Common Yellowthroat
Geothlypis trichas (Linnaeus, 1766) (0, 1)
Photo © By Mike's Birds from Riverside, CA, US - Common yellowthroat, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=81470593
STATUS
Nearctic. Polytypic.
OVERVIEW
Since this first record a further nine individuals have made it across the Atlantic, the last occurring in 2012.
1950-57 RECORD
1). 1954 Devon Lundy, first-winter male, trapped, 4th November.
(B. Whitaker, British Birds 48: 145-147; M. Brooks-King, Devon Bird-Watching and Preservation Society Report 1954: 46; BOURC (1956), Ibis 98: 155; I. C. T. Nisbet, British Birds 56: 204-217).
History Barbara Whitaker (1955) in British Birds, Vol. XLVIII. pp. 145-147, says: 'On 4th November 1954 a first winter male Yellowthroat (Geothlypis trichas) was trapped on Lundy Island, Devon, detained over night, and released the following morning after being ringed. It had not been seen before it was caught, but may well have been present on the island for a few days, as it did not appear to be exhausted and, in fact, seemed in good condition.
When first glimpsed flying into the trap, it was thought to be a Chiffchaff (Phylloscopus collybita). A more adequate view showed that it was a bird quite unfamiliar to us, the most striking feature being a brilliant canary-yellow chin, contrasting sharply in the malar region with the ear-coverts and lores, which were black, mottled with grey. It was taken to the laboratory, where measurements and a full description were obtained, as follows: - Plumage. Crown, olive-green to olive-brown. Nape, hind neck, mantle, back, rump and upper tail-coverts, all greenish-grey to olive-green. Primaries and secondaries: inner webs, greyish-black; outer webs, olive- green. Wing coverts, olive-green. Tail, olive-green-grey, with greenish- yellow tint on outer webs. No eye-stripe. Feathers of ear-coverts, lores, and immediately below the eyes were black, tipped with grey, giving a mottled effect. Chin, canary-yellow. Throat, canary-yellow, grading into a paler cinnamon-yellow at the sides of the neck. Across the throat was a faint cinnamon-tinted band. Breast, pale yellow, grading into fawn-yellow beneath wings. Flanks, pale fawn. Belly, pale cream-yellow. Under tail-coverts, yellow tinted with cinnamon.
Soft parts. Bill, horn-coloured, with cutting edge of both mandibles and the centre ventral surface of the lower mandible pinkish. Legs, pale pinkish-brown. Iris, dark brown.
Measurements and structure. Total length about 120 mm.; wing 57 mm.; tail 51 mm.; tarsus 23 mm.; bill 11 mm. Wing formula. 1st primary 2.5 mm. shorter than the longest; 2nd, 3rd and 4th equal and longest; 5th 2.5 mm. shorter; 6th to 9th, each decreasing by 1.5-2.0 mm. 2nd, 3rd and 4th emarginated.
Tail. 10 feathers approximately equal in length, each sharply pointed and abraded.
Weight, (at 1300 hours on 4th November) 11.7 gms.
It was in general appearance like a small round-winged Phylloscopus, though some of its movements when released in cover were reminiscent of a Wren (Troglodytes troglodytes), as it moved just above the ground in thick bramble and grass cover. When released on the window-sill of the laboratory it frequently flitted its wings, most movements being accompanied by a mono- syllabic "chat"; at the same time it half raised the feathers of crown and forehead.
When released in the cage of the Heligoland trap, it soon disappeared from view in the cover available, but continued to "chat" while I was near the cage.
The bird was shown to F. W. Gade, and an attempt was made by Fred Jones, of the South Light, to photograph it. We were at the time quite unable to name it, and a full description, together with specimen feathers from various parts of the body, was sent to W. B. Alexander, who identified it.
The specimen feathers were quite sufficient to confirm the identification, when compared with skins in the British Museum (Natural History). 12 races of Yellow throat were recognised by the 1931 American Ornithologists' Union Check-List, but neither the specimen feathers nor my recollection of the bird are sufficient to attempt a subspecific determination.
