Iv HUMMING-BIRDS 323 
are found in the temperate (northern and southern) parts of 
the continent are migrants, which retire in the winter to the 
warmer lands near or within the tropics. In the extreme 
north of America two species are regular summer visitants, one 
on the east and the other on the west of the Rocky Mountains. 
On the east the common North American or Ruby-throated 
humming-bird extends through the United States and Canada, 
and as far as 57° north latitude, or considerably north of 
Lake Winnipeg ; while the milder climate of the west coast 
allows the Rufous Flame-bearer to extend its range beyond 
Sitka to the parallel of 61°. Here they spend the whole 
summer, and breed, being found on the Columbia River in the 
latter end of April, retiring to Mexico in the winter. Sup- 
posing that those which go farthest north do not return 
farther south than the borders of the tropics, these little 
birds must make a journey of full three thousand miles each 
spring and autumn. The antarctic humming-bird visits the 
inhospitable shores of Tierra-del-Fuego, where it has been 
seen visiting the flowers of fuchsias in a snowstorm, while 
it spends the winter in the warmer parts of Chili and 
Bolivia. 
In the south of California and in the Central United 
States three or four other species are found in summer ; but 
it is only when we enter the tropics that the number of 
different kinds becomes considerable. In Mexico there are 
more than thirty species, while in the southern parts of 
Central America there are more than double that number. 
As we go on towards the equator they become still more 
numerous, till they reach their maximum in the equatorial 
Andes. They especially abound in the mountainous regions ; 
while the luxuriant forest plains of the Amazons, in which so 
many other forms of life reach their maximum, are very poor 
in humming-birds. Brazil, being more hilly and with more 
variety of vegetation, is richer, but does not equal the Andean 
valleys, plateaux, and volcanic peaks. Each separate district 
of the Andes has its peculiar species and often its peculiar 
genera, and many of the great volcanic mountains possess 
kinds which are confined to them. Thus, on the great 
mountain of Pichincha there is a peculiar species found at an 
elevation of about fourteen thousand feet only; while an 
