Stray Feathers/Volume 1/July 1873/Indian and European Eagles, No. II.
STRAY FEATHERS.
Vol. I. ] JULY, 1873. [ No. 5.
Notes upon some of the Indian and European Eagles.
By W. Edwin Brooks, C. E.
No. II.
Since ray former notice (vide page 290,) I have received additional information of great interest to the ornithologist.
I have two specimens of the eagle known as Aquila orientalis, Cab., and erroneously termed by some authors Aq. clanga of Pallas. One of these specimens was sent to me by Dr. Bree of Colchester, and is labelled Aq. orientalis, Cabanis, in Mr. Gurney's own handwriting, the other was sent me by Mr. Dresser, and was shot near Sarepta.
The extreme similarity of these two birds to our Indian Aquila bifasciata when nearly mature, frequently struck me; but none of my Indian specimens corresponded exactly with them as regarded the tail, although in other respects they accorded perfectly. Now, however, I have just received Indian examples of Aq. bifasciata, with tails exactly corresponding with those of the two European A. orientalis above referred to. I have no hesitation whatever in pronouncing the two species to be identical. Aq. bifasciata is, I believe, the older term, and if so, Aq. orientalis, Cab., will sink into a synonym.
I have thus now in my possession three examples of Aq. bifasciata shot in Europe, which I consider quite sufficient to establish the species as European. I keep them by me with their Indian counterparts, and whoever doubts my conclusion can satisfy himself by examination. It was not to be expected that a migratory eagle of similar size and power to A. mogilnik should be restricted to Eastern Europe, considering that we have in India A. chryscRtos, A. mogilnik vel imperialis, A. ncBvioides and A. navia.
The migratory eagles are not local, but are, as a rule, very widely spread.
Speaking of the mature example of Aq. bifasciata which was sent to me by Captain Elwes, Mr. Gurney (Ibis, 1870, pp. 67 and 68) attaches considerable importance to the two parti-colored feathers in the scapular region of this specimen; and he con- cludes that the presence of these two little parti-colored feathers demonstrates that the bird is Aq. nevioides. Iu answer to this I may observe, that I found a specimon of Ag. vindhiana with parti-colored small scapulars. I have also seen a specimen of 19. mogilnik with parti-colored scapulars. Mr. Anderson too speaks of one (P. Z. S., 1872, p. 621). The other day I exam- ined an exainple of Cancuma leucogaster with some of the sca- pular feathers having one side of the feather fulvous, and the other brown. I believe occasional parti-colored leathers are to be found in most eagles, although to a greater extent in Ag. navioides, which I believe retains them permanently in its most advanced stage of plumage. Al all events the Bosphorus 4. vifasciuta is structurally opposed to Ay, narioides, and its nos- tril, thongh a dried me, is most perfect ; having never hat auy thread or string passed through it to keep the bill closed.
Mr. Gurney suggests in Epist.) that the process of desicca- may have distorted the nostril ; so that though originally a round one, it may now be lengthened : but this supposition is quite out of the question. This climate, of all others, will thoroughly desiccate the whole bird, especially the hot winds of the North-Western Provinces to which all my birds have been exposed ; and after examining my numerons specimens of eagles, I find no material alteration ; certainly notliing to the extent suggested by Mr. Gurncy; and it is still easy in every case, by looking at the nostril alone, supposing the body of the bird to be covered to tell to wliat class of eagle it belongs. By no process of desiccation whatever, could the rather small round pos- tril of 44. uavioides become the large long vertical one of Aguila bifusciata. The size of the nostril in the two birds is so differ- enti. I bare not before observed that Aq. bifasciata, as a rule, is Imperiul Eagle size, which Aq. sovioides is not; and once vuore I maintain that the tail of the latter is a plain black onc, very rarely barred, and theu with the faintest possible barring square to the shaft of ihe feather, and not extending more than half way to the edge of the feather, if so much.
Mr. Gurney informs me that if his memory does not deceive him, he has seen specinons of Aq. næviides with tails as strongly barred as that of the Bosphorus .. bifasciata in ques. tion. All I can say to this is, that the birds with grey well barred tails were not sq. uavioides, but some olher species, pro- bably A. bifuscialo. I have again strongly drawn attention to this question for my conclusions are disputed by English ornithologists. They won't believe it possible that they have overlooked so large a bird in Europe as an eagle; but the specimens themselves which I possess are very solid facts which tle best men in Europe cannot contend against.
It is now admitted by Messrs. Gurncy aud Dresser, that the adults of Aquila hastata, and what they call the North German or small race of the spotted eagle, (the true Aguila nevin of the old authors, in their opiniou,) are not to be distinguished; but they contend that the immature birds are different. In opposi- tion to this, I snbmit that the Danzic bird sent me as 14. necia by Mr. Dresser is a veritable 4q. hastata, and immature birds of this species must occur in the same region. The spotted birds which differ may not have been satisfactorily connected with the adults to which they were said to belong: Did any one take the immature one from the nest, and rear it? The statement that the immature plumage of the little Ponneranian spotted eagle is different from that of dq, hastata, I regard, at all events for the present, as theoretical.
