You can recognize a heron as it flies overhead: Its long legs held out straight, and its neck characteristically pulled back to form an “S.” They are often seen in flight, or when fishing in their favorite area. They are not so commonly seen at their nest site.
Herons nest in colonies called “rookeries” that are usually located in places isolated from disturbance. Herons often select mature sycamore trees along streams as rookery sites. A large tree may have many nests that can be used for decades. The largest nests are built toward the center of the crown where they are safest. Newer, flimsier nests are built at the edges. The bigger, older nests reach three or four feet across. They’re repaired and given a fresh lining each year as part of the birds’ courtship behavior. The female builds and maintains the nest, while the male brings her the materials. Each pair defends the area immediately surrounding their nest from other herons.
The pair produces one brood of three to six young each year. The adults disperse after the young fledge. The young stay on at the rookery and are the last to leave in mid- to late-July. Rookery activity begins about this time of year.
Learn more about the great blue heron in the MDC’s Field Guide.