Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 9, Pt. 1

BIRDS- SYLVICOLIDAE-DENDROICA AESTIVA.
several cases are almost entirely brown, excepting on the inner edge. Such is the case in
10170, from Fort Tejon, 5295, Yellowstone, and 758, Carlisle, all apparently young of the
year. Some adult females, too, have more or less of a brown margin on the inner side of the
shaft towards the base.
In nearly all full plumaged males of this species from the Missouri plains there is a strong
indication of a brownish orange (like the pectoral spots) on the top of the head, especially along
the shafts of the feathers. It is this plumage, with perhaps a little greater intensity of red on the
crown, which I consider to be the [otacilla petechtia of Linnaeus, as stated further under the
head of lD~enctroica p?almarunm, and as the former name has priority over ae8ti_va, it is a question
whether it should not be used for the present species. By some authors the two states of
plumage are considered distinct, in which case both names could be used. I agree with
Bonaparte, however, (Notes Orn. Delattre,) in considering them the same, but as indicating a
variety, not the average of the species; and in view of there being after all some doubt as to
what Motacilla petechia really is, I have retained the name of aestiva. The same objections
apply to the use of Gmelin's name of ruficapilla.
The ANotacila albicollis of Gmelin answers tolerably well to this species, and the name would
have priority over aestiva. As, however, the neck is not white, but yellow, the term albicollis
would convey a false idea of the species, and to be rejected.
The Sylvia foava of Vieillot comes nearer this species than any other North American, but
does not exactly agree with it.
There is a South American species to which this is closely related, differing in larger ire,
and in having the entire head all round of a brownish orange. The quills and tail feathers
are much darker, showing a more vivid contrast with the yellow. This is called "Syvia
ruficapilla, Latham," by Vieillot, in Nouv. Dict. XI, 1817, 228, but is not Latham's species, nor
is it the "Sylvia ruficapillus" of Vieillot on a preceding page, (187.) He quotes for it a name
of Feuillee in "Observations Physiques, 1714-1725," of Chioris erithachorides, and its description, referring evidently to the bird before me. Should the species, therefore, have received no
better name it may be called Dendroica erihtachorides.
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