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Full-Text Articles in Life Sciences
Isotopic Discrimination In The Double-Crested Cormorant (Phalacrocorax Auritus), Elizabeth C. Craig, Brian S. Dorr, Katie C. Hanson-Dorr, Jed P. Sparks, Paul D. Curtis
Isotopic Discrimination In The Double-Crested Cormorant (Phalacrocorax Auritus), Elizabeth C. Craig, Brian S. Dorr, Katie C. Hanson-Dorr, Jed P. Sparks, Paul D. Curtis
Brian S Dorr
The diet-tissue discrimination factor is the amount by which a consumer’s tissue varies isotopically from its diet, and is therefore a key element in models that use stable isotopes to estimate diet composition. In this study we measured discrimination factors in blood (whole blood, red blood cells and plasma), liver, muscle and feathers of Double- crested Cormorants (Phalacrocorax auritus) for stable isotope ratios of carbon, nitrogen and sulfur. Cormorants exhibited discrimination factors that differed significantly among tissue types (for carbon and nitrogen), and differed substantially (in the context of the isotopic variation among relevant prey species) from those observed in …
Foraging Ecology And Depredation Management Of Great Blue Herons At Mississippi Catfish Farms, James F. Glahn, Brian S. Dorr, John B. Harrell, Lester Khoo
Foraging Ecology And Depredation Management Of Great Blue Herons At Mississippi Catfish Farms, James F. Glahn, Brian S. Dorr, John B. Harrell, Lester Khoo
Brian S Dorr
No abstract provided.
Avoidance Of Cabbage Fields By Snow Geese, J. Russell Mason, Larry Clark
Avoidance Of Cabbage Fields By Snow Geese, J. Russell Mason, Larry Clark
Larry Clark
now Goose activity levels were significantly less in cabbage fields than in control fields. Although the data do not unambiguously address the issue of sulfur repellency, we believe that the activity difference is consistent with avoidance of the former and not preference for the latter. Sulfurous volatiles were readily apparent to us during our visits to cabbage fields throughout the study period. Similar odors were not detected in control fields. If sulfurous volatiles were important, then avoidance could reflect some characteristic of the cover crop (e.g., unpalatability acquired through the absorption and translocation of degra dation products) or it could …
Thermal Constraints On Foraging Activity Of Adult Starlings, Larry Clark
Thermal Constraints On Foraging Activity Of Adult Starlings, Larry Clark
Larry Clark
The operative temperature of the environment was estimated for starlings using hollow, unheated taxidermic mounts. On average, adults foraging in full sun were characterized by shorter foraging bouts than those adults foraging in full shade. Simultaneous observations of air temperature, operative temperature, and the foraging duration of adults indicated that air temperature was a poor predictor of the maximum length of a foraging bout. The operative temperature of the environment was not correlated to the maximum and mean length of foraging bouts for temperatures below 31.5 ~ C, but was negatively related to maximum and mean foraging duration for values …