If there is an ambassador from the avian world to the human world, it is the Great Blue Heron. It is widespread and is North America’s largest heron. It is the heron we all notice. LeRoy’s flight photo, taken at the Edmonds marsh, conveys the size and wingspread of this bird.
The Great Blue Heron breeds in colonies, typically in trees near water. The nest is a platform of sticks, brought by the male and worked into the nest by the female. Many Edmonds residents were excited a few years back as Great Blue Herons built a nesting colony in deciduous trees on the south side of the marsh, along Willow Creek. Each year a few more nests were added to the colony until there were 18 – 20 nests. Then the breeding colony failed for unknown reasons and the nests were abandoned.
Great Blue Heron nest sites are vulnerable for several reasons. First, they are conspicuous by nest size and numbers. Second, they are sensitive to human disturbance. Third, it takes the parents almost a month to incubate the eggs. Fourth, the young herons are not capable of flight until two months after birth. They remain in the nests, exposed, for almost three months.
There has been some speculation that Bald Eagle harassment drove the herons away from the Willow Creek site. Bald Eagles are known to kill and eat Great Blue Herons on occasion. But before you become indignant on behalf of the herons, be aware that smaller birds are part of their varied diet. The Great Blue Heron will hunt for rails at the edge of marshes and will eat many species of small water birds. It primarily eats fish, but will also hunt amphibians, snakes and rodents. LeRoy’s second photo shows a heron that has caught a penpoint gunnel, an eel-like fish found in Puget Sound’s intertidal areas at a depth of 0 – 6 feet.
The Great Blue Heron is still a fixture at the Edmonds marsh and along the waterfront, although not now in the larger numbers seen when Willow Creek hosted the nesting colony.
There is nothing pretty about sounds of a Great Blue Heron. You can listen to the squawks at this link: http://www.xeno-canto.org/192288 .
– By Carol Riddell
Carol Riddell, author of our new “Bird Lore” feature, manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.