Last year I heard my first hollow, mournful cooing of the mourning dove Feb. 22. It was calling from the peak of the Snyder Building at the Minnesota Landscape Arboretum.

These wintering-over birds are usually heard by the end of February, heralding spring. It's the male mourning doves that produce the distinctive four-part song: coah, cooo, cooo, cooo.

Thirty five years ago, a wintering mourning dove was a rare sight in the Twin Cities and area. Now they are quite common at feeding stations in southern Minnesota throughout the frozen season. Still, most head for the southern part of the United States in autumn. Reports from avid birders confirm that the mourning dove's winter range is moving north, year by year. Climate change and proliferating feeding stations account for the extended winter range.

Pairs of mourning doves are seen in the summer perched on utility wires or picking up gravel along roadsides. These birds are a foot long, have small heads, long, pointed tails, and are mostly gray and brown. Their flight is swift and direct. The whistling of their wings is distinctive.

Mourning doves eat huge numbers of seeds from weeds in fields and other grassy areas. In fact about 98 percent of their diet is seeds. At feeding stations, they go for millet and cracked corn scattered on the ground, near trees or shrubs with low branches that offer protection and roosting spots.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.