peter T. Boag, Bradley N. White, and Laurene M. Ratcliffe
Facultative Helping by Pygmy Nuthatches
William J. Sydeman
Feeding Time and Brood-rearing Capacity in the Common Treecreeper (certhia Familiaris)
Markku Kuitunen and Jukka Suhonen
Diet of Murres Caught Incidentally during Winter in Northern Japan
Haruo Ogi and Kouzi Shiomi
The Type Locality of Fringilla Savanna Wilson
Kenneth C. Parkes and Robin K. Panza
The Adaptive Value of Thick-shelled Eggs for Brown-headed Cowbirds
Patrick J. Weatherhead
Commentaries
The Taxonomic Status of the Small Genovesa Ground-finch in the Gal
Dolph Schluter, Laurene M. Ratcliffe, and Peter R. Grant
Response to Schluter, Ratcliffe, and Grant
Joseph Vagvolgyi and Maria W. Vagvolgyi
The Use of Flow Cytometry for Rapid Identification of Sex in Birds
Terrence R. Tiersch, Ronald L. Mumme, Robert W. Chandler, and Dean Nakamura
On Forming an Ornithological Council
Richard C. Banks
Response to T M Blackburn
Frank C. Rohwer