Tag Archives: American Crow

Licorice In The Sky: A seasonal gathering of crows

Posted on November 13, 2018 by Wayne Petersen

Crows © Craig Gibson

An annual late autumn phenomenon in New England is the spectacular crepuscular gathering of American Crows into large nocturnal communal roosts. Felt by many to be large, raucous, and often pesky, crows in fact are intelligent, crafty, and creative survivors in a world heavily populated with humanity.  A crow aficionado ever since kidnapping a baby American Crow from a nest for a pet in my boyhood (don’t try that at home), I have been fascinated by crows.  Their myriad vocalizations, their ability to count at least to three, to eat practically anything, and to survive seemingly everywhere are collectively worthy attributes. But to fully appreciate the magnificence of crows in all their glory is to observe them at a winter roost.

To dispel the erroneous perception that American Crows are sedentary residents in Massachusetts throughout the year is to visit any of the leading autumn hawk watching sites in Massachusetts from late September to early November. As autumn’s foliage is acquiring its brilliance and then falling, small groups of crows daily stream southward from northern New England and eastern Canada, some following ridge lines and valleys, others the course of major river ways or the seacoast. As fall transitions to winter these northern migrants join more southerly resident crows every evening to form what are often aggregations of many thousands of individuals.  Wherever these nightly roosts happen to be, the late afternoon and nightly behavior of the crows within the roosts is a matter of considerable interest to the careful and dedicated watcher.  And there are lots of unanswered questions surrounding these winter roosts.

For example one might assume that every evening crows from far and wide simply fly directly to a communal roost site for the night, or that in the morning the crows utilizing a roost might routinely head for the same daytime foraging areas.  Not only are these assumptions untrue, they also offer insight into the mysteries of crow behavior.  Normally relatively solitary during the mid-spring nesting season, by mid-summer crows become increasingly gregarious, and by winter they have gathered into large roosts that may contain many thousands of individuals from great distances away.

© Craig Gibson

The behavior of crows near these evening roosts is particularly curious, if not mercurial.  For instance, from night to night crows approaching a roost will regularly make several pre-roosting stops (called staging areas), sometimes more than a mile from the final roost site.  These short stops are generally accompanied by much raucous vocalizing, before the birds present often suddenly depart and head off to another staging site where this behavior is then repeated.  This may occur several times before dark within a several mile diameter area of the final roost, and the staging areas may change location from day to day.

Finally, during deep dusk or shortly after dark, most of the birds in these staging areas will make a last and often silent flight to the ultimate roost site.  Surprisingly for birds as timid and wary as crows normally are during the day, at these nighttime roosts the birds often perched on bare, leafless deciduous tree branches where it is sometimes possible to literally walk under roost tree without disturbing them – something that would be virtually impossible during the day.

American Crow © Craig Gibson

Undoubtedly a number of important functions occur in these enormous winter roosts.  One is the opportunity for crows in a winter roost to “meet other crows.”  Since crows do not breed in their first year after nesting, these roosts may serve as “dating bars” for un-mated immature crows to meet at the winter roost, then eventually breed for the first time in the spring with mates established in the winter roost.  Similarly, first-year immature crows probably learn what it truly means to be a crow in a winter roost.  They likely acquire important winter foraging skills, learn how to avoid predators and other related dangers, and how to modify the many nuances of complex crow vocabulary.  While seemingly speculative, there is also good evidence to reinforce and support these concepts.

To best appreciate some of the spectacular mysteries described above, currently there are few better places in eastern Massachusetts to experience them firsthand than a huge, well established American Crow and Fish Crow roost located in the city of Lawrence.  This Lawrence roost has been well described in a previous Distraction Display post.

So to appreciate one of winter’s most impressive avian spectacles, try spending a late afternoon in the months ahead near the New Balance building in downtown Lawrence adjacent to the Merrimack River and behold the sight of Licorice in the Sky for yourself.

 

Give the gift of birds this holiday season. You can make a gift to Mass Audubon in honor of your loved ones.

 

A River Of Crows

Posted on March 15, 2018 by William Freedberg

Every night between November and March, a steady trickle of American Crows pours through the skies of Lawrence and Andover, MA. The trickle quickly becomes a stream. Soon, a deluge. Crows spread from horizon to horizon as they fly together to their communal roost. The number of crows varies every year, but there can be as many of 12,000 or 15,000 at a time.

The word “Hitchcockian” does not accurately describe every mass gathering of birds, though the term is used broadly. Murmurations of European Starlings dance and contort themselves in the sky, recalling a moving sculpture. Staging flocks of migratory Tree Swallows are clamorous and chaotic, but the birds move with a light and airy agility that lends a whimsical feel to the spectacle. American Crows, on the other hand, flow by steadily in a single direction. Their pace is deliberate, and their rowing wingbeats inexorable. Uniformly black, crows appear at dusk as large, dark shadows against the sky. They even sometimes approach people out of curiosity and stare at us with an unreadable avian gaze. These are the birds that inspired Hitchcock’s eponymous movie, playing off humans’ unease. In reality, though, members of the crow family are harmless, cooperative, and even empathetic. And while some causal observers might find a crow roost uncanny, birdwatchers and nature-lovers often find in them a source of wonder and beauty.

Why Roost in Numbers?

As some of the world’s most intelligent birds, what could American Crows be up to at these roosts? Traditional theories dictate that crows roost together for safety or warmth, or use communal roosts to be able to select mates from a larger pool of candidates. But hungry crows also follow better-fed birds from the roost in the morning, suggesting they are seeking out productive feeding sites, and that roosts can facilitate cooperation. Some roosts are furthermore located strategically near feeding sites, such that crows can grab a reliable snack when they leave for the day and when they return at night.

Thousands of crows gathering together in the same place every night make easy pickings for predators like Great Horned Owls. As a result, American Crows gather at a secondary location, or “staging area,” before continuing on to their real roost after nightfall. American Crows will further confuse predators by changing the location of the staging area, or even the roost itself, every few nights. Some human observers confuse these staging areas for the actual roost, not knowing the roost is several hundred feet to several miles away— unless they stay after dark to watch the crows move a second time.

The American Crows in Lawrence are surprisingly wide-ranging when not at their roost. Pellets they cough up have revealed saltmarsh snails, telling us that they forage at least as far away as the New England coast. Some of the birds are seasonally migratory, and spend the breeding season far to the north on the St. John’s River in Canada.

Viewing The Mass Roost

To find the crow roost in Lawrence, park in the lot for the New Balance factory on the east side of South Union Street. Cross the street and slowly, quietly, walk partway over the bridge on the Merrimack River.  The crows should be in the trees on the north side, numbering into the thousands.  Check out the surrounding area for the crows’ staging grounds as well- they have a particular affinity for the parking lots in the industrial park between South Canal Street/Andover Street and the river, as well as Island Street and Pemberton Park.

Some of these birds will be returning to their breeding ground soon, with the rest pairing off and dispersing throughout the state- shutting down the roost until November. Try to catch the spectacle while you still can, or make a plan to check it out next winter.