Eastern/Western Bonelli's Warbler sp.

Phylloscopus orientalis/bonelli (0, 1) (Brehm, CL, 1855) / (Vieillot, 1819)

1280px-Phylloscopus_Tarn_Midi-Pyrénées_France.jpg

Photo © By Pierre Dalous - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=22413474

STATUS

Palearctic.

OVERVIEW

Indeterminate records.


1950-57 RECORD

1). 1954 Devon Lundy, trapped, 1st September.

(B. Whitaker, British Birds 48: 285; M. Brooks-King, Devon Bird-Watching and Preservation Society Report 1954: 46; M. J. Rogers and the Rarities Committee, British Birds 91: 122-123; Moore, 1969).

History Barbara Whitaker (1955) in British Birds, Vol. XLVIII. p. 285, says: 'On 1st September 1954 a Bonelli's Warbler (Phylloscopus bonelli) was trapped on Lundy. Before being caught, the bird was seen briefly at the mouth of the trap, when its generally pale colour was the most outstanding feature. The following description of it was taken in the hand. Head grey. Ear-coverts greyish-white. Indistinct whitish stripe above eye. Nape, hind neck and mantle grey blending to brownish olive-green on lower mantle and back. Rump and upper tail-coverts, yellowish-green. Rectrices olive-brown with outer webs yellow. Under-parts white. Wing-coverts olive-brown. Primary and secondary feathers olive-brown with leading edges yellow giving the closed wing a yellowish appearance. Legs brown. Iris dark brown. Bill horn-coloured.

After a preliminary examination, the bird was put into a box for transportation to the Old Light, so that a more detailed study could be made. Unfortunately it escaped, but having examined a series of skins at the British Museum (Natural History) I have no doubt about its identification. This is the second record for Britain.'

NOT PROVEN

0). 1874 Sussex Near Brighton, shot, June.

(Clifton, Field 29th Mar., 1879: 369).

[Clifton, Field 19th Apr., 1879: 442].

History Lord Clifton (1879) in The Field of 29th Mar., Vol. LIII. p. 369, dated 20th March, says: 'Happening the other day to be at Mr. Swaysland's, the well-known Brighton birdstuffer, I noticed a bird of the willow wren class, evidently thrown aside, and covered with dust and dirt. I was informed by Mr. Swaysland, jun., that it was a Wood Wren in bad faded plumage, which he or one of his family had shot in the neighbourhood (one leg being broken by the shot), and probably on the Earl of Chichester's property. On examining this "faded Wood Wren", I was agreeably surprised to find it a Bonelli's Warbler, the white underparts and eyebrow, greyish back, and yellow-green rump at once distinguishing it from any other member of the genus. There can be no reasonable doubt as to its been obtained near Brighton for Mr. Swaysland never had occasion to buy so common a bird as a Wood Wren, and it was obviously a bird mounted by himself from the flesh, and not from a foreign skin. He thinks it was shot about June 1874.

My conviction is now strengthened that the original bird seen by me in Kent in 1877, and recorded in The Field, was of this species, although I shot a Willow Wren from the same bushes in mistake for it. Although the specimen is very grey on the back compared with its congeners, there is a perceptible tinge of green, which I think was absent in those I got in Egypt in 1878. Compared with one of the two greyest Willow Wrens that I ever saw (Mr. E. T. Booth, of Brighton, has the other), the latter is much browner on the back, and the underparts are tinged with pale buffy yellow, whereas the Bonelli's Warbler is very nearly pure white below, with only a very little pale yellow at the extreme side of the breast.'

Lord Clifton (1897) in The Field of 19th Apr., Vol. LIII. p. 442, says: 'I regret to say that I have a second time failed in establishing Bonelli's Warbler as a British bird. I had thought that the white throat and breast were conclusive marks of P. bonelli; but the wing-formula is against this - the second quill being longer than the fifth, the third the longest, and the bastard-quill excessively small. It is evidently therefore a Wood Wren, which has doffed its bright colouring almost entirely in the summer, just as the Willow Wren does in the Arctic regions, and sometimes in England.

I perceived, on closer examination of my specimen, that the grey colouring of the back was only in the basal parts of the feathers, the tips being green. In Bonelli's Warbler the tips would have been brownish-grey, only slightly, if at all, tinged with green.

