VERMILLION, S.D. -- Warming temperatures have caused migrating birds associated with water habitats to arrive earlier this spring in South Dakota, said David Swanson, Ph.D., professor of biology at the University of South Dakota and an acknowledged ornithology expert.
“Migrating snow geese arrived early this year,” said Swanson, co-author of the "Birds of South Dakota." "The bulk of the snow goose migration through South Dakota typically occurs from mid-March to early April. The first migratory flocks showed up this year on Feb. 19.”
Swanson said the earlier migration is caused by warmer winters. Average temperatures during winters in the Northern Plains states of South Dakota and Minnesota have warmed about 2 degrees per decade since the 1970s, he said.
“This year’s early spring arrival of migrating flocks of snow geese fits the overall trend during recent decades,” said Swanson. “Even though this past winter was snowier than average, it was also relatively warm, and warmer winters allow ice-out to occur earlier on lakes and ponds, which opens up habitat for water birds and allows them to push north earlier.”
Swanson said it's a good time to be outdoors observing geese and other birds moving through the area.