PRELIMINARY CLASSIFIED NOTES 321 



" due to climatic pressure, set in with the first severe weather, and recur with each 

 outburst, but in gradually diminishing volume." The corresponding return spring 

 immigration " from Southern Europe, commences in February and continues until 

 the middle of March." (&) It is noteworthy " that the thrush does not participate 

 in the east to west autumn, and west to east spring, movements across the southern 

 waters of the North Sea to and from Central Europe." But with Northern Europe 

 there is a regular intermigration : " the first immigrant thrushes winter visitors 

 and birds of passage appear on our shores from the N.E. during the latter days 

 of September." The great influx takes place during October, marked "rushes" 

 being frequently noted about the middle and end of the month respectively. 

 Immigration practically ceases with the close of October, considerably earlier than 

 is the case with the song-thrush's more strictly northern congeners. The immigra- 

 tion takes place on the east of Great Britain from Orkney to Norfolk, but the 

 birds spread westwards, and many cross to Ireland. The cold weather movements 

 within our area, later in the season, take a similar course, the mild south-west of 

 Ireland harbouring great numbers of the birds. The return departures for Northern 

 Europe " set in and are continued throughout April, and sometimes into May." 

 (c) Our various coasts are also visited by thrushes which are on passage from 

 Northern to Southern Europe. The seasons of these purely passage movements 

 correspond with those of the other migrations already described. A certain further 

 number of individuals are birds of passage in the sense that they remain with 

 us only to participate later in the cold weather emigrations already alluded to. 

 These winter movements, however, are more to milder parts of our area than 

 completely beyond its limits. The song-thrush is chiefly a nocturnal migrant, 

 and is frequently killed at the lighthouse lanterns, but it also travels by day. It 

 is a gregarious migrant, and also often accompanies its congeners and other species. 

 (For fuller details of these complex movements, cf. Clarke, loc. cit. ; Ussher and 

 Warren, loc. cit. ; Ticehurst, B. of Kent, 1909, p. 4 ; and B. 0. C. Migration Reports, 

 iii. p. 187, and iv. p. 179.) [A. L. T.] 



4. Nest and Eggs. Nesting place : often in evergreens in gardens, hedge- 

 rows or bushes, in sheds, sometimes on the ground, or on bank-sides, and in ivy. 

 The nest is built usually of dry grass, moss, a few twigs, leaves, and, more rarely, 

 gorse, bracken, wool, etc., lined with a fairly smooth plaster composed of one or 

 more of the following materials decayed wood, decayed vegetable matter, mud, 

 dung, with the occasional addition of chips of straw or of grass stalks (see p. 377). 

 (Pis. xni.-xiv.) It is constructed by the hen, but the cock has been seen to help. 



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