32 Cuvier, ‘Règne Animal,’ vol. ii. 1829, p. 242.

33 See Mr. Warington’s most interesting description of the habits of the Gasterosteus leiurus, in ‘Annals and Mag. of Nat. Hist.’ November, 1855.

34 Prof. Wyman, in ‘Proc. Boston Soc. of Nat. Hist.’ Sept. 15, 1857. Also W. Turner, in ‘Journal of Anatomy and Phys.’ Nov. 1, 1866, p. 78. Dr. Günther has likewise described other cases.

35 Yarrell, ‘Hist. of British Fishes,’ vol. ii. 1836, p. 329, 338.

36 Dr. Günther, since publishing an account of this species in ‘The Fishes of Zanzibar,’ by Col. Playfair, 1866, p. 137, has re-examined the specimens, and has given me the above information.

37 The Rev. C. Kingsley, in ‘Nature,’ May, 1870, p. 40.

38 Bell, ‘History of British Reptiles,’ 2nd edit. 1849, p. 156-159.

39 Bell, ibid. p. 146, 151.

40 ‘Zoology of the Voyage of the “Beagle,”’ 1843. “Reptiles,” by Mr. Bell, p. 49.

41 ‘The Reptiles of India,’ by Dr. A. Günther, Ray Soc. 1864, p. 413.

42 Bell, ‘History of British Reptiles,’ 1849, p. 93.

43 J. Bishop, in ‘Todd’s Cyclop. of Anat. and Phys.’ vol. iv. p. 1503.

44 Bell, ibid. p. 112-114.

45 Mr. C. J. Maynard, ‘The American Naturalist,’ Dec. 1869, p. 555.

46 See my ‘Journal of Researches during the Voyage of the “Beagle,”’ 1845, p. 384.

47 ‘Travels through Carolina,’ &c., 1791, p. 128.

48 Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615.

49 Sir Andrew Smith, ‘Zoolog. of S. Africa: Reptilia,’ 1849, pl. x.

50 Dr. A. Günther, ‘Reptiles of British India,’ Ray Soc. 1864, p. 304, 308.

51 Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615.

52 The celebrated botanist Schleiden incidently remarks (‘Ueber den Darwinismus: Unsere Zeit,’ 1869, s. 269), that Rattle-snakes use their rattles as a sexual call, by which the two sexes find each other. I do not know whether this suggestion rests on any direct observations. These snakes pair in the Zoological Gardens, but the keepers have never observed that they use their rattles at this season more than at any other.

53 “Rambles in Ceylon,” ‘Annals and Mag. of Nat. Hist.’ 2nd series, vol. ix. 1852, p. 333.

54 ‘Westminster Review,’ July 1st, 1867, p. 32.

55 Mr. N. L. Austen kept these animals alive for a considerable time, see ‘Land and Water,’ July, 1867, p. 9.

56 All these statements and quotations, in regard to Cophotis, Sitana and Draco, as well as the following facts in regard to Ceratophora, are taken from Dr. Günther’s magnificent work on the ‘Reptiles of British India,’ Ray Soc. 1864, p. 122, 130, 135.

57 Bell, ‘History of British Reptiles,’ 2nd edit. 1849, p. 40.

58 For Proctotretus see ‘Zoology of the Voyage of the “Beagle:” Reptiles,’ by Mr. Bell, p. 8. For the Lizards of S. Africa, see ‘Zoology of S. Africa: Reptiles,’ by Sir Andrew Smith, pl. 25 and 39. For the Indian Calotes, see ‘Reptiles of British India,’ by Dr. Günther, p. 143.

59 ‘Ibis,’ vol. iii. (new series) 1867, p. 414.

60 Gould, ‘Handbook to the Birds of Australia,’ 1865, vol. ii. p. 383.

61 Quoted by Mr. Gould, ‘Introduction to the Trochilidæ,’ 1861, p. 29.

62 Gould, ibid. p. 52.

63 W. Thompson, ‘Nat. Hist. of Ireland: Birds,’ vol. ii. 1850, p. 327.

64 Jerdon, ‘Birds of India,’ 1863, vol. ii. p. 96.

65 Macgillivray, ‘Hist. Brit. Birds,’ vol. iv. 1852, p. 177-181.

66 Sir R. Schomburgk, in ‘Journal of R. Geograph. Soc.’ vol. xiii. 1843, p. 31.

67 ‘Ornithological Biography,’ vol. i. p. 191. For pelicans and snipes, see vol. iii. p. 381, 477.