I should not be in a position myself to say what the immature plumage of sq. vinilhiana was, unless I had brought up the young from the nest. How do Messrs. Gurney and Dresser prove that the immature of the Pomeranian spotted eagle is distinct from that of 4. hastata ?
They say the immature plumage of 4. hastala has not occurred in Europe, and is not known there, but against this I say, it is only the other day that 19. nogilnik, in the lincated stage was found to occur in Europe, and it is a plentiful bird there! Again A. bifasciata has been bodily overlooked, so that I can quite understaud that neither Messrs. Gurney nor Dresser lave yet seen an immature European 4g. hastata. They will see them, lowever, before long, and the immature typical All, Vifasciala too, unless I am greatly mistaken. They have, I believe, at last seen the lineatel Aq. mogilnik to begin with; at all eveuts they must have heard of it this time, and the others will follow in due course. How long is it since it was denied upon the best authority, that there was such a thing as a lineated Imperial Eagle in Europe, and it was conteuded that the Indian bird was quite distinct from the true imperialis or mogilnik? Now they are uniled, and a distinct Western bird (Aq. adatherti, Brelom) is separated. These birds were not scen, because they were not properly looked after; and after all Jurope with its numerous ornithologists and collectors, and with a climate facilitating the operations of the naturalist to the utmost, so widely different from the scorching Indian one, hus been but very lazily explored, and there is no knowing what may tun up there in the future in the way of identifications.
I do not think that dg. clanga, of Pallas, has any connection with Aq. bifasciata vel orientalis j for Pallas says, the tail is: black, " Cauda nigra" ; again he says, the back is black, dorsum nigrum." This could only apply to our Indian spotted eagle which frequently has the plumage very dark indeed and nearly black. The legs are said to be " nigricante albo varies" The white tarsus, or partly white tarsus is characteristic of Aq. navia, I mean of Aquila nmvia, as we know it in India, for Mr. Gurney now separates our bird as Aq. vittata, Hodgson. This I cannot understand, and he must prove the assertion before it can be generally received. Pallas, after saying that the back is black as well as the tail, and surely he could not have overlooked the strongly barred grey tail of Aq. bifasciata vel orientalis, says, the wing coverts are spotted with white, (" tectricibus albo variegatis"). Altogether, as far as I can understand his description, it is utterly impossible to apply it to Aquila bifasciata vel orientalis, but it suits large examples of our Indian spotted eagle and no other bird that I know of. This bird I have procured measuring 2 feet 44 inches total length wing, 20^ inches; and weighing 6j lbs., a female of course. This species varies excessively in size, and I have some very small examples, barely exceeding Aq. hastata, in size. The way in which A. hastata and our Indian spotted eagle, which we call navia approach each other as regards size, renders it difficult to find out which the original A. navia was. I have an excessively meagre description by Gmelin, which to
- me appears to indicate the bird we
recognize as naevia in India, although some of the English naturalists evidently receive another bird as ncBvia. I believe the original description, which I have never seen, is by Brisson. The two Turkish spotted eagles sent me by Captain Elwes, as I mentioned before, are identical to a feather with our Indian A. ncevia in the same plumage. Mr. Gurney suggests that I may have received the immature of Aq. orientalis. This is quite impossible, for the two birds have the perfect ncevia spotted plumage, and, moreover, have the small roundish nostril of that species ; besides, they have plain black tails, which Aq. orientalis has not. It would be rather strange too, if I who have shot so many of this species in this very plumage, and who have had at least four times the number of specimens through my hands that any of the English ornithologists "have had, should not know the bird when I see it from Europe. I have seen most of the specimens belonging to Messrs. Hume, Anderson, and Marshall However, when I submit the birds at a as well as my own. meeting of Z. S., there will be no doubt upon this point, and To separate this I shall do unless my identifications are accepted. Phylloscopus Tytleri from P. viridanus and Hippolais agricolensis from P. Rama were real difficulties^ but to recog-nize Aq. ncevia in the spotted plumage is within the powers of the 'veriest tyro.
Very little is known of the nestling", or first plumage of the various eagles. I have not even described that of the two young Aq. vindhiana {A. ftdvescens) I procured from the nest two years ago. The eggs of eagles are so keenly sought after, that the important point of the first plumage has been neglected. Perhaps something may be done this year towards a knowledo-e of the first plumage of two or three of our eagles_, if only the love for egg-collecting be moderated. It would be interesting to shew whether the young eagles moulted their first plumage in the autumn after they were hatched or not. I cannot believe judging from the analogy of the common Indian kite, that the lineated stage of Aq. mogilnih is the first one. It ought to be the second. This, and many other similar points, will, it is to be hoped, be cleared up before long, as the study of natural history extends.
