|SREL Reprint #0361|
Avian Versus Mammalian Predation on a Population of Cotton Rats
A population of cotton rats (Sigmodon hispidus)
in a 1-acre field enclosure was completely protected from predation (April
1965-February 1966) by a cover of nylon net.
Removal of the cover exposed the population to avian predators, but
mammalian predators were excluded. The
presence of a cover affected neither seasonal recruitment nor the spring and
summer mortality. However,
mortality in autumn-winter, after the peak density of summer, was much lower
with the cover in place. When
exposed only to avian predators, the population showed cumulative recruitment
and mortality curves similar to those of free-living populations of cotton rats.
The conclusion was that mammalian predators are much less important than
avian predators in reducing the annual increment of cotton rats.
SREL Reprint #0361
Wiegert, R.G. 1972. Avian versus mammalian predation
on a population of cotton rats. Journal of Wildlife Management