705 



FALCONID^E. 



FALCONID^E. 



708 



Wilson, the crow blackbirds, or grakles, are sometimes allowed refuge 

 by the ospreya, and construct their nests in the very interstices of 

 their eyry. It would appear sometimes, that, as with swallows, a 

 general assistance is given in the constructing of a new nest ; for, 

 previous to this event, a flock have been seen to assemble in the same 

 tree, squealing, as is their custom, when anything materially agitates 

 them." 



Mr. Vigors is of opinion that this group presents us with a decidedly 

 characteristic difference from all the other species of the family, except 

 those of Elanus, in the internal parts of the nails being rounded instead 

 of grooved. The culmen of the bill, he observes, is also broader 

 than usual, and much rounded ; the toes are entirely separated, and 

 the tarsi are covered with strong, prominent, and thickly reticulated 

 scales. The same author remarks that the Osprey (Palco Haliceetus 

 of Linnaeus) is the type of the genus to which the valuable researches 

 of Dr. Horsfleld in Java have added a second species, P. Ichthyceetus. 

 In this species however, which agrees with Pandion in the more 

 essential characters, Mr. Vigors finds a strong approximation to the 

 following genus, Haliceetus. Its bill, he adds, is more compressed than 

 that of Pandion, its acrotarsia are scutellated, and the 4th quill-feather, 

 as in Ualiaetus, is the longest. It thus stands, in the opinion of Mr. 

 Vigors, osculant between the two groups. 



The last group of the Fishing Eagles, according to Mr. Vigors, is 

 comprised in the next genus, 



llaliceetus (Savigny). Beak convex above ; nostrils lunulated, 

 transverse ; cere subhispid ; tarsi semiplumed ; acrotarsia scutellated. 

 Toes free, the external toe versatile ; claws unequal. 



Mr. Vigors notices the difference of this form from Pandion in the 

 structure of the nails, and the more compressed culmen of the bill ; 

 in the tarsi also, which have the acrotarsia scutellated, and are feathered 

 half way below the knee. There are several species ; for instance, 

 Falco leucocephaliu, P. albiciUa, F. Pondicerianiu, F. blayru*, P. rocifer, 

 &c. &c. 



//. leucoceplialut, the Sea-Eagle, Bald Eagle, White-Headed Eagle 

 the symbol of the United States of America. 





Hi'a-1 and foot of the Sea-Eagle (Ilaliactut leucoccphalut). 



Before we proceed to the description of our example, it may be 

 necenary, with Mr. Bennett's assintauce, to clear up the confusion 

 which, M he observes, has existed in the synonymy oUfaiiieetiu albicitla, 

 the difference of the colour.-) of the plumage in the various stages of 

 to growth having induced authors to record it under several distinct 



HAT. HIST. DIV. vor.. n. 



names. Three of these were almost universally admitted till about 

 twenty-six years ago, when the result of F. Cuvier's observations 

 on the individuals kept in the Jardin des Plantes led him to unite 

 Palco ossifi-agus, P. allicaudus, and P. albiciUa of Gmeliu under one 

 name : subsequent inquiry has confirmed this conclusion. In the 

 earlier stages of life, the beak of H. albiciUa is of a bluish horn- 

 colour ; its head and neck deep brown ; the plumage above, brownish- 

 black mixed with whitish or ash-coloured spots on the back and tail. 

 In this state it is Falco ossifragus of systematists. About the third 

 or fourth year the head and neck become ashy-brown; the beak 

 gradually changes from bluish to pale-yellow, the white spots on the 

 back vanish, and the tail becomes uniformly grayish-white. It is now 

 Falco albicaudus of Gmelin, Petit Pygargue of Buffon, and the Lesser 

 White-Tailed Eagle of Latham. In its fifth year it is come to 

 maturity, and the change is complete. The head and neck have 

 little of the brown tinge left, the back is throughout of a dusky-brown 

 intermingled with ashy-gray, and the tail is quite white. In this its 

 perfect state it is Falco albiciUa, the Grande Pygargue, the White- 

 Tailed or Cinereous Eagle. In all the stages of this the Great Sea- 

 Eagle which inhabits nearly the whole of Europe and of Northern 

 Asia, the cere and naked parts of the legs are yellow ; the under part 

 of the body is of a lighter hue than the upper, and more thickly 

 interspersed with pale cinereous spots ; the claws are completely black. 

