Wood duck and mallard ducklings and pairs of Canada geese with their goslings easily catch our attention now. So do nesting American robins and common grackles.

Still, this also is warbler migration time, when the small birds are migrating through, often active but hidden in the foliage and going unnoticed by many people. Most experienced birders love the warblers and look forward to their arrival as a highlight. On a single day between about May 12 and 20, if conditions are right, 15 or 20 species of these 4- to 5-inch warm-weather songsters can be observed.

Most warblers winter in the tropics, from Mexico and the Caribbean to South America. These warm-weather birds feed mainly on insects, coming into Minnesota and places farther north for the nesting season. Although a good share of the warblers are brightly patterned and flit in the trees, some are more solid-colored and work closer to or on the ground.

A few of the warblers — the American redstart, common yellowthroat and yellow warbler — are summer residents throughout much of Minnesota. Many of the warblers head into Canada for the nesting season. The Tennessee, yellow-rumped, blackburnian, parula and black-throated green are among the species that nest in northeastern and north-central Minnesota and north into Canada.

Jim Gilbert’s 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.