[The end of October and the beginning of November would not, as might at first be thought, be phenomenally late for a migratory bird like a Yellowthroat to be in the United States at a latitude sufficiently far north for it to be possible for it to be drifted across the Atlantic to the British Isles.
In A. C. Bent's Life Histories of North American Wood Warblers are given a number of October to December "late dates" for autumn departure, and particularly under New York it is stated that there are "numerous November and December records near the coast".
Mr Kenneth Williamson has made an analysis of the weather conditions and this shows that these were ideal for a crossing between 31st October and 4th November, but here it should be added that the bird's condition and more particularly its weight of 11.7 gms. suggest that it had probably been on Lundy, or at least in the British Isles, for some time before it was trapped. Mrs. Margaret Nice has kindly drawn our attention to the following weights of Yellowthroat in America, given by Mrs. Olive P. Wetherbee (1934, Bird-Banding, Vol. V. pp. 55-64): Male, 11th July. 9.72 gms. Female, 29th July, 10 gms. 20 immatures, 21st July-7th September, 8.9-12.6 gms. (average 10.44 g ms.).
Even allowing for the fact that the normal weight for a warbler of this kind in late October may be higher than at any of the times when the above weights were obtained, these figures suggest that the Lundy bird was at worst not much below its normal weight.
The occurrence of this bird, and also of a Myrtle Warbler (Dendroica coronata) near Exeter, Devon, between 5th January and 10th February 1955 (details will appear in our next issue), have forced us, in conjunction with the BOU Records sub-Committee, to consider the whole question of the occurrence of American Passerines in Britain. Neither of these species is at all likely to have escaped from captivity (we are grateful to Miss Phyllis Barclay-Smith, Mr. Derek Goodwin, and Mr A. A. Prestwich for confirmation of this point), and so the only reason that could possibly be put forward for either of these birds not to be regarded as genuine candidates for the British list, is the possibility of the so-called "assisted passage" by boat.
Whether or not small insectivorous birds are capable of surviving a trans-Atlantic passage on a boat (necessarily a much slower crossing than if they were swept over by high wind), does not concern us here, for in consultation with the BOU Records sub-Committee we have come to the conclusion that the possibility of "assisted passage" should not necessarily deny to a bird the right of admittance to the British List. Consideration of the following points led to this conclusion, which obviously applies more particularly to American Passerines.
(a) Small Passerines migrate regularly between Greenland and Europe. Recent work suggests that a direct crossing from the N. American mainland is not inherently impossible under exception ally favourable conditions.
(b) Ships are an ever-present feature of the N. Atlantic and their influence on birds and bird distribution should not be regarded as more unnatural than any other man-made object or alteration to the land or sea-scape, nor indeed do they in effect differ from flotsam, on which a bird might rest.
(c) There is no possibility whatever of knowing whether or not any bird that reaches Britain has settled on a ship nor, if it did so, the length of time it remained there. To deny American Passerines a place on the British list on the ground that they had not made or could not have made the journey unaided in this way is to imply that all of the American birds already included in the list have had an unaided passage. With this implication we are not prepared to agree. Whether or not the passage was unaided should be regarded as irrelevant in the light of (b) above.
(d) Consideration of meteorological reports may be of consider able value, but the weather prevailing immediately before a bird's discovery is not necessarily of great significance, for the bird may have been in this country for some time before it was seen.
(e) With the sub-Committee we are prepared to accept for admission to the British list as a genuine wild bird any that in our opinion has reached Britain in a free state. Each case must be carefully considered on its merits; the possibility of escape from captivity must be judged; the status of a bird, whether migratory or sedentary in its own country, must have weight in forming a decision. - Eds.]
Admitted nationally as the first for Britain (BOURC (1956) Ibis 98: 155).
I. C. T. Nisbet (1963) in British Birds, Vol. LVI. pp. 204-217, discusses 'American passerines in western Europe, 1951-62'.
