Dissertation Research: Testing Alternative Hypotheses Concerning Why Parental Care Improves With Age

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In many animals, parents produce more and better offspring as they get older. Two different explanations have been suggested for this improvement. The first is that as parents near the end of their lives, offspring become increasingly valuable. Older parents therefore expend more effort on those offspring. The second explanation is that older animals have accumulated experience and skills with age that allow them to be more efficient with their time and energy. Thus older individuals would be able to produce more offspring than younger individuals for the same effort. This research will explore these two mechanisms in a population of house sparrows, common birds found in backyards and on farms. Older and younger parent birds will be observed to compare how often they return to the nest to feed young and how long they search for food for their chicks. Parental ability will be tested by changing the number of young the parent birds have to feed, and by measuring learning ability at various ages.This research contributes to our understanding of changes in reproduction with age and examines potential behavioral causes of these changes. This will improve our understanding of the ecology of parental behavior and how life patterns of behavior affect reproduction.