Tip of bill horny and strongly convex forming a "nail" which is often
of a shade or color different from that of the soft, contracted, basal
portion; covering of nostril generally tumid; toes four, three in
front, cleft to the base or with a slight web; hind toe not elevated;
legs and toes never much lengthened; tarsus either slightly longer or
slightly shorter than middle toe without claw; wing flat and rather
long; in several genera the primaries variously cut or attenuated;
tail usually square or slightly rounded; never forked; in Macropygia
and Geopelia the rectrices are greatly graduated. A few genera are
terrestrial, but most of them are more or less arboreal and generally
capable of strong, swift, and sustained flight. Their food is largely
grain and small seeds; the larger species feed on the fruits of trees,
rarely on the leaves. The nest is a slight structure of twigs placed on
the ground, in a shrub, or in a tall tree. Eggs one or two, pure white
or slightly cream-colored; in shape rather long, equal ended, ovals.
Suborder COLUMBÆ.
Characters same as those given for the Order.
Families.
a1. Soles very broad; tarsus stout, more or less feathered, and
generally shorter than middle toe without claw.
b1. Nostril coverings flat or but slightly swollen ... Treronidæ
(p. 24)
b2. Nostril coverings swollen forming a grape-seed shaped prominence
on each side of culmen ... Columbidæ (p. 51)
a2. Soles not greatly expanded on sides of toes; tarsus more slender,
unfeathered, and longer than middle toe without claw ... Peristeridæ
(p. 54)
Family TRERONIDÆ.
Soles very broad; tarsus stout, more or less feathered; bill stout
or large; gape very wide in some; nostril covering flat or somewhat
swollen; tail moderate in length, nearly square; medium to large
sized species.
Subfamilies.
a1. Under tail-coverts long, their tips reaching well beyond toes;
size generally smaller; length, 340 mm. or less.
b1. First primary not attenuated; third primary scooped on
middle of inner web, except in Phapitreron which has mostly brown
plumage. ... Treroninæ (p. 24)
b2. First primary abruptly attenuated, except in Spilotreron which
has mostly green plumage; third primary normal ... Ptilopodinæ
(p. 36)
a2. Under tail-coverts moderate, their tips reaching little if
any beyond toes; size generally larger; length, 360 mm. or more
... Muscadivorinæ (p. 42)
Subfamily TRERONINÆ.
Genera.
a1. General color green or greenish yellow; rectrices fourteen,
under coverts usually equal to or longer than shortest rectrix;
third primary deeply scooped near middle of inner web.
b1. Horny nail of bill reaching feathers of forehead ... Treron
(p. 25)
b2. Horny nail of bill not reaching feathers of forehead.
c1. Tail slightly graduated; under tail-coverts broadly streaked,
the shafts black ... Sphenocercus (p. 26)
c2. Tail square; under tail-coverts not streaked, the shafts of
the same color as the webs ... Osmotreron (p. 26)
a2. General color brown; rectrices twelve, under coverts shorter than
shortest rectrix; third primary not scooped ... Phapitreron (p. 29)
Genus TRERON Vieillot, 1816.
This genus differs from the other green pigeons in having the horny
portion of culmen extending back to frontal feathers; a small naked
area around eye; pattern and colors of the plumage very similar to
those of Osmotreron axillaris.