MIGRATION AND WEATHER 85 



take place the birds in the lowlands of Lancashire 

 and Cheshire move westward towards Ireland, and are 

 observed at different points along the North Wales 

 coast. They are sometimes seen travelling in a 

 snow-storm and sometimes in advance of it. In 

 eastern Cheshire I have seen parties of lapwings 

 passing over westward just in advance of snow, 

 which when it reached the East Cheshire fields, 

 started the local lapwings after their relatives from 

 farther east. 



During regular migration birds start in favourable 

 weather but frequently meet with unfavourable 

 weather before their arrival at the point aimed at ; 

 most of the bird " disasters ' at the lighthouses 

 and lightships, and more occasionally inland, can 

 be explained in this way. 



In his digest of the observations at lighthouses 

 and lightships Mr Eagle Clarke shows that spells 

 of genial weather are favourable and that during 

 these spells migration is even flowing and con- 

 tinuous (15). Slightly unsettled conditions have 

 little effect, but an increase of the irregularities 

 accelerates migration. Sooner or later cyclonic 

 disturbances interrupt regular movements, and, 

 if these are extraordinary, act as barriers, either 

 holding the birds in one place or forcing a hurried 

 departure or " rush." Favourable weather immedi- 

 ately following a check or " hold up " often causes 



