508 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



more saucer -shaped than that of Martin, open at top and resting 

 on support of some kind in most cases. Exceptionally nests on 

 outer walls, not unlike Martin but more open at top. Lining of 

 grasses, feathers, etc. Eggs. Usually 4-5, sometimes 3 or 6, and 

 8 on record, white, spotted finely or boldly with red -brown and 

 ashy shell-marks. Average of 50 British eggs, 20.2x13.9 mm. 

 Breeding -season. From mid-May onward. Incubation. Just over 

 15 days (Owen). Two, occasionally a third brood. Fledging- 

 period. Normally 21 days (Owen). 



FOOD. Insects taken on the wing, chiefly diptera (Chironomidse, 

 Tipula, Empis, Borborus, Calliphora, etc.), but also coleoptera 

 (Curculio, Helophorus, Tachinus, Aphodius, etc.), hymenoptera 

 (winged ants), neuroptera (Calopteryx], and exceptionally lepi- 

 doptera. 



DISTRIBUTION. British Isles. Summer-resident (occasionally stay- 

 ing throughout winter). Generally distributed, but breeds rarely 

 in extreme west of Ireland, north-west of Scotland and Orkneys, 

 and very rarely Shetlands and O. Hebrides (Barra, 1896, and 

 probably on occasions in Uists and Lewis). 



MIGRATIONS. British Isles. Early arrivals of summer-residents 

 begin end of third week March (early dates Feb. 29, 1912, Cornwall, 

 Mar. 2, 1912, Cardigan, Mar. 5, 1918, Lanes., Mar. 6 and 13, 1913, 

 Scilly) ; main arrival variable, from April 1 to end second week, 

 merging end April into arrival of passage -migrants and continuing 

 to fourth week May. Passage-movements last to end first week 

 June with stragglers in north to end of month, and take place 

 throughout country, but coastal routes are well marked, especially 

 east (Channel to northern isles) though greater number apparently 

 cross North Sea without reaching latter. Western routes, west 

 coast, England and Wales and east coast Ireland and through 

 Hebrides are probably to Fseroes and Iceland. Summer -residents 

 begin to move south last week July and emigration from south 

 coasts begins second week Aug., later departures become merged 

 in those of passage-migrants that begin to arrive northern isles 

 early Sept. ; numbers in north comparatively small, but larger 

 on east coast, Forth southward. Numbers probably pass inland 

 and through country and by west coast England and Wales ; no 

 evidence Ireland. Passage and emigration continue to nearly 

 end Oct. Majority of later Oct. records are from east and south- 

 east coasts pointing to movement being almost entirely those of 

 passage -migrants ; others doubtless accounted for by lateness of 

 some broods which are frequent in some seasons. Stragglers 

 frequent in Nov. up to end third week. (Late dates Dec. 1, 1908, 

 Norfolk, Dec. 20, 1911, Berks., Jan. 3, 1913, Dorset, Jan. 23, 

 1913, Kerry). Irish summer-residents apparently arrive and 

 depart mainly by south-east coast. Birds ringed as nestlings in 



