BRITISH GENERAL MIGRATORY MOVEMENTS 589 



season : the farther north the bird nests the farther south it winters, was the contention of 

 this school. Neither argument is supported by the recovery in Natal of a swallow which was 

 ringed in Staffordshire, though either theory may be correct for other species. 1 This single 

 instance proves nothing, except the foolishness of unsupported theories, but it indicates and 

 paves the way towards the discovery of further facts. 



Many European and Asiatic summer visitors travel from Central and Southern Africa 

 along the fertile Nile valley and cross the Mediterranean at various points, but the actual 

 track of the northward bound British summer visitors still awaits elucidation. Ringed 

 birds have been recovered in Portugal and France, and vast numbers of northward bound 

 migrants follow the shores of the Iberian Peninsula and Western France. This is probably the 

 main route by which they reach the English Channel, which is crossed to the southern shores 

 of England and south-eastern Ireland. This class, and indeed all the others, includes birds of 

 many widely differing orders, subsisting upon varied foods, although the majority of insect- 

 feeders are forced to be migratory when the lands in which they nest cease to provide sufficient 

 food for their winter needs. 



A few of the regular summer visitors remain to winter in England in exceptionally mild 

 seasons the chiffchaff, blackcap, and stone-curlew are examples but this habit is exceptional, 

 and these birds must be looked upon as normally absent in winter. 



If the reports and maps, published annually by the Migration Committee as bulletins of the 

 British Ornithologists' Club, which describe and depict the movements of the immigrant 

 summer visitors be studied, it will be seen that the first arrival of any particular species is 

 seldom an indication of large and general distribution throughout the country. A vanguard, 

 usually a small movement numerically, arrives early, but it is followed by one, two, or more 

 waves of incoming birds which spread inland and northwards. In 1905, for instance, the first 

 body of willow-warblers appeared between March 31st and April 8th, but this wave had not far- 

 reaching effect. Between April 9th and 14th a second wave struck the whole length of the 

 south coast, and by the 13th its margin, flowing north-west, was reaching North Wales, 

 Cheshire, Lancashire, and even Westmorland, though its eastward advance was slower. At the 

 end of April, when the winds were strong from the S.W., willow-warblers were again arriving in 

 large numbers, but this later wave was supposed to be mainly composed of birds of passage, the 

 observations at the lights showing the existence of a simultaneous emigratory wave. At that 

 time the writer was watching the west coast movements on the western shores of Anglesey. 

 During the night of May lst-2nd the wind veered to the N.W., and on the morning of the 2nd 

 was blowing from the N. On that morning the whole of the land near the shore was full of 

 willow-wrens, which had, no doubt, been stopped or driven eastward when travelling northward 

 over the Lleyn Peninsula. 



In the same year the chiffchaff arrived in no fewer than six well-marked waves, the advance 

 of which were all noticeable throughout the country. The first, on March 20th and 21st, was 

 slight, and the fifth, the largest, struck the coast from Devon to Sussex in an extended front 

 between the 21st and 25th of April. 



Many of the summer visitors are also represented in our area by birds of passage. These 

 are marked P. in the following list. A few of them the petrels and fulmar are pelagic in 

 their winter wanderings, and some may be met with in winter in territorial waters. 



Yellow-wagtail. Tree-pipit. P. Whinchat. Whitethroat. P. 



Blueheaded- wagtail. P. 2 Ring-ousel. P. 3 Redstart. P. Lesser-whitethroat. P. 



White-wagtail. P. Wheatear. P. 3 Nightingale. Blackcap. P. 



1 Britith Birds, vol. vi. p. 277. 



2 Four subspecies of M.flava, in addition to the yellow- wagtail, have occurred in the British Islands. 



s The northern willow-wren, a local race, is a regular bird of passage, and distinct geographical races of other 

 species marked occur as irregular visitors. 



VOL. IV. 4F 