One is always sorry to add to the already long list of erroneously recorded British birds. Looking back, I do not think I am responsible for any positive record that is erroneous, except the trifling case of a Peregrine Falcon seen in Kent, which was probably some other large bird of prey. But I think my "supposed Savi's Warbler", "supposed Mottled Owl", and "Rough-legged Buzzards in August", as recorded in the Zoologist, were all erroneous. I mention this, as one of them has been quoted elsewhere.'

Comment Misidentified. Another Swaysland mystery! Not acceptable.

0). 1877 Kent Cobham, seen, 25th April.

(Clifton, Field 5th May 1877: 517; Clifton, Field 12th May 1877: 573; Clifton, Field 26th May 1877: 626; "Phylloscopus tristis" Field 2nd June 1877: 640; Clifton, Field 2nd June 1877: 640; Clifton, Field 16th June 1877: 723; Clifton, Field 7th July 1877: 4; Clifton, Field 14th July 1877: 33).

[Clifton, Field 13th Oct., 1877: 413].

History Lord Clifton of Cobham, Kent (1877) in The Field of 5th May, Vol. XLIX. p. 517, says: 'I wrote to you only last week about a pipit seen by me in Sutherland (misprinted Sunderland), which I identified with Anthus cervinus, and I scarcely thought at the time that I should so soon have to record another new British species, So far as subjective certainty can go, as opposed to objective certainty where the bird is obtained. I allude to a Bonelli's Warbler which has most unexpectedly turned up here. I have not the precise date of its arrival, for it was at first confused with the Willow Wren; but I saw in on the 25th, and I think it had been here at least a week then.

At any distance, or when high up in a tree, it is almost indistinguishable from the Willow Wren. There is a difference in the song, but it is difficult to formulate, and requires a good ear. I should say that it was more a difference of time than of quality, the note of Bonelli's being weak and rather monotonous, while that of the Willow Wren rises cheerfully at first, and then rapidly falls. Still the resemblance was sufficiently great in this case as nearly to prevent my paying any further attention to what seemed to be a common Willow Wren.

However, passing the spot again, a bright sun shining, I saw the bird hovering over the dead bracken, and was greatly struck at the bright golden colour of the rump whenever the wings were spread. I now carefully stalked the bird with my field glass, and eventually had a view of it on the ground within ten feet. I had now but little doubt that it was a Bonelli's Warbler. Instead of being "greyish-brown dashed with yellowish green", as Mr. Seebohm so well describes the upper plumage of the Willow Wren, the ground-colour was decidedly greenish, more like that of the Wood Wren, though not so warm on the head and back as in that species; on the rump the dull green passes into bright yellowish green, and the feathers of the wing and tail are also edged with yellowish green.

I particularly noticed this last fact, the warm colour of the rump and upper tail-coverts being continued along the outer edges of the outer tail feathers. The breast was very white, nor could I detect a trace of yellow on the under parts. The eye streak also was whitish, and much more defined than in the Willow Wren. There was one great peculiarity in this bird, which may or may not be characteristic of the species; the middle tail-feathers were so long that the end of the tail was as nearly as possible level, instead of slightly forked as in the Willow Wren.

The situation it selected was a close thicket of young birches 14 ft. to 15 ft. high, standing on open common-like ground, and it made frequent excursions to the ground, alternately hovering over the brackens like a Goldcrest, and hopping bolt upright like a Redstart. it very rarely adopted the stooping wren-like attitude so often assumed by its congeners, and I was most especially struck by its upright and decided gait on the ground.'

Lord Clifton (1877) in The Field of 12th May, Vol. XLIX. p. 573, dated 8th May, says: 'In continuation of my last letter, I have the pleasure to inform you that there is now a pair of Bonelli's Warblers at the same spot where I first detected a single bird last month, and by their actions I am convinced that they intend nesting. The male is still conspicuous by his square-tipped tail; but curiously enough, the female has the tail more forked. Probably in the male the feathers intermediate between the central pair and the extreme outside feathers of the tail are deficient in length, instead of the central pair being excessively long, as I conjectured at first; or possibly this species may be specially prone to variation in shape of tail. However this may be, in both these birds the length, breadth, and flexibility of the tail is a striking feature. Added to the curious habit of sailing with shivering wings from one bush top to another, this flexibility of tail has a very Tree Pipit like appearance. On the ground, as before noticed, it alternately hovers like a Goldcrest and hops like a Nightingale. It is particularly fond of creeping through thick whitethorn bushes, and under these circumstances it has a very peculiar habit of stretching its neck to the fullest extent to look round. Constantly only the head can be seen peering through from among the thorns. I have already found one, if not two, of this species in quite a different locality, but again sharing a thicket with Nightingales, and creeping through whitethorn bushes like a Whitethroat. I now remember that I saw a pair of unknown birds in June two or three years ago, evidently nesting, for they were in great excitement. I never found the nest, and my changes of diagnosis were remarkable - first Phylloscopus, then Acrocephalus palustris, then Hypolais, then Acrocephalus again. I now see that these birds were not Acrocephalus palustris, being shorter and greener, and I am equally certain that they were Phylloscopus bonellii. This adds another to the anomalous habits of this bird, for the pair seen on that occasion clung to the fern stems exactly in the attitude of Sedge Warblers. It is altogether one of the most distinct species I ever met with, and I may add that when seen very near its light-coloured lower mandible is very distinct.'

