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Published on: August 22, 2018
Food and predators affect egg production in song sparrows
Liana Zanette1, Michael Clinchy, James N M Smith
1Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada. lzanette@uwo.ca
Ecology
|November 9, 2006
Summary
Food addition and predator abundance interact to influence Song Sparrow egg production. Food limits total eggs, while predator interactions affect how eggs are distributed among nests, impacting clutch size and number.
Area of Science:
- Ecology
- Avian Demography
- Behavioral Ecology
Background:
- Avian population dynamics are influenced by food availability and predation pressure.
- Previous research indicated interactive effects of food and predators on Song Sparrow reproductive success.
Purpose of the Study:
- To experimentally investigate the effects of food addition on Song Sparrow egg production.
- To determine how predator abundance modifies the impact of food on egg production and its components.
Main Methods:
- Manipulative food addition experiment conducted over three breeding seasons.
- Study sites varied in predator abundance near Victoria, British Columbia.
- Demographic data, including egg production, clutch number, and clutch size, were collected.
Main Results:
- Food addition significantly increased total egg production, independent of year.
- Food addition reduced nest predation, with significant interannual variation.
- Interactions between food, predators, and year affected clutch number and clutch size.
Conclusions:
- Food availability is a primary limit on total egg production in Song Sparrows.
- Predator abundance and its interaction with food availability influence the partitioning of eggs into clutches.
- Complex interactions between food, predators, and environmental variability shape avian demography.
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