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.
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. 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.