abstracts of oral and poster presentations - Pacific Seabird Group

WING SHAPE AS CORRELATED WITH FLIGHT BEHAVIOR IN PELECANIFORM SEABIRDS
Michael L. Brewer* (mlb30675@csun.edu) and Fritz Hertel; Department of Biology, California State
University, Northridge, CA USA
Tropical seabirds often traverse great distances in search of prey; therefore, selection on wing
morphology is likely to be intense. Wing morphology of five pelecaniform species from Johnston Atoll was
analyzed to determine how wing size and shape correlate with observed foraging behavior. Digital photos of
wings were used to compute aspect ratio and wing loading for a species comparison. To explore more subtle
shape differences, landmarks were created on the digital photos and analyzed using the Thin-Plate Spline-
Relative Warps program. This analysis summarizes variation in the positions of each landmark into composite
variables called relative warps, thereby providing a more detailed view of shape differences throughout the
entire wing. Significant differences were found among species with regards to the wing base, curvature of the
mid wing, and size/shape of the distal wing. Significant differences were also found between sexes of the Great
Frigatebird, but not the Brown Booby. In the case of the Red-tailed Tropicbird, explanations are suggested that
may help explain why this species deviates from predicted wing loading and aspect ratio. Differences in wing
shape can be correlated with feeding and foraging ecology for most of these species. Future analyses
incorporating more species will help us to understand the evolution of wing shape among seabirds as they
radiated to utilize oceanic resources.
PENGUINS WALK A STRAIGHT LINE UNLESS DISORIENTED
Francis Brown (fsb4@u.washington.edu) and P. Dee Boersma; Dept. of Biology, University of Washington,
Seattle WA USA
We followed 105 Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Argentina, as they
returned to their nests and recorded their GPS positions along the route. Some penguins walked nearly 1 km to
reach their nest, and their routes were highly directional. We measured straightness by plotting the GPS
coordinates in decimal degrees on an X–Y graph for each penguin and used the r-value to determine straightness
(average r for all areas is 0.980, n = 82 routes with more than 4 coordinates used). In areas with obstacles (e.g.,
large, dense bushes), penguins take longer to arrive at their nest than in unobstructed areas. Penguins passing
through the area with the most obstacles had a significantly slower average speed of 0.247 m/s than penguins
that walked through two areas that had small bushes (average speed = 0.318 and 0.327 m/s), (ANOVA: F =
10.86, df = 2, 74, P < 0.0001). We also displaced 30 blindfolded penguins 50, 100, and 200 m from their entry
point into the colony to determine if they followed a straight line to their nest. Moving penguins even 50 m
caused disorientation. Penguins that were displaced looked around with their necks extended for a longer period
of time than penguins that were held but not moved. Apparently, they were looking for which way to go. After
being displaced, some penguins walked in the direction of where they had entered the colony and, as soon as the
bird reached its usual route, it turned 90 degrees and walked in a straight line to the nest.
WADING-BIRD MIGRATION THROUGH CENTRAL TURKEY: 2004 VS. 1988
Timothy Brush 1 (tbrush@panam.edu) and Uygar Ozesmi 2 ; 1 Department of Biology, University of Texas–Pan
American, Edinburg, TX USA; 2 Department of Environmental Engineering, Erciyes University, Kayseri
TURKEY
We studied migratory and other waterbirds using wetlands in Kayseri Province, central Turkey, during
March–May 2004. Study areas were the Sultan Marshes and other closed-basin wetlands. Common waders
included Ruff, Black-tailed Godwit, Northern Lapwing, Glossy Ibis, and Black-winged Stilt. Wood Sandpipers,
Little Stints, Spotted Redshanks, Eurasian Spoonbills, and Pied Avocets were much less common than expected,
based on a 1988 study of the same areas. Waterbirds such as Pygmy Cormorant, Great Crested Grebe, and
Slender-billed Gull were rare, as was their open-water habitat. Increased agricultural water usage in
surrounding watersheds, causing lower water levels in wetlands, appears to be the main process causing
waterbird declines. Species migrating through in May and those requiring open, unvegetated pools and mudflats
for foraging were hardest hit, while those migrating in March or April and those capable of using marsh habitats
or wet meadows were less affected. Local, regional, and national agencies and groups will need to employ more