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RICHARDSON’S LESTRIS.

Lestris Richardsonii, Swains.

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Tus is by far the most c rasitic G i
y fe common parasitic Gull on our coast. It breeds in the Orkney, Shetland, and

Western Isles in very consider; ance ; and fr is, i y
y considerable abundance ; and from this, its most southern boundary of incubation, it may

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be found in all the intermediate countries to the polar regions of both continents

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It was discovered by
Dr. Richardson, breeding on the barren ground north of Hudson’s Bay at a considerable distance from the

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sea, from whence he brought specimens, which we have had opportunities of comparing with others procured

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in the Orkneys, and find them to be strictly identical. Some confusion appears to have existed in reference

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to the specific differences of these birds; and had it been consistent with the plan of the present work,

would have been a gratification to us to have figured all the known species contained in this interesting and

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well-defined genus: they are, however, not numerous ;—we are not acquainted with more than two others

extra-European, both of which are natives of America. The present species has hitherto been considered as

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the Larus parasiticus of Linneus ; and it is somewhat surprising, that its claims to a distinct specific title should

so long have escaped the notice of European Ornithologists, and especially the scientific and discriminating ey

of M. Temminck. We have had opportunities of examining numerous examples of both species, and also

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specimens of the bird figured by Edwards under the name of the Arctic Bird, Plate 148, which has legs of a

bright yellow colour, and tail-feathers much more elongated. This bird we also consider to differ both from
L. Richardsonii and L. parasiticus; but as it has never been known to visit Europe, further description must,

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in accordance with our plan, be omitted.
The Lestris Richardsonii first received its specific title from Mr. Swainson, in honour of Dr. Richards

2 153; and it is with

a figure and description of it being published in the Fauna Boreali-Americana, part 2, p. 408 ;

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no small degree of pleasure, that our work affords us an opportunity of illustrating a bird bearing the name
of so distinguished a traveller, whose arduous and indefatigable exertions have done so much for science.
The Lestris Richardsonii is subject to so great a variety of changes in the colour of its plumage, that a mot

than usually minute detail in the description is required. ‘The dark chocolate coloured bird figured in out

oe io a
i pao E Ea spending’ British Isles: and fron
Plate, characterizes at least three fourths of the specimens found breeding in the British Isle ah
i in e inter no shan
this colour to that of the light-coloured bird on the same Plate, it may be seen in all the intervening sh:
Both sexes appear to be subject to the same law, and a very lig
a dark female, and vice versd. We are therefore led to believe, from the circumstance a |
i i vails solely < o o birds, yet sufficiently mature
birds forming the greater portion, that this colour prevails solely among young bird , yet sufficiently maturé
The young birds of the year present preci
istic of the Lestris Pomarinus, being brown, numerously barred
f that part of the web nearest the tarsus

 

ht-coloured male may be often seen paired with

of the darker-coloured

: . : sely the same disposition of
for the reproduction of the species. : }

markings and colouring which is so character

with transverse lines of a richer colour; the legs and a portion 0 a
- this very conspicuous character formerly obtaine¢

are flesh-coloured ; the other part of the membrane is black :
of Black-toed Gull (Larus crepidatus

robust and powerful

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for thi ies tl ), an appellation which has long sunk into
or this species the name
synonyme. The Lestres Richardsonii is a more
arker and more uniform 10

aise > tarsus, COeS,
hes ; and the tarsu

bird than the Lestris parasitic s; and the

colour; the two middle tail-feathers scarcely

and interdigital membrane are also con-

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upper surface of its plumage 1s d
ever exceed the others more than three inc
tail

pecuously Bo ‘ . Q inches long, exceeding the rest ol the
Total length 2] inches; wing

3 inches; beak 1% inch; tarsus 1 inch 9 lines.

13 inches ; middle tail-feathers

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