406 , REPORT— 1900. 



north-easterly of the Orkneys, and the extreme southern portion of the 

 main island of Shetland are annually visited, but these stations mark the 

 northern limit of the Thrush's regular distribution during migration in 

 Britain, for the bird is recorded very rarely further north, and is practi- 

 cally unknown in Unst. The Thrush's travelling companions are chiefly 

 its congeners the Redwing {Turdus iliacus), Fieldfare {T. pilaris), Ring 

 Ousel {T. torquatus), and Blackbird (?'. merula) ; and also the Brambling 

 (Fringilla montifringilla), Goldcrest {Begulus cristatus), Redbreast 

 {UrifJiacus riibecula), Woodcock {Scolojyax rusticula), &c.^ 



Along with these species many Thrushes perish at the lanterns of the 

 lighthouses and light- vessels, especially when the night is hazy, with light 

 rain. 



Unlike its congeners just named, it is somewhat remarkable that the 

 Thrush does not occur as an immigrant in numbers in November. The 

 immigi'ation of the Thrush practically ceases with the great arrivals which 

 characterise the latter half of October, though stragglers do arrive up to 

 the middle of November. After this the autumn immigration of the 

 Thrush entirely ceases. Many of the immigrants upon arrival proceed 

 south, as birds of passage, along our eastern and southern coasts, and 

 finally quit our shores, the majority to seek more southern lands, others 

 to cut across St. George's Channel to winter in Ireland. Others, again, 

 remain as winter visitors, and work their way to Western Britain - and 

 Ireland after an overland passage. Many of the birds, however, quit our 

 islands, after a longer or shorter sojourn, under the pressiire of severe 

 weather conditions.'' 



Winter Movements. — The great emigratory movements of the winter 

 commence in October,'' and are continued during November, December, 

 January, and February.-'' They are synchronous with outbursts of cold, 

 snow, or of extremely unsettled weather. Such untoward conditions 

 may prevail generally over our islands, or they may be circumscribed ; 

 ancl their influence on the emigrations of the Thi'ush is in more or less 

 direct consonance with their distribution. 



In genial months little or nothing is recorded. In others the few 

 local movements are traceable to topical weather conditions. But sooner 

 or later during each season great outpourings take place, often extending 

 over several successive days and nights and affecting all our coasts. The 

 Thrushes aflfected are not merely our would-be resident birds, but a very 



' For the weather conditions controlling the movements of the British autumn 

 immigrants, see the ' Digest of Observations,' Brit. Assoc. Jtep., 1896, pp. 469-471. 



- The Thrush is a -winter visitor only to certain isles off our western coasts, among 

 others Tiree in the Inner Hebrides. From careful observations made on that island 

 by Mr. Peter Anderson, we learn that this bird makes its first appearance there for 

 the winter on dates varying from October 4 to 30, some considerable time after its 

 first arrival on our shores. 



' It has been stated that a small dark race of the Thrush occurs on passage on 

 the east coast of England. These birds are supposed to be of Hebridean origin. 

 I. have never seen specimens of such a race, and I do not believe that they can have 

 found their way to our eastern coast from the Hebrides. I have examined a number 

 of Thrushes from Barra in the Outer Hebrides, where the bird is a resident, and do 

 not find them to differ either in size or colour from the ordinary mainland form. 



■• In 1886, as early as October 4 and 6, there were great emigratory movements on 

 all our coasts, due to extremely unsettled weather, with thunder in the N. and N.W., 

 accompanied on the 5th by a great fall of temperature— a fall of fifteen degrees below 

 that of the previous daj"-. 



^ There are also movements during March in some years ; but they are of a local 

 nature, and are not to be regarded as emigratory. 



