(Chelsea Update would like to thank Tom Hodgson and the Waterloo Natural History Association for the photos and the information in this story.)
The Great Blue Heron is the western hemisphere’s largest and most widespread member of the heron family.It can be found from Alaska to Central America.
Great blues nest in colonies called heronries, and there are several in the Waterloo Area, most in rather remote, inaccessible parts of the park.
Each heronry may consist of 20 to 40 nests, which may be used for several years in succession.
Nesting activity usually begins in April. This year, due to the cold spring, nesting may be late.
In this area, nests are built in the outer-most branches of large trees located at the edges of wetlands or on islands of high ground surrounded by marsh or open water. Nests are large and bulky and made primarily of sticks and branches gathered by breeding pairs from nearby woodlands.
Great Blue Herons are frequent visitors to most of the lakes in the area. However, one cannot assume that because a heron is observed on a lake that it has a nest nearby. The adults may travel several miles from their nests each day to forage for food.
Their favorite foods include small fish, frogs, tadpoles, crayfish, small snakes and aquatic invertebrates. When they return to the nest, they feed their young by regurgitation. Nesting herons may consume four times the amount of food of non-nesting birds, as they have two or three extra mouths to feed back at the nest.
Great Blue Herons are impressive birds any time of the year, but are particularly handsome during the breeding season when they grow special nuptial plumages designed to make them more attractive to potential mates. Other heron species like the great egret and snowy egret were nearly hunted to extinction in pursuit of these nuptial feathers to adorn lady’s hats.
However, the Migratory Bird Treaty Act of 1918 was passed in response to the concerns for the future of these birds and now the act protects all native migratory birds from unregulated hunting.
In flight, the great blue heron is sometimes mistaken for a crane.
Cranes fly with their necks outstretched; the heron flies with neck folded back and head resting on its shoulders.
Herons have an opposable toe on each foot that allows them to grip branches, which makes them very comfortable nesting or roosting in trees. Cranes have no such toe and will never be seen off the ground except in flight.
Young cranes leave the nest as soon as they hatch and follow their parents into nearby wetlands and fields to feed.
Young herons remain in the nest until they are able to fly, and the Great Blue Heron will stay in the area as long as there is open water.
They are forced to migrate when the lakes freeze over and are only rarely seen here in winter.