Pelican island: Birds nest at Chase Lake National Wildlife Refuge
CHASE LAKE NATIONAL WILDLIFE REFUGE, N.D.—Nearly 40,000 birds are nesting this year on a 14-acre island that formed over the past two decades in Chase Lake National Wildlife Refuge, according to Brandon Oksendahl, a biological science technician at the refuge.
"This island is relatively new," he said. "It use to be a peninsula. The water rise has flooded the other islands (traditional nesting habitat for pelicans and other species) since 1995 and formed a new island from a previous peninsula."
Oksendahl said recent aerial surveys showed about 28,000 American white pelicans maintaining about 14,000 nests on the island.
"It is the largest breeding colony of white pelicans in North America," he said. "It amounts to about one-third of the total population."
Along with nearly 30,000 pelicans, the island provides nesting space for about 2,500 herons and egrets, 3,000 cormorants and 3,600 seagulls, Oksendahl said.
That amounts to about 2,700 birds per acre, leaving each bird with about 15 square feet of space. That many birds concentrated in a small space creates a busy area.
"There is never any calm airspace above the island," Oksendahl said.
This year's breeding population of pelicans is comparable to recent years. It exceeds the number of birds in 2004 when the pelicans abandoned their nests and 2005 when the number of nesting birds was low.
"The two biggest threats to the birds are weather events and disease," Oksendahl said. "You can imagine how much damage a cold rain does when they are sitting on their eggs."
The island is popular with the birds because it represents safety.
"The rise of the lake has created the ideal habitat on the island," Oksendahl said. "Predators can't reach them."
Pelicans arrive early in the spring sometimes prior to the ice melting on Chase Lake. As the spring progresses, they build nests and the females lay eggs. Nesting activity utilizes any weeds growing on the island resulting in bare ground covered with nests over much of the island as the season progresses.
"Usually they hatch two eggs," Oksendahl said, referring to the pelicans. "It is not unknown for the first chick hatched to kill the second chick."
The chicks are without feathers or down when they hatch but develop a downy fluff within a few days. By the first weeks of August, most of the new chicks will have developed feathers and be able to fly, Oksendahl said.
While the chicks are growing, one of the pair of adults usually flies off each morning in search of food. The pelicans can fly as far as the Red River in the east or Missouri River in the west, although many stop at small sloughs and lakes that are closer to Chase Lake.
"Mostly they are catching small fish and salamanders," Oksendahl said. "They bring them back and regurgitate them for the chicks."
That activity contributes to an odor from the island that is noticeable at quite some distance downwind, Oksendahl said.
Traveling to surrounding lakes is necessary because the natural water quality in Chase Lake doesn't support a fish population.
Visitors can view the island and the nesting birds from an observation area on the north shore of the lake. The area includes information panels and a telescope for viewing the island across the lake. The best time to view the pelicans is now through the middle of July before the chicks begin to fly and leave the nesting area, Oksendahl said.
There are also displays on the lifecycle of pelicans and information on other wildlife species and an auto tour route at the refuge headquarters.
This year, for the first time in the 110-year history of Chase Lake National Wildlife Refuge, visitors will see cattle grazing on refuge land.
Oksendahl said the agreements with local ranchers allow livestock to graze grasslands that haven't been grazed in more than a century in an effort to promote more diversity in the plant species.