Contents
Morphological and Vocal Variation across a Contact Zone Between the Chickadees Parus Atricapillus and P Carolinensis
Mark B. Robbins, Michael J. Braun, and Emily A. Tobey
Extensive Protein Similarity of the Hybridizing Chickadees Parus Atricapillus and P Carolinensis
Michael J. Braun and Mark B. Robbins
Mitochondrial Dna: a Source of Genetic Markers for Studies of Similar Passerine Bird Species
Andrew L. Mack, Frank B. Gill, Robert Colburn, and Christina Spolsky
Notes and News
The Auk
Egg Formation in Cassin's Auklet
Lee B. Astheimer
100 Years Ago in the Auk
The Auk
Low Genic Variation Between Black Ducks and Mallards
C. Davison Ankney, Darrell G. Dennis, Lisa N. Wishard, and James E. Seeb
The Diet of American Robins: an Analysis of Us Biological Survey Records
Nathaniel T. Wheelwright
Daily Activity Patterns of South Polar and Brown Skuas near Palmer Station, Antarctica
Pamela J. Pietz
A Phylogenetic Analysis of Recent Anseriform Genera Using Morphological Characters
Bradley C. Livezey
Population Ecology of the Long-billed Curlew (numenius Americanus) in Western Idaho
Roland L. Redmond and Donald A. Jenni
Role of Sibling Aggression in Food Distribution to Nestling Cattle Egrets (bubulcus Ibis)
Bonnie J. Ploger and Douglas W. Mock
Foraging Behavior of Gentoo and Chinstrap Penguins as Determined by New Radiotelemetry Techniques
Wayne Z. Trivelpiece, John L. Bengtson, Susan G. Trivelpiece, and Nicholas J. Volkman
Density Trends and Range Boundary Constraints of Forest Birds along a Latitudinal Gradient
John T. Emlen, Michael J. Dejong, Michael John Jaeger, Timothy C. Moermond, Kurt A. Rusterholz, and Robin P. White
Reidentification of Phalacrocorax" Subvolans Brodkorb as the Earliest Record of Anhingidae"
Jonathan J. Becker
In Memoriam: Lester L Snyder
R. Charles Long and Jon C. Barlow
In Memoriam: Finn Salomonsen, 1909-1983
F. G. Cooch
In Memoriam: Frank Richardson, 1913-1985
Tony Angell
Report of the American Ornithologists' Union Committee for the Conservation of the Red-cockaded Woodpecker
J. David Ligon, Peter B. Stacey, Richard N. Conner, Carl E. Bock, and Curtis S. Adkisson
Index to Volume 103
The Auk
Covers
Front Matter
The Auk
Back Matter
The Auk
Short Communications
Dynamics of Nest Parasitism in Wood Ducks
Brad Semel and Paul W. Sherman
Changes in Plasma Prolactin Associated with Laying and Hatch in the Spotted Sandpiper
Lewis W. Oring, Albert J. Fivizzani, and Mohamed E. Halawani
Composition and Quantity of Feather Sheaths Produced by White-crowned Sparrows during the Postnuptial Molt
Mary E. Murphy and James R. King
Estimating Nest Detection Probabilities for White-winged Dove Nest Transects in Tamaulipas, Mexico
James D. Nichols, Roy E. Tomlinson, and Gary Waggerman
Diving Depths of Atlantic Puffins and Common Murres
Alan E. Burger and Mark Simpson
Commentaries
The Possible Impact of Observer Bias on Some Avian Research
David F. Balph and H. Charles Romesburg
Mass or Weight: what is Measured and what Should Be Reported?
John W. Chardine
Why Hummingbirds Hover: a Commmentary
F. Reed Hainsworth
Response to F R Hainsworth
Richard S. Miller
The Adaptive Significance of Anting
Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye