512 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



BREEDING-HABITS. Usually nests on outer walls of houses under 

 eaves ; exceptionally also inside roofs of sheds. Also on face of sea- 

 cliffs and in some districts also on inland cliffs. Nest. Generally 

 found in colonies, sometimes built on to one another, in shape like 

 a section of a cup, with narrow opening at top, built of mud 

 moistened with saliva and mixed with bents, etc., lined with 

 feathers, bits of straw, etc. Eggs. 4-5, sometimes 3 or even 6, 

 white, slightly glossy. Average of 54 British eggs, 19.4x13.2 mm. 

 Breeding-season. From latter part of May onward, many birds 

 nesting in June. Incubation. Shared by both sexes ; period about 

 14 days. Double brooded, sometimes a third. 



FOOD. Insects taken on the wing, chiefly diptera, especially the 

 smaller species (Chironomidse, etc.), but also coleoptera (Tachyporus, 

 Aphodius, Coccinella, etc.), occasionally lepidoptera (Pieris, Tri- 

 phcena, Agrotis, etc.) and neuroptera (Oldham). 



DISTRIBUTION. British Isles. Summer -resident. Generally dis- 

 tributed, but more local, especially in Ireland, than Swallow. Scarce 

 breeder Orkneys, only occasionally nests and not common migrant 

 Shetlands, and rare vagrant (about a dozen times) to O. Hebrides. 



MIGRATIONS. British Isles. Early arrivals of summer -residents 

 begin first week April (early dates Mar. 23, 1913, Devon ; Mar. 

 25, 1912, Sussex; Mar. 26, 1919, Somerset; Mar. 27, 1913, 

 Essex, 1909, Devon ; Mar. 28, 1910, Mar. 29, 1912, Mar. 30, 

 1907, Hants. ; Mar. 30, 1910, Salop) ; main arrival begins mid- 

 April (variable, second to fourth week) and lasts to end May, 

 becoming merged in movements of passage-migrants that pass 

 through country and by east coast route (Channel to northern isles) 

 to end first week June, with stragglers in north to end of month. 

 Probable passage-migration west coast also (England and Wales 

 and Inner Hebrides) but evidence not clear. Summer -residents 

 begin to move south mid-July, emigration south coast begins first 

 week Aug. and lasts to third week Oct., stragglers frequent to mid- 

 Nov. and occasional to first week Dec. (late date Jan. 10, 1912, 

 Hampton Court). Later part becomes combined with passage- 

 migration east coast (northern isles to Channel) that begins 

 occasionally in mid- July, but main movement in Sept. and Oct. ; 

 very small numbers only in north, bulk appear to arrive south of 

 Humber. Majority of Oct. records relate to this movement. No 

 evidence of passage west coast. Irish summer -residents appear 

 to arrive and depart mainly by south-east coast ; no evidence of 

 passage-migration. 



DISTRIBUTION. Abroad. Europe, from lat. 70 north in Scandi- 

 navia to Mediterranean, east to Yenisei and Turkestan. Wintering 

 in south-east Africa and Mossamedes, and in north-west India. 

 Casual Iceland and Greenland, also Madeira. Replaced by shoit- 



