32 KANSAS ACADEMY OF SCIENCE. 



or rim from two to three inches above the water ; eggs in several touched the water, and 

 were more or less stained in their wet beds; color of eggs when fresh, white, with a 

 light bluish shade; average measurement of the ten eggs, 1jq% by l T ? o°iy inches. I 

 watched the birds closely, during the three days I remained. Those out upon the lake 

 were noisy and active, keeping near the center and closely together. It was their court- 

 ship and matin»; -ground, but the birds in going to and from their nesting-places were 

 silent and watchful. In leaving their nests, would dive off, come up quite a distance 

 away, and then swim rapidly for the flock in the lake. I noticed at all times, not far 

 from the breeding-grounds, from five to eight birds, evidently sentinels, sitting upon the 

 water with heads high, ever upon the lookout and ready to give the alarm, but slow to 

 leave their station — in fact never leaving the little bay, taking good care, however, to 

 keep out of reach. As soon as I passed by, the birds frightened from their nests would 

 cautiously but quickly return, join the sentinels, from which point they would dive and 

 come up among the rushes. In no instance did I see them swim to or from their nests; 

 they may, however, do so when not disturbed. 



As papers of this character are written solely to present the observations and views 

 of the different writers, in order that in the end its history may be known and correctly 

 given, I will say that Mr. II. W. Henshaw, in paper of like character (Am. Nat., VIII, 

 1874, 243), found the birds nesting in similar lakes and places in southern Colorado, but 

 I think him somewhat in error in the conclusions reached, from the following portion of 

 his observations, viz. : 



"The eggs were wholly concealed from view by a pile of weeds and other vegetable 

 material laid across. That they were thus carefully covered, merely for concealment, I 

 cannot think, since in the isolated position in which these nests are usually found, the 

 bird has no enemy against which such precautions would avail. On first approaching 

 the locality, the grebes were all congregated at the further end of the pond, and shortly 

 betook themselves through an opening to the neighboring slough ; nor, so far as I could 

 ascertain, did they again approach the nests during my stay of three days. Is it not then 

 possible that they are more or less dependent for the hatching of their eggs upon the 

 artificial heat induced by the decaying vegetable substances of which the nests are 

 wholly composed?" 



Surely the birds have enemies in the vicinity, especially in the hawks and gulls, that 

 would quickly notice the eggs if uncovered. In the grass, not fifty feet from the nests I 

 have described, a marsh hawk {Circus hudsonim) was found sitting upon five eggs. I also 

 noticed several hawks in the vicinity, and several ring-billed gulls (Larus ddawarensis) 

 were skimming over and about the lake. Further, I do not think it "possible" to create 

 artificial heat from the slow decay of the vegetable matter composing the nests, resting 

 as they do in and upon ice-cold water, the eggs often touching the same. Before wading 

 out to the nests, I removed my boots and socks, and during the short time I was in the 

 water my feet and limbs were painfully cold. Colorado lies farther south, and the ele- 

 vation not so great, but the waters are made largely from the melting snows, and must 

 be chilly and cold so early in the season. I am inclined to think rather, that at the 

 time the birds were first discovered, the males, and hen birds not mated, or laying, were 

 near their nesting-grounds, and that those on their nests, after covering their eggs, dived 

 off, came up in the flock, and swam away with them, returning one by one when the 

 cause for alarm was removed. By swimming under water with only bill out at times to 

 breathe (a habit of the birds well known), they could easily reach their nests unnoticed. 

 Or it may be, as Mr. Henshaw only found three eggs in the nest — four to five being a 

 full set — that none of the birds were sitting. In this case there would be no necessity 

 for a hurried return, as absence during the day would do no harm. 



