150 STUDIES IN BIRD MIGRATION 



which no longer have ties (the tending of their young), 

 that the time has arrived when they should bid adieu to 

 our shores for the year. 



These departures from our islands are the most 

 difficult of all migratory movements to observe, since the 

 birds as a rule slip away unnoticed during the hours of 

 darkness. In order to obtain reliable information con- 

 cerning them, and the various conditions under which 

 they are performed, the author spent a month in the 

 Eddystone lighthouse during the autumn of 1901, and 

 his experiences there will be related in a subsequent 

 chapter. 



Passage Movements from the North} — As the result 

 of the climatic incentives to emigration already alluded 

 to, great numbers of birds from Northern Europe arrive 

 on our shores during the month, the majority of them 

 en route for countries further south. One of the main 

 features of these movements is the passage along our 

 shores of hosts of insectivorous Passerines — Warblers, 

 Chats, Fly-catchers, Wagtails, Pipits, Swallows, Martins, 

 etc. The appearance of these little travellers may be 

 said to commence in September, and practically, though 

 not entirely, to cease with its close. When the weather 

 conditions especially favour their passage across the 

 northern seas, they arrive in great force, particularly 

 during the latter half of the month, and the observer at 

 favourably situated points has a very busy and intensely 

 interesting time recording their kinds and noting the 

 changed habits of many of them under the influences 

 exerted by the exigencies of travel. 



Later in the month, the members of the frugivorous 



' For particulars of the dates of Passage Movements, see p. 129. For 

 dates of arrival of Winter Visitors, see p. 157. 



