One of the biggest and quite possibly the oldest Great Blue Heron I ever saw here visited the North Basin close to the park’s eastern shore. The darkness of the beak, the layers of blue and grey on top of it, and the white “beard” distinguish a veteran. As I watched, it stood in shallow water, looking for fish, but decided after a while that pickings were slim, and flew off. We have had a number of visiting Great Blues, but no permanent resident since “Oscar” in 2014-15.
The Cornell bird lab website has a number of “Cool Facts” about Great Blue Herons. Among them are these:
Despite their impressive size, Great Blue Herons weigh only 5 to 6 pounds thanks in part to their hollow bones—a feature all birds share.
Great Blue Herons in the northeastern U.S. and southern Canada have benefited from the recovery of beaver populations, which have created a patchwork of swamps and meadows well-suited to foraging and nesting.
Along the Pacific coast, it’s not unusual to see a Great Blue Heron poised atop a floating bed of kelp waiting for a meal to swim by.
Great Blue Herons have specialized feathers on their chest that continually grow and fray. The herons comb this “powder down” with a fringed claw on their middle toes, using the down like a washcloth to remove fish slime and other oils from their feathers as they preen. Applying the powder to their underparts protects their feathers against the slime and oils of swamps.
Great Blue Herons can hunt day and night thanks to a high percentage of rod-type photoreceptors in their eyes that improve their night vision.
Great Blue Herons congregate at fish hatcheries, creating potential problems for the fish farmers. A study found that herons ate mostly diseased fish that would have died shortly anyway. Sick fish spent more time near the surface of the water where they were more vulnerable to the herons.
The oldest recorded Great Blue Heron was found in Texas when it was at least 24 years, 6 months old.
Thanks to specially shaped neck vertebrae, Great Blue Herons can quickly strike prey at a distance.