Finally with warmer temperatures, maple syrup producers could experience good sap runs this week, and spring bird migration really got going.

American robins, red-winged blackbirds, killdeers, eastern bluebirds, sandhill cranes, wood ducks, and flocks of Canada geese had been held back by days of below-normal temperatures and cold winds. I for one am looking forward to the many spring happenings that will come our way with moderating air temperatures.

Watch for migrating American robins. They will be the darker-colored males and will be flighty and vocal. Many flocks of red-winged blackbirds now are arriving here in southern Minnesota, while the snow still lies deep in the north.

The widespread and familiar red-winged blackbirds winter in the southern states. They can gather in large flocks. But at the first hints of spring, mature males head north to stake out their territories. Marshy areas with old tan-brown cattail plants are where to look for the glossy blackbird, flashing bright red epaulets and singing their cheery songs.

These harbingers of spring with their "o-ka-leeee" or "tonk-a-leeee" songs are observed by mid-March, with females spotted about a month later. The female looks very different from the male — she is brown with well-defined striping on her lower body.

Red-wings prefer to nest in marshes and swamps but will nest near almost any body of water. They like to feed in open fields and plowed lands. Although they have been condemned as grain eaters by farmers, only a small part of their diet is made up of grain. Insects and weed seeds make up most of their diet.

It's time to get the wood duck and eastern bluebird boxes up. House finches, year-round residents, are investigating nesting sites. They often nest in old holiday wreaths and hanging plant baskets.

Jim Gilbert has taught and worked as a naturalist for more than 50 years.