along the Des Plaines River you may come upon a great blue
heron gliding overhead
or sitting motionless at the water's edge watching quietly
and patiently for an unsuspecting fish or frog to swim by.
At four feet, with a six-foot wingspan, this is the largest
of the North American herons. It is easy to identify the majestic
long legged dark blue-gray birds with brown neck, chestnut
thighs and white cheeks, throat and crown; the adults with
long black stripes along each side of their head.
build their nests
along waterways in large trees with wide, open, spreading branches such as sycamores
or cottonwoods. Constructed of sticks, the nests are lined with reeds, grasses
and moss to make a soft bed for the two to four large blue eggs that are laid
in the spring. Eggs hatch in just 28 days. Both parents care for the chicks as
they grow, flying up to 15 miles in search of food. In about two months, the young
herons are ready to fly and leave the nest.
their first winter is the hardest, but then, with a good environment, the great
blue herons may live up to fifteen years.
heron diet consists mainly of small fish which they spear with sharp pointed beaks
and swallow whole. They will also eat turtles, crayfish, lizards, frogs, snakes,
insects and even small birds and rodents.
warm winters, some of the herons may winter over along the Des Plaines River which
remains largely unfrozen. But generally, the birds begin to fly south in autumn
as wetlands and ponds begin to freeze. They will return to the same nesting sites
in the spring, although over time, the trees will begin to deteriorate and die
as year upon year of waste is deposited on their branches. Then the herons will
have to find a new stand of trees for their nests.
pesticides were the greatest threat to our populations of herons and other large
birds such as the egrets and double-crested cormorants which were once on the
Illinois endangered species list. In recent years, the birds have faced new challenges
with the disappearance of nesting sites and changes in habitat and water quality.
Lake county is fortunate to have several successful colonies of great blues nesting
within its boundaries. With wetland restoration projects, installations of some
man-made nesting structures, and construction of reservoirs that provide additional
feeding at many of our corporate centers, their chances of survival continue to
(photo of heron nests courtesy McHenry County
(photo courtesy Fermi Natrional Accelerator