During a recent mild winter day, the sound of birds chirping outside a Bozeman window sparked a simple question: Is Montana’s unusually warm winter affecting bird migration patterns?
Some of the birds being heard are exactly where they should be this time of year. House finches, for example, are common winter residents in Montana, according to Lou Ann Harris, a former president and current conservation member of the Sacajawea Audubon Society.
But Harris said not all recent sightings fit the typical seasonal pattern.
This past fall, birders across the region reported extremely rare sightings of species usually found much farther south.
Birds such as white-eyed vireos, cattle egrets and scissor-tailed flycatchers were spotted in Montana as early as November — an unusual occurrence.
“These birds are usually way down south like Texas, so to have them show up here in the fall is really unusual,” Harris said.
WATCH: How mild winter weather is affecting bird migration
At the Sacajawea Audubon Society’s 40-acre wetland near Bozeman, year-round residents like magpies and crows continue to dominate the skies. However, Harris said other species are lingering longer than expected.
“We’ve seen big movements of waterfowl,” she said.
Harris believes open,unfrozen water is playing a significant role. With ponds and wetlands remaining ice-free longer than usual, some birds that typically spend summers in Montana are now staying through the winter.
One example is the pied-billed grebe, a bird normally considered a summer visitor in the state, which has been spotted swimming in open water as recently as January.
“If whatever water that it is living in freezes, it won’t survive,” Harris said.
At the same time, some birds that typically migrate to Montana for the winter are notably absent. Harris said species such as Arctic and rough-legged hawks have not appeared in expected numbers this season.
“That’s probably because they’re finding plenty of prey and open country farther north,” she said.
Despite the warmer temperatures, Harris emphasized that most birds do not base their migration timing on weather alone. Instead, daylight remains the primary factor.
“Most birds are timing their flight north by daylight,” she said. “So they are not going to show up here any earlier than they normally do.”
Harris also noted the importance of conservation areas, such as the wetland near Main Street in Bozeman, which provide critical habitat during times of environmental change.
“For birds, it provides nesting, migration stopover and habitat,” she said.
As Montana continues to experience a winter that feels more like spring, local bird experts say these protected spaces may become increasingly important for wildlife adapting to changing conditions.
For more information: https://sacajaweaaudubon.org