Although I and others have been writing about the various stages of plumage in eagles, we are still, many of us, ignorant of the first plumage ; and this ignorance might have been removed long ago, if the young birds had been looked to, instead of the mere acquisition of the egg shells. A knowledge of the eggs is no doubt interesting, but the birds themselves are of far greater interest ; and after all, eggs are but eggs, and merely temporary cases for the young, althoug'h they are often so beautiful. P. 8. Since writing the foregoing, I have seen the original' description of Aquila ncsvia by Brisson. The synonyms are Aquila navia, Schwenck, Avi. Sil., page 219. Aquila clanga, Klein. Avi., page 41, No. 6. Morjphio congener, Aldror, Avi. Tom. I., page 214. MorpJmo congener, Aldrova^idi, Willugh. Ornith., page 32.
In his description of Aquila clangx, Pallas quotes the above synonyms, omitting however the last, but adding Aquila minor, Bufibn, Orn. I., p. 91. It is thus clear, that to apply the term clanga to any eagle but the original spotted eagle described by the older authors, is a great mistake ; and it is utterly impossible to apply the term to Aq. hifasciata, which I have shewn is identical with Jq. orientalis, Cal. Clanga is not Pallas^s term, but is a synonym of A. ncevia ; and why it was preferred by Pallas, I do not know.
The total length of Aqtiila ncevia given by Brisson, is 2 feet equal to 2 feet 8f inches English 7 inches and six lines measurement I should have been inclined to think that there was some error here, but a second measurement of 2 feet 5 inches from tip of bill to end of claws 2 feet 6^ inches Eng:
!
= lish, confirms the first measurement. It will be thus seen, that the bird described is full Imperial Eagle size; and this renders Mr. Gurney's conclusion, that original A. nævia was a bird the size of Aq. hastala, impossible to be received. The tail is said to be 12 inches long 12 inches English! Now what Aquila hastata or even A. nævia, as we receive the bird in India, has a 12 in. tail? Is it possible that the specimen described was terribly elongated skin? But though this would get rid of the difficulty of total length, what becomes of the extra long tail, which certainly would not stretch. What a pity the old writers omitted the all-important measurement of length of wing from carpal joint! But the expanse is said to be only 1 feet, feet 14 English. This is too little for eveu dq. hastata; so that too much importance should not be attached to Brisson's total length measurement. In the description of the colors there are a few points noted, which strongly indicate the bird we recognize in India as dq. nævia. "Ale subtus maculis multis, ovalibus, albis, hinc inde sparsis, insigniuntur. Crura et pedes pennis vestiuntur ad principium diguitorum usque, et albis similiter notis sunt aspersa." This reference to oval white spots could hardly apply to any other eagle. The general color of the body is thus described: In universo ferè corpore obscure ferrugineo colore tingitur. Guttur tamen obscure albet." The tail feathers are said to be white at their bases and their tips, and they are also said to be transversely barred. "Rectrices in ewrortu et apice albent; in reliqua longitudine obscurè ferrugineo tinguntur, et maculis latiusculis, fuscis transversim notantur." I have noticed that some of the younger spotted examples have fairly barred tails, although this is not the rule; and frequently the inner webs of the secondaries and tertials are barred. The only other eagle, any thing like the description by Brisson, is the young lineated Aquila mogilnik, and the dimensions, save expanse, would agree well. Can it be possible that this spotted stage of the Imperial eagle was the original 4. nævia? I leave this for better judges than myself to settle. It is important to settle the point, if possible, who was the original describer; and which has priority, Aquila navia, Schwenck, or Aquila clanga, Klein? One of the two latter authors may give some explicit reference which will remove all doubt as to what the original Aquila navia was. Again, it is possible, that although Pallas and Brisson unite the two terms, they may after all refer to two distinct species? Brisson's reference to white on the tarsus, as in the case of Pallas's description of Aq. clanga, points to onr Indian Nevia or the spotted eagle of south-east Europe in con- tradistinction to the small Pomoranian eagle. The latter I have identified with our Indian Aq. hastata. If Mr. Gurney reads Brissour's description carefully over, he cannot apply it to that small eagle, and pronounce it to be the true A. nævia of the old authors.”
In the identification of Aquila orienlalis vitli Ag. bifoseinta ; of Aq. hartute with the small Pomeranian eagle, of the Bospho- rus eagle (thonght to be Aq. nævioides by Mr. Gurney) with 44. bifasciata, and if the two Turkish spotted eagles, with one Indian Ag. nevis, I am not alone, but am confirmed by Dr. Stoliczka, Mr. V. Ball, and Captain G. F. L. Marshall who have carefully examined the differeut series which were used.
If, after all, it turns ont that the immature of the Pomeranian spotted eaglc are distinct from those of Aq. hastata, it will be one of the most wonderful of ornithological facts ; but since the im- mature lineated Imperial eagle was for ages overlooked and said not to occur in Europe, so also immature Aquila hustata may turn ap plentifully some of these days in Europe.
P.P.S.--With reference to priority of terms, Brisson gives a list of authors quoted, with dates of publication. Schwenck- feld's work is dated 1603, and Klein's 1750. Aguila revia is therefore much the older term for the spotted eagle, and Aquila clanga, Klein, is bnt a synonym. I did not notice the list of authors titt alter I had sept my paper.