Although Great Egrets (Ardea alba) do 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. (This Great Egret is about to dine on a crayfish.)
Birds have a number of ways of keeping cool, which is a good thing, given the number of hot days we’ve experienced this summer, and probably for summers to come. They don’t sweat, nor do they pant, but birds do have several behavioral adaptations which reduce their temperature. Often, while exposed to the relentless heat of the sun, Great Blue Heron nestlings resort to what is called gular fluttering. They open their mouths and “flutter” their neck muscles, promoting heat loss – an avian version of panting. An even easier behavior to observe is the position Great Blue Herons will often assume on a hot day. They droop their wings (see photograph) while standing, which allows air to circulate across their body and sweep away the excess heat.
Although Great Blue Herons are colonial nesters, they forage by themselves, usually by slowly wading or standing in wait of prey in shallow water. Fish are the mainstay of their diet, but they also consume amphibians, invertebrates, reptiles, mammals, and birds. When prey is located (by sight), the heron rapidly thrusts its neck forward and grabs it with its beak. If it is small, it is sometimes tossed in the air before it is swallowed, as the photograph depicts. Most prey are swallowed whole.
Green herons are typically solitary and secretive birds, but if you find one, you often have an extended period of time to observe it, as they often slowly stalk their prey, or pose statue-like, sometimes for minutes at a time, while waiting to strike at a fish, frog or invertebrate. Three characteristics tell you that the green heron in the photograph is a juvenile: the tufts of down that remain on its head, its streaked neck (adults have solid rufous necks) and its yellow legs (adults have orange legs).
I had to laugh recently when I noticed a chain reaction going on in a Great Blue Heron nest I was watching. There were five chicks, and one of them yawned. At least I presume it was a yawn, though perhaps it could have be re-aligning its beak or perhaps cooling off. Exactly like humans, each of the remaining four birds followed suit and proceeded to stretch their beaks open wide in succession. It struck me as quite comical, especially when I discovered myself yawning as I observed the heron chicks doing the same.