8 Stup.BS, Tlic Use of Wind by Migrating Birds. 



coast of Norfolk {cf. Richards Brit. Birds, vol. 2, p. 200). 

 The barometer stood at 30"28 over Sweden, and at 

 29"8 over Ireland and south-west England. On the 25th 

 the depression had reached the North Sea, and on this 

 day we are informed that the migration considerably 

 decreased. The occurrence of such continental birds as 

 Red-breasted Flycatchers {Muscicapa parvd). Blue-throats 

 {Cyanecula suecicd), and Yellow-browed Warblers {Phyllo- 

 scopHS superciliosus) on these days would be due to the 

 prevailing southerly winds on the western edge of the 

 anti-cyclone carrying the birds out of their proper courses. 

 For an example of the effect of cyclonic movements, I 

 may refer to Mr. Clarke's invaluable observations at 

 Fair Isle {Anna/s Scott. N.ff., 1908, pp. 72-75, fide Brit. 

 Birds, vol. i., p. 982). The appearance at this island of 

 the Yellow-browed Warbler and the Siberian Chiff-chaff 

 {P. tristis), both birds of Northern Europe, coincides with 

 a period of strongly marked cyclones over the western 

 parts of the continent from October 20th to 24th, 

 1807. I have not been able to consult any barometric 

 readings for October 13th, 1 891, but on this date there was 

 a very heavy migration of enormous numbers of Gold- 

 crests, Robins, Buzzards, Owls, Blackbirds, and many other 

 birds. The zvind zvas east, blowing more than half a gale. 

 These observations were made on the coast of Yorkshire, 

 and published in Natural Science, vol i, p. 779, in a review 

 that has internal evidence of being the work of the late 

 J. Cordeaux. I should expect to find that on the date 

 given above there was a deep depression over France 

 or Holland. Of course, these meteorological charts have 

 been used before, but apparently without a knowledge of 

 the connection between wind and cyclones, and with a 

 wrong idea of the position of a bird flying in a moving 

 body of air. 



