What’s This?February 28th, 2019
Is it a reptile’s skin? A snake’s? A lizard’s? Or maybe those are fish scales?
It is the skin of an animal, but not a reptile or a fish. It belongs to a bird! A Great Blue Heron to be exact. The skin on the legs of a Great Blue Heron is leathery and scaly – a waterproof covering to protect this wading bird’s legs.
Great Blue Herons are able to stand in near-freezing water as they hunt their prey without getting frostbite or losing their body heat. They do this through a process called countercurrent heat exchange. Unlike in humans, the Great Blue Heron’s veins and arteries in their legs are touching. Heat transfers from the warm artery blood to the cold venous blood. By the time the blood reaches the feet, it has cooled down enough so that there is little heat lost to the environment. This adaptation allows the Great Blue Herons to stay in Vancouver even through the winter.
In Stanley Park you can observe Great Blue Herons hunting along the seashore, at Beaver Lake or at Lost Lagoon. Perhaps the most impressive place to view the herons, however, is at their rookery located behind the Park Board offices near the tennis courts. This area hosts about 100 nests up in the trees. The first chicks will hatch in early April.
Come see the rookery, or check out the Vancouver Park Board’s live heron cam to watch all the egg laying, chick hatching and flying practice within the rookery. A SPES naturalist will be online and on the ground at the rookery to answer your most pressing heron questions. Everything doesn’t start, though, until the herons return to begin their breeding season – which could be any day now! So stay tuned for an announcement on Facebook, Twitter and our website.