68 Gould, ‘Handbook of Birds of Australia,’ vol. i. p. 395; vol. ii. p. 383.

69 Mr. Hewitt in the ‘Poultry Book by Tegetmeier,’ 1866, p. 137.

70 Layard, ‘Annals and Mag. of Nat. Hist.’ vol. xiv. 1854, p. 63.

71 Jerdon, ‘Birds of India,’ vol. iii. p. 574.

72 Brehm, ‘Illust. Thierleben,’ 1867, B. iv. s. 351. Some of the foregoing statements are taken from L. Lloyd, ‘The Game Birds of Sweden,’ &c., 1867, p. 79.

73 Jerdon, ‘Birds of India:’ on Ithaginis, vol. iii. p. 523; on Galloperdix, p. 541.

74 For the Egyptian goose, see Macgillivray, ‘British Birds,’ vol. iv. p. 639. For Plectropterus, ‘Livingstone’s Travels,’ p. 254. For Palamedea, Brehm’s ‘Thierleben,’ B. iv. s. 740. See also on this bird Azara, 'Voyages dans l’Amérique mérid.’ tom. iv. 1809, p. 179, 253.

75 See, on our peewit, Mr. R. Carr in ‘Land and Water,’ Aug. 8th, 1868, p. 46. In regard to Lobivanellus, see Jerdon’s ‘Birds of India,’ vol. iii. p. 647, and Gould’s ‘Handbook of Birds of Australia,’ vol. ii. p. 220. For the Hoplopterus, see Mr. Allen in the ‘Ibis,’ vol. v. 1863, p. 156.

76 Audubon, ‘Ornith. Biography,’ vol. ii. p. 492; vol. i. p. 4-13.

77 Mr. Blyth, ‘Land and Water,’ 1867, p. 212.

78 Richardson, on Tetrao umbellus, ‘Fauna Bor. Amer.: Birds,’ 1831, p. 343. L. Lloyd, ‘Game Birds of Sweden,’ 1867, p. 22, 79, on the capercailzie and black-cock. Brehm, however, asserts (‘Thierleben,’ &c., B. iv. s. 352) that in Germany the grey-hens do not generally attend the Balzen of the black-cocks, but this is an exception to the common rule; possibly the hens may lie hidden in the surrounding bushes, as is known to be the case with the grey-hens in Scandinavia, and with other species in N. America.

79 ‘Ornithological Biography,’ vol. ii. p. 275.

80 Brehm, ‘Thierleben,’ &c., B. iv. 1867, p. 990. Audubon, ‘Ornith. Biography,’ vol. ii. p. 492.

81 ‘Land and Water,’ July 25th, 1868, p. 14.

82 Audubon’s ‘Ornitholog. Biography;’ on Tetrao cupido, vol. ii. p. 492; on the Sturnus, vol. ii. p. 219.

83 ‘Ornithological Biograph.’ vol. v. p. 601.

84 The Hon. Daines Barrington, ‘Philosoph. Transact.’ 1773, p. 252.

85 ‘Ornithological Dictionary,’ 1833, p. 475.

86 ‘Naturgeschichte der Stubenvögel,’ 1840, s. 4. Mr. Harrison Weir likewise writes to me:—“I am informed that the best singing males generally get a mate first when they are bred in the same room.”

87 ‘Philosophical Transactions,’ 1773, p. 263. White’s ‘Natural History of Selborne,’ vol. i. 1825, p. 246.

88 ‘Naturges. der Stubenvögel,’ 1840, s. 252.

89 Mr. Bold, ‘Zoologist,’ 1843-44, p. 659.

90 D. Barrington, ‘Phil. Transact.’ 1773, p. 262. Bechstein, ‘Stubenvögel,’ 1840, s. 4.

91 This is likewise the case with the water-ouzel, see Mr. Hepburn in the ‘Zoologist,’ 1845-1846, p. 1068.

92 L. Lloyd, ‘Game Birds of Sweden,’ 1867, p. 25.

93 Barrington, ibid. p. 264. Bechstein, ibid. s. 5.

94 Dureau de la Malle gives a curious instance (‘Annales des Sc. Nat.’ 3rd series, Zoolog. tom. x. p. 118) of some wild blackbirds in his garden in Paris which naturally learnt from a caged bird a republican air.

