SYLVIAD^E.
The preceding digressions on the natural arrangement of those two important
families, the Laniadw and the Merulidw, have occupied so much space, that our
observations on the remaining groups of the Insessores must be restricted to
results, leaving the facts upon which they repose to be stated on some future occasion.
In treating of the Sylviadai, we more particularly regret this necessity for
abridgment. No group in the whole circle of Ornithology, as confessed by all
writers, is in such a chaotic state of confusion ; yet no group throughout nature
that has yet been analyzed, offers a more perfect demonstration of the trinary system
of distribution than his. This subject, as assuming such an important aspect,
will be more fully discussed in another work*, now nearly ready for the press.
The Sylvia die, or Warblers, may be also termed A mbulating F lycatchers ;
since, when viewed collectively, they are only separated from the Musdcapinm by
a different mode of feeding, indicated by the superior length and structure of their
feet: these members, in th§ Sylvia die, are adapted for constant locomotion, either
among branches, or upon the ground ; whereas, in the true Flycatchers, the feet
are short, small, and feeble, corresponding to the sedentary habits of those birds.
Comparing the Warblers, on the other hand, with the Thrushes, we see that the
best distinction between the two groups lies in the very character which assimilates
the Sylviada: to the Flycatchers, namely, the basal depression of the bill. We
allude, of course, to typical examples; since all these distinctions are softened
down, in proportion as the three groups approximate.
A careful analysis of this family will show it is composed of three primary
circles, each returning into itself. One of these embraces the three aberrant subfamilies,
the two others constituting the typical and the sub-typical sub-families,
as follows :—
SYLVIA1L®.
1 . ƒ Bill very slender, suddenly compressed be- 1 „
Typical group. I yond the base ; stature very small. J S '
2. j Bill stronger, gradually compressed beyond 1 p
Sub-lypical group\ the base; stature more robust. J *nL0JfEI'IN-®* {Feet more especially adapted for one parti- j S a x icolin je.
cular purpose, either for walking, run- r M otacillixa:.
ning, or climbing. J P a ria n.®.
An Encyclopedia of Zoology, one thick octavo volume, with numerous wood-cuts.
In offering the foregoing characters as distinctions of the three primary divisions,
the ornithologist will bear in mind the difficulty of defining differences between
groups so closely united by imperceptible gradations in their aberrant forms. It
may, however, be observed, that the true Sylviadw are the most perfectly organized,
since they not only search for their food, like the Nightingales. (PMomelimeJ, among boughs and trees,—catch insects upon the wing, like Flycatchers, but
are frequently seen on the ground, upon which they move with perfect facility*.
From the subtypical group the fly-catching habits seem to be withheld; and, on
proceeding to the aberrant group, we’find a still further diminution in the powers
of locomotion; they are less varied, but more concentrated. The Saxicolinw
walk, but do not explore trees, or habitually catch insects on the wing from a
fixed station. The Motacillinie rarely perch, and never climb, yet they run with
amazing celerity. The Parianw, again, are excluded from the ground, and from
capturing winged insects, yet they excel all others of their family in climbing
among branches. The genus Sylvicola, Sw., standing intermediate between the
true Titmice and the typical Sylvianie, present us, of course, with a union of both
habits. All these modes of progression are distinctly indicated by a corresponding
variation in the structure We shall shortly noticoef tthhee fpeerti.ncipal forms which enter into these groups.
The first, or typical circle, is marked by the following genera:—Sylvia, L. ;
Malurus, Vieil.; Prinea, Horsf.; Hyliota, Sw.; and Culidnora, Sw. The
second, or sub-typical, is indicated by Synallams ? Vieil.; Curruca, Bech.;
Philomela, Antiq. ; Phwnicura, Sw.; and Thamnobia, Sw. ; but the affinities of
this latter group are by no means certain. In regard to the third, or aberrant
division, the ornithologist will immediately perceive the union of the Saxicolinw with the Parianw, by looking to the following birds, having before him our well-
known Robin, as one of the first links in the chain :—Petro'ica multicolor, Sw. j*
P. Lathami, Sw. $ Setophaga (Erythrosoma) picta §, Sw. S. (-E.) mmiata,
S-w F. r||o, man dt hSee totphhraeeg ap rruimtidarllya , dSivwis.ions thus indicated, we proceed to the subfamilies,
in which we have a perfect representation of the five principal groups
of the Merulidw. We shall, however, get a more accurate notion of the whole
family, by comparing it with the tribes of the Insessores.
* This fact, in reference to the Sylvia hippolais, we have had frequent opportunities of observing in our own
garfd eZno, owlohgeircea lt hIlel ussptercaiteiso niss ,v eseryco cnodm smeroiens.—, pSi.w 3.6 . t Muscicapa Lathami, Vig•. , ■Lin. Trans., vol. xv., p. 205.
& Zool. 111., second series, pi. 2. II Synop. of Mexican Birds, N.o. 18.
2 D