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Unusually High Body Mass In Virginia Meadow Voles, Sara B. Longtin, Robert K. Rose
Unusually High Body Mass In Virginia Meadow Voles, Sara B. Longtin, Robert K. Rose
Biological Sciences Faculty Publications
We used monthly capture-mark-recapture information to determine growth rates and life spans for 2 populations of meadow voles studied for 28 and 29 months in eastern Virginia in order to learn whether the exceptionally large body masses of some voles were due to rapid growth, long lives, or both. On 1 study grid, 64 males (19%) and 43 nonpregnant females (11%) were ≥70 g, with the largest male being 89 g. Mostly positive growth rates (averaging 1.1-3.9 g/month) were recorded, even in autumn and winter months, times when meadow voles are losing mass in northern populations, where most studies of …
Brooding, Provisioning, And Compensatory Care In The Cooperatively Breeding Acorn Woodpecker, Walter D. Koenig, Eric L. Walters
Brooding, Provisioning, And Compensatory Care In The Cooperatively Breeding Acorn Woodpecker, Walter D. Koenig, Eric L. Walters
Biological Sciences Faculty Publications
We analyzed reproductive investment in parental care (brooding and the provisioning of nestlings) in the acorn woodpecker (Melanerpes formicivorus), a cooperatively breeding species in which both polygynandry and helping-at-the-nest are common. As predicted based on the strategies pursued by birds of different sex and status, breeders generally invested more in parental care than helpers, and breeder females invested more than breeder males. Contrary to expectations, however, the degree to which individuals reduced their effort with increasing group size (i.e., patterns of load lightening or compensatory care) did not match overall investment. Instead, as group size increased, there was …