My Attention
Was First Thoroughly Aroused, By Comparing Together
The Numerous Specimens, Shot By Myself And Several Other
Parties On
Board, of the mocking-thrushes, when, to my
astonishment, I discovered that all those from Charles Island
belonged to one
Species (Mimus trifasciatus) all from
Albemarle Island to M. parvulus; and all from James and
Chatham Islands (between which two other islands are situated,
as connecting links) belonged to M. melanotis. These
two latter species are closely allied, and would by some
ornithologists be considered as only well-marked races or
varieties; but the Mimus trifasciatus is very distinct.
Unfortunately most of the specimens of the finch tribe were
mingled together; but I have strong reasons to suspect that
some of the species of the sub-group Geospiza are confined
to separate islands. If the different islands have their
representatives of Geospiza, it may help to explain the
singularly large number of the species of this sub-group in this
one small archipelago, and as a probable consequence of their
numbers, the perfectly graduated series in the size of their
beaks. Two species of the sub-group Cactornis, and two of
the Camarhynchus, were procured in the archipelago; and
of the numerous specimens of these two sub-groups shot by
four collectors at James Island, all were found to belong to
one species of each; whereas the numerous specimens shot
either on Chatham or Charles Island (for the two sets were
mingled together) all belonged to the two other species:
hence we may feel almost sure that these islands possess
their respective species of these two sub-groups.
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