As many as 180 great blue herons were killed, injured or are missing after Sunday's tornado that struck north Minneapolis. The birds were nesting on an island in the Mississippi River near North Mississippi Regional Park. The island had been home to three dozen heron nests, each of which would likely have held three eggs or hatchlings and would have been tended by a pair of adult herons.
All of those nests were destroyed by the storm and only a few of the estimated 50 trees remain standing on the island. Adult herons were seen flying circles around the mangled island or sitting on broken trees.
On Monday, two dead adult herons were found on shore. Park personnel picked up one Monday. Allan and Darnell Hancock of Brooklyn Center found another later that day. They, along with other bird watchers, had gone to the rookery to see if it had been hit by the storm.
"We've visited here often to watch the herons," Hancock said.
By Monday, seven live chicks found by birders were taken to the Wildlife Rehabilitation Center in Roseville. On Tuesday morning, a rescue team with representatives from the Three Rivers Park District, the Minnesota Department of Natural Resources and the Animal Humane Society went to the island to search for birds.
Sharon Stiteler, a National Park Service ranger, said the rescue team had found 60 dead heron chicks by mid-morning Tuesday.
"The hardest sight for some of us has been three dead chicks beside a dead adult," she said.
Kathy Swenson, also with the National Park Service, agreed that while the storm had severely damaged the rookery, she was still hopeful.
"The herons will recover," she said.
Able birds could have abandoned the site, said Stiteler. Some are likely to try to renest this year, though it's not certain that a second nesting would be successful, given the late start.
And the surviving birds are likely to breed again next year.
Herons readily abandon rookery locations when disturbed, so it's not clear if the birds will return to the island next spring.
This colony is believed to have moved to the island several years ago from another island upstream. Herons prefer to nest near water, usually in trees, most often in colonies on islands or swamps. It is believed those locations help protect the birds from predators.