95 Bishop, in ‘Todd’s Cyclop. of Anat. and Phys.’ vol. iv. p. 1496.

96 As stated by Barrington in ‘Philosoph. Transact.’ 1773, p. 262.

97 Gould, ‘Handbook to the Birds of Australia,’ vol. i. 1865, p. 308-310. See also Mr. T. W. Wood in the ‘Student,’ April, 1870, p. 125.

98 See remarks to this effect in Gould’s ‘Introduction to the Trochilidæ,’ 1861, p. 22.

99 ‘The Sportsman and Naturalist in Canada,’ by Major W. Ross King, 1866, p. 144-146. Mr. T. W. Wood gives in the ‘Student’ (April, 1870, p. 116) an excellent account of the attitude and habits of this bird during its courtship. He states that the ear-tufts or neck-plumes are erected, so that they meet over the crown of the head.

100 Richardson, ‘Fauna Bor. Americana: Birds,’ 1831, p. 359. Audubon, ibid. vol. iv. p. 507.

101 The following papers have been lately written on this subject:—Prof. A. Newton, in the ‘Ibis,’ 1862, p. 107; Dr. Cullen, ibid. 1865, p. 145; Mr. Flower, in ‘Proc. Zool. Soc.’ 1865, p. 747; and Dr. Murie, in ‘Proc. Zool. Soc.’ 1868, p. 471. In this latter paper an excellent figure is given of the male Australian Bustard in full display with the sack distended.

102 Bates, ‘The Naturalist on the Amazons,’ 1863, vol. ii. p. 284; Wallace, in ‘Proc. Zool. Soc.’ 1850, p. 206. A new species, with a still larger neck-appendage (C. penduliger), has lately been discovered, see 'Ibis,’ vol. i. p. 457.

103 Bishop, in Todd’s ‘Cyclop. of Anat. and Phys.’ vol. iv. p. 1499.

104 The spoonbill (Platalea) has its trachea convoluted into a figure of eight, and yet this bird (Jerdon, ‘Birds of India,’ vol. iii. p. 763) is mute; but Mr. Blyth informs me that the convolutions are not constantly present, so that perhaps they are now tending towards abortion.

105 ‘Elements of Comp. Anat.’ by R. Wagner, Eng. translat. 1845, p. 111. With respect to the swan, as given above, Yarrell’s ‘Hist. of British Birds,’ 2nd edit. 1845, vol. iii. p. 193.

106 C. L. Bonaparte, quoted in the ‘Naturalist Library: Birds,’ vol. xiv. p. 126.

107 L. Lloyd, ‘The Game Birds of Sweden,’ &c., 1867, p. 22, 81.

108 Jenner, ‘Philosoph. Transactions,’ 1824, p. 20.

109 For the foregoing several facts see, on Birds of Paradise, Brehm, 'Thierleben,’ Band iii. s. 325. On Grouse, Richardson, ‘Fauna Bor. Americ.: Birds,’ p. 343 and 359; Major W. Ross King, ‘The Sportsman in Canada,’ 1866, p. 156; Audubon, ‘American Ornitholog. Biograph.’ vol. i. p. 216. On the Kalij pheasant, Jerdon, ‘Birds of India,’ vol. iii. p. 533. On the Weavers, ‘Livingstone’s Expedition to the Zambesi,’ 1865, p. 425. On Woodpeckers, Macgillivray, ‘Hist. of British Birds,’ vol. iii. 1840, p. 84, 88, 89, and 95. On the Hoopoe, Mr. Swinhoe, in ‘Proc. Zoolog. Soc.’ June 23, 1863. On the Night-Jar, Audubon, ibid. vol. ii. p. 255. The English Night-Jar likewise makes in the spring a curious noise during its rapid flight.

110 See M. Meves’ interesting paper in ‘Proc. Zool. Soc.’ 1858, p. 199. For the habits of the snipe, Macgillivray, ‘Hist. British Birds,’ vol. iv. p. 371. For the American snipe, Capt. Blakiston, ‘Ibis,’ vol. v. 1863, p. 131.

