Mentioning the flight of the pigeon leads me to consider that of other birds. All other animals have one determinate mode of progression, which in every kind is always the same; birds alone have two modes of moving—on the ground, and in the air. Some of them walk, such as the crow, for instance; some hop¹, as the sparrow and the blackbird; some run, as the partridge and the woodhen; while others throw one foot before the other, like the stork² and the crane. Then again, in their flight, some birds expand their wings, and poising³ themselves in the air, only move them from time to time; others move them more frequently, but then only at the extremities⁴; while others expand them so as to expose the whole of the side. On the other hand, some fly with the greater part of the wings kept close to the side; and some, after striking the air once, others twice, make their way through it, as though pressing upon it enclosed beneath their wings; other birds dart⁵ aloft in a vertical⁶ direction, others horizontally, and others come falling straight downwards⁷. You would almost think that some had been hurled⁸ upwards⁹ with a violent effort, and that others had fallen straight down from aloft; while others still are seen to spring forward in their flight. Ducks alone, and the other birds of that kind, in an instant raise themselves aloft, taking a spring from the spot where they stand straight upwards towards the heavens; and this they can do directly from the water. They are the 216 only birds that can make their escape from the pitfalls¹⁰ which we employ for the capture of wild beasts.

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