Lord Clifton (1877) in The Field of 26th May, Vol. XLIX. p. 626, says: 'As two letters of mine have with regard to a supposed Bonelli's Warbler have appeared in the Field, it is only right that I should allude to a most unfortunate blunder I have made. Urged by an ornithological friend to shoot a specimen, I did shoot a bird close to the original spot, which I persuaded myself was the mate of the bird first seen and therefore, according to my view, a female Bonelli's Warbler. I saw directly I picked it up that it was different from the bird I had been describing in the Field. It was yellowish instead of white on the breast; the rump feathers were more green than yellow, though lighter than the back; there were no bright edgings to the tail feathers, and none to speak of to the wings. Nevertheless, I thought it must be a female Bonellii - (1) because the tail seemed too square for a Willow Wren; (2) because it had been laid down by a writer to the Ibis for January last that the Willow Wren had a dark, and Bonelli's Warbler a light under-mandible. Therefore, I considered this must be a Bonelli's Warbler, though unusually dull on the upper and yellow on the lower surface because it has a light-coloured lower mandible - Q.E.D. Of course I sent the bird to the friend who asked me to shoot it, and of course he and other leading ornithologists pronounced it to be the common Willow Wren, and no doubt it was one. But that, I would submit, does not affect my original bird the miniature Wood Wren with white breast, yellow rump, broad edgings to the wing and tail feathers. A misleading article in the Ibis, and the clashing of two species in the same locality, have led me into taking two distinct birds for the male and female of one species, that is all. In fact, now that the doubtful bird is authoritatively pronounced to be a Willow Wren, I see all the more clearly the very broad distinctions between that species and the bird originally seen by me, which I have now even less hesitation than formerly in pronouncing to be Bonelli's Warbler; though I have got rather confused about birds seen subsequently to April 26.'

"Phylloscopus tristis" (1877) in The Field of 2nd June, Vol. XLIX. p. 640, says: 'The British Ornithologists' Union is certainly to be congratulated on the enlistment of so fortunate and sharp-sighted a naturalist as Lord Clifton, With him two birds in the bush are not only good as one in the hand, but much better. That he should have made a mistake in the species as soon as he had killed a specimen for examination is no evidence against the trustworthiness of his original opinion, for the blame rests with a misleading article in the Ibis - in other words, with Mr. Seebohm's recent monograph of the group. I trust that, as soon as Lord Clifton has cleared up the confusion into which he says he has fallen as to birds seen subsequently to April 26, he will favour us with an exposure of all errors of a writer whom many of us have hitherto regarded as one of our most accurate and experienced field ornithologists. Till then I remain with another illusion shattered.'

Lord Clifton (1877) in The Field of 2nd June, Vol. XLIX. p. 640, says: 'Although this is my fourth letter on this subject, I think that the description of a new British bird and its breeding habits needs little or no apology on my part for trespassing on your space. Four nests of my Willow Warbler have been found, the eggs remove all doubt as to its being a new British species, and this, taken in connection with the similarity in habits and general appearance of this bird and the Wood Wren, leaves no doubt of its being, if not Bonelli's Warbler, at any rate a species closely allied to the Wood Wren and Bonelli's Warbler. Of these four nests three were placed on the ground, and partly domed; the fourth, strange to say, was eight or ten feet from the ground in an elder bush, at a point where the twigs were rather closely interlaced, and was not domed. This occurrence, supposing the bird to be Bonelli's Warbler, confirms the much-ridiculed statement of Malherbe that it sometimes breeds in poplars and other thick-foliaged trees. This nest was lined with rabbits' fur and hair; the other three were lined with feathers....'

Comment Misidentified. Not acceptable.

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Western Bonelli's Warbler

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Yellow-browed Warbler (1/2)