THE WESTWARD FLIGHT OF THE SWALLOW, ETC. 109 



THE WESTWARD FLIGHT OF THE SWALLOW, 

 HOUSE -MARTIN AND SAND-MARTIN ON 

 THE TAY ESTUARY IN AUTUMN. 



By Henry Boase. 



During the past eight years the migration of birds in the 

 district west of Dundee has been watched, and, among 

 various matters brought to light, the westward passage of 

 the Hirundina; in autumn is perhaps the most unexpected, 

 and it is with a view of learning more of this movement that 

 I submit the following particulars. 



In spring the arrival, in all cases where the passage has 

 been witnessed, has been from the east, with westward 

 passage inland during the period of maximum movement. 

 In no case so far has the slightest indication of immigration 

 from the west been observed. 



It is with the details of the autumn movements I wish 

 to deal. In general, after the first fluctuations of numbers 

 have been noted, passage to the east along the south slope 

 of the higher ground behind Dundee goes on, followed later, 

 about the end of August or beginning of September, by a 

 passage from north-west to south-east over the same ground, 

 the two movements being sometimes in progress simulta- 

 neously, and it is at this time that the local nesting birds 

 depart. The eastward passage, as far as actual visible move- 

 ment is concerned, rarely continues beyond mid-September, 

 though possibly some of the resting parties seen after that 

 time may, in some cases, continue on passage to the east. 

 The latest date recorded for eastward passage of the Swallow 

 is 28th September. The westward passage seems variable 

 in its time of first appearance. It has been noticed once 

 during the first half of August, but the beginning of the 

 fourth week marks its usual first occurrence. The maximum 

 movement, in the case of the Swallow and House-martin, is 

 undoubtedly during mid-September, and in five out of seven 

 records the last Swallows seen have been on actual passage 

 to the west, the dates lying between 26th September and 



