EGGS AND EGG-COLLECTING. 7 
vast tracts of land by night, on wings the length and 
strength of which have been specially developed for such 
long flights. Some fly across great stretches of country, 
yet are never seen except at the points from which they 
start and finish their flight. Neither can these journeys 
be performed always under the guidance of leaders, for all 
migratory birds do not travel in flocks. 
I will endeavour to point out how Nature has solved 
the problem of preservation ; and it is equally interesting 
whether by the self-governed action of the bird, or the 
blind following of an impulse known only as instinct, 
Because we are unable to find any protective colouration 
in the plumage of a bird, its eggs or nest, we must not 
conclude that such peculiarity is a mere accident or useless 
decoration, for it either serves some wise end unknown to us, 
or has done so in far past ages, and is perpetuated because 
its possession is not distinctly harmful, and may at some 
future date be again called into requisition against danger. 
The extinction of nearly all birds whose existence 1s 
reasonably well known has not been due to natural causes, 
but to man or the influence his civilisation has introduced. 
Nature never made such a mistake as the introduction of 
rabbits and sparrows into Australia. They are two potent 
forces turned loose into practically unrestricted space, with- 
out any of their natural limiting influences. 
Protective Colouring of Birds.—The protective 
colour of the plumage of certain birds is the great source 
of their safety during incubation. For instance, birds 
which nidificate on the ground, such as Black and Red 
Grouse, Pheasants, Partridges, and Sandpipers, all subject 
to the depredations of winged and creeping enemies, are 
preserved by the modification of their tints. The same 
