Caw! Caw! Caw! Loud, raucous, and highly intelligent, you may not see many crows at your backyard bird feeder, but that doesn’t mean you won’t see crows in a group.
Why do crows gather and caw? Members of the Corvidae family, crows, are highly social birds with tight-knit family structures that gather, or roost, in large numbers (1).
There can be a number of other reasons that may cause crows to gather in large numbers, from social behaviors to protective measures, read on to learn why do crows gather and what it means when they do.
Why do crows gather and caw?
So why do crows gather and caw? There can be a number of different answers to this question, but the most common reason for a large gathering of crows is to form large communal roosts (2).
Flocks gather in fall and winter to these roosts that may contain anywhere from hundreds to thousands of birds (3). Smaller flocks congregate and join together to create one large roost for the night. As the morning comes, smaller groups break off from the flock to disperse for the day, returning to the roost later in the afternoon.
Although little research has been done on the communal roosting of crows, this behavior is thought to play an important social role for crows, helping them exchange information, look for mates, and generally socialize. There may be other reasons for crows to gather as well, including funeral behavior, feeding, and social gatherings.
One of the common names for a group of crows is known as a murder. The name seems especially fitting for the behavior crows to display when a death occurs amongst their number. Very few animals have what is known as a grieving ritual, other than humans, of course, so the behavior of “holding a funeral” that is sometimes observed in crows is particularly intriguing (4).
Crows flock to members of their own species after death and may interact with the dead bird in a variety of ways. Although the behavior may look like mourning, scientists believe it serves other purposes as well. Crows are incredibly intelligent and maybe trying to learn from the situation at hand, trying to ascertain both what may have befallen their comrade, and whether they need to be on the watch for new predators (5).
As the incredibly clever birds they are, crows also share information and use these funerals as a way to both gather information and redistribute it amongst the group allowing individuals to respond and adapt to environmental changes immediately (6). Their ability to categorize the information gleaned from a crow funeral, or griefing, is critical to their survival that depends on differentiating friend from foe.
Just before dark, you may start to see large swarms of crows gathering and descending on one common location. Flying back and forth, they seem to flit from branch to branch as more feathered friends arrive. You’ll hear crows squawking and maybe even fighting as individuals jostle for position in a large tree or urban structure.
This phenomenon, known as roosting, is when a large number of birds congregate into a single group to sleep (7). So where do crows sleep and what is a crow roost? Crows gather in large numbers to sleep for a variety of reasons. Experts believe that these large gatherings of crows may provide warmth, protection, social opportunities, and a chance to share knowledge about food sources. Before heading to the roost, smaller groups of crows gather in what’s known as staging areas, rather than flying directly to the roost.
During the day, these groups may be spread out over a much wider area, but come together for communal roosting at dark. Although little is known about the exact reasons for these communal roosts, they are often made up largely of younger, unmated birds without their own territory although all crows will join a roost, numbers peak in winter and decline as breeding season approaches.
Other possible reasons
Crows have been gathering in large swarms and roosts for as long as there have been crows. Roosts can range in size from several hundred birds to numbers in the hundreds of thousands and can be located almost anywhere – remaining stable for years if they are left undisturbed (8).
They will travel long distances to reach their nightly roosts and even though we don’t know exactly why crows congregate in such large groups, there are a number of hypotheses that have been presented. The most prevalent hypothesis is simply needs-based.
All members have the same needs (protection from predators and elements, suitable spot, etc.), so it makes sense for them to gather in a spot where all their needs can be met in the same place. Along this same line of thinking, there is safety in numbers, and large communal roosts offer individual members protection from predators they wouldn’t otherwise afford.
Most experts agree, however, that large communal roosts serve some sort of information center function (9). Crows are incredibly intelligent birds that are able to learn new information and adapt their behaviors accordingly. Communal roosts provide members an opportunity to share information about rich food sources as well as the people and places to avoid.
What attracts crows to an area?
Crows are opportunistic birds known for their intelligence and adaptability, so it’s little wonder that they can be found in a variety of habitats (10). Although American Crows prefer open areas such as agricultural land and grasslands with trees nearby, but they thrive in urban and suburban areas as well.
Crows are opportunistic birds that thrive in habitats we create, so as agriculture and urbanization spread throughout the world, so did crows. Given that crows are omnivores, they have a variety of food sources available to them and will be most likely drawn to stable and predictable food sources. Once thought to be a major pest to crops, crows can also prevent damage by eating injurious insects and pests in the area (11). Natural foragers crows also clean up dead animals and garbage, so securing trash and compost can be a natural deterrent.
Because of their omnivorous nature, crows often come for one food source, such as a crop or garden produce, and stay for another like the insects found near them. Due to their incredibly smart and intelligent ways, keeping crows away from areas they aren’t wanted can be a time consuming and aggressive activity. Once crows are settled in an area, it can be a daunting task to convince them to leave.
Crow behavior has been a source of scrutiny and curiosity for almost as long as there have been crows. They have long had an unfortunate association with death and the macabre, perhaps because their behavior was misunderstood for a long time or perhaps because they, as a group, they are known as a murder.
Originally cast aside in the animal intelligence world, crows rank amongst the most intelligent birds and have a number of highly intelligent behaviors like recognition, social learning, deceit, and language (12). They are now known for their problem-solving and communication skills and much research exists to highlight this fact. Most interesting to come from this research are some of the common behaviors of crows and why they exist. Although some crows are solitary, they come together in groups for feeding, roosting, and social interaction.
For instance, when one dies, the group will surround the deceased, circling, and cawing to both mourn the dead and find out what killed their feathered friend. In a behavior known as mobbing, they will even band together and chase predators away once they have determined the threat. Highly intelligent creatures crow not only recognize individual humans but learn from one another as to the safety of that interaction. Crow behavior continues to be a fascinating source of study for scientists.