We have a proof of this in the fact that so few, comparatively, of our perfectly hardy garden plants ever run wild; and even the most persevering attempts to naturalize them usually fail.
On the 17th of February 1847, Abel was dismissed, for publishing his memorandum against the proposal to naturalize Lola, who was an Irishwoman; and the Protestant Georg Ludwig von Maurer took his place.
At least one species of Tinamou has bred not infrequently in confinement, and partly successful attempts to naturalize the species Rhynchotus rufescens have been made in England.
Attempts have also been made to naturalize continental insects in Britain, in places where the proper food-plants abound and the conditions seem generally favourable, but in no case do they seem to have succeeded.
Birds of prey are, unjustly enough, regarded with so little favour that few attempts have been made to naturalize them; the continental little owl (Athene noctua), however, has for some time been well established in England, where it has hardly, if ever, appeared naturally.
Attempts to naturalize that well-known Australian grass-parrakeet the budgerigar (Melopsittacus undulatus) in England have so far proved abortive, and none of the species experimented with in Norfolk and Bedfordshire effected a settlement.