Encyclopaedia Britannica > Volume 21, ROT-Siam

782
S H E - S H E
considerably larger, while some are smaller, and of the
former several are almost whole-coloured, being of a sooty
or dark cinereous hue both above and below. All over the
world Shearwaters seem to have precisely the same habits,
laying their single purely white egg in a hole under ground.
The young are thickly clothed with long down, and are ex¬
tremely fat. In this condition they are thought to be good
eating, and enormous numbers are caught for this purpose
in some localities, especially of a species, the P. brevicaudus
of Gould, which frequents the islands off the coast of Aus¬
tralia, where it is commonly known as the “Mutton-bird.”
For works treating of the Shearwaters, see those cited
under Petrel (vol. xviii. p. 712). (a. n.)
SHEATHBILL, a bird so-called by Pennant in 1781
{Gen. Birds, ed. 2, p. 43) from the horny case1 which
ensheaths the basal part of its bill. It was first made
known from having been met with on New-Year Island, off
the coast of Staten Land, where Cook anchored on New
Year’s eve 1774.2 A few days later he discovered the
islands that now bear the name of South Georgia, and
there the bird was again found,—in both localities
frequenting the rocky shores. On his third voyage, while
seeking some land reported to have been found by Ker¬
guelen, Cook in December 1776 reached the cluster of
desolate islands now generally known by the name of the
French explorer, and here, among many other kinds of
birds, was a Sheathbill, which for a long while no one
suspected to be otherwise than specifically identical with
that of the western Antarctic Ocean; but, as will be seen,
its distinctness has been subsequently admitted.
The Sheathbill, so soon as it was brought to the notice of
naturalists, was recognized as belonging to a genus hitherto
unknown, and the elder Forster in 1788 {Enchiridion, p. 37) con¬
ferred upon it, from its snowy plumage, the name Chionis, which
has most properly received general acceptance, though in the same
year the compiler Gmelin termed the genus Vaginalis, as a render¬
ing of Pennant’s English name, and the species alba. It has thus
become the Chionis alba of ornithology. It is about the size of and
has much the aspect of a Pigeon ;3 its plumage is pure white, its bill
somewhat yellow at the base, passing into pale pink towards the tip.
Round the eyes the skin is bare, and beset with cream-coloured
papillae, while the legs are bluish-grey. The second or eastern
species, first discriminated by Dr Hartlaub {Rev. Zoologique, 1841,
p. 5 ; 1842, p. 402, pi. 2)4 * as C. minor, is smaller in size, with
plumage just as white, but having the bill and bare skin of the face
black and the legs much darker. The form of the bill’s “ sheath ”
in the two species is also quite different, for in Q. alba it is almost
level throughout, while in C. minor it rises in front like the pom¬
mel of a saddle. Of the habits of the western and larger species
not much has been recorded. It gathers its food, consisting chiefly,
as Darwin and others have told us, of sea-weeds and shell-fish, on
rocks at low water ; but it is also known to eat birds’ eggs. There
is some curiously conflicting evidence as to the flavour"of its flesh,
some asserting that it is wholly uneatable, and others that it is
palatable,—a difference which may possibly be due to the previous
diet of the particular example tasted, to the skill of the cook, or
1 A strange fallacy arose early, and of course has been repeated late,
that this case or sheath was movable. It is absolutely fixed.
2 Doubtless some of the earlier voyagers had encountered it, as
Forster suggests {Descr. Animalium, p. 330) and Lesson asserts
{Man. d'Ornithologie, ii. p. 343) ; but for all practical purposes we
certainly owe its discovery to the naturalists of Cook’s second voyage.
By some error, probably of transcription, New Zealand, instead of
New-Year Island, appears in many works as the place of its discovery,
while not a few writers have added thereto New Holland. Hitherto
there is no real evidence of the occurrence of a Sheathbill in the waters
of Australia or New Zealand.
3 In the Falkland Isles it is called the “ Kelp-Pigeon,” and by
some of the earlier French navigators the “ Pigeon blanc antarctique. ”
The cognate species of Kerguelen Land is named by the sealers
“Sore-eyed Pigeon,” from its prominent fleshy orbits, as well as
Paddy-bird”—the last doubtless from its white plumage calling to
mind that of some of the smaller Egrets, so-called by the English in
India and elsewhere.
