LAN1US EXCUBITORIDES.
Exterior lateral scales of the tarsus divided
into several pieces, exclusive of those towards
the base of the claws, jj
Extreme length of the wing, when closed,
3-$y inches.
Proportionate length of .the primaries the
same in both.
Tail considerably graduated, the outer feather
being l-^'shorter than the middle ones.
LANIUS EXCUBITOR.
Exterior lateral scales of the tarsus entire,
exclusive of those at the base.
Extreme length of th<? wing, when closed,
nearly inches.
Tail less graduated, the outer feather being,
in one specimen, only and, in the other,
shorter than the middle ones.
Upon these data we ground our opinion that this is not the excubitor of
Europe.
It therefore now only remains to be considered whether, in this intricate inquiry,
we can derive any assistance from the writings of the last age. On this
task we shall enter, not only from a wish of satisfying ourselves on this subject,
but to exemplify, by one striking instance, the impossibility of adopting names or
relying upon descriptions, published at a time when ornithology was in its
infancy. The following details will further show that, so far from facilitating the
researches of the moderns by reviving these dubious names and vague records,
with the laudable intention of establishing the priority of nomenclature, we shall
involve the whole in inextricable confusion ; and, worse than this, we shall do
signal injustice to those faithful and accurate ornithologists who, like Wilson,
Bonaparte, and Say, have stamped their descriptions by a name, the right understanding
of which is intelligible to every one who peruses their works. Such
names, indeed, may be compared to good and lawful coin of the realm of science,
which will bear analyzing ; while those of former compilers, when thoroughly
assayed, are not unfrequently found alloyed by heterogeneous mixtures, which
almost defy the power of the alchemist to part.
The first systematic writer, in whose works we find the name of Lanius Ludovi-
cianus, is Brisson, a naturalist whom no one of ancient or modern times has
excelled in exact and faithful description : unfortunately, in this instance, there is
nothing positive to assist our research, further than that his specimen came from
Louisian i. We are, however, indirectly informed that its plumage is decidedly
darker than that of excubitor ; for the latter is described (vol. ii., p. 143) as “ d’un
fo r t jo li cendré clair," but the former as merely “ cendré." He further observes,
that the two middle tail feathers only are black ; but we place no great reliance
on this character either way, subject, as it frequently is, to the mere effects of age.
So far, therefore, as the original description of Ludoviciams is concerned, we find
no admixture or inconsistency ; it is made by an original writer, who describes
only what he sees. We shall now show that upon this account, faultless as it is,
all the subsequent errors have been engrafted. On the authority of Brisson, the
L. I/udovicianus was included in the Systema Naturoe (Ed. xiii., Vimb. 1767) ;
but, in the specific character, the tail is. here first stated to be cinereous (p. 134),
instead of partially black. In the Syn. o f Birds (i., p. 162), we find Brisson s
account accurately abridged; but, unfortunately, a reference is given to the PI.
Enl. 397, which represents a Thamnophilus, instead of a true Shrike. The error
in the Systerna Natural, and the false synonyme in the General Synopsis, are next
adopted by Gmelin ; and although we find the latter mistake rectified in the Index
Ornithologicus, its author brings in a third species, the Black-crowned Shrike of
Pennant, and frames his description so as to make it apply to both,—rthe “ pileus
niger ” belonging to Pennant’s bird ; for Brisson distinctly states that, in his
I/udovicianus, “ les parties supérieures de la tête, du col, le dos, êfc., sont cendrées."
All these errors are transferred into the General History o f Birds, with an opinion
expressed, that the L. I/udovicianus, as there characterized, may be a variety of
the same author’s L. nengeta (under which he comprises the ardosiaceus of Vieillot)
or of the excubitor. Before proceeding further, let us remember that we first began to lose sight of
the true L. I/udovicianus by an unlucky error in the S y sterna N aturoe ; that it
became more obscure in Gmelin’s compilation ; and that it was finally lost in the
Index Ornithologicus, the I/udovicianus of which work and of the General History is an imaginary bird. It shall now be shown that the L . nengeta of the same work,
to which its author thinks his I/udovicianus may be referred, as “ varieties of each
other,” is itself an imaginary speciesdecomposed of three real birds of different
Linnæan genera, and also of a fourth, which we have already shown to be fictitious,
namely, the ardosiaceus of Vieillot. Referring, therefore, to the synonymes at
p. 80 of the work last mentioned, wè need only observe that the Grey Pye of
Brazil (Edw., pi. 318) is a modern Nengetus and a Linnæan Fly-catcher ; that
the Cotinga cinerea of Brisson, as Le Vaillant remarked twenty years ago, is the
young of Ampelis pompadoura, L. ; and that the Grey Shrike of Pennant is either
the L . excubitor or borealis, loosely assimilated by Pennant with the bird of
Edwards.