Browsing Biology by Author "Leonard, Marty L."
Now showing items 1-9 of 9
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Aggressive nest intrusions by male Humboldt Penguins
Taylor, Sabrina S.; Leonard, Marty L.; Boness, Daryl J. (2001-02)During observations at a breeding colony of Humboldt Penguins (Spheniscus humboldti), we noted five male penguins enter nests occupied by breeding pairs and engage in aggressive interactions with the resident adult. These ... -
Characteristics of predators and offspring influence nest defense by Arctic and Common Terns
Whittam, RM; Leonard, Marty L. (2000-05)Nest defense is a critical aspect of parental care that entails both costs and benefits. The purpose of this study was to examine patterns of nest defense in a colony of Arctic and Common Terns (Sterna paradisaea and S, ... -
An experimental test of offspring recognition in Western Bluebirds
Leonard, Marty L.; Dickinson, JL; Horn, AG; Koenig, W. (1995-10)No abstract available. -
Mitochondrial DNA variation, species limits, and rapid evolution of plumage coloration and size in the Savannah Sparrow
Zink, RM; Rising, JD; Mockford, S.; Horn, AG; Wright, JM; Leonard, Marty L.; Westberg, MC (2005-02)We compared sequences from two mitochondrial DNA (mtDNA) genes (ND2, ND3) in Savannah Sparrows (Passerculus sandwichensis; n = 112) sampled from Baja California (five sites), coastal Sonora and the continental range (eight ... -
Observer Effects and Avian-Call-Count Survey Quality: Rare-Species Biases and Overconfidence
Farmer, Robert G.; Leonard, Marty L.; Horn, Andrew G. (2012-01)Wildlife monitoring surveys are prone to nondetection errors and false positives. To determine factors that affect the incidence of these errors, we built an Internet-based survey that simulated avian point counts, and ... -
The role of development, parental behavior, and nestmate competition in fledging of nestling Tree Swallows
Michaud, T.; Leonard, Marty L. (2000-10)Fledging (i.e. leaving the nest) in altricial birds is a major step toward independence. The timing of this important event may be influenced by nestling development, parental behavior, and sibling interactions. In this ... -
Seasonal and Age-Dependent Dietary Partitioning between the Great Black-Backed and Herring Gulls
Steenweg, Rolanda J.; Ronconi, Robert A.; Leonard, Marty L. (2011-11)Studies of seabird diets may reveal subtle ways in which sympatric species partition resources to facilitate co-existence. We studied the variability and partitioning of diets between the Herring (Larus argentatus) and ... -
Sex-specific, seasonal foraging tactics of adult grey seals (Halichoerus grypus) revealed by state-space analysis
Breed, Greg A.; Jonsen, Ian D.; Myers, Ransom A.; Bowen, W. Don; Leonard, Marty L. (2009-11)In many large pelagic animals, observing behavior is limited to observation by radio or satellite telemetry. In many cases, discriminating different behaviors from telemetry data has been a key, but often elusive, goal. ... -
Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America
Shutler, Dave; Hussell, David J. T.; Norris, D. R.; Winkler, David W.; Robertson, Raleigh J.; Bonier, Frances; Rendell, Wallace B.; Belisle, Marc; Clark, Robert G.; Dawson, Russell D.; Wheelwright, Nathaniel T.; Lombardo, Michael P.; Thorpe, Patrick A.; Truan, Melanie A.; Walsh, Robert; Leonard, Marty L.; Horn, Andrew G.; Vleck, Carol M.; Vleck, David; Rose, Alexandra P.; Whittingham, Linda A.; Dunn, Peter O.; Hobson, Keith A.; Stanback, Mark T. (2012-06)Data from the North American Breeding Bird Survey (BBS) suggest that populations of aerial insectivorous birds are declining, particularly in northeastern regions of the continent, and particularly since the mid-1980s. ...