INDEX 



{All numbers refer to pages. Numbers in heavy type indicate pages 

 on which figures occur) 



Activity, 6, 7. 



Adaptations to flight, 6-12. 



Air-sacs, 11. 



Alaska, 68, 92. 



Alberta, 7, 50, 61, 76, 92, 93, 96, 



111, 116, 128, 129, 135, 136 

 Altitude and land marks, 82. 

 Amphibia, 9, 47. 

 Anatomy of birds, 5-44. 

 Antarctica, 68. 

 Apes, 16. 



Archaeopteryx, 64, 67, 68, 103 

 Archaeornis, 64, 68, 103. 

 Arctic tern, 107. 



Balance, organs of, 29. 



Barometric pressure, 114, 129. 



Bats, 9, 10. 



Bavaria, 64, 68. 



Black-billed cuckoo, 97. 



Bluebird, 131. 



Bobolink, 42. 



Bone, 11. 



Brain, 13, 16-19, 20, 21, 22. 



Brain-stem, 17. 



Budgerigar, 56. 



Calcarius lapponicus, 95. 



Canary, 23, 24, 56. 



Captivity, behavior of birds in, 

 7, 55, 116, 130. 



Castration, effects of, 43, 139. 



Cere, 29. 



Cerebellum, 18. 



Cerebral cortex, 19. 



hemisphere, 19. 



Chordeiles virginianus, 106. 



Cinclus cinclus, 23. 



Climate, northern, 53 et seq. 



, of the past, 67-74. 



Coccyzus erythropthalmus, 97. 



Cochlea, 33. 



Collicuh, 33 



Coloeus monedula, 23. 



Color of leaves as stimulus to mi- 

 gration, 115. 



Color-vision, 35. 



Columella, 33. 



Cones (of retina), 34, 35. 



Cornea, 34. 



Corpus callosum, 20. 



striatum, 21. 



Correlation centre, 18. 



147 



