Fun Facts About American Tree Sparrows

The American Tree Sparrow’s name is somewhat misleading due to the fact that the breeding grounds for most of these birds are found in the treeless tundra habitats of the far north. Early settlers, seeing the birds on their southern wintering grounds, named them for their similar appearance to the Eurasian Tree Sparrows they left behind in Europe.
American Tree Sparrows are known to eat large amounts of common weed seeds. Each year they are estimated to eat 875 tons of the weed seeds in the state of Iowa alone.
American Tree Sparrows eat almost 100% animal matter (mostly insects) during the summer. In the winter they switch entirely to seeds and other plant foods.
When the ground is snow covered, American Tree Sparrows have been observed to fly around a weed plant, using their wings to dislodge its seeds onto the snow below for easy retrieval.
Studies have proven that increasing day length is what triggers reproductive activities in American Tree Sparrows. However, vision apparently plays no role in this phenomenon. Blind tree sparrows demonstrate the same reactions to increased day length as do birds with sight.
An American Tree Sparrow eats about 30% of its own body weight in food every day during the summer. They also drink about 30% of their own body weight of water each day.
No one knows for sure, but some estimates project that there may be as many as 10 to 20 million pairs of American Tree Sparrows nesting across a vast expanse of northern Canada and Alaska.
Which is your dominant eye? A recent study found that American Tree Sparrows seems to prefer to look for predators out of their left eye, while Dark-eyed Juncos prefer their right.
American Tree Sparrows migrate in flocks at night.
Bird banding records show that the longevity record for the American Tree Sparrow is 10 years and 9 months.