They were black silhouettes scattered among a maze of tree limbs set on a backdrop of blue sky. What were they? Crows, and lots of them, and with more to come.
For the most part this group of birds remained unnoticed in their perches well above the line of sight of those at ground level.
Usually during winter crows migrate south. However crows can be found within the Commonwealth year round. Those that breed here migrate south beginning in late September or early October and fly south as far as the Gulf of Mexico. Those birds are replaced by crows from the north which overwinter in PA.
A small population of crows will remain across the state. However the crows that fly in from the north establish overwintering grounds in the southern portion of the state. There the migrant birds generally form into large flocks then roost together for the night.
Rookeries, as these roosting sites are called, are generally areas that have been established over decades. In some areas rookeries cover a large area where hundreds if not thousands of crows will roost in trees for the night.
One of the best examples of a rookery I observed for over a decade was located near the western border of PA and Ohio.
The rookery was located south of Youngstown, OH, situated along RT 680 leading to the Boardman/Poland exit.
As evening approached, hundreds of crows would be seen in the air. The crows were approaching trees where an unbelievable number of birds had already come to roost within trees situated along the busy highway. The rookery was the largest I have ever seen.
After a night’s rest the crows depart the rookery in small groups or as individuals to feed and go about their daily business. Amazingly crows have been known to range up to 30 miles a day in winter in search of food. Then in the hours before sunset
the crows return along the same route they departed.
As the winter season begins to head toward spring, crows also begin to migrate north, disperse, and establish themselves in other areas.
Crows are generally considered to be gregarious, however as the flocks begin to break-up, mate selection begins to take place.
Males vie for mates by fighting and displaying spectacular flight routines. Once paired, the male and female search out a secluded woodlot to establish a nest site.
Both share nest-building and egg-incubation chores.
Crows prefer to construct their nest in the crotch of a tree that is between 10 and 70 feet (the average height is 25 ft.) above the ground.
Typically the nest is constructed of twigs, sticks, bark, and vines and will be 22 to 26 inches across. The center of the nest is lined with moss, shredded bark, grass, deer hair, fur, feathers, and the like.
The female crow will lay between 3 –8 bluish-green eggs and the average is 4 to 6.
The eggs are incubated for 18 days. Ten days after hatching the young crows are nearly fully feathered. The crows will fledge at five weeks of age.
Crows are among the most intelligent of birds. They’re wary and quick to identify danger. The can imitate other sounds, including barking dogs, mewing cats, and the chants of a songbird, and are both devious and ingenious in their pursuits of food
and life in general.
Anyone who has been entertained by crows harassing owls or hawks, knows the varied sounds the crow can make.
Crows have a dislike for birds of prey. And with good reason. Great-horned owls in particular are opportunistic and will prey on a meal of crow fledglings. The same is true of hawks.
Listen to crows for very long and you’ll learn they have quite a vocabulary.
It is believed that crows possess a sophisticated communication system with caws and coos. Their melodious chatter of varying volumes and pitch has specific meanings.
Crows are also curious and will pilfer shiny objects from picnic tables, trash heaps, and backyards.
In addition to the common crow, Pennsylvania is home to three additional members of the Corvidae family that includes the fish crow and the raven. The blue jay is the fourth member of the family, although it is classified in a different sub-family.
If the opportunity presents itself, invest some time watching crows. From one session to the next you’ll be amazed just how entertaining these birds can be.
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Charlie Burchfield is an active member and past president of the Pennsylvania Outdoor Writers Association, an active member of the Professional Outdoor Media Association, Outdoor Writers Assoc. of America and the Mason-Dixon Outdoor Writers. Gateway Outdoors e-mail is GWOutdoors@comcast.net