1 62 
SUMMER BIRDS. 
rested, and his investigation disclosed the fact that the mosses which 
abounded immediately about the nest had not been utilized as build- 
ing material. As determined by Professor Eaton, the species of 
moss composing the bed were: Hyp Am umbratum, H splendens, 
H. Schreberi , H. Crista-castrcnsis. Those appearing in the nest : 
Hypnum Muller ionum , H. Muhlenbeckii (? ) , Dicranum longifolium , 
D. flag ell are, Polytrichum commune, P. formosum. With these oc- 
curred the following Hepaticse : Mastigobryum trilobatmn, Scapania 
albicans, Cephalozia bicuspidata. In addition were found among the 
materials of construction, catkin scales of the birch, leaves of the 
balsam, and fragments of the dried pinnae of ferns, but, as suggested 
by Professor Eaton, the presence - ot some of these was probably 
accidental. Springing from the verdant moss beds immediately 
about the nest were scattered plants of Oxalis acelosella, Trientalis 
Americana , Solidago thy r so idea, and Clintonia borealis. 
It is rather surprising to find specimens of the Yellow-bellied Fly- 
catcher — undoubtedly a bird of the Canadian Fauna* — from southern 
New York to be of large size for the species. We might well have 
expected the reverse to be the case, and the fact of maximum spe- 
cific size thus obtaining at, so far as we now know, the southernmost 
breeding limit of the species, illustrates well the close correspondence 
between the conditions imposed by altitude and by more advanced 
latitude without elevation, on organic nature. 
The following measurements and comparison will show the relative 
size of the Catskill birds with the largest examples of eleven specimens 
taken on the migrations at New York. 
New York Specimens. 
Date. 
Sex. 
Length. 
Wing. 
Tail. 
Tarsus. 
Middle 
Bill.culmen and 
toe. 
from nostril. 
Aim. 
0 
20, ’81, 
? 
5.45 
2.6 3 
2-33 
.64 
•33 
•4I--3I 
May 
29. ’7 9- 
$ 
5.47 
2.60 
2.3O 
.65 
•3° 
-4i--3 1 
l f 
24, ’78, 
6 
5.5o 
2.65 
2.25 
.67 
•33 
•43--33 
Aug. 
25, ’;5, 
S (?)5.56 
2.65 
2.32 
.68 
•32 
•43--33 
Slide Mountai 
n Specimens. 
June 
12, ’80, 
8 
5.6o 
2-73 
2.48 
•63 
•33 
•44--34 
“ 
26, ’82, 
8 
5.57 
2.65 
2-37 
.64 
't ^ 
•3° 
•42-32 
As compared with the specimens from New York those from the 
Catskills, besides greater size, also present some difference in the 
* That this bird has been suspected to breed in regions thoroughly Alleghanian or even more 
southern in Fauna, is to be accounted for from the fact that the times of its migration are such as 
might easily give rise to the impression. The species is one of the latest of the migrants to remain 
with us in the spring, and one of the first to reappear on the return movement. Thus, in the neigh- 
borhood of New York, where it occurrs strictly as a transient semi-annual migrant, it remains, 
on the advance movement, sometimes into June, and is always to be again looked for early in 
August ; and, though I have no actual July records, individuals doubtless sometimes appear by the 
latter part of that month. 
