24 THE WARBLERS 



migration (B. 0. C. Migration Reports). The earliest arrivals reach our shores about 

 the middle of April. The spring immigration lasts about six weeks, until the 

 end of May, but may be said to be at its height during the last few days of April 

 and the first week in May, and the evidence tends to show, though by no means 

 conclusively, that the later immigrations are merely those of birds of passage en 

 route presumably for Scandinavia. In Scotland and Ireland the date of arrival is 

 about ten days to a fortnight later than it is on the south coast of England. The 

 return migration to winter quarters in Africa takes place, so far as the bulk of our 

 native birds are concerned, during the first fortnight of August, and this is further- 

 more very clearly demonstrated by the records from Ireland, where birds of 

 passage would be very scarce, if not entirely absent (Barrington, Migration of 

 Birds, p. 62). In Scotland and England, however, a considerable number pass 

 through during the last fortnight of September and even during the first few days 

 of October, but these are almost certainly on passage, [j. L. B.] 



4. Nest and Eggs. Nesting place : usually in rank grass, thick bushes, 

 coarse vegetation, hedges, etc., often in low-lying and marshy spots, but also on 

 hillsides at some distance from water. The height from the ground is also variable, 

 but seldom exceeds 4 or 5 ft., and often the nest is built close to the ground. It is 

 composed of moss, dead grasses, stalks, etc., mixed with willow-down and lined 

 generally with hair, but sometimes with feathers or flowering grasses. (PL xxn.) 

 It is built by the hen alone, closely accompanied by the male (H. E. Howard, British 

 Warblers, Part i. p. 8), but Naumann states that both sexes build. Eggs, 5 or 

 6, rarely 7, not unlike those of the yellow-wagtail in colour, being very thickly 

 and uniformly speckled with light or dark ochreous or yellowish brown. Some eggs 

 have a mottled appearance, while black hairstreaks are frequently found at the big 

 end. Pure white and also beautiful pink varieties have been occasionally met with. 

 (PL D.) Average size of 100 eggs, -70 x -52 in. [17-8 x 13-2 mm.]. Laying begins 

 about mid-May in the south and early June in the north of the British Isles, while 

 exceptionally clutches have been taken quite early in May. Incubation lasts 13-15 

 days, and is chiefly performed by the hen, though the cock relieves her for two hours 

 in the afternoon (Naumann). Although one brood is normal, there is little doubt 

 that a second is sometimes reared. [F. c. B. j.] 



5. Food. Insects and their larvse, especially flies such as Chironomi and 

 others whose lives are partly aquatic. According to Naumann, the sedge-warbler, 

 like its congeners, eats berries in autumn. The young are fed by both parents on 

 insects, [w. F.] 



