Why Do Bluebirds Attack Squirrels?

by Derrick | Last Updated: December 6, 2020

Bluebirds are very pleasant looking birds and the blue color gives them almost a peaceful look.  But like any wild animal if you mess with the animals home or young they will do everything they can to repel the threat including attacking the aggressor.

Why do bluebirds attack squirrels? The short answer to that question is that often, squirrels manage to get into a bluebird’s nest and eat the bird’s eggs and even young bluebird chicks and hatchlings. Sometimes, they can go as far as taking up residence in a bluebird’s nest after it invades it and kills its young ones. So, to keep predators like squirrels and other rodents away, bluebirds, mostly the male ones, will fight them, to protect its nest, eggs, hatchlings and mate.

Predators to Bluebirds

Raccoons, large rats, chipmunks and squirrels pose a great threat to bluebirds and their nests. Birds like sparrows have a particular enmity with bluebirds, after squirrels, of course. Other predators include cats, snakes, frogs and even coyotes.

Do squirrels eat bluebird eggs?

Yes, squirrels will eat the eggs of bluebirds, generally they will not eat bluebird hatchlings.

The most carnivorous of its kind are red squirrels. They are intelligent and are deft climbers that can climb into the nests or birdhouse holes in gardens where bluebirds have made their nests and get to their eggs and chicks.

Signs that a squirrel has managed to get into a bluebird’s nest include:

Missing or broken shells of eggs
Broken nest or parts of the nest like twigs and leaves on the ground
Nest hole is enlarged or damaged
Nestlings partially eaten or missing
Even, occasionally, a dead adult

Why do bluebirds attack?

Bluebirds come off as elegant and gentle birds, who appear to be poor fighters when compared to other birds like sparrows or even starlings, crows and pigeons.

Believe it or not, male bluebirds keep an eye out to make sure the female bluebirds stay monogamous. They guard their mates very closely and will know if their significant other has stepped out on them. Male-male bluebirds fight and show aggression mostly to assure and defend the paternity of their hatchlings and these battles can become quite intense, and sometimes be fatal or crippling.

Another reason for bluebirds to fight is, of course, to protect their nests, eggs or chicks from predators. During the spring and summer months, when the bluebirds nest, they get protective of their nests and guard it from prey.

If a squirrel gets too close to the nest, it will either be quickly chased off by the bluebird- usually the male bluebird- or if it is particularly persistent, a rather nasty scuffle will ensue between the two. As squirrels are known to attack and invade nests when they are empty of the parent bluebirds, either the male or the female will try to stay in the nest with the eggs or chicks at all times, while the other forages for food and keeps an eye out for predators.

Will a squirrel kill a bird?

Yes, squirrels sometimes do kill birds. It depends largely on how big the bird is, in relation to how big the squirrel is.

Squirrels will pick fights with birds either smaller or at least the same size as itself, and will not venture into the nests of, or dare fight with larger birds, out of fear that it will get injured or killed in the process.

However, it must be noted that squirrels are primarily nest invaders, and egg or chick eaters. They mostly only kill and subsequently eat grown birds when they get into a fight trying to get into those nests to eat the eggs. They are not picky when it comes to their meals. While they are largely vegetarian and their diet consists mostly of acorns, nuts, lichens, fruits, roots, mushrooms, leaves and even insects, they do kill and eat birds too.

Why do squirrels eat birds? Squirrels, especially red squirrels, according to research, have a streak of vicious aggressiveness that make them kill their own pups.  Researchers believe that squirrels have been taught, over years and years in the wild, that only the fittest survive, and these little rodents will do anything to get food and to survive.

How to keep squirrels away from bluebirds’ nest and eggs

To restrict squirrels from getting to bluebirds’ nests, at least if the nests happen to be in your yard or you have a feeder or birdhouse at home, you can take certain precautions.

Add a predator guard like wobbling baffles or a pole.

Do not mount your birdhouse on a tree or on a fence or postline that will give the squirrel easy access to climb into it.

Place your birdhouse at least 6-10 feet away from anything a squirrel can jump off of and onto it.

Grease the pole of the bird house with butter or soap, so squirrels can’t climb up.

Consider putting up a feeder for squirrels, with rodent blocks or nuts, well away from the nests.

Lastly, if the bluebirds are nested in a bird house you an put sheet metal around the bird house hole this will prevent the squirrel from chewing the hole wider allowing them to get to the bluebird eggs.