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Taxonomic Differences Between Birds And Mammals In Their Responses To Chemical Irritants, Russell Mason, Larry Clark, Pankaj Shah
Taxonomic Differences Between Birds And Mammals In Their Responses To Chemical Irritants, Russell Mason, Larry Clark, Pankaj Shah
Larry Clark
Ninety-five products are registered with the u.s. Environmental Pro tection Agency as bird damage control chemicals, but 38 (40%) are non lethal chemical repellents (Eschen and Schafer, 1986). Of these products, the active ingredients in 27 (71%) are methiocarb (a physiologic repellent that acts through food avoidance learning) or polybutene (a tactile repel lent). In general, chemical repellents are effective either because of aversive sensory effects (irritation), or because of post-ingestional ma laise (sickness). If the former, then chemicals are usually stimulants of trigeminal pain receptors (i.e., undifferentiated free nerve endings) in the nose, mouth, and eyes (Mason and Otis, …
A Model For Evaluating Time Constraints On Short-Term Reproductive Success In Altricial Birds1, Larry Clark
A Model For Evaluating Time Constraints On Short-Term Reproductive Success In Altricial Birds1, Larry Clark
Larry Clark
We develop a simple single dimension model incorporating the time and energy commitments of breeding altricial birds in an effort to understand the evolutionary constraints on parental care. We chose time as the dimension of preference, because it is a naturally bounded constraint, e.g., length of day or breeding season. The utility of the model was evaluated by comparing simulations of time allocation of various breeding scenarios for the European starling (Sturnus vulgaris) to field data. The structure of the model may prove useful in determining the evolutionary constraints on parental care imposed by the developmental pattern of chicks.