111 Mr. Salvin, in ‘Proc. Zool. Soc.’ 1867, p. 160. I am much indebted to this distinguished ornithologist for sketches of the feathers of the Chamæpetes, and for other information.

112 Jerdon, ‘Birds of India,’ vol. iii. p. 618, 621.

113 Gould, ‘Introduction to the Trochilidæ,’ 1861, p. 49. Salvin, 'Proc. Zoolog. Soc.’ 1867, p. 160.

114 Sclater, in ‘Proc. Zool. Soc.’ 1860, p. 90, and in ‘Ibis,’ vol. iv. 1862, p. 175. Also Salvin, in ‘Ibis,’ 1860, p. 37.

115 ‘The Nile Tributaries of Abyssinia,’ 1867, p. 203.

116 For Tetrao phasianellus, see Richardson, ‘Fauna Bor. America,’ p. 361, and for further particulars Capt. Blakiston, ‘Ibis,’ 1863, p. 125. For the Cathartes and Ardea, Audubon, ‘Ornith. Biography,’ vol. ii. p. 51, and vol. iii. p. 89. On the White-throat, Macgillivray, ‘Hist. British Birds,’ vol. ii. p. 354. On the Indian Bustard, Jerdon, ‘Birds of India,’ vol. iii. p. 618.

117 Gould, ‘Handbook to the Birds of Australia,’ vol. i. p. 444, 449, 455. The bower of the Satin Bower-bird may always be seen in the Zoological Society’s Gardens, Regent’s Park.

118 See remarks to this effect, on the “Feeling of Beauty among Animals,” by Mr. J. Shaw, in the ‘Athenæum,’ Nov. 24th, 1866, p. 681.

119 Mr. Monteiro, ‘Ibis,’ vol. iv. 1862, p. 339.

120 ‘Land and Water,’ 1868, p. 217.

121 Jardine’s ‘Naturalist Library: Birds,’ vol. xiv. p. 166.

122 Sclater, in the ‘Ibis,’ vol. vi. 1864, p. 114. Livingstone, ‘Expedition to the Zambesi,’ 1865, p. 66.

123 Jerdon, ‘Birds of India,’ vol. iii. p. 620.

124 Wallace, in ‘Annals and Mag. of Nat. Hist.’ vol. xx. 1857, p. 416; and in his ‘Malay Archipelago,’ vol. ii. 1869, p. 390.

125 See my work on ‘The Variation of Animals and Plants under Domestication,’ vol. i. p. 289, 293.

126 Quoted from M. de Lafresnaye, in ‘Annals and Mag. of Nat. Hist.’ vol. xiii. 1854, p. 157: see also Mr. Wallace’s much fuller account in vol. xx. 1857, p. 412, and in his Malay Archipelago.

127 Wallace, ‘The Malay Archipelago,’ vol. ii. 1869, p. 405.

128 Mr. Sclater, ‘Intellectual Observer,’ Jan. 1867. ‘Waterton’s Wanderings,’ p. 118. See also Mr. Salvin’s interesting paper, with a plate, in the ‘Ibis,’ 1865, p. 90.

129 ‘Land and Water,’ 1867, p. 394.

130 Mr. D. G. Elliot, in ‘Proc. Zool. Soc.’ 1869, p. 589.

131 ‘Nitzsch’s Pterylography,’ edited by P. L. Sclater. Ray Soc. 1867, p. 14.

132 The brown mottled summer plumage of the ptarmigan is of as much importance to it, as a protection, as the white winter plumage; for in Scandinavia, during the spring, when the snow has disappeared, this bird is known to suffer greatly from birds of prey, before it has acquired its summer dress: see Wilhelm von Wright, in Lloyd, ‘Game Birds of Sweden,’ 1867, p. 125.

133 In regard to the previous statements on moulting, see, on snipes, &c., Macgillivray, ‘Hist. Brit. Birds,’ vol. iv. p. 371; on Glareolæ, curlews, and bustards, Jerdon, ‘Birds of India,’ vol. iii. p. 615, 630, 683; on Totanus, ibid, p. 700; on the plumes of herons, ibid, p. 738, and Macgillivray, vol. iv. p. 435 and 444, and Mr. Stafford Allen, in the ‘Ibis,’ vol. v. 1863, p. 33.

