Date of Award
Master of Science
Matthew James Parris
Stephan J Schoech
Delayed plumage maturation (DPM) is a phenomenon in which birds retain immature plumage until their second breeding season despite reaching sexual maturity earlier. This study investigated DPM in Amethyst Sunbirds (Chalcomitra amethystina) and Scarlet-chested Sunbirds (Chalcomitra senegalensis). I used museum specimens to describe duration, intensity and scheduling of molt in immature and adult males. I hypothesized that in these African Sunbirds 1) rainfall seasonality acts as a molt constraint and 2) molt intensity and duration differ between age groups. I found that while primary molt was initiated during the rainy season, body molt occurred at low intensities throughout the year. Age-based differences in molt intensity and duration were largely inconclusive. I also documented the occurrence of interrupted molt, which indicates that molt is energetically constrained. Low intensity and interrupted molt may be adaptive strategies which allow balance among molt, nomadic movements and opportunistic breeding in a changing and unpredictable environment.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Benesh, Mariah Kathryn, "Does Seasonal Rainfall Act as a Molt Constraint in African Sunbirds? The Role of Climate in the Adaptation and Evolution of Delayed Plumage Maturation" (2011). Electronic Theses and Dissertations. 294.