- Do you have questions about birds, bugs, bees, butterflies or other wildlife? Send your questions to Wild Things and we will try to find the answers.
Claire B. writes: “Hello, we love you guys. Longtime fans. We just moved to Camberville and we have a tree in our yard. Two squirrels are always chasing each other on our tree. Are they having fun? Or are they mad at each other? Are they having a turf war? Are they flirting? Please tell us. Thanks!”
These are very good questions, and any of reasons you listed could be true depending on the time of year, the age of the squirrels, whether there is a nest in your tree and other factors. There are clues to look for that can help you determine what is going on. Eastern gray squirrels (Sciurus carolinensis) most often chase each other for one of four reasons.
Mating. Male squirrels chase females during mating season. Females are in heat for only a few hours twice a year, so males get excited when this occurs. The male smells the branches that the female has traveled over to determine that it is time. He and possibly other potential suiters chase the female for an extended period – sometimes for hours. They run up and down trees and jump from branch to branch. The largest and most dominant male usually chases the longest and wins the female’s heart. (This makes sense because the female wants the fittest male to father her offspring.) Mating takes less than a minute, and then the squirrels settle down again.
In one study, the four most dominant males (of 18 males in one woodlot) mated with 65 percent of the females. These mating chases usually occur in February and June in Massachusetts. Other than this brief period, males and females do not associate with each other. They do not form pair bonds like many other species.
Males and females share the building of nests, called dreys, for warmth and protection from the elements. These nests are large – a foot or more in diameter, about 20 feet up in a tree that produces nuts or seeds, such as an oak, hickory, maple, elm or beech. If you see a poorly built nest, it was probably done by a male. A female has to build a nest good enough to protect herself and her offspring. If food is abundant, females have two litters of about four kits each in about April and August. Only about one in four young squirrels survives to reach its first birthday. About half of those remaining will reach their second birthday. After this, about two-thirds survive each year.
Dominance. Gray squirrels have social hierarchies. Larger, older squirrels are dominant. They will chase younger, smaller squirrels away from bird feeders. They will also chase young squirrels away from food on the ground, in trees or in dumpsters. Squirrels understand the social hierarchy, so there is not a great deal of conflict. Younger squirrels avoid the older ones. If a young squirrel eats from a bird feeder, for example, it will keep a close watch out for the approach of another squirrel. If an older squirrel comes along, the young squirrel rushes off before an altercation can ensue. Young squirrels are so skittish, in fact, that if one eats from a bird feeder when another young squirrel approaches, they’re both likely to run away.
Defending territory. Gray squirrels are not as territorial as other species of squirrels, and their territories often overlap without too much squabbling. If a squirrel gets too close to a female’s nest, though, the female will chase the intruder away. Female squirrels with youngsters will not allow other squirrels near the nest or the young. Once squirrels venture out from the nest at six or seven weeks, they don’t follow the mother around but do tend to stay in her general vicinity, as she will defend them against intruders. The mother squirrel weans her youngsters at about 12 weeks. At this point, she may move back into an old nest, leaving her youngsters to fend for themselves. If food is abundant, she may prepare for a second litter. Squirrels from the second litter born in late summer often overwinter with mom.
Play. Young squirrel siblings are playful and chase each other around for fun. They are practicing adult squirrel behaviors but in a safe environment. Their playful actions help their brain develop pathways that will be needed in adulthood.
So to answer your question: Why are two squirrels chasing each other in your tree? I do not know for sure, but if a mama squirrel has a nest in your tree, she is probably chasing away other squirrels that get too close to her nest. It’s also possible that two sibling squirrels from an April litter are playing, practicing their adult running, jumping and chasing behaviors. If there is mast (nuts, seeds, fruit) in the tree, one squirrel may be chasing another away from the food. Unless the chase you observed was long and occurred in June, it is unlikely the chase was a mating chase.
Reader photo
Alan Nazerian of Chicago spotted this eastern comma butterfly recently in DuPage County, Illinois.
Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name and the general location where the photo was taken.
Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.
A stronger
Please consider making a financial contribution to maintain, expand and improve Cambridge Day.
We are now a 501(c)3 nonprofit and all donations are tax deductible.
Please consider a recurring contribution.