380 
TROPICAL NATURE 
v 
away with the rapidity of a flash of light. Such active 
creatures would not be an easy prey to any rapacious bird ; 
and if one at length was captured, the morsel obtained would 
hardly repay the labour. We may be sure, therefore, that 
they are practically unmolested. The immense variety they 
exhibit in structure, plumage, and colour, indicates a high 
antiquity for the race; while their general abundance in 
individuals shows that they are a dominant group, well 
adapted to all the conditions of their existence. Here we 
find everything necessary for the development of accessory 
plumes and colour. The surplus vital energy shown in their 
combats and excessive activity has expended itself in ever- 
increasing developments of plumage, and greater and greater 
intensity of colour, regulated only by the need for specific 
identification which would be especially required in such 
small and mobile creatures. Thus may be explained those 
remarkable differences of colour between closely-allied species, 
one having a crest like the topaz, while in another it resembles 
the sapphire. The more vivid colours and more developed 
plumage of the males, I am now inclined to think, may be 
almost wholly due to their greater vital energy, and to those 
general laws which lead to such superior developments even 
in domestic breeds ; but in some cases the need of protection 
by the female while incubating, to which I formerly imputed 
the whole phenomenon, may have suppressed a portion of the 
ornament which she would otherwise have attained. 
The extreme pugnacity of humming-birds has been noticed 
by all observers, and it seems to be to some extent propor- 
tioned to the degree of colour and ornament in the species. 
Thus Mr. Salvin observes of Eugenes fulgens, that it is “ a most 
pugnacious bird,” and that “ hardly any species shows itself 
more brilliantly on the wing.” Again of Campylopterus 
hemileucurus : “ the pugnacity of this species is remarkable. 
It is very seldom that two males meet without an aerial 
battle ; ” and “ the large and showy tail of this humming-bird 
makes it one of the most conspicuous on the wing.” Again, 
the elegant frill-necked Lophornis ornatus “ is very pug- 
nacious, erecting its crest, throwing out its whiskers, and 
attacking every humming-bird that may pass within its range 
of vision ; ” and of another species, L. magnificus, it is said 
