From the arid badlands of Makoshika State Park to the snowy peaks of Glacier National Park, many different plants and animals flourish in Montana.

Taking Wing:
Montana's Osprey

Hunting on the wing, an osprey appears to glide effortlessly over the water. Ospreys have narrow wings, which they bend while soaring and scanning for fish beneath the surface. Their backs are dark brown and their bellies are white, with a mostly white head marked by a dark brown eye stripe that runs from the eye to the neck and shoulders. The undersides of the wings are mostly white except for dark “wrist” patches and brown-barred flight feathers. Although smaller than eagles, ospreys are still large birds, about 21 to 24 inches long with wingspans of roughly 54 to 72 inches.

Ospreys nest in places that offer safety, open views, and plenty of fish. Nests are usually near a lake, reservoir, river, or large wetland, and even during migration these birds travel along water, often following river valleys. Many ospreys that nest in Montana leave by October for wintering areas that can extend into Mexico, Central America, and South America. Some juveniles migrate even earlier, following established flyways south.

Because they live so closely with water, ospreys are fish-eating specialists. Nearly their entire diet consists of fish, and it is rare for them to eat anything else. Along the upper Missouri River in Montana, studies show that “rough fish” such as suckers are the most common prey, with trout and other salmonids, minnows, and perch also eaten. Barbed pads on the soles of an osprey’s feet and long, sharp, curved claws help it grip slippery fish, while dense, oily feathers and nasal valves that close during dives help keep water out when they plunge feet-first into a river or lake.

Ospreys usually build their nests at the tops of stout dead trees or snags, often above the surrounding canopy. When natural nest sites are scarce, they readily use man‑made structures such as power poles, channel markers, and special nest platforms. These platforms have become an important tool for helping ospreys return to shorelines where tall trees are limited.

Ospreys arrive in much of Montana in March and April to build or refurbish nests. Both parents collect sticks and other materials, but the female does most of the arranging, lining the nest with grasses, moss, and bits of light debris. In April or May they lay a typical clutch of about three eggs. The eggs do not hatch all at once, so the first chick may be several days older than the last. The oldest chick often bullies its younger siblings and gets the most food, while predators such as bald eagles, great horned owls, and raccoons sometimes take eggs or nestlings. If the chicks receive enough food and stay safe from predators and storms, they usually leave the nest in July or August at around two months old.

Osprey numbers declined sharply in the 1950s and 1960s after the pesticide DDT became widely used, but they have rebounded across much of North America, including Montana, since DDT was banned in 1972. In western Montana, ospreys nesting along the Clark Fork River and its tributaries still help scientists track pollution from historic mining and smelting. The fish they eat can carry heavy metals such as arsenic, cadmium, copper, lead, zinc, and especially mercury. Long‑term studies of blood from osprey chicks on the Clark Fork have found mercury concentrations much higher than levels considered safe for people, making these birds important indicators of lingering contamination and the progress of river cleanup at one of the nation’s largest Superfund sites.

Today, ospreys are valuable indicator species for monitoring the health of large rivers like the Missouri and Clark Fork. Because they rely on fish and are sensitive to pollutants that build up in aquatic food webs, changes in their numbers or health can signal changes in river ecosystems. Ospreys also attract bird‑watchers and other visitors to rivers, lakes, and nest‑camera sites throughout Montana, supporting local tourism and outdoor education. For two decades Missoula’s minor league baseball team honored this graceful raptor by playing as the Missoula Osprey before rebranding in 2019 as the Missoula PaddleHeads.

You can listen to an osprey’s loud whistled call here.

Updated: February 2, 2026