Scott on Birds observed at Twin Lakes, Colorado. 91 
I shall simply give those absolutely noted, passing the better known 
with but a word to indicate their occurrence. As a whole, this 
seems to be a very thickly populated region, considered ornitho- 
logically, there being very many individuals of most of the species 
noted. 
1 . Turdus migratorius. Robin. — - Very common at the level of the 
Lakes. Begins to breed about June 5. The breasts of the males are more 
c5 
tawny, and the general coloring lighter, than in individuals from the East- 
ern States. Young fully fledged were observed June 29. All the nests 
found are curiously built of sage-brush, and the “ mud walls ” were not 
prominent. 
2. Turdus pallasi. Hermit Thrush. — Not common. Noted on 
the hills to the south of Lower Lake. 
3. Oreoscoptes montanus. Mountain Mocking-Bird. — Not 
common. Not met with about the Lakes, but at a point five miles north 
in a small park. 
4. Sialia arctica. Arctic Bluebird. — Abundant. Breeds about 
June 1 in deserted Woodpeckers’ holes and hollow trees. 
5. Cinclus mexicanus. Water Ouzel. — Not common. Occur 
above the Upper Lake on the stream flowing into it, and on the Arkansas 
River at the junction of Lake Creek. On the 22d of June I found a pair 
on a pond of still water about a hundred yards from the stream that flows 
into the Lakes, the pond and stream not being connected. The female 
showed no signs of having laid eggs or of incubation. This pair was not 
at all shy, allowing my close approach as they walked about on some float- 
ing logs feeding on the aquatic larvae that abounded. 
6. Regulus calendula. Ruby-crowned Kinglet. — Abundant. 
One of the most common song-birds, and heard everywhere. On the 20th 
of June I saw a female fly to a pine-tree with material in her bill for build- 
ing a nest. On looking I found a nest nearly finished. On the 25th of 
June I took this nest with five fresh eggs, and the female showed signs of 
having incubated. I think no more eggs would have been laid. The nest 
is before me as I write, and presents the following peculiarities : It is semi- 
pensile, being suspended to the leaves of the pine, and to one small branch, 
much like the Red-eyed Yireo’s nest. It is very large in proportion to the 
builder, and is made of the bark of sage-brush and of green moss very 
firmly twisted together, and forming a soft outer wall, of from half to a full 
inch in thickness. This is lined with feathers and hair. The whole nest 
is very soft, and has the following dimensions : Four inches deep outside ; 
three inches deep inside ; three inches in diameter outside, and two inches 
at the top inside, but narrowing to an inch and a half at the bottom. On 
the outside it is as wide at the bottom as at the top, being in this respect 
like a Baltimore Oriole’s. It was placed at the very outermost twigs and 
leaves of the tree, about twelve feet from the ground. The eggs are five 
