Biology: Recent submissions
Now showing items 121-140 of 228
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Seasonal and Age-Dependent Dietary Partitioning between the Great Black-Backed and Herring Gulls
(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 ... -
Aggressive nest intrusions by male Humboldt Penguins
(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 ... -
Mitochondrial DNA variation, species limits, and rapid evolution of plumage coloration and size in the Savannah Sparrow
(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 ... -
Characteristics of predators and offspring influence nest defense by Arctic and Common Terns
(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, ... -
The role of development, parental behavior, and nestmate competition in fledging of nestling Tree Swallows
(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 ... -
Sex-specific, seasonal foraging tactics of adult grey seals (Halichoerus grypus) revealed by state-space analysis
(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. ... -
An experimental test of offspring recognition in Western Bluebirds
(1995-10)No abstract available. -
Observer Effects and Avian-Call-Count Survey Quality: Rare-Species Biases and Overconfidence
(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 ... -
Natural Selection, Variation, Adaptation, and Evolution: a Primer of Interrelated Concepts
(2010-11)Natural selection is an elegantly simple concept but one that can manifest in complex ways. I review how the basic model of single-trait viability selection has been extended to more complex forms of selection on multiple ... -
Conservation genetics as applied evolution: from genetic pattern to evolutionary process
(2008-02)Conservation genetics can be seen as the effort to influence the evolutionary process in ways that enhance the persistence of populations. Much published research in the field applies genetic sampling techniques to infer ... -
Adaptive Value and Costs of Physiological Plasticity to Soil Moisture Limitation in Recombinant Inbred Lines of Avena barbata
(2010-02)Costs are hypothesized to constrain the evolution of adaptive phenotypic plasticity, but they have been difficult to quantify because strong selection should eliminate costly genotypes from natural populations. However, ... -
Diazotrophic bacteria respond to Saharan dust additions
(2012)Three bioassay experiments were performed to study the effects of nutrient and Saharan dust additions on natural diazotrophic communities in the tropical North Atlantic Ocean. Samples for nucleic acid analysis were collected ... -
Compartmental models of nitrogen cycling in tropical and temperate marine environments
(1987)Time-course measurements of super(15)N tracer kinetics in particulate organic and in NH super(+) sub(4) pools from tropical and temperate regions were used to test several compartmental models describing the exchange of ... -
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Symmetry, change, perturbation, and observing mode in natural communities
(1986)Like a kaleidoscope, nature presents continuously fleeting images of natural communities. It has been difficult to discern patterns of community structure in these elusive images. For both theoretical and applied considerations, ... -
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Male and female pollination success in a deceptive orchid, a selection study
(1998-06)We carried out phenotypic selection analyses to assess the relative importance of several Horal traits, as well as microhabitat, in determining both male and female pollination success in a nonrewarding orchid (Cypripedium ... -
Correlations among Fertility Components Can Maintain Mixed Mating in Plants
(2009-01)Classical models studying the evolution of self-fertilization in plants conclude that only complete selfing and complete outcrossing are evolutionarily stable. In contrast with this prediction, 42% of seed-plant species ... -
Pollen limitation of plant reproduction: Ecological and evolutionary causes and consequences
(2004-09)Determining whether seed production is pollen limited has been an area of intensive empirical study over the last two decades. Yet current evidence does not allow satisfactory assessment of the causes or consequences of ... -
Polar Bear Diets and Arctic Marine Food Webs: Insights from Fatty Acid Analysis
(2008-11)We used quantitative fatty acid signature analysis (QFASA) to examine the diets of 1738 individual polar bears (Ursus maritimus) sampled across the Canadian Arctic over a 30-year span. Polar bear foraging varied over ...