MiNOT on Colorado Birds. 223 



color is a peculiar pale olive-bufiP, not matched by one of more than 

 five hundred eggs of the Royal Tern with which they have been 

 compared, and the markings, distributed nearly equally over the 

 entire surface, consist of small spots (roundish on the smaller egg, 

 irregular on the larger) of deep sepia-brown and pale lavender. In 

 every respect except size they quite closely resemble some eggs of 

 the Oyster-catcher, but are, of course, very much larger. 



As regards the abundance of the species along the Virginia coast 

 in summer, our experience is the same as that of last year, not more 

 than one pair being observed ; and the fact that this pair was 

 isolated from all other birds, while an immense colony of the Royal 

 Tern was breeding on a remarkably restricted area not more than a 

 quarter of a mile distant, induces us to believe that this is a normal 

 habit of the bird, although we have no other evidence that the spe- 

 cies may not sometimes breed in colonies. 



The Caspian Tern when seen flying may be distinguished, by a 

 careful observer, from the Royal Tern by its more robust build, 

 shorter, much less deeply forked tail, and by the uniform blackish 

 appearance of the end-half of the wing, the greater part of the inner 

 webs of the quills being white in the Royal, while the whole sur- 

 face is dark slaty in the Caspian. The two are so much alike in 

 appearance, however, that it requires the closest observation to dis- 

 tinguish them. 



NOTES ON COLORADO BIRDS. 



BY H. D. MINOT. 



Boulder, where many of the following observations were made, 

 lies just below the foot-hills, about thirty miles northwest of Den- 

 ver, and 5,500 feet above the sea. Here I stayed from May 12 to 

 19, and from May 24 to June 1, inclusive. Eighteen miles west- 

 ward, among the hills, is Nederland, over 8,000 feet up. Colorado 

 Springs is almost a degree south of Denver, with a season that 

 among the birds is at least a week in advance of Boulder, and which 

 this year (1880) has corresponded to that of Boston. Five miles 

 back from this city of the plains, along Fountain Creek, and among 

 the scrub-oaks that mark the latitude, is Manitou, over G,000 feet 



