98 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Having become a ground feeder, a habit doubtless very 
gradually acquired, it began less and less to use its wings, 
whilst the superabundance of its food alike tended to 
induce indolent habits, and rendered unnecessary the use 
of flight to take the bird to pastures new. The conditions 
of existence became too easy for it, with the usual result of 
degeneration setting in. Under the usual conditions of 
life, nature would have stepped in and silently quenched 
the tendency towards too indolent a habit of life, by 
cutting off those individuals which, by showing a definite 
leaning thereto, rendered themselves thereby a more easy 
prey to the attacks of enemies. But New Zealand, as is 
well known, prior to the advent of the white man, pos- 
sessed no predatory mammals—no mammals at all, indeed, 
except a rat, which was frugivorous in its habits—and 
consequently there were no enemies of this class to check 
the tendency to degeneration; whilst from diurnal birds 
of prey, of which indeed, New Zealand does not possess 
many, the nocturnal habits of Stringops sufficiently pro- 
tected it. Hence, having no inducement to fly either to 
obtain food or to escape from enemies, the disuse of its 
wings became a permanent habit, and along with this 
went atrophy of the structures, which rendered flight 
possible. That Stringops was, however, well adapted to 
its particular environment 1s evidenced by its former great 
abundance, whilst its scarcity now 1s owing to a change in 
that environment and the complete incapacity of the poor 
bird to adjust itself to its new conditions. LHre long its 
destruction will be completely accomplished, and one of 
the most interesting forms of bird-life will have passed 
from us for ever. 
This and other similar examples serve to indicate that 
the power of flight 1s no essential and necessary attribute 
of birds; it is a function acquired solely for the purpose of 
