Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 4 of 4
Full-Text Articles in Life Sciences
Population Dynamics And Dispersal Coalitions In The Cooperatively Breeding Acorn Woodpecker, Natasha Hagemeyer
Population Dynamics And Dispersal Coalitions In The Cooperatively Breeding Acorn Woodpecker, Natasha Hagemeyer
Biological Sciences Theses & Dissertations
Dispersal is a critical life-stage with consequences not only for the individual, but for population dynamics and thus the fate of the whole species. The creation of dispersal coalitions can lead to complex outcomes and affect how changes in abundance occur on the landscape. I examined population dynamics and dispersal coalitions in a population of cooperatively breeding acorn woodpeckers in central California, USA. Using a 34-year dataset on occupancy and abundance, I determined that increases in abundance were determined by dispersal to new locations. This resulted in increased occupancy, rather than increases in group size and larger coalitions. I then …
Wandering Woodpeckers: Foray Behavior In A Social Bird, Sahas Barve, Natasha D. G. Hagemeyer, Russell E. Winter, Samuel D. Chamberlain, Walter D. Koenig, David W. Winkler, Eric L. Walters
Wandering Woodpeckers: Foray Behavior In A Social Bird, Sahas Barve, Natasha D. G. Hagemeyer, Russell E. Winter, Samuel D. Chamberlain, Walter D. Koenig, David W. Winkler, Eric L. Walters
Biological Sciences Faculty Publications
In many cooperatively breeding taxa, nonbreeding subordinates, or helpers, use extra-territorial forays to discover dispersal opportunities. Such forays are considered energetically costly and foraying birds face aggression from conspecific members of the territories they visit. In contrast, breeders in cooperatively breeding taxa are expected to foray seldomly. We used novel tracking technologies to follow 62 acorn woodpeckers (Melanerpes formicivorus), a cooperatively breeding bird, to study extra-territorial foray behavior. Both helpers and breeders engaged in extra-territorial forays routinely and often several times per day. Helpers forayed earlier in the day and invested more time when foraying to high-quality territories. …
Temporal Variability And Cooperative Breeding: Testing The Bet-Hedging Hypothesis In The Acorn Woodpecker, Walter D. Koenig, Eric L. Walters
Temporal Variability And Cooperative Breeding: Testing The Bet-Hedging Hypothesis In The Acorn Woodpecker, Walter D. Koenig, Eric L. Walters
Biological Sciences Faculty Publications
Cooperative breeding is generally considered an adaptation to ecological constraints on dispersal and independent breeding, usually due to limited breeding opportunities. Although benefits of cooperative breeding are typically thought of in terms of increased mean reproductive success, it has recently been proposed that this phenomenonmay be a bet-hedging strategy that reduces variance in reproductive success (fecundity variance) inpopulations living inhighly variable environments. We tested this hypothesis using long-term data on the polygynandrous acorn woodpecker (Melanerpes formicivorus). In general, fecundity variance decreased with increasing sociality, at least when controlling for annual variation in ecological conditions. Nonetheless, decreased fecundity variance …
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 …