Photos of the Week: A Rookery Full of Great Blue Heron Fledglings

At a rookery along the Clinton River Trail west of Dequindre Road, young Great Blue Herons (Ardea herodias) are preparing to go out on their own. According to the Stokes Guide to Bird Behavior Volume III, both adults care for the eggs for 28 days, and the nestling phase lasts 7-8 weeks. Now, in mid-July, the young are fully fledged but still at the nest practicing their wing techniques. Their hard working parents will feed them for another 2 or 3 weeks, and the young herons will take their first flights during this time.

According to both Stokes and the Cornell Lab of Ornithology, the young can be identified by two-toned beaks (rather than all yellow), black and white striped necks (rather than solid color),  and a solid black crown (rather than the black and white adult crown). So I’m guessing that all the herons you’ll see below are fledglings. In the slide show below, a young heron tries out different wing movements, perhaps to build up necessary muscles or just get the feel for different positions – arched high, extended flat,  curved forward for slowing down to a stop, etc.  One youngster also seemed to practice spearing with its huge beak, striking down into the edge of the huge nest of twigs.

It’s important to be very quiet and unobtrusive around heron rookeries. The birds are easily disturbed and can abandon rookeries where there’s too much activity and noise. Luckily this one is protected from the busy trail by a scrim of trees. So if we’re quiet, careful and stay on the trail, the herons can continue to ignore hikers, bikers and the occasional curious amateur photographer sticking her camera between the leaves!

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