When a bird is perching or walking on the ground, it is almost never standing with its legs under the entirety of its body. A bird is like a rectangular box who

When a bird is perching or walking on the ground, it is almost never standing with its legs under the entirety of its body. A bird is like a rectangular box whose long axis is parallel to the ground with two sticks just slightly aft. In contrast, a standing human has a rectangular torso whose long axis is at 90 degrees to the ground with the legs coming out of one end. To see this, do an image search for an Ostrich, which shows the 'box' effect perfectly. Smaller birds have a body box that is often at more of an angle to the ground, and with legs that are tiny compared with a human's. The bird's hips are near the back of the box but there are usually bones behind them, which is where the tail is mounted. The equivalent of the femur is tilted forward and short compared with a human's, and a bird's sternum may actually be between and below the equivalent of our knees. Very different anatomy.