The intrinsic muscles of the syrinx fixed to the ends of the bronchial semi-rings; the edges of both mandibles smooth or the upper one with a single simple notch; hinder aspect of tarsus smooth, composed of two entire longitudinal laminae; wing with ten primaries; tongue non-tubular; nostrils always clear of the line of forehead, the space between the nostril and the edge of the mandible less than the space between the nostril and the culmen; the plumage of the young is like that of the adult female but brighter, in many cases more yellow or rufous; tail-feathers ten or twelve, sexes generally alike; a partial or complete Spring moult in addition to the complete Autumn moult.
The Sylviidae, or Warblers, comprise a large number of birds of small size and, with few exceptions, plain plumage. Hartert includes them in. his Muscicapidae, or Flycatchers, but these birds have the nestlings spotted or squamated, a perfectly sufficient reason for dividing them from this family. The Sylviidae have a complete or partial Spring moult, which not only generally causes a change in the colour of the plumage but in some also changes the length and shape of the tail. In some Warblers this moult affects only the quills of the wings and tails.
In the Sylviidae, though the young are often more highly coloured than the adults, they have the same colour-pattern. Some young Warblers appear to have no moult in the first Autumn, whilst in a few this moult, as in Locustella, appears to form a transition-stage between the nestling plumage and that of the adult. Others of the Sylviidae change direct into the adult plumage at their first Spring moult and others again do not obtain the adult plumage until their second Autumn moult.
Many species of Warblers are migratory, others are resident and in a few there are both resident and migratory subspecies of the same species.
The Sylviidae found within the limits of this work comprise about 150 species and subspecies referable to 33 genera. I follow Oates in the main features of his key and divide them in two classes, the first of which includes all Warblers with twelve tail-feathers and the second those with ten.
Key to Genera.
A. Tail of twelve feathers.
a. Feathers of the forehead short, rounded, their shafts not elongate; no hairs or bristles on the margin of the forehead, except the ordinary rictal ones near the gape.
a1. Rictal bristles arranged in a horizontal row.
a2. Feathers of head and neck soft, not spinous.
a3. First primary less than a third of the length of the second.
a4. Wing longer than tail by about
the length of tarsus……………………… Agrobates, p. 385.
b4. Wing and tail about equal in length.
a5. Rictal bristles well developed; tail-feathers less graduated,
the outermost more than ¾ length of tail ………………..Acrocephalus, [p. 387.
b5. Rictal bristles very small; tail much graduated, outermost
feathers less than 3/4 length of
tail Locustella, p. 399.
b3 First primary longer than a third of the second.
c4 Rictal bristles extremely short.
c3. First primary not more than
half second Tribura, p. 403.
d3. First primary equal to 3/4 second…………..ELAPHRORNIS,
d4. Rictal bristles well developed. [p. 408.
e3 Bill as long as, or longer than,
the head Orthotomus, p. 410.
f3 . Bill decidedly shorter than the head.
a6. First primary shorter than half second.
a7. Wing pointed Lusciniola, p. 417.
b7. Wing rounded……………….…Cisticola, p. 419.
b6. First primary longer than half second.
c7. Third primary not longest nor equal to longest.
a8. Two rictal bristles……………..Franklinia, p. 424.
b8. More than two rictal bristles.
a9. Tail more than 1 ½ times length of wing………Laticilla, p. 430.
b9. Tail less than 1 1/2 times length of wing…………Graminicola, [p. 432
d7. Third primary reaching to tip of wing.
c8. Tail much longer than wing ………………….Megalurus, p. 434.
d8. Tail about equal to wing…………………Schaenicola, p.436.
b1. Rictal bristles arranged vertically …………..Chaetornis, p. 438.
b. Feathers of the forehead disintegrated, the shafts lengthened; supplementary bristles
in front of rictal bristles.[p. 439.
c1. Tail greatly graduated and rounded …….Phragmaticola,
d1. Tail nearly even or slightly forked.
b2 Supplementary bristles short, no frontal hairs over nostrils.
c3. Bill from gape to tip longer than
middle toe with claw Hippolais, p. 441.
d3. Bill from gape to tip shorter than
middle toe with claw Sylvia, p. 446.
c2. Supplementary bristles very strong
and numerous, no frontal hairs; bill
stout Herbivocula, [p. 452.
d2. Supplementary bristles numerous but
not strong, no frontal hairs; bill
slender Phylloscopus, [p. 453.
e2. Supplementary bristles very strong and numerous, extending over nostrils up
to centre of culmen; bill large and
wide; first primary small Acanthopneuste, [p. 471
f2. Supplementary bristles similar but extending up to tip of bill; first primary
small Seicercus, p. 485.
g2. Supplementary bristles reaching to middle of bill; first primary large,
exceeding half second………………Muscitrea, p. 483.
B. Tail of ten feathers.
e. Tail no longer in Winter than Summer; not cross-rayed or only obsoletely so ; graduated slightly or not at all.
e1 Wing and tail about equal in length.
h2. Nostrils overhung by long hairs,
e3 Tail very slightly rounded.
e4. Rictal bristles of great length; wing longer than tail.
g3. Bill short and pointed Abrornis, p. 493.
h5. Bill long and blunt Tickellia, p. 499.
f4. Rictal bristles moderate ; wing
shorter than tail Scotocerca, p 501.
f3.Tail considerably rounded Neornis, p. 502.
i2. No&trils not overhung by hair.
g3. Supplementary bustles in front of rictal bristles; feathers of fore-head with shafts prolonged Horornis, p. 504.
h3. No supplementary bristles ; feathers of forehead with shafts not prolonged, [p. 516.
g1. Bill broad, blunt and long Phyllergates,
h1. Bill sharp and slender.
i3 . Outer tail-feathers much shorter
than central Horeites, p. 512.
j3 . Outer tail-leathers very little
shorter than central Cettia, p. 514.
f1. Wing about twice as long as tail Urophlexis, p. 515-
d. Tail longer in Winter than in Summer, cross-rayed and greatly graduated.
g1. Tail twice as long" as wing Suya, p. 518.
h1. Tail one and a half times as long as wing. Prinia, p. 525.