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Articles 1 - 11 of 11
Full-Text Articles in Life Sciences
Opposing Mechanisms Drive Richness Patterns Of Core And Transient Bird Species, Jessica R. Coyle, Allen H. Hurlbert, Ethan P. White
Opposing Mechanisms Drive Richness Patterns Of Core And Transient Bird Species, Jessica R. Coyle, Allen H. Hurlbert, Ethan P. White
Biology Faculty Publications
Studies of biodiversity typically assume that all species are equivalent. However, some species in a community maintain viable populations in the study area, while others occur only occasionally as transient individuals. Here we show that North American bird communities can reliably be divided into core and transient species groups and that the richness of each group is driven by different processes. The richness of core species is influenced primarily by local environmental conditions, while the richness of transient species is influenced primarily by the heterogeneity of the surrounding landscape. This demonstrates that the well-known effects of the local environment and …
Origin Of Amphibian And Avian Chromosomes By Fission, Fusion, And Retention Of Ancestral Chromosomes, Stephen R. Voss, D. Kevin Kump, Srikrishna Putta, Nathan Pauly, Anna Reynolds, Rema J. Henry, Saritha Basa, John A. Walker, Jeramiah J. Smith
Origin Of Amphibian And Avian Chromosomes By Fission, Fusion, And Retention Of Ancestral Chromosomes, Stephen R. Voss, D. Kevin Kump, Srikrishna Putta, Nathan Pauly, Anna Reynolds, Rema J. Henry, Saritha Basa, John A. Walker, Jeramiah J. Smith
Biology Faculty Publications
Amphibian genomes differ greatly in DNA content and chromosome size, morphology, and number. Investigations of this diversity are needed to identify mechanisms that have shaped the evolution of vertebrate genomes. We used comparative mapping to investigate the organization of genes in the Mexican axolotl (Ambystoma mexicanum), a species that presents relatively few chromosomes (n = 14) and a gigantic genome (>20 pg/N). We show extensive conservation of synteny between Ambystoma, chicken, and human, and a positive correlation between the length of conserved segments and genome size. Ambystoma segments are estimated to be four to 51 times longer than homologous …
The Future Of Blue-Winged And Golden-Winged Warblers In Connecticut, Robert A. Askins
The Future Of Blue-Winged And Golden-Winged Warblers In Connecticut, Robert A. Askins
Biology Faculty Publications
No abstract provided.
Time's Arrow Flies Like A Bird: Two Paradoxes For Avian Circadian Biology, Vincent M. Cassone, Jiffin K. Paulose, Melissa G. Whitfield-Rucker, Jennifer L. Peters
Time's Arrow Flies Like A Bird: Two Paradoxes For Avian Circadian Biology, Vincent M. Cassone, Jiffin K. Paulose, Melissa G. Whitfield-Rucker, Jennifer L. Peters
Biology Faculty Publications
Biological timekeeping in birds is a fundamental feature of avian physiology, behavior and ecology. The physiological basis for avian circadian rhythmicity has pointed to a multi-oscillator system of mutually coupled pacemakers in the pineal gland, eyes and hypothalamic suprachiasmatic nuclei (SCN). In passerines, the role of the pineal gland and its hormone melatonin is particularly important. More recent molecular biological studies have pointed to a highly conserved mechanism involving rhythmic transcription and translation of "clock genes". However, studies attempting to reconcile the physiological role of pineal melatonin with molecular studies have largely failed. Recent work in our laboratory has suggested …
Fruit Quality And Consumption By Songbirds During Autumn Migration, Susan B. Smith, Kathleen H. Mcpherson, Jeffrey M. Backer, Barbara J. Pierce, David W. Podlesak, Scott R. Mcwilliams
Fruit Quality And Consumption By Songbirds During Autumn Migration, Susan B. Smith, Kathleen H. Mcpherson, Jeffrey M. Backer, Barbara J. Pierce, David W. Podlesak, Scott R. Mcwilliams
Biology Faculty Publications
Seasonal fruits are an important food resource for small songbirds during autumn migration in southern New England. Therefore, conservation and management of important stopover sites used by migrating birds requires knowledge about nutritional requirements of songbirds and nutritional composition of commonly consumed fruits. We measured nutrient composition and energy density of nine common fruits on Block Island, Rhode Island, and conducted a field experiment to estimate consumption rates of three of these fruits by birds during autumn migration. Most common fruits on Block Island contained primarily carbohydrates (41.3–91.2% dry weight), and little protein (2.6–8.6%) and fat (0.9–3.7%), although three contained …
Conservation Of Grassland Birds In North America: Understanding Ecological Processes In Different Regions, Robert A. Askins, Felipe Chávez-Ramírez, Brenda C. Dale, Carola A. Haas, James R. Herkert, Fritz L. Knopf, Peter D. Vickery
Conservation Of Grassland Birds In North America: Understanding Ecological Processes In Different Regions, Robert A. Askins, Felipe Chávez-Ramírez, Brenda C. Dale, Carola A. Haas, James R. Herkert, Fritz L. Knopf, Peter D. Vickery
Biology Faculty Publications
Many species of birds that depend on grassland or savanna habitats have shown substantial overall population declines in North America. To understand the causes of these declines, we examined the habitat requirements of birds in six types of grassland in different regions of the continent. Open habitats were originally maintained by ecological drivers (continual and pervasive ecological processes) such as drought, grazing, and fire in tallgrass prairie, mixed-grass prairie, shortgrass prairie, desert grassland, and longleaf pine savanna. By contrast, grasslands were created by occasional disturbances (e.g., fires or beaver [Castor canadensis] activity) in much of northeastern North America. The relative …
Relationship Between Habitat Area And The Distribution Of Tidal Marsh Birds, Lori K. Benoit, Robert A. Askins
Relationship Between Habitat Area And The Distribution Of Tidal Marsh Birds, Lori K. Benoit, Robert A. Askins
Biology Faculty Publications
To assess the relationship between marsh area and relative abundance of tidal marsh bird species, we surveyed birds on 86 circular plots in 40 salt and brackish tidal marshes in Connecticut. We measured marsh area in two ways: the amount of contiguous marsh vegetation not interrupted by broad barriers (>500 m of open water or >50 m of upland habitat) and by narrow barriers (>30 m of open water or >10 m upland). We determined the relationship between marsh area and the relative abundance of particular species (mean number of individuals per survey plot) with linear or logistic …
Helping Shrubland Birds, Robert A. Askins
Helping Shrubland Birds, Robert A. Askins
Biology Faculty Publications
Dr. Askins argues that shrublands were part of the pre-Colonial landscape in Connecticut, so it's logical to create forest openings to help shrubland birds.
Conservation Of Grassland Birds In The Northeast, Robert A. Askins
Conservation Of Grassland Birds In The Northeast, Robert A. Askins
Biology Faculty Publications
No abstract provided.
Forest Fragmentation And The Decline Of Migratory Songbirds, Robert A. Askins
Forest Fragmentation And The Decline Of Migratory Songbirds, Robert A. Askins
Biology Faculty Publications
No abstract provided.
Protecting Forests For Wildlife, Robert A. Askins
Protecting Forests For Wildlife, Robert A. Askins
Biology Faculty Publications
The subject of managing forests for wildlife is being viewed from a new perspective, a perspective that has developed primarily as a result of studies of forest-interior birds. Forest-interior birds are dependent to a large extent on how forest lands are managed. They are essentially forest specialists and are not normally seen in open areas such as the suburbs, open fields or meadows. In Connecticut and other parts of the northeastern United States, most forest-interior birds are members of one taxonomic group, the wood warblers.