About the size of an English sparrow; bill very small, triangular, much broader than high, without bristles; wings long and pointed; legs short; feet weak; tail very short, ending in stiff spines; plumage compact. (Ridgway.) Food: entirely insects. Sexes alike. Found in the air or inside chimneys or hollow trees. 21. Caprimulgidæ: GOATSUCKERS. Larger than a robin; bill very short; gape enormously long and wide; mouth open to behind the eyes; wings long; plumage soft. (Ridgway.) Food: insects. Sexes nearly alike. One species found in the edge of woods, and another species about towns. 22. Picidæ: WOODPECKERS. Larger than an English sparrow; bill usually straight, pointed or chisel-shaped at tip; tongue extensile and except in one species barbed at point; tail stiff and feathers pointed at tip for a prop; toes, except in three-toed species, two forward and two backward for climbing. (Ridgway.) Insectivorous. Sexes unlike. Found on trees (except one species) in woods or orchards. 23. Alcedinidæ: KINGFISHERS. Usually larger than a robin; bill long and straight; tongue small; head large, crested; wings short; legs small; outer and middle toe united half their length. (Ridgway.) Food: fishes. Sexes slightly unlike. Found by water. 24. Cuculidæ: CUCKOOS. Larger than a robin; bill narrow and high, rather long and curved downward; wings long; tail long, soft, and rounded; toes in pairs. (Ridgway.) Insectivorous. Sexes alike. Found on trees. 25. Bubonidæ: OWLS. Mostly larger than a robin, a few smaller; bill hooked; eyes directed forward and surrounded by radiating feathers; plumage soft and lax; feathers beside forehead often stand up like ear tufts; legs usually feathered; feet sometimes feathered. (Ridgway.) Sexes alike. Flesh eaters. Usually nocturnal. Most species found in holes in trees or old buildings. 26. Strigidæ: BARN OWLS. Much larger than a robin; bill hooked; eyes very small; triangular-shaped eye disk; tail emarginate; claws sharp and strong; very downy plumage. (Ridgway). Food: mice and other small mammals. Sexes alike. Exclusively nocturnal. Found in barns and deserted buildings. 27. Falconidæ: HAWKS AND EAGLES. (There are several subfamilies.) Mostly very large birds; bill strongly hooked; eyes directed sideways; eyelids with lashes; toes never feathered. (Ridgway.) Carnivorous and insectivorous. Sexes usually alike, but female larger. 28. Cathartidæ: AMERICAN VULTURES. Large as a turkey, one species much larger; whole head and sometimes neck bare of feathers; eyes prominent; tail rounded. (Ridgway.) Food: carrion. Found sailing about in the air. INDEX References to the FIRST BOOK are indicated by ~1~; those to the SECOND BOOK by ~2~. Affections, ~1~, 78-82. Air-sacs, ~1~, 92, 94. Alaudidæ, ~2~, 131, 202. Alcedinidæ, ~2~, 170, 203. Ampelidæ, ~2~, 63, 200. Arrival in spring, ~1~, 3, 4. Attraction and Protection of Birds, ~1~, 131-135. Audubon, John James, ~1~, 60.