46 BRITISH BIRDS. [vol. xiii. 



of migration would be enough to account for the total absence 

 or great diminution of a species in any given year. It is 

 probably what goes on to a large extent everywhere, but being 

 confined here to a limited and easily examined area with a 

 normally low population the result is more marked and more 

 ■evident. 



No attempt has been made to arrive at any deductions from 

 our autumn observations, the facts as observed have simply 

 been summarized. It would be too hazardous to draw any 

 conclusions from observations made in a single season and 

 •over so short a period. There are several points on which 

 speculation might be made, but much more work requires 

 to be done ; more observations than we were able to make at 

 the north-western corner of the island would undoubtedly 

 help, while further visits at other times, particularly in October, 

 would furnish a great deal of additional and interesting 

 information. These, of course, have for obvious reasons 

 been out of the question for the last four years. 



In order to make this account as complete as possible I 

 have gathered together and summarized as far as can be done 

 from the lighthouse reports the status of each species as a 

 migrant, and these being based on a period of six years should, 

 so far at any rate as the autumn is concerned, be fairly accurate. 

 The spring returns not being nearly so full, their summary 

 is probably less so, and may need subsequent amendment. 

 Mr. Aplin's and Mr. Coward's notes as published are referred 

 to also under the species which they recorded, while the records 

 from the British Association migration reports are also 

 mentioned where necessary. 



The following records of the weather during our stay in 

 September 1913 will save repetition : — 



Sept. 3. — A dull misty night, wind E. to N.E. slight. 

 „ 4. — Cloud}^ night, wind E.S.E. sHght, increasing to a very strong 



S.E. breeze during the day, fine to 4.0 p.m. 

 ,, 5. — Overcast night, with a moderate breeze from E.S.E. and 



passing showers, followed by a fine, hot morning. 

 „ 6. — Cloudy night, with a moderate E.S.E. breeze, rain in the 



early morning ; a dull day, wind dropping at 4.0 p.m. 

 ^, 7. — Cloudy night, with a moderate E.S.E. breeze, increasing to 



a strong breeze from the E. during the day, fine. 



