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When spring-time arrives in Venice, Florida, the thoughts
of all the male Great Blue Herons turn to images of love - time to find
his lifelong mate!
With all that marvellous breeding plumage, he has to put it to a practical use, and attract a wonderful female! Great blue herons nest together in colonies, usually known as a heronry or rookery, often of hundreds of breeding pairs. Most species construct their loose, flat, platform-style nests high in the branches of swamp trees. The Venice Rookery is located in Venice, Florida, 60 miles north of Sanibel Island. There dozens of people a day come within 70 feet of the birds rookery year after year with no harmful effects. There are Great Egrets and Anhingas nesting with the Great Blues Herons also. For more information (and photos) about the Venice Rookery, click here. |
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Herons form pair-bonds, usually in March and April, after a series of courtship rituals performed by both sexes. The occipital crests are raised in display during courtship and both sexes change body coloration, although the male becomes more brightly adorned. Herons are monagomous, mating for life. |
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The male heron may build a new nest or revitalize one that survived the winter. Nest sites are usually in living, but occasionally dead, trees and bushes. They build rickety nests of sticks sometimes lined with grass, reeds and moss. Most are situated high in the tree canopy, safe from predators on the ground. |
The location of the colony depends upon an available
food supply for raising the young in close proximity to nesting trees;
however, the birds show a preference for stands of loblolly pine, beach,
oak and large, old sycamore trees. Initially, the inner section of a stand
of trees is utilized, but continual colony use may eventually kill that
area. When the center of the tree stand dies, the colony moves circularly
outward in succeeding years. This strategy creates a "donut" or "bullseye"
effect when the tree stand is aerially viewed. Nests are constructed of
sticks and, if not collapsed by winter weather, may be repaired and
used year after year. The nest is lined with reeds, mosses and grasses
to help cushion three to seven eggs that are laid during March and April.
Eggs hatch after about 28 days, and both parents care for the chicks.
Both parents feed regurgitated fish to the newly hatched nestlings. Although herons lay several eggs, they usually raise only one or two; the others starve after hatching. After about 60 days, the young fledge and leave the nest. |
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Sixty-nine percent of new born Great Blue Herons die in their first year (Hancock and Kushlan 1984). Two of the oldest known great blue herons have lived 23 years, 3 months (Clapp et al 1982) and 20 years (Kennard 1975), respectively. |