Term of Award
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (open access)
Department of Biology
C. Ray Chandler
Committee Member 1
Committee Member 2
Nest sanitation is an important aspect of parental investment in birds with altricial nestlings. Passerine nestlings produce fecal matter that is encased in a mucous membrane for easy disposal. These fecal sacs are either removed from the nest and transported a distance away or they are ingested by the adult. A decline in fecal sac ingestion rates as nestlings age has been observed in several species. The parental nutrition hypothesis posits that this pattern can be attributed to increasing digestive efficiency as nestlings age. The parental nutrition hypothesis makes three predictions: fecal sac consumption rates should decrease as nestlings age, the nutritional value of fecal sacs should decline as nestlings age, and females should consume more fecal sacs than males. I tested these predictions in Eastern Bluebirds (Sialia sialis) using video cameras in order to quantify changes in behavior over the nestling cycle and analysis of protein content of fecal sacs. Both male and female bluebirds consumed fecal sacs significantly less often as nestlings aged. Protein content (μg/g) of fecal sacs also declined with age. Female bluebirds consumed more fecal sacs than males. Overall, my results support the parental nutrition hypothesis, although multiple selective factors may affect consumption of fecal sacs.
Burns, Amanda W. 2016. The Nutritional Value of Fecal Sacs: Testing the Parental Nutrition Hypothesis.