equent visitors, often in great numbers, but
are never able to establish themselves. On the same principle we account
for the fact that, of the many continental insects and birds that have
been let loose, or have escaped from confinement, in this country,
hardly one has been able to maintain itself, and the same phenomenon is
still more striking in the case of plants. Of the thousands of hardy
plants which grow easily in our gardens, very few have ever run wild,
and when the experiment is purposely tried it invariably fails. Thus A.
de Candolle informs us that several botanists of Paris, Geneva, and
especially of Montpellier, have sown the seeds of many hundreds of
species of exotic hardy plants, in what appeared to be the most
favourable situations, but that in hardly a single case has any one of
them become naturalised.[170] Still more, then, in plants than in
animals the absence of a species does not prove that it has never
reached the locality, but merely that it has not been able to maintain
itself in competition with the native productions. In other cases, as
we have seen, facts of an exactly opposite nature occur. The rat, the
pig, and the rabbit, the water-cress, the clover, and many other plants,
when introduced into New Zealand, nourish exceedingly, and even
exterminate their native competitors; so that in these cases we may feel
sure that the species in question did not exist in New Zealand simply
because they had been unable to reach that country by their natural
means of dispersal. I will now give a few cases, in addition to those
recorded in my previous works, of birds and insects which have been
observed far from any land.

_Birds and Insects at Sea._

Captain D. Fullarton of the ship _Timaru_ recorded in his log the
occurrence of a great number of small land-birds about the ship on 15th
March 1886, when in Lat. 48 deg. 31' N., Long. 8 deg. 16' W. He says: "A great
many small land-birds about us; put about sixty into a coop, evidently
tired out." And two days later, 17th March, "Over fifty of the birds
cooped on 15th died, though fed. Sparrows, finches, water-wagtails, two
small birds, name unknown, one kind like a linnet, and a large bird like
a starling. In all there have been on board over seventy birds, besides
some that hovered about us for some time and then fell into the sea
exhausted." Easterly winds and severe weather were experienced at the
time.[171] The spot where this remarkable flight of