no intervening land. After the island had been settled a year, and traversed in
every direction, his son paid it a visit; and just as the schooner was coming to an
anchor, a bird was seen flying from seaward which fell into the water exhausted
before it could reach the shore. A boat was sent to pick it up, and it was found to
be a Nicobar pigeon, which must have come from New Guinea, and flown a
hundred miles, since no such bird previously inhabited the island.
This is certainly a very curious case of adaptation to an unusual and
exceptional necessity. The bird does not ordinarily require great powers of flight,
since it lives in the forest, feeds on fallen fruits, and roosts in low trees like other
ground pigeons. The majority of the individuals, therefore, can never make full
use of their enormously powerful wings, till the exceptional case occurs of an
individual being blown out to sea, or driven to emigrate by the incursion of some
carnivorous animal, or the pressure of scarcity of food. A modification exactly
opposite to that which produced the wingless birds (the Apteryx, Cassowary, and
Dodo), appears to have here taken place; and it is curious that in both cases an
insular habitat should have been the moving cause. The explanation is probably
the same as that applied by Mr. Darwin to the case of the Madeira beetles, many
of which are wingless, while some of the winged ones have the wings better
developed than the same species on the continent. It was advantageous to these
insects either never to fly at all, and thus not run the risk of being blown out to
sea, or to fly so well as to be able either to return to land, or to migrate safely to
the continent. Pad flying was worse than not flying at all. So, while in such
islands as New Zealand and Mauritius far from all land, it was safer for a
ground-feeding bird not to fly at all, and the short-winged individuals
continually surviving, prepared the way for a wingless group of birds; in a vast
Archipelago thickly strewn with islands and islets it was advantageous to be able
occasionally to migrate, and thus the long and strong-winged varieties
maintained their existence longest, and ultimately supplanted all others, and
spread the race over the whole Archipelago.
Besides this pigeon, the only new bird I obtained during the trip was a rare
goat-sucker (Batrachostomus crinifrons), the only species of the genus yet found
in the Moluccas. Among my insects the best were the rare Pieris arum, of a rich
chrome yellow colour, with a black border and remarkable white antenna—
perhaps the very finest butterfly of the genus; and a large black wasp-like insect,
with immense jaws like a stag-beetle, which has been named Megachile Pluto by
Mr. B. Smith. I collected about a hundred species of beetles quite new to me, but
mostly very minute, and also many rare and handsome ones which I had already
found in Batchian. On the whole I was tolerably satisfied with my seventeen