Birds have been called “bellwethers of watershed health.” Because they respond to basic changes in landscape and habitat conditions, birds can be excellent indicators of watershed health.
Roger Tory Peterson, an American naturalist who published many books about birds and garnered multiple awards in his field, once said “Birds are an ecological litmus paper. Because of their rapid metabolism and wide geographic range, they reflect changes in the environment quickly and they warn us of things out of balance, sending out signals whenever there is deterioration in the ecosystem.”
GLA’s Watershed Biologist Rob Karner, a former ornithology instructor, helps the GLA monitor our bird variety, patterns, and health as a potential leading indicator of overall watershed health. The robust variety and health of our year-round resident birds and migratory birds points to a healthy watershed, and we want to introduce you to some of them.
This is a green heron, which can often be seen near the canal that joins Fisher Lake and Big Glen Lake. The habitat and foraging area of the green heron includes riparian zones, wetlands, ponds, and lakes, as well as human-made canals and ditches.
The green heron is a small, stocky heron found in North and Central America. Green herons migrate to our watershed in late winter and early spring, usually at night and in large flocks. They head back south in late August through October.
The green heron’s call is a loud and sudden kyow; it also makes a series of more subdued kuk calls. During courtship, the male gives a raah-rahh call with wide-open bill, makes noisy wingbeats and whoom-whoom-whoom calls in flight, and sometimes calls roo-roo to the female before landing again. While sitting, an aaroo-aaroo courtship call is also given.
Green herons are about the size of a crow with a velvet-green back, chestnut body, and dark cap. They have a thick neck, dagger-like bill, and broad, rounded wings.