ON ÏIIE MIGRATION OF UiRDS AS OBSERYED ON THE EAST COAST 



OF GREAT TIRITAIN. 



BY JOHN CORDEAUX-GEEAT cotes. 

 (DELIYEEED BEFORE THE III. SECTION „MIGRATIO ET AVIGEOGRAPHIA" ON THE IS MAI 1891). 



From 1879 to 1887 inclusive, observations on the Migration of Birds at ligiit- 

 houses and liglitvessels were made by a committee annual!}^ rea^Dpointed by the 

 British Association for the .advancement of Science, and the results published in 

 nine reports. 



Altogether, about 200 stations were supplied with letters of instruction and 

 t^prined schedules for the recording of observations, under the separate heads of — 

 (i.) Date, (ii.) Number, name or species of bird, (iii.) Time when seen, (iv.) Power 

 and direction of wind, (v.) Weather, clear or fog, rain or snow, (vi.) Number striking 

 glass of lantern, and whether killed or otherwise, (vii.) drenerai observations. Large 

 prepaid linen-lined envelopes were also supplied to the light-keepers, with a request 

 that in all doubtful cases of identity, where Inrds are killed againts the lanterns, 

 a wing should be cut off and a label attached with the date, and these forwarded 

 by post to the recorders of the various districts. 



The range of the enquiry covered the coasts of Great Britain and Ireland, with 

 all the outlying Islands and Skerries, the Channel Islands, Heligoland, and occasional 

 notes from the Faroes. Iceland, and one Baltic Station on the coast of Sjaelland. 



The best and inost complete returns, as a rule, have been obtained from isolated 

 stations, at lighthouses placed on islands or skerries, or at the extremity of head- 

 lands, as well as from light-ships moored at a considerable distance from land in 

 the North Sea; and the regular occurrence of land birds, apparently of weak power 

 of flight, around these lanterns, is a matter of surprise to those unacquainted with 

 the facts of migration. Lighthouses situated some short distance inland, or surrounded 

 by houses, have made few returns or none. 



Notwithstanding the very large number of immigrants which are recorded as 

 seen on passage at the more favourable stations for observation, it is quite certain 

 that they represent a very small percentage of the birds on actual passage. (.)n days 

 of uncertain light, or on clear and starlight nights, when migration is going forward 

 at a great height, birds might be passing any of the stations for hours without 

 being observed, and it is not improbable that if the whole of the three hundred 

 miles of the east coast of England was studded with floating posts of observation 

 at the distance of half-a-mile, equal average results might have been obtained. The 

 present stations on the lightvessels affording no more special line of advantage than 

 any other intermediate position. 



The observations taken during nine years undoul)tedly point to the fact, that 

 wàth few exceptions, all birds in the Western Palaearctic region are to a greater 



