closely in every habit and even tone of voice. Secondly, there are two
owls, representing the short-eared and white barn-owls of Europe.
Thirdly, a wren, three tyrant-flycatchers (two of them species of
Pyrocephalus, one or both of which would be ranked by some
ornithologists as only varieties), and a dove--all analogous to, but
distinct from, American species. Fourthly, a swallow, which though
differing from the Progne purpurea of both Americas, only in being
rather duller colored, smaller, and slenderer, is considered by Mr.
Gould as specifically distinct. Fifthly, there are three species of
mocking thrush--a form highly characteristic of America. The remaining
land-birds form a most singular group of finches, related to each other
in the structure of their beaks, short tails, form of body and plumage:
there are thirteen species, which Mr. Gould has divided into four
sub-groups. All these species are peculiar to this archipelago; and so
is the whole group, with the exception of one species of the sub-group
Cactornis, lately brought from Bow Island, in the Low Archipelago. Of
Cactornis, the two species may be often seen climbing about the flowers
of the great cactus-trees; but all the other species of this group of
finches, mingled together in flocks, feed on the dry and sterile ground
of the lower districts. The males of all, or certainly of the greater
number, are jet black; and the females (with perhaps one or two
exceptions) are brown. The most curious fact is the perfect gradation
in the size of the beaks in the different species of Geospiza, from one
as large as that of a hawfinch to that of a chaffinch, and (if Mr.
Gould is right in including his sub-group, Certhidea, in the main
group) even to that of a warbler. The largest beak in the genus
Geospiza is shown in Fig. 1, and the smallest in Fig. 3; but instead of
there being only one intermediate species, with a beak of the size
shown in Fig. 2, there are no less than six species with insensibly
graduated beaks. The beak of the sub-group Certhidea, is shown in Fig.
4. The beak of Cactornis is
[picture]
1. Geospiza magnirostris. 2. Geospiza fortis. 3. Geospiza parvula.
4. Certhidea olivasea.
somewhat like that of a starling, and that of the fourth sub-group,
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