124 STCTDIES IN BIRD-MIGRATION 



Another feature of the spring migration, already briefly 

 alluded to, is worthy of consideration. We have seen 

 that the Birds of Passage are the latest of all the spring 

 migrants to appear on our shores. At the time that 

 many of them are traversing our islands on their way 

 to the north, the British residents and summer visitors 

 of the same species are already either deeply occupied 

 in the incubation of their eggs or actually tending their 

 broods — among others the Song-Thrush, Blackbird, 

 Ring - Ouzel, Wheatear, Golden Plover, Woodcock, 

 Dunlin, Snipe, Redshank, Common Sandpiper, and 

 Curlew. 



In most cases it would be utter folly for the migrants 

 bound for the Far North to seek their summer haunts 

 there at earlier periods, since the climatic conditions 

 then prevailing render them totally unsuited for their 

 reception.^ 



Spring Castial Visitors. — A considerable number of 

 rare visitors of various species appear annually in the 

 British Islands as waifs during the period covered by 

 the spring migratory movements. Each year produces 

 a more or less abundant crop. Most of them belong to 

 species whose breeding haunts are in Southern and 

 Central Europe, and some may have reached our shores 

 by accident, when journeying from their African winter 

 quarters to their native land, having for some reason 

 overshot their customary northern or western limit. 

 These visits may be, and no doubt often are, accounted 

 for by the voyagers having encountered strong southerly 

 or easterly winds when en route for their Continental 

 summer haunts, and thus having been swept out of their 



' See Plate III., showing the advance of spring. 



