In winter, bald eagles roost in the trees near Lake Hasty

On the Eastern Plains, the best wildlife show often happens in the coldest months.

John Martin Reservoir sits on the Arkansas River, where a big stretch of open water meets prairie and riverside cottonwoods. That mix of lake, grassland, and streamside woods makes the park one of Colorado’s stronger spots for birdwatching, and very different birds can be found within a short drive of each other. The park is part of the Colorado Birding Trail, and the area has a long official bird list — hundreds of species have been documented here — for people who want to keep track.

Winter is when bald eagles show up. They roost in the trees near the Lake Hasty area, downstream of the dam, where open water and tall cottonwoods give them a place to perch and hunt. On a good winter day you may see several at once.

If you are visiting or live nearby, a few simple courtesies help: watch from a distance, stay in your vehicle or on the trail when birds are resting, and do not try to flush them for a better photo. Roosting eagles are using energy carefully in the cold, and a startled bird burns what it needs to survive.

Seasons, water levels, and where birds gather change from year to year. For the current bird list, viewing tips, and any seasonal closures, check the Colorado Parks and Wildlife page for John Martin Reservoir State Park.