246 
U. S. P. K. R. EXP. AND SURVEYS ZOOLOGY — GENERAL REPORT. 
OPORORNIS, 1 Baird. 
Ch. — Bill sylvicolino, rather compressed ; distinctly notched at tip ; rictal bristles very much reduced. Wings elongated, 
pointed, much longer than the tail ; the first quill nearly or quite the longest. Tail very slightly rounded ; tail leathers 
acuminate, pointed ; the under coverts reaching to within less than half an inch of their tip. Tarsi elongated, longer than 
the head ; claws large, the hinder one as long as its digit, and longer than the lateral toes. Above olive green ; beneath 
yellow ; tail and wings immaculate. Legs yellow. 
This group of American warblers is very distinct from any other. The typical species is 
quite similar in color to Geothlypis Philadelphia, but is at once to be distinguished by much 
longer wings, more even tail, and larger toes and claws. It is also very similar to Seiurus, 
differing chiefly in the longer wings, larger claws, and absence of spots beneath. 
Throat and crown ash color ; a white ring round the eye. No black on the side of 
the head 0. agilis. 
Throat and superciliary stripe yellow ; top of the head and a streak beneath the eye 
black 0. formosas. 
Comparati ve measurements of species. 
Catal. 
No. 
2309 
10153 
Species. 
Locality. 
Sex. 
Length. 
Stretch 
of wings 
Wing. 
Tail. 
Tarsus. 
Middle 
[ts claw 
alone. 
Bill 
above. 
Along 
gape. 
Specimen 
measured. 
Oporomis agilis 
8 
5.20 
5.9L 
5.00 
4.76 
5.36 
2.86 
3.00 
2.74 
2.60 
0.80 
0.76 
0.18 
0.48 
0.62 
9.00 
Fresh.... 
2.30 
2.20 
2.10 
0.80 
0.82 
0.93 
0.70 
0.72 
0.71 
0 16 
0.18 
0.18 
0.43 
0.40 
0.44 
0.56 
0.54 
0.58 
Oporornis formosus 
8 
9 
Dry 
South Illinois. . ... 
Dry 
OPOROKNIS AGILIS, Baird. 
Connecticut Warbler. 
Sylvia agilis, Wilson, Am. Orn. V, 1819, 64 ; pi. xxxix, f. 4.— Bonap. Obs. Wils. 1825, no. 163.— Aud. Orn. Biog. 
II, 1834, 227 ; pi. 138. 
Sylvicola agilis, Jaudine ed. Wilson, 1832.— Rich. List, 1837.— Aud. Synopsis, 1839, 63.— Ib. Orn. Biog. II, 1841, 
71 ; pi. 99. 
Trichas agilis, Niittall, Man. I, 2d ed. 1840, 403. 
Trichas tephrocotis, Nuttall, Man. I, 2d ed. 1840, 462, (Chester county, Penn., adult with whole head ash.) 
Sp. Ch. — Upper parts and sides of the body uniform olive green, very slightly tinged with ash on the crown. Sides of the, 
head ash tinged with dusky beneath the eye. (Entire head sometimes ash.) Chin and throat grayish ash, gradually becoming 
darker to the upper part of the breast, where it becomes tinged with dark ash. Sides of the neck, breast, and body, olive, like 
the back ; rest of under parts light yellow. A broad continuous white ring round the eye. Wings and tail feathers olive, 
(especially the latter,) without any trace of bars or spots. Bill brown above. Feet yellow. Length, 6 inches ; wing, 3 ; 
tail, 2.2.5. 
Hah. — Eastern United States. (Very rarely seen.) 
In this species the wings are long and pointed, reaching beyond the middle of the tail or 
within an inch of the end, (in the fresh specimen.) The primaries are .85 of an inch longer 
than the secondaries. The primaries become successively and decidedly shorter than the first, 
which is longest. The tail feathers are broad, acuminate, and slightly graduated. 
A second specimen (2939) is similar, but differs in having the crown dark plumbeous ash. 
Both of these are spring specimens. In fall, when the species is much more frequently seen, 
1 The name is used in reference to the abundanco of O. agilis in autumn, compared with its excessive rarity in spring. 