134 On the moulting of the ptarmigan, see Gould’s ‘Birds of Great Britain.’ On the honey-suckers, Jerdon, ‘Birds of India,’ vol. i. p. 359, 365, 369. On the moulting of Anthus, see Blyth, in ‘Ibis,’ 1867, p. 32.

135 For the foregoing statements in regard to partial moults, and on old males retaining their nuptial plumage, see Jerdon, on bustards and plovers, in ‘Birds of India,’ vol. iii. p. 617, 637, 709, 711. Also Blyth in ‘Land and Water,’ 1867, p. 84. On the Vidua, ‘Ibis,’ vol. iii. 1861, p. 133. On the Drongo shrikes, Jerdon, ibid. vol. i. p. 435. On the vernal moult of the Herodias bubulcus, Mr. S. S. Allen, in ‘Ibis,’ 1863, p. 33. On Gallus bankiva, Blyth, in ‘Annals and Mag. of Nat. Hist.’ vol. i. 1848, p. 455; see, also, on this subject, my ‘Variation of Animals under Domestication,’ vol. i. p. 236.

136 See Macgillivray, ‘Hist. British Birds’ (vol. v. p. 34, 70, and 223), on the moulting of the Anatidæ, with quotations from Waterton and Montagu. Also Yarrell, ‘Hist. of British Birds,’ vol. iii. p. 243.

137 On the pelican, see Sclater, in ‘Proc. Zool. Soc.’ 1868, p. 265. On the American finches, see Audubon, ‘Ornith. Biography,’ vol. i. p. 174, 221, and Jerdon, ‘Birds of India,’ vol. ii. p. 383. On the Fringilla cannabina of Madeira, Mr. E. Vernon Harcourt, ‘Ibis,’ vol. v., 1863, p. 230.

138 See also ‘Ornamental Poultry,’ by Rev. E. S. Dixon, 1848, p. 8.

139 ‘Birds of India,’ introduct. vol. i. p. xxiv.; on the peacock, vol. iii. p. 507. See Gould’s ‘Introduction to the Trochilidæ,’ 1861, p. 15 and 111.

140 ‘Journal of R. Geograph. Soc.’ vol. x. 1840, p. 236.

141 ‘Annals and Mag. of Nat. Hist.’ vol. xiii. 1854, p. 157; also Wallace, ibid. vol. xx. 1857, p. 412, and ‘The Malay Archipelago,’ vol. ii. 1869, p. 252. Also Dr. Bennett, as quoted by Brehm, ‘Thierleben,’ B. iii. s. 326.

142 Mr. T. W. Wood has given (‘The Student,’ April, 1870, p. 115) a full account of this manner of display, which he calls the lateral or one-sided, by the gold pheasant and by the Japanese pheasant, Ph. versicolor.

143 ‘The Reign of Law,’ 1867, p. 263.

144 For the description of these birds, see Gould’s ‘Handbook to the Birds of Australia,’ vol. i. 1865, p. 417.

145 ‘Birds of India,’ vol. ii. p. 96.

146 On the Cosmetornis, see Livingstone’s ‘Expedition to the Zambesi,’ 1865, p. 66. On the Argus pheasant, Jardine’s ‘Nat. Hist. Lib.: Birds,’ vol. xiv. p. 167. On Birds of Paradise, Lesson, quoted by Brehm, 'Thierleben,’ B. iii. s. 325. On the widow-bird, Barrow’s ‘Travels in Africa,’ vol. i. p. 243, and ‘Ibis,’ vol. iii. 1861, p. 133. Mr. Gould, on the shyness of male birds, ‘Handbook to Birds of Australia,’ vol. i. 1865, p. 210, 457.

147 Tegetmeier, ‘The Poultry Book,’ 1866, p. 139.

148 Nordmann describes (‘Bull. Soc. Imp. des Nat. Moscow,’ 1861, tom. xxxiv. p. 264) the balzen of Tetrao urogalloides in Amur Land. He estimated the number of assembled males at above a hundred, the females, which lie hid in the surrounding bushes, not being counted. The noises uttered differ from those of the T. urogallus or the capercailzie.

