Weird Squirrel Behavior: A Reference Question

From the Ask a Librarian Reference Desk:

“The squirrels in my neighborhood are clipping little twigs off of ornamental trees and throwing them on the ground. So many twigs everywhere! Why are they doing this?”

Dear Patron,

Thank you for contacting The Seattle Public Library for assistance unraveling your squirrel-related mystery! Experts in squirrel behavior, such as the folks who work for University Extension programs and wildlife organizations, are not entirely sure why squirrels do this. They have two main theories:

1. They’re eating parts of the tree — The cambium layer beneath the bark of trees is rich in minerals and other nutrients, which can be in short supply during winter. Squirrels may be trimming branches and peeling bark to gain access to this food supply. (See the University Extension Ask an Expert database and Michigan State University Extension.)
2. They’re cutting clippings for nesting material – Some Squirrels build nests, called “dreys,” in tree branches using a combination of leaves, twigs, bark and other vegetation. Some even build two or three nests at one time, to create multiple avenues of shelter and escape.  It could be that your squirrels have a construction project and are throwing rejected building materials on the ground below. (West Virginia Wildlife Magazine speaks to this.)

Many observers also note that squirrels are rodents, whose teeth must be worn down constantly because they never stop growing. Others note that squirrels… well, that squirrels are simply little rascals. Whether this is frustrating or endearing is in the eye of the beholder.

To learn more about squirrel behavior, check out these books and other materials available through The Seattle Public Library!

• A Squirrel’s Guide to Success (DVD – 2008) — “There are almost 300 species of squirrels that can glide through the air, outwit rattlesnakes, and survive the coldest temperatures of any mammal. Uncover the extraordinary abilities of these cheeky nut lovers as a filmmaker puts their problem solving to the test on a specially designed obstacle course.”
• Squirrels: The Animal Answer Guide, by Richard Thorington (Book – 2006) — “Thorington and Ferrell cover every aspect of this diverse animal family, from the first squirrels of 36 million years ago to the present day. With over one hundred photographs and an intuitive question-and-answer format, this authoritative and engaging guide sheds light on a common mammal that is anything but commonplace.”
• Squirrels of North America, by Tamara Eder (Book – 2009) — “This guide describes 66 species of the squirrel family (Sciuridae) found in the United States and Canada. The brief descriptions for each species include information on where they may be found, their eating, nesting, and wintering habits as well as size, coloring and identifying marks.”

Thank you for your question, and best of luck with your squirrel neighbors! Please let us know if we can be of any further assistance, with this or any other question.

Sincerely,
Anne
The Seattle Public Library
Reference Services