Proposal (851) to South American Classification Committee

Add Spizella pallida to the South American list

Tigreros et al. (2019) recently presented a brief article with photos, to document the addition of the Clay-colored Sparrow (Spizella pallida) to the South American avifauna. They presented comparisons with the known species of Ammodramus (humeralis, aurifrons, savannarum) that clearly demonstrate that the photographed bird cannot be placed in this genus, all species of which are much more brownish to buffy in color than the bird in the photo. However, they did not make a detailed comparison between the specimen and other species of Spizella, especially S. breweri, to justify their identification.

The specimen was collected on 11 May 2016 in Cali after its collision with a window and was immediately frozen. Posterior dissection and preparation of the specimen led them to conclude that the specimen represented S. pallida. However, the rather poor preparation may have left the identification in doubt: evidently the tail was partly disarticulated, leaving its measurement doubtful. It was sexed as an adult male with abundant fat, but evidently data on its gonads and skull ossification were not taken, such that its age could not be determined precisely, and not all of its characteristics excluded S. breweri. I have consulted several sources comparing the two species, both of which regularly winter as far south as northern Central America. There are records of vagrant individuals of pallida from as far south as central Panama, making it the more likely for the Cali specimen. Nonetheless, a more detailed comparison between this species and breweri seems in order, because in most features the two species are quite similar. The following table presents this analysis, based on Sibley (2000), Pyle et al. (1987) and National Geographic (2004), and the photographs of the specimen.

	S. pallida	S. breweri	Cali specimen	Tentative conclusion
Breast coloration	Strong buffy wash, esp. In HY; faint in ASY	Grayish white, no trace of buffy color	Grayish white, at most faint trace of buffy color	breweri?(NG does not mention buff in adult pallida)
Cheeks and auriculars	Buffy-brown to brown	Pale grayish-brown	Pale grayish-brown	?
Postocular and malar stripes	Distinctly darker brown to blackish	Fairly distinct, slightly darker gray-brown	Fairly distinct, blackish-brown	pallida?
Superciliary	Buffy	Pale grayish to whitish	Buffy-whitish	pallida?
Crown pattern	Streaked blackish and brown, distinct whitish medial stripe	Streaked blackish and brownish, pale medial stripe weak or lacking	Streaked blackish and brownish, distinct pale gray medial stripe	pallida
Lateral throat stripe	Distinct, dark brown to blackish	Narrow, indistinct, gray	Narrow, fairly distinct, gray-brown	?
Nape	Clear gray, unmarked	Gray, more or less streaked with blackish-brown	Gray, anteriorly immaculate, lightly streaked posteriorly	¿
Other facial markings	No distinct pale eye-ring	Distinct pale eye-ring	No distinct pale eye-ring	pallida
Rump	Grayish-brown, unstreaked	Grayish-brown, light darker streaking	Grayish-brown, very lightly streaked darker	breweri?

Clearly, the well-marked pale gray central crown-stripe is the most marked character supporting the specimen’s identification as pallida; various other characters are less distinctive. The wing measurements provide no clue, beyond being OK for males of both species. Pyle gives wing minus tail as usually greater than 1.5mm in pallida, less than this in breweri, but because r5 has been clearly displaced in the specimen, no conclusion can be drawn. The May date of the specimen would indicate that it should be in breeding plumage, assuming that it molted on schedule (but the specimen is described as molting r5.) The abundant fat of the specimen suggests that it was in migratory condition, but the May date indicates that it was late for spring migration, because Sibley states that birds of both species appear to reach their breeding grounds by March; a retarded or partial prealternate molt in the specimen is thus at least possible. Pyle indicates that individuals in worn breeding plumage are often faded and thus with less contrast in facial markings, .i.e., more difficult to distinguish from breweri. Hence, a more detailed examination of its plumage would be desirable: are the remiges fresh or worn?

In conclusion, based on the crown pattern, the specimen is most probably S. pallida, but more details on its plumage would be desirable to clinch the case. Hopefully, the authors can contribute this information.

Literature cited

National Geographic guide to North American birds, fourth edition (2004). National Geographic, Washington, D.C.

Pyle, P., S.N.G. Howell, R. P. Yunick & D. F. DeSante. 1987. Identification guide to North American passerines. Slate Creek Press, Bolinas, CA.

Sibley, D. A. 2000. The Sibley guide to birds. National Audubon Society, Alfred A. Knopf, NY.

Tigreros A., A.-F., S. G. Dávila, and G. Londoño. 2019. First record of the Clay-colored Sparrow (Passerellidae: Spizella pallida) for South America. Ornitología Neotropical 30: 85-87. http://journals.sfu.ca/ornneo/index.php/ornneo/article/view/427/ON%2030%20%282019%29%2085-87.pdf

Comments from Remsen: “YES. Photographs in published paper are S. pallida in my opinion because of strong facial pattern, median stripe, and general color tone. This species is still migrating in the USA into at least the second week of May. Although fat level was not mentioned in the paper, the body weight (10 g) suggests no fat, however.”

Comments from Robbins: “YES. I vote to accept the record based on the photos that clearly indicate a Clay-colored and not a Brewer's.”

Comments from Jaramillo: “YES. Apart from the pale central crown stripe, I can see the well-marked “surround” to the auriculars typical of pallida. In addition, gray and contrasting areas on the side of the neck are visible; these are not usually obvious on breweri, which is browner and streaked here. It looks fine for Clay-colored Sparrow (Spizella pallida) and one can exclude breweri.”

Comments from Claramunt: “YES. I agree with the identification and a voucher was preserved.”

Comments from Areta: “YES. Although my personal experience with Spizella taxa is limited, I agree in that the specimen can be confidently identified as pallida.”

Comments from Zimmer: “YES. In spite of the condition of the specimen, photos B (lateral view) and C (dorsal view) clinch the identification of S. pallida in my opinion. The dorsal view shows that the rump is the same sandy brown color as the ground-color of the back (not contrastingly gray), which eliminates S. passerina from consideration. Both the dorsal and lateral views indicate a broad, contrastingly gray hind-collar, the dorsal photo shows a clear (unstreaked) pale median crown stripe (framed by boldly contrasting dark lateral crown stripes), and the lateral view shows a buffy brown auricular patch, outlined by a narrow dark posterior border and malar stripe, all of which are perfect for S. pallida, and too pronounced and contrasting in all respects for S. breweri, which would have a more uniformly and finely streaked crown (without an obvious median stripe), a less boldly patterned face, and a less contrastingly colored hind-collar. The bold, pale eyebrow, typical of pallida, appears to have been largely destroyed by specimen preparation, but there is still enough here that I feel certain of the identification.”

Comments from Pacheco: “YES, based on the features visible on the photo, as well as all the comments posted here.”