149 With respect to the assemblages of the above named grouse see Brehm, ‘Thierleben,’ B. iv. s. 350; also L. Lloyd, ‘Game Birds of Sweden,’ 1867, p. 19, 78. Richardson, ‘Fauna Bor. Americana,’ Birds, p. 362. References in regard to the assemblages of other birds have previously been given. On Paradisea see Wallace, in ‘Annals and Mag. of Nat. Hist.’ vol. xx. 1857, p. 412. On the snipe, Lloyd, ibid. p. 221.

150 Quoted by Mr. T. W. Wood in the ‘Student,’ April, 1870, p. 125.

151 Gould, ‘Handbook of Birds of Australia,’ vol. i. p. 300, 308, 448, 451. On the ptarmigan, above alluded to, see Lloyd, ibid. p. 129.

152 On magpies, Jenner, in ‘Phil. Transact.’ 1824, p. 21. Macgillivray, 'Hist. British Birds,’ vol. i. p. 570. Thompson, in ‘Annals and Mag. of Nat. Hist.’ vol. viii. 1842, p. 494.

153 On the peregrine falcon see Thompson, ‘Nat. Hist. of Ireland: Birds,’ vol. i. 1849, p. 39. On owls, sparrows, and partridges, see White, 'Nat. Hist. of Selborne,’ edit. of 1825, vol. i. p. 139. On the Phœnicura, see Loudon’s ‘Mag. of Nat. Hist.’ vol. vii. 1834, p. 245. Brehm, 'Thierleben,’ B. iv. s. 991) also alludes to cases of birds thrice mated during same day.

154 See White (‘Nat. Hist. of Selborne,’ 1825, vol. i. p. 140) on the existence, early in the season, of small coveys of male partridges, of which fact I have heard other instances. See Jenner, on the retarded state of the generative organs in certain birds, in ‘Phil. Transact.’ 1824. In regard to birds living in triplets, I owe to Mr. Jenner Weir the cases of the starling and parrots, and to Mr. Fox, of partridges; on carrion-crows, see the ‘Field,’ 1868, p. 415. On various male birds singing after the proper period, see Rev. L. Jenyns, ‘Observations in Natural History,’ 1846, p. 87.

155 The following case has been given (‘The Times,’ Aug. 6th, 1868) by the Rev. F. O. Morris, on the authority of the Hon. and Rev. O. W. Forester. “The gamekeeper here found a hawk’s nest this year, with five young ones in it. He took four and killed them, but left one with its wings clipped as a decoy to destroy the old ones by. They were both shot next day, in the act of feeding the young one, and the keeper thought it was done with. The next day he came again and found two other charitable hawks, who had come with an adopted feeling to succour the orphan. These two he killed, and then left the nest. On returning afterwards he found two more charitable individuals on the same errand of mercy. One of these he killed; the other he also shot, but could not find. No more came on the like fruitless errand.”

156 For instance, Mr. Yarrell states (‘Hist. British Birds,’ vol. iii. 1845, p. 585) that a gull was not able to swallow a small bird which had been given to it. The gull “paused for a moment, and then, as if suddenly recollecting himself, ran off at full speed to a pan of water, shook the bird about in it until well soaked, and immediately gulped it down. Since that time he invariably has had recourse to the same expedient in similar cases.”

157 ‘A Tour in Sutherlandshire,’ vol. i. 1849, p. 185.

158 ‘Acclimatization of Parrots,’ by C. Buxton, M.P. ‘Annals and Mag. of Nat. Hist.’ Nov. 1868, p. 381.

159 ‘The Zoologist,’ 1847-1848, p. 1602.

160 Hewitt on wild ducks, ‘Journal of Horticulture,’ Jan. 13, 1863, p. 39. Audubon on the wild turkey, ‘Ornith. Biography,’ vol. i. p. 14. On the mocking thrush, ibid. vol. i. p. 110.

161 The ‘Ibis,’ vol. ii. 1860, p. 344.

162 On the ornamented nests of humming-birds, Gould, ‘Introduction to the Trochilidæ,’ 1861, p. 19. On the bower-birds, Gould, 'Handbook to the Birds of Australia,’ 1865, vol. i. p. 444-461. Mr. Ramsay in the ‘Ibis,’ 1867, p. 456.