Management-Induced Reproductive Failure and Breeding Dispersal in Double-Crested Cormorants on Lake Champlain
1 November 2007 Management-Induced Reproductive Failure and Breeding Dispersal in Double-Crested Cormorants on Lake Champlain
ADAM E. DUERR, THERESE M. DONOVAN, DAVID E. CAPEN
ADAM E. DUERR,1,*,** THERESE M. DONOVAN,2 DAVID E. CAPEN3
1aVermont Cooperative Fish and Wildlife Research Unit, University of Vermont, Aiken Center, Burlingto
2bUnited States Geological Survey, Vermont Cooperative Fish and Wildlife Research Unit, University of
3cRubenstein School of Environment and Natural Resources, University of Vermont, Aiken Center, Burlin
* E-mail: aduerr@wm.edu
** Present address: The Center for Conservation Biology, College of William and Mary, P.O. Box 8795, Williamsburg, VA 23187, USA
We studied breeding dispersal of double-crested cormorants (Phalacrocorax auritus) associated with management practices that suppressed their reproduction on Lake Champlain in the northeastern United States. We implemented an experiment on one colony by spraying corn oil on cormorant eggs in portions of the colony and leaving other portions untreated. Gulls (Larus spp.) consumed cormorant eggs during the oiling process, but we reduced and then eliminated predation levels after the first year of the study. We used mark–recapture techniques within the experimental framework to measure rates of breeding dispersal for cormorants from the experimental colony and an unmanaged colony in Lake Champlain. Egg oiling increased the movement rate to the unmanaged colony by 3% during the year with no egg predation by gulls. When gulls depredated cormorant eggs at high rates during egg oiling, movement to the unmanaged colony increased by 20%. When cormorants are managed to reduce population sizes, methods that limit dispersal away from the managed colony may be most effective. Such methods would mitigate effects to nontarget populations and allow for a greater portion of the metapopulation to be managed.
ADAM E. DUERR, THERESE M. DONOVAN, and DAVID E. CAPEN "Management-Induced Reproductive Failure and Breeding Dispersal in Double-Crested Cormorants on Lake Champlain," Journal of Wildlife Management 71(8), 2565-2574, (1 November 2007). https://doi.org/10.2193/2006-527
mark–recapture analysis
multistrata modeling
ADAM E. DUERR, THERESE M. DONOVAN, DAVID E. CAPEN "Management-Induced Reproductive Failure and Breeding Dispersal in Double-Crested Cormorants on Lake Champlain," Journal of Wildlife Management, 71(8), 2565-2574, (1 November 2007)