4 Lesson {loc. cit.) cites a brief but correct indication of this
species as observed by Lesquin {Lyc6e Armoricain, x. p. 36) on
Crozet Island, and, not suspecting it to be distinct, was at a loss
to reconcile the discrepancies of the latter’s description with that
given of the other species by earlier authors.
the need of the taster. Though most abundant as a shore-bird, it
is frequently met with far out at sea, and its most northern recorded
limit is by Fleurieu {Voy. de Marchand, i. p. 19), in lat. 44° S.,
some 260 miles from the eastern coast of Patagonia. It is not
uncommon on the Falkland Isles, where it is said to breed {Ibis,
\ 1861, p. 154), though confirmation of the report is as yet wanting,
j and from thence is found at both extremities of the Strait of
Magellan, and southward to Louis-Philippe Land in lat. 60° S.
On the other hand, thanks to the naturalists of the British and
] United States expeditions to Kerguelen Land for the observation
of the transit of Venus in 1874, especially Mr Eaton {Philos. Tram-
actions, clxviii. pp. 103-105) and Dr Kidder {Bull. U. S. National
Museum, 1875, No. 2, p. 1-4), much more has been recorded of the
eastern and smaller species, which had already been ascertained by
Mr Layard {Proc. Zool. Society, 1871, p. 57, pi. iv. fig. 7) to breed
on the Crozet Islands,6 and was found to do so still more numer¬
ously on Kerguelen, while it probably frequents Prince Edward’s
Islands for the same purpose. The eggs, of which a considerable
number have now been obtained, though of peculiar appearance,
bear an unmistakable likeness to those of some Plovers, while
occasionally exhibiting a resemblance—of little significance, how¬
ever—to those of the Tropic-birds.
The systematic position of the Sheathbills has been the
subject of much hesitation—almost useless since 1836, when
De Blainville {Ann. Sc. Naturelles, ser. 2, vi. p. 97) made
known certain anatomical facts proving their affinity to the
Oyster-catchers (vol. xvii. p. Ill), though pointing also
to a more distant relationship with the Gulls (vol. xi. p.
274). These he afterwards described more fully {Voy.
“ Bonite” Zoologie, i. pt. 3, pp. 107-132, pi. 9), so as to
leave no doubt that Chionis was a form intermediate be¬
tween those groups. Yet some writers continued to refer
it to the Gallinse, and others to the Columbae. The matter
may now be regarded as settled for ever. In 1876 Dr
Reichenow in Germany {Jour. f. Orn., 1876, pp. 84-89)
and in America Drs Kidder and Coues {Bull. U. S. Nat.
Museum, No. 3, pp. 85-116) published elaborate accounts
of the anatomy of C. minor, the first wholly confirming
the view of De Blainville, the last two6 agreeing with
him in the main, but concluding that the Sheathbills
formed a distinct group Chionomorphx, in rank equal to
the Gecomorphse and Charadriomorphse, of Prof. Huxley
(which are, to speak roughly, the Gavix and Limicolx of
older systematists), and regarding this group as being
“ still nearer the common ancestral stock of both.” These
authors also wish to separate the two species generically;
but their proposals are considered needless by Garrod IP.
Z. S., 1877, p. 417) and M. Alph. Milne-Edwards {Ann.
Sc. Naturelles, ser. 6, xiii. art. 4, p. 24). The opinions
of De Blainville and Dr Reichenow are borne out by the
observations of Mr Eaton (loc. cit.), and no one knowing
the habits of an Oyster-catcher can read his remarks
without seeing how nearly related the two forms are.
Their differences may perhaps justify the separation of
each form into what is vaguely called a “Family,” but
the differences will be seen by the comparative anatomist
to be of slight importance, and the intimate affinity of the
Gavix and Limicolx, already recognized by Prof. Parker
and some of the best taxonomers (cf. Ornithology, vol.
xviii. p. 45) is placed beyond dispute.7 (a. n.)
SHEBA. See Yemen.
SHEBOYGAN, a city of the United States, capital of
Sheboygan county, Wisconsin, stands on Lake Michigan,
5 A previous announcement of the discovery of its egg {Ibis, 1867,
p. 458) was premature, the specimen, now in the possession of the
present writer, proving to be that of a Gull—a fact unknown to the
American writer named above.
6 In some details their memoir is unfortunately inaccurate.
7 The little group of very curious birds, having no English name,
of the genera Thinocorys and Attagis, which are peculiar to certain
localities in South America and its islands, are by some systematists
placed in the Family Chionididx and by others in a distinct Family
Thinocoridse (more correctly Thinocorythidm). They are undoubtedly
Limicoline, though having much the aspect of Sand-Grouse, but their
precise position and rank remain at present uncertain. Cf. Garrod
(ut supra) and Prof. Parker (Trans. Zool. Soc., x. pp. 301 sq.).