Driving through Eagle Bluffs Conservation Area this morning, it was clear that the transition from spring migrants to summer residents is well advanced. Waterfowl were limited to Canada geese, wood ducks, a small flock of blue-winged teal and a few mallards; shorebirds, recently represented by large, mixed flocks are now limited to killdeer and spotted sandpipers.
With the exception of great blue herons, indigo buntings and the ubiquitous red-winged blackbirds, dickcissels were the most conspicuous birds this morning, delivering their distinctive song from the tops of reeds or shrubs; favoring open grasslands, pastures and weedy fields, these vocal, sparrow-like birds have recently arrived from wintering grounds in Central and South America. They feast on both insects and seeds and will soon pair off and build a nest in the tall grass; 4-6 eggs are generally laid.
As the summer heat builds, dickcissels and other open country birds will dominate the scene as woodland species retreat to the cool shade of forests or riparian groves; already, these tree-dwelling birds are heard more than seen, active behind a dense canopy of leaves. Throughout the summer months, those hoping to see these birds must arrive early or late in the day, when solar radiation is less intense and cool air settles across the floodplain.