Osprey adventures: tracked migratory birds make continental travels

Ospreys are like the human snow bird, enjoying the cool rivers and lakes of Montana during the summer, while traveling thousands of miles south to enjoy a coastal retreat for the winter.

Recently discovered research shows just how amazing some of these birds can be, like flying across the gulf of Mexico, or returning to the exact same spot along the Clark Fork River from Central America.

"Some of these birds have amazing stories," said Rob Domenech, the executive director of the Raptor View Research Center. "If you see an osprey raising young, you should know that bird has been to hell and back."

The osprey talk was part of the Swan Valley Connections quarterly potluck held in the Swan Valley Community Hall.

Domenech has been counting and tagging raptors in Montana since the early 2000s. Since tagging ospreys with colorful bands that can be identified from a couple hundred feet away, Domenech said people have reported tagged Montana birds all over America.

One of the reasons ospreys have been studied was to get a sense of toxic chemicals that flow through western Montana rivers. The Upper Clark Fork complex is the largest superfund site in the country, with mining chemicals from Butte and earlier historically polluting waterways.

"Ospreys that feed at the top of the food chain are the perfect organism to study," Domenech said, explaining that chemicals that are absorbed by the bottom of the food chain are magnified with each level of the food chain.

The project, now 17 years in, has expanded from heavy metals to anything that their data can try to explain: where ospreys go after summer, how do they establish a wintering grounds and why they return to the same location year-after-year.

Ospreys have some of the most daunting tasks for a bird of prey. Once born during the summer in the northern U.S and Canada, ospreys must fly solo for more than 1,000 miles to find a place to stay during the winter.

Some birds make good choices from the first flight - going straight south towards a good beach along the coastline. Others go on vast continental journeys that often lead to dangerous encounters with predators or humans.

One bird Domenech highlighted was C-5, a bird banded near Warm Springs. The next year, C-5 was spotted on the Yucatan Peninsula with a shark in its mouth. Bird M-8 was banded in Missoula's Osprey baseball stadium and was next spotted in Rockport, Texas, by an oil refinery.

"It's just a glimpse into their lives, but it shows us something," Domenech said

In 2015, the Raptor View Research Institute started tracking ospreys using satellite devices. Instead of only seeing the birds using the bands, the institute gets real time data of where nearly a dozen birds are at all time.

One bird, named Boots, actually flew to Minnesota after first leaving its nest, making researchers doubt if the bird would survive year-round. After feeding at a fish hatchery, the bird went directly south over Louisiana and spent two days flying over the Gulf of Mexico to Cuba.

Boots made several more flights over the gulf, this time to the Yucatan Peninsula, before realizing it could fly over Mexico instead, and changed its route on the way back. For some reason, it kept going back over the Midwest before going back to its wintering grounds.

"We don't know what happened to Boots, the transmitter simply stopped working," Domenech said. It doesn't necessarily mean that Boots died, because transmitters usually keep working after an osprey dies.

Many times researchers go to find the transmitter because of how expensive they are.

Ospreys are common along rivers and lakes as their main source of food is fish. Domenech said the Seeley Swan Valley has some osprey, but they usually stay away from the area because of golden and bald eagles.

"Some estimates show a bald eagle will eat every third fish an osprey catches," Domenech said, adding that golden and bald eagles will actually eat ospreys on occasion.

Some of the biggest threats to osprey come from humans. Baling twine kills a significant number of ospreys, prompting bird experts to have to remove the twine from nests around western Montana.

Domenech summarized that there are a lot of barriers to becoming a full grown osprey, yet new generations of the bird keep persisting across the continent to keep their species alive.

Anytime you are around western Montana and you see an osprey, look for a band, Domenech said. "You might find a cool story with it."