A large group of white pelicans entertained dozens of people on the Rock River in Janesville over the weekend and into Monday.
Neil Deupree of the Bird City-Janesville Facebook page said he counted about 200 over the weekend but saw 30 to 50 on Monday.
The birds have wingspans of up to 9 feet, making them among the largest in North America.
Deupree organized a pelican-viewing party Sunday, when he said upwards of 70 people came to view the birds.
Deupree has seen pelicans on the river before, including one pair in January, but he said he has never seen so many.
“Nobody that was there last night—and some of them were people who’ve lived in the area for a long time—can ever remember seeing such a collection of pelicans here,” said Kay Deupree, Neil’s wife.
Kay said she suspects the removal of the Monterey Dam has something to do with the birds being upriver of the dam site.
The river has receded somewhat since the dam was removed, Kay said, and the shallows that were created might attract the birds. Fish the dam once blocked also could have moved upstream, attracting the pelicans.
A group of the large birds flew upstream over the weekend, a behavior that Kay has read could be a way to chase fish into shallower water.
“They were really putting on a show,” she said.
Unlike brown pelicans, the whites don’t dive for fish, but they will cooperatively work to concentrate fish in an area for easier fishing, according to audubon.org.
They prefer so-called rough fish, which include the carp and suckers, according to a state DNR paper.
The paper said pelicans were common in the state before 1870, including on Lake Koshkonong, but then went into decline. Nationwide, their numbers have increased since the 1970s, and pelicans have been nesting on the bay of Green Bay since 1994.
The prominent bump on the pelicans’ bills is there only during their breeding season.
White pelicans breed predominantly in the summer in Western states and Canadian provinces, several sources said.