Voyageurs begins cormorant study

Voyageurs National Park is initiating a study of the double-crested cormorant colony in Lake Kabetogama starting this month.
This study, funded by the U.S. National Park Service, has four principle objectives:
•determine population size and other demographic characteristics, including numbers of fledged young/produced per nest;
•describe foraging behaviour of adult birds using radio telemetry and sightings of colour-banded individuals;
•estimate diet composition of adults and chicks; and
•determine prevalence of diseases such as West Nile virus, Newcastle disease, and avian influenza (including the highly pathogenic strain HPAI) in local cormorant populations.
NPS staff and collaborators will visit the colony periodically to outfit cormorants with radio transmitters and colour bands, and to collect samples.
This study will provide valuable information to the NPS and the Minnesota Department of Natural Resources regarding the status of cormorants in the area and their role in aquatic ecosystems.
Three other colonies in the Ontario portions of Rainy Lake also may be studied, in part to allow comparisons in cormorant population characteristics and diet composition between Kabetogama and Rainy.
Cormorants are native to Minnesota, and have been in the Voyageurs National Park area since at least 1500, according to archeological evidence and records from early explorers.
The colony on Kabetogama was first settled in 1999, peaked at 330 breeding pairs in 2005, and currently contains between 100-150 pairs.
By comparison, Lake of the Woods harbours more than 5,000 breeding pairs.
Double-crested cormorants are a protected species under U.S. National Park Service policies.
“Cormorants are really a hot topic right now,” said Steve Windels, terrestrial ecologist for Voyageurs National Park.
“This study will also allow us and other agencies to make management decisions based on the best scientific evidence available,” he added.
For more information, contact Windels at 1-218-283-6692.