TURDUS SWAINSONI, OLIVE-BACKED THEUSH. 5 



EiDGW., Pr. Phila. Acad. 1869, 129.— Dall & Bann., Tr. Chic. Acad, i, 1869, 

 275.— Coop., B. Cal. i, 1H71, 5.— Lawj!., Pr. Bost. Soc. June, lb71 (Tres JL-aiusj. 

 Turdus Bwainmni var. uatulalus, Coues, Key, lb72, T.i. 



Edb. — ^The typical form ranges over nearly the whole of North America; north to 

 the Arctic Ocean, northwest to Behring's Straits, west to the Columbia, Kouth to Cen- 

 tral America, New Granada, and Ecuador. Cuba. Greenland, Europe, and Siberia (acci- 

 dental). Not observed in Southwestern United States. Breeds from Maine and New 

 Hampshire northward (f from New York, Gregg, Pr. Elmira Acad. IdTU). Winters 

 from Florida southv>'ard. Var. aliciw has a nearly coincident range, but on the wb(jle 

 appears somewhat more northeily; south to Costa Rica (r. i^ranteii^). Yav. ustulatiis 

 inhabits the Pacific coast, from Biika to Mexico (Tres Marias Islands, Gratjmn). 



List of specimens. 



Lieittoiaiit Warren's Expedition. — 4707, mouth of the Mis.sonri River ; 4710, "Nebraska;" 

 8818, Black Hills. Var. uUcUh : 4708, Upper Missouri ; 4711, Jacques River ; 4709, 4712, 

 Vermilion River. 



Late information bas greatly extended tlie known range of tbi.s species, 

 and in time the above-mentiooed exception of its apparent non-occur- 

 rence in tbe Soutbwestern United States will probably be done away 

 witb. 



As Mr. Allen bas repeatedly contended, tbe characteristics formerly sup- 

 posed to be specifloally distinctive of T. aliciw have proved inconstant and 

 not always tangible. I am now nearly satisfied of the propriety of treat- 

 ing it as a variety, though I entertained tbe contrary opinion for some 

 years. Tbe evidence best favoring tbe supposition of its validity lies in 

 the fact that, while occupying substantially the same range as typical 

 su-ain.soHij it generally shows .some slight peculiarities; these, however, 

 apparently shade into those of swainsoni. The fact of intergradation may 

 be proved, however we may account for the discrepancies observed in 

 most cases. I think the solution of the problem may be looked for in 

 tbe probability that alicice as a rule consists of more northerly-born indi- 

 viduals ; this would bring the case under some known rules, that might 

 account for its iieculiarities of larger size and darker color. 



Tbe relationships of var. nutulatus were long supposed to be with /«s- 

 cescens, which is by no means the case. The clew to its true interpreta- 

 tion wa.s found in the discovery that tbe eggs are speckled as in su-ain- 

 soui, not plain as in fuscescens. Attention was first called to this and 

 other evidences of relationship by Mr. Eidgway in the paper above 

 quoted. He then, however, treated ustulatus as specifically distinct. 

 Nothing appears to contradict the view I have adopted, and published 

 as above, that ustulatus is a geographical variety, the features of which 

 depend upon tbe moisture of the heavily wooded coast region it inhabits?. 



All tbe forms of this species nest alike in bushes, and lay speckled 

 eggs, usually four, measuring about 0.92 by 0.02 inc^ies. The Olive- 

 backed Thrush is a very abundant bird in the Eastern Unite4 States 

 during the migrations in April and October. It has not been observed 

 to breed south of Maine and New Hampshire, nor is the evidence satis- 

 factory that it winters north of Florida. As will be seen by the above 

 quotations, it penetrates very far southward in winter. 



p . TUEDUS FCrSCESCENS, Stepb. ,.- 

 Wilson's Thrash; Tawny Thrush; Veery, 



Ttirdus mustelinus, WiLS., Am. Orn., v, 1812, 98, pi. 43 (iicc Gm., nee aiicft.) 

 Turdus fuscescens, Steph., Shaw's Gen. Zool. x, 1817, 182.— Cab., J. f. O. 18.55, 470 

 (Cuba).-BD., B.N.^^^^|,^2^4^-^«^^P. Z^^^59, 326; Cat. 1862,2.-Coui=s& 



