Eurasian Tree Sparrow
(Passer montanus)
The Eurasian Tree Sparrow is a passerine bird (also called a song bird) of the sparrow family. It is somewhat smaller and much more shy than the house sparrow. It lives in many parts of Asia and all over Europe with the exception of Iceland and central and northern Scandinavia. The sociable Eurasian Tree Sparrow winters with buntings and finches in integrated flocks. The adult birds feed mainly on seeds of herbs, grass and grain.
For brooding the Eurasian Tree Sparrow builds a rather untidy nest with an entrance at the side. The nest is typically located in cavities of old trees and constructed of stems, feathers, leaves and even flowers. The female lays four to six eggs and broods for 11 to 13 days. Some mates stay together for a lifetime and even use the same cavity for years in a row while other Eurasian Tree Sparrow males court a new female every spring.
Catapult and Jackknife *
Can you be patient a little longer? Take another look at my feet! They don’t look like much, but they’re really a fairly refined design. It’s true: all you can see are my feet and toes. The rest of my leg, calf, knee and thigh, are all hidden in my body. And if you think I’m standing upright, I’m actually crouching with my knees bent. For you, this position might be uncomfortable, but not for me. If I suddenly straighten my knees out, my muscles launch me upwards like a catapult, and I immediately put my wings into action. During flight, I simply retract my “landing gear” up under my feathers, and extend it again when I’m ready to land. Here again, its high elasticity is most helpful.
Have you ever stopped to wonder how I can sit for hours at a time on a twig, and can even sleep in this position? My Creator made that possible by means of a very special mechanism, which automatically wraps my toes around the branch so that they hold on tight. A whole bundle of ligaments are connected from the toes to the thigh muscle. If I sit on a branch, these ligaments are tightened simply by my body weight, and they pull the toes together. Besides that, at a certain place on the ligaments there are tiny hooks. When I sit down, these hooks fasten themselves firmly into tiny teeth – again, this is no accident – exactly in the right place in the coating of the ligament sheath. So the ligaments remain under tension, without any effort on my part, and I don’t fall from the tree.
For long-legged birds like storks and herons, who have to stand for long periods of time, the design is a little bit different. They have been given a special knee joint that engages like a jackknife. So they have no problem standing for hours.
continued: The Art of Brooding
* quotes from the book "If Animals Could Talk"
