An avian field mark that warrants special attention this time of year is the color of a bird’s lores — the area between a bird’s eye and bill on both sides of its head. In some birds, especially wading birds, lores change color quite dramatically during the breeding season.
Because birds can see blue, green and red (like humans) as well as UV light, and because the change takes place just as the breeding season begins for birds, the change in lore color, often to a more vibrant hue, is thought to play a part in attracting a mate. (The bills, legs and feet of some birds also change color at this time.)
At the height of the breeding season, Great Egret lores go from yellow to an emerald green. Green Heron lores turn from a yellowish-green to a bluish-black. Snowy Egrets (pictured) lores become bright pink. This happens to both sexes ever year.
Although Great Egrets breed sporadically as far north as Vermont, seeing one in northern New England is always noteworthy. The likelihood of a sighting increases as summer progresses, due in large part to the phenomenon of post-breeding dispersal. After young Great Egrets have fledged, individuals wander well outside their typical breeding range, as far north as southern Canada. The northward dispersal of juvenile birds peaks in August and September. Most Great Egrets migrate in the fall, from September through December.The extent of their migration is influenced by annual fluctuations in temperature. When winters are mild, individuals may remain as far north along the Atlantic Coast as Massachusetts.
After overwintering in Central America and southern U.S., Great Egrets head as far north as the New England coast and Vermont’s Champlain Valley to breed. The peak of their spring migration occurs in April so now is a good time to look for them in wetlands where they stop to rest and refuel en route. Great Egrets eat mainly fish, but also crustaceans (see crayfish in insert), amphibians, reptiles, birds and small mammals.