 (' Gardens and Menagerie of the Zool. Soc.') 



Mr. Bennett, in the work last quoted, remarks, that in the earlier 

 stages of its growth there is little to distinguish this species from 

 the Great Sea-Eagle. M. Vieillot indeed, following the example of 

 Daudin, has united the White-Headed Eagle to the list of synonyms 

 of the Great Sea-Eagle. " That such a union," writes Mr. Bennett, 

 ' is founded upon insufficient data is proved by the gradual develop- 

 ment in the bird under consideration of a character which, after a 

 certain age, at once distinguishes it from the remainder of its tribe. 

 This character consists in the pure whiteness of its head and neck, 

 from whence it has derived the popular but inappropriate title of the 

 Bald Eagle, by which it is most commonly known." The young are 

 clothed at first with a thick whitish or cream-coloured cottou-like 

 down, and they become gradually gray as the development of the true 

 plumage goes on. In the third year the white may be traced upon 

 the head, neck, tail-coverts, and tail ; and by the end of the fourth 

 year these parts become completely white, or sometimes tinged 

 slightly with cream-colour. The eye, which is at first hazel, changes 

 to a brilliant straw-colour as the head whitens. (Wilson.) "This 

 account of the metamorphoses in colour of the White-Headed Sen- 

 Eagle," says Mr. Bennett, " derived from the personal observations 

 of the accurate author of the ' American Ornithology,' has been in 

 a great measure verified under our own inspection in the specimen 

 now before us, which remained for several years in the possession of 

 Mr. Brookes, before it was presented by him to the Society. 



" During a considerable part of the time it was regarded as the 

 Common Sea-Eagle; and it was not until its gradual change of 

 plumage had at length rendered obvious its true character, that it 

 was ascertained to be in reality a distinct species. The same error 

 appears frequently to have existed with regard to it ; and M. Tem- 

 miuck observes that the only mark of distinction that can be traced 

 in it until it has assumed the adult colouring, consists in the some- 

 what greater length of its tail. He might however have added ita 

 smaller size, which is probably one-fourth less than that of the pre- 

 ceding bird, at the same age and under similar circumstances. From 

 the observations which we have been enabled to make upon the 

 subject, we should be led to conclude that the period in which it 

 attains its full growth and perfect colouring is, in this country at least 

 and in captivity, two or three years longer than that stated by Wilson. 

 In its immature state, that is to say about the third year, the upper 

 parts of the head and body exhibit a mixture of brown and dirty 

 white, the separate feathers having a ground of the latter colour, and 

 being deeply tipped and broadly barred along the centre with the 

 former. The quill-feathers and primary wing-coverts are black, with 

 their shafts of a pale-brown ; the secondary are considerably lighter ; 

 and the tail, which projects in a trifling degree beyond the extremities 

 of the wings, is brown on the outer quills and of a mixed white and 

 brown on the inner. The under surface, as far backwards as the 

 middle of the belly, is of a much lighter shade than the upper, being 

 of a dull white, with numerous broad streaks of pale-brown. In the 

 posterior part it is of a deep brown, the feathers being only slightly 

 margined with white. A similar hue prevails on the upper parts of 

 the legs, which are plumed somewhat below the knees. The beak is 

 of a dusky brown ; the cere and legs of a golden yellow ; the iris 

 somewhat lighter; and the talons deep blackish-brown. The latter 

 are long, strongly curved, of considerable power, and extremely sharp 

 at the points. The full-grown bird measures upwards of 3 feet in 

 length from beak to toil, and more than 7 feet in the expanse of its 

 wings. Its beak is changed to a bright-yellow; and its head, a 

 greater or less proportion of the neck (according as the bird is moro 

 or less advanced in age), and tha entire tail, are become perfectly 

 white. An analogous change, iu we have before seen, takes place in 

 the plumage of the preceding species ; but the head and neck of that 

 bird always retain more or less of a brownish tinge, seldom changing 

 fully into gray, and never turning completely white. These obser- 



2 r. 



