Fig. 3.4.

Visual fields of different species. The top image of the cattle egret is a typical visual field for most birds (with some variations). The binocular field in front of the eyes (3) is small but so is the blind area behind the head (1) important for detection of predators. The wedge-tailed eagle, on the top of the food chain, has a much larger blind area and even a smaller range of vision in the vertical field than most birds. The tawny frogmouth belongs to the small range of birds (largely nocturnal) with a very wide binocular field, sacrificing vision in the monocular field (2).