adaptation, 31
Aeschylus, death of, 186
Aeschylus on vultures, 172
ani, feeding rates of, 168
anointing feathers, 25
anting, 27
anvil, thrush's, 15
apartment houses, 77
Arctic fox and snowy owl, 49
association of: burrowing owl, prairie dog, snake, 73
lizard, petrel, 75
parrot, duck, opossum, 75
social weaver, falcon, 74
baby sitters, 35
bad and good birds, 152
bathing in dust, 204
bathing in snow, 204
bathing in water, 22, 205
beehives, guiding to, 125
beeswax as bird food, 125
bird of paradise, 162
boat names, 84
booming of nighthawk, 135
bower, painting of, 16
brigands, birds as, 19
brush turkey, 54
bucket drawing by jay, 190
buried eggs, 45
buried young, 45
cassowaries swim, 149
cattle disease and oxpeckers, 129
_Chicago Tribune_ farm, 151
cliff dwellers, 78
colony, mixed, 73
colony nesters, 77
color, change in jay, 164
color and palatability, 63
communistic care of young, 37
community nests, 35
conditioning, 136
conservation, 151
co-operation, 117
co-operation: birds and monkeys, 51-53
cow and ani, 167
in carrying prey, 118
in fishing by pelican, 118
in killing skunk, 119
co-op nursery, 35
cormorant: fishing with, 57
training, 58
cosmetics, various, 26
counting, of photographers, 193
distinguishing more from less, 193
courtship feeding, 195
function of, 197
significance of, 195
covering eggs: by eider duck, 47
by grebe, 47
cows, use as hunting dogs, 167
credit and snowy owl, 48
cripples, cared for, 201
crocodile bird, 45
crow, intelligence of, 98
crows profit by experience, 99
curiosity, 210
dangerous prey, 198
death: caused by clam, 199
by porcupine, 202
by spiders, 200
decoration: function of, 209
in nests, 207
snakeskin in, 113
droppings things: 186
by crows, 16
by gulls, 16, 187
by lammergeier, 186
by sparrow, 187
reason for, 188
drumming: of grouse, 134
of woodpecker, 133
drunkenness, 32
duck, muscovy, 162
ecological competition, 173
eggs: buried, 55
covered, 46, 47
in other birds' nests, 91
specializations, 93
eider down, 71
environment modifies heredity, 139
Eskimo, credit to, 48
experience: crows profit by, 99
learning by, 189
feathers: and size of bird, 67
and temperature, 67
number of, 66
feeding rates of ani, 168
fish eats bird, 95
fishing with cormorants, 57
flavor of flesh, 63, 142
flesh: flavor of, 63, 142
poisonous, 141
fluctuations in the Arctic, 48
food: impaling of by shrike, 61
storage of, 32, 61
foster parents, 93
foster young, specialization in, 93
foxing, 166
frogs mistaken for birds, 109
gardens: animal, 183
ecological balance in, 153
of Arctic fox, 185
good and bad birds, 152
grackles, character of, 152
graveyards: 180
in hollow tree, 181
on island, 182
penguins', 180
green hunting jay, 164
guarding birds' nests, by insects, 121
guides to honey, 124
hair pulling, 102
helpers at nesting time, 81
heredity modified by environment, 139
hibernation, 108
honey guides: 124
lead to big game, 125
hornbills' nests, 42
households, mixed, 73
identification: caution in making, 161
errors in, 161
over the telephone, 160
sight, 161
incubation, artificial, 56
incubators, bird-made, 54
infantile behavior modified, 137
inquisitive birds, 210
instrumental music, 133
intelligence, comparative, 98
intoxication, 32
jays: change of color in, 164
helping at nest, 81
kingfisher: a painting of, 143
classical allusions to, 145
on the telephone, 143
variation in, 144
lammergeier and Aeschylus, 186
larder, shrike's, 60
laughing jackass, voice of, 145
learning, 189
lemming and Arctic fox, 49
lichens and birds, 184
listing of birds, early, 171
maladaptation, 31
megapode nesting, 54
migration, 28
mixed households, 73
monkey birds: 51
and birds, various, 52-53
mound builder and nest, 54
music, instrumental, 133
names: appropriateness, 51, 85
available scientific, 85
domestic and foreign, 157
euphony needed, 84
for boats, 84
how given, 51
natural selection not operating, 203
nests: co-operative, 79
decoration of, 207
Guarded by insects, 121
helpers at, 81
in soup, 38, 48
last year's, 69
leaves in, 207
megapodes, 54
parasitism, 91
secondhand, 69
subleases on, 69
transportation of, 28
use by man, 71
use of snakeskin in, 111
walled, of hornbill, 42--44
nest building, co-operative, 79
nidification, reptile type, 56
nursery, 35
oil glands, 25
owl, and toad, 190
owl, intelligence of, 98
oxpecker: 127
value to herds, 128
painting a kingfisher, 143
painting of bower, 16
palatability, 63
penguins, maternal, 36
people, birds perching on, 102
pilfering: 104
by grackle, 106
by kingfisher, 105
by shrike, 105
by starling, 105
poison fruit, 31
poisonous birds, 140
poor-will in hibernation, 109
powder down, 26
preening, 25
probe, used by finch, 17
references, 213
retarded development, 137
rhino bird, 128
robbery: by birds, 19,104
by eagle, 19, 20
by frigate bird, 20
by raven, 99
by skua, 21
Rome, founding of, 171
Romulus and Remus as bird watchers, 171
Salvador bird voices, 157
sand grouse carrying water, 178
sea serpents: identification of, 147
in Kenya, 148
in New Guinea, 148
sentinel of the monkey, 53
sewing nests, 89
sexes: battle of, 173
different diets of, 175
sexual differences, ecological significance of, 173
shrike's larder, 60
shrike, young, infantile behavior prolonged, 137
slave of the monkeys, 52
snails, broken on anvil, 15
snakeskins: in nests, 111
as decorations, 112
bibliographic work on use of, 114
reasons for using, 115
theories of use, 113
snowy owl, as trade index, 49
social parasites, 33, 91
soothsayers use birds, 172
sounds produced mechanically, 134
soup, birds'-nest, 38
storage: of acorns, 32
of fish, 33
survival of unfit, 201
swifts' nests, 38-41
symbiosis, 73
tables turned, 198
tailorbirds, 89
tameness, 101
taste in birds, 189
telephone: conversations on, 143, 151
identification over, 160
theft, petty, 104
thrush, breaking snail's shell, 15
tick bird, 128
ticks, food of oxpecker, 128
tolling of ducks, 211
tool, use of, 15
torpidity, 108
trade index, snowy owls as, 49
unfit survive, 201
vegetation and penguins, 183
washing food: 154
reasons for, 156
watchdogs at nests, 121
water: carried by birds, 46, 178
flights to, 178
need of, 177
weaving nests, 88
wing music of owl, 134
wings: use of, 130
in feeding, 131
winnowing of snipe, 134
wisdom, owl, symbol of, 98
young: buried, 45
communistic care of, 37
fed by other young, 81, 203
honey-guide's, 33
independent from hatching, 55
* * * * *