Mountain Bluebird

Here the details of the Mountain Bluebird named bird below:

SCI Name:  Sialia currucoides
Protonym:  Motacilla s. Sylvia Currucoides Allg.Uebers.Vogel[Latham] 3 p.546 pl.121
Taxonomy:  Passeriformes / Turdidae / Sialia
Taxonomy Code:  moublu
Type Locality:  Virginien [= western America].
Author:  Bechstein
Publish Year:  1798
IUCN Status:  Least Concern

DEFINITIONS

SIALIA
(Turdidae; Ϯ Eastern Bluebird S. sialis) Specific name Sylvia Sialis Wilson, 1808; "SIALIA. Sw. in Zool. Journ. No. 10.  37. Sialia azurea?  Sylvia Sialis? Wilson i. pl. 3. f. 3.  Common on the Table land at Real del Monte and other places. I have some doubts whether this is not a distinct species: my specimen is of a young bird." (Swainson 1827, Philos. Mag., new ser., I (May)); "SIALIA.   ...   Bill short, the base depressed, the sides compressed, culmen slightly elevated: nostrils partly hid by setaceous feathers: mouth wide, and slightly bearded" (Swainson 1827, Zool. Journ., III (September)); "Sialia Swainson, 1827, Phil. Mag., n.s., 1 (5), p. 369. Type, by monotypy [and virtual tautonymy], Sialia azurea Swainson = Motacilla sialis Linnaeus." (Ripley in Peters 1964, X, 83). Although famed in song and literature, the Eastern Bluebird is a declining bird of eastern North America.
Synon. Erythaca, Scyrornis, Sialis.

currucoides
Specific name Motacilla curruca Linnaeus, 1758; Gr. -οιδης -oidēs resembling; "179. Die grauliche Grasmücke.  (S. die 121ste Kupfertafel.)  Motacilla s. Sylvia Currucoides. BORKH.  Darmstädt. Mus.   Dieser Vogel hat viel Aehnlichkeit mit dem Müllerchen (Motacilla Curruca, L.)*)  An Größe gleicht er der großen Nachtigall (Motacilla Philomela, mihi).   ...   *) Da die Diagnose auf zwey ganz verschiedene Vögel paßt, so kann diese nach Herrn. Borkhausens Angabe folgendergestalt geändert werden:  Motacilla Curruca.  M. supra grisea fusca, subtus albida, vertice et stria infra oculari cinereis, remigum margine exteriori rufescente, rectrice extima marigine [sic] tenuiore alba.    Motacilla Currucoides.  M. supra griseo-fusca, mento cinerascente, remigum margine exteriore, rectrice extima margine tenuiore albida." (Bechstein 1798) (Sialia).