By David Spector Gazette Contributing Writer
The great southbound migration of birds starts around the last week of June and continues for about half a year, with hundreds of millions of birds flying south across North America. This southward movement reaches its greatest intensity in August, September and October, and continues into early winter. Not all birds, though, follow the pattern. In the late summer, here in western Massachusetts, we can sometimes see spectacular birds that have flown north from the southern states.
At this time of year a lucky observer at one of our local ponds or marshes might see an elegant egret gracing the shoreline, although we are not in its breeding range. White herons that can show up here include the great egret, the snowy egret, the cattle egret and the little blue heron, all members of the heron family. The black-crowned night-heron, glossy ibis and, rarely, several other southern wading bird species sometimes also show up.
Many water birds in the Deep South, including these species, breed in the late winter and early spring, so that by midyear young birds are independent and ready to disperse, even while many birds in the North are still in the middle of their breeding season.
Why fly north? It’s summertime and the living in southern wetlands might not be so easy. Mosquitoes, heat, drying up of small bodies of water, competition with the increased population at the end of the breeding season—all can make life difficult for water birds in Florida and nearby areas of the southeastern United States. Birds flying north may escape some of these conditions, and young birds can explore areas where they might someday attempt to nest away from the crowded conditions where they hatched.
The three egret species and the young of the little blue heron are all white, and attention to detail is necessary to identify a white heron as to species. The great egret has a relatively long yellow bill, the snowy egret has a dark bill with a small patch of yellow facial skin near the base of the bill, the cattle egret has a proportionately short and thick yellow bill and the young little blue heron has a blue-gray bill that is paler at the base. A good look at the wingtips of the little blue heron might reveal a tiny smudge of gray at the ends of the longest flight feathers, a small indication of the coloring that the entire bird will have as an adult.
Experienced observers can often identify these birds at a glance based on structure and hunting behavior, even if color details can’t be seen. The great egret commonly hunts with slow movements and its neck stretched nearly straight out. The snowy egret is the most active hunter of the herons likely to be seen in western Massachusetts and often wades rapidly about in the water, perhaps startling fish and frogs with its bright yellow feet. The cattle egret, proportionately the most compact of these species, frequents fields where it accompanies cattle and catches small animals, such as grasshoppers, voles and frogs that are startled by the movement of the cattle. The little blue heron, like the great egret, usually stalks its prey slowly, behavior that helps to distinguish it from the snowy egret, to which it is similar in size and shape.
Although these species overlap in hunting behavior, attention to these typical styles of stalking will usually lead to a correct identification.
Fascination with these birds is not new. The spectacular breeding plumes of the egrets (usually not seen on the individuals that wander to western Massachusetts) made them both the target of hunters collecting plumes for hats and the successful symbol of early bird protection efforts a century ago. The best known literary snowy egret gives its name to Sarah Orne Jewett’s classic 1886 short story “A White Heron,” in which it helps a young girl develop her sense of self in nature. I hope that you, like Jewett’s heroine, are fortunate to find one of these graceful visitors offering a taste of Florida wetlands at your local pond.
David Spector is a former board president of the Hitchcock Center for the Environment and teaches biology at Central Connecticut State University.
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