LE3 .A278 2014

2014

Shutler, Dave

Acadia University

Bachelor of Science

Honours

Biology

Biology

Bird nests protect eggs, developing young, and incubating adults from inclement weather and predation. In Tree Swallows (Tachycineta bicolor) females are solely responsible for incubating eggs. Prior to and while females are incubating, males compete with rivals for feathers that they use to line nests. The thermal benefits hypothesis proposes that this is because maintenance of proper egg temperatures is critical. I tested the thermal benefits hypothesis: I predicted that artificially heating Tree Swallow nests would result in addition of fewer feathers. I quantified feathers from Tree Swallow nests in the Annapolis Valley, Nova Scotia, and St. Denis, Saskatchewan. Nesting started the first week of May and continued into mid June. At both locations nests were randomly assigned to control or experimental treatments. In Nova Scotia wire platforms were added under nests early in nest-building so that later manipulations would cause reduced disturbance. Experimental nests had 24h heating pads (spent pads were used for controls) placed under them that were replaced daily until culmination of incubation. Contrary to the thermal benefits hypothesis, there was no statistically significant difference in feather numbers between control and experimental nests. However, nests initiated earlier in the season had significantly more feathers than those initiated later in the season. Further studies will have to be conducted to determine if feather addition is also facultative in response to other variables. Key words: artificial heating, nest feathering, Tachycineta bicolor, Tree Swallow.

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https://scholar.acadiau.ca/islandora/object/theses:1132