WILLMAR – Minnesota roadways come with advisory signs to watch for all kinds of wildlife, from moose and deer to turtles.
But only in Kandiyohi County will motorists find signs urging them to slow down for purple martins as the birds congregate at an end-of-summer roosting site just south of Willmar.
Please do, asks Richard Doll, of Willmar.
The purple martins are now staging at the roost site, and a number of the birds have already been struck by vehicles. He counted 15 that were downed one day earlier this week; that’s more than were struck all of last year.
The birds began roosting this week, and can be expected to continue to congregate at the site until September 1. That’s when they will depart en masse for destinations in South America, primarily in the Amazon rainforest area of Brazil.
The Willmar roosting site is located in farm fields near 45th Avenue Southeast (County Road 19), about one mile south and one mile east of the Mill’s Auto Center near the Highway 23 bypass. The county recently paved the road. The seasonal sign advising motorists that birds are staging there is erected.
Doll said residents living along the road and others familiar with the area have been very mindful of the need to slow down for the birds. He suspects the unfortunate collisions this week were the result of motorists unfamiliar with the area.
The tendency is to look up to spot the birds, but the real concern is for birds that may be on the roadway or road shoulder. They can be slow to take wing when vehicles approach. The younger birds are most vulnerable, said Doll.
Motorists might also spot Doll near the roosting site. He maintains a purple martin colony at his home north of Willmar, and works with scientists to monitor the birds. He uses a spotting scope to read the bands on the birds that join at the Willmar roost.
He also bands birds that make his colony their summer nesting home, and in more recent years, has worked with the Purple Martin Working Group to place tiny geo-locators on some of the birds. The geo-locators are helping scientists learn about the birds and their annual migration route and destinations.
At the Willmar roost, he’s been able to spot birds with bands from colonies all over Minnesota and the Dakotas. This year and last, he’s also spotted bands that identify birds from Alberta and Saskatchewan, Canada. Scientists did not realize that purple martins in the two western Canadian provinces veered this far east on the northern leg of their migration.
Doll was also surprised to learn that the Canadian birds are among the first to reach the Willmar roost. He always suspected that the more northerly birds followed in the wake of southern birds on the trip to their winter homes.
The purple martins can be seen near the roosting site at the end of the day. They’re easy to spot as they congregate on power lines. They’ll swoop into the roost area- mainly a corn field today- around sun down.
No one is sure how long the Willmar roost site has existed. Doll suspects it may have been established by purple martins when wetlands connected to Lake Wakanda existed in the area where corn fields are now found. Purple martin roosts elsewhere are more typically associated with wetlands.
No doubt about this: The Willmar roosting site is an important, seasonal destination for a large proportion of the state’s purple martins. When the birds take flight at the start of the day, they show up on Doppler radar as an expanding “doughnut hole.”