This is an instance of a concept.
The squirrel belongs to the Sciuridae family. We only have one type of squirrel in our garden, the red squirrel. Squirrels are abundant in my garden, and we see several every day.
Our squirrels love to sit on the birdhouses. As you can see in the picture below, the birdhouses get tilted from squirrels sitting on one side.
At the moment it is autumn, and many of our squirrels are busy collecting nuts for winter. As a gardener, this is problematic as many of the buried nuts will sprout to produce small trees next summer, generally in places where you do not want trees.
To learn more about squirrels, you can check the following link.