Vol. XXIX1 



1912 



J Rhoads, Birds of the Paramo of Central Ecuador. 147 



Paramo, but, as we near the frost line and the tussock grass dwarfs 

 and disappears, a curious, straggling, prickly, evergreen shrub, 

 the Chuquiraga insignis of Humboldt, is found growing in belts 

 and patches and attaining a stature of six or eight feet. It has 

 erect, thistle-shaped flowers of a brownish yellow hue and on these 

 the Pichincha Hill-Stars seemed almost solely to feed. Away 

 from these stony wastes, on the very verge of desolation, they never 

 wander far, though their strength and rapidity of flight is truly 

 wonderful and they seem to be the most restless of a restless family. 

 We secured several specimens and were disappointed to find nearly 

 every one in shabby, moulting plumage. The female Hill-Stars 

 are one of the plainest of their sex in the family, a sort of frosty 

 gray with only a faint tinge of the dorsal green which characterizes 

 nearly all of the Hummingbirds. The males are truly beautiful, 

 their pure white underparts and white, median tail feathers con- 

 trasting strongly with the dark wings and purple head and outer 

 tail. The tail is large and used with fine effect in their curvets and 

 airy gambols over the boulder-strewn arenal, down into the que- 

 bradas and up into the black, basaltic cliffs that overtop the crater. 

 Gould asserts this species is distinct from the Hill-Star, Oreo- 

 trochilus chimborazo, which inhabits a like region on Mt. Chimbo- 

 razo, though that mountain is only 40 miles distant and could be 

 reached by these wonderful aeronauts in as many minutes ! What 

 invisible barriers can the,y be which have set the bounds of such a 

 bird's wanderings? The close resemblance of the two species to 

 each other and to some ancestral type is unmistakable. We are 

 led to think that ancestor must have lived when the lower country, 

 now separating these two mountains, was at an average elevation 

 of 13,500 feet, or rather so elevated that the floral conditions then 

 and there obtaining favored the life of this Hummer. As that 

 region became depressed, the Hummers of the two localities nat- 

 urally advanced upward along the mountain slopes with the chang- 

 ing flora, and eventually became separated by a lower floral region, 

 unsuited to their needs. After that, local differentiation became 

 not only possible but probable, but it must have covered a period 

 of many thousands of years. In short, just as many an island 

 of the Pacific, due to depression, has been cut off from land affinities 

 it once shared with neighboring islands, resulting in the strangest 



