Photo: M. Noonan
The Common Grackle is a member of
the Blackbird family, and is not related to the American Crow as
many think. Common Grackles are dichromatic which means that
males and females are have different colorations. The male common grackle is an iridescent black, with the
upper chest and head glistening blueish or purplish in the sun.
The female is slightly smaller and more brownish, less
iridescent. The Common Grackle has a very long, dark gray beak.
They are 28-34 cm (11-13 in) in size with a wingspan of 36-46 cm (14-18 in).
Bobolinks weigh about
74-142 g (2.61-5.01 ounces).
The Common Grackle is a very widespread bird, residing all
over North America east of the American Rockies. Their numbers
may be upwards of 100 million in North America. This bird is
known to migrate up to Canada for the summer and reside east of
the Canadian Rocky Mountains. Common Grackles are found in open
areas with scattered trees, particularly in suburban
developments. They are not usually found in very wooded areas
because they like to forage on open ground. Grackles will also
forage in shallow water or in shrubs. The grackle has also been
known to steal food from other birds. Grackles are omnivorous
and will eat insects, minnows, frogs, eggs, berries, seeds and grain,
even small birds.
are very social, and are commonly found around other grackles,
Red-winged Blackbirds, and European Starlings. However, the
Common Grackle becomes very territorial around its nest and will
attack other birds, even humans. Common Grackles do not mate for
life but they are monogamous. From pair formation
through incubation, the male remains in close association with
his mate by perching near her, following her, and engaging in
ritual displays. This exhibition by the male probably
functions to guard against extra-pair copulations. Once
incubation has begun, his attentiveness decreases steadily. The
Common Grackle's cup shaped nest is large and bulky, constructed of woody
stems, leaves and fine grasses and lined with
mud and usually fine grasses or horse hair. Eggs are a light
blue or pearl gray, usually spotless. A Common Grackle's clutch
size is about 4 to 6 eggs. One clutch a year is laid. The eggs
are incubated by the female and hatch in 12-14 days. At this
time, about half the males have deserted the mother and the
nest. Those who remain will participate in parental care,
including brooding and feeding. The young are able to leave the
nest after 16-20 days, however they
remain near the nest several days thereafter.