no THE SCOTTISH NATURALIST 



15th October. The House-martin has not been observed on 

 this passage as frequently as the Swallow, but in the main it 

 agrees fairly closely with the movements of that bird. The 

 last records of three different years (1912, 1914, and 1917), 

 all in the early days of October, refer to birds on westward 

 passage. The movements of the Sand-martin differ some- 

 what from the foregoing ; its passages occupy a compara- 

 tively short period and most records have been got in 

 August. Practically all records refer to westward passage; 

 once only has passage to the south-east been witnessed, and 

 passage to the east has been recorded on a very small scale. 

 The Sand-martin has nested in the immediate neighbour- 

 hood but once during the period covered by the observations, 

 and outside the area it is scarce. It is worth noting that in 

 the west, particularly in the Earn valley, the Sand-martin 

 nests in large colonies, but the birds in these colonies must 

 travel in some other direction than eastward in their autumn 

 emigration. 



As to the durations of these movements, the Swallow, 

 during the past autumn, was first noticed on westward 

 passage on 21st July, by far the earliest record. This move- 

 ment, however, was not again witnessed until 19th August, 

 after which date it was frequent. In 1916 the first 

 flights were seen on 9th August, but in preceding years 

 records 'refer to dates in the last week of August. As 

 already mentioned the passage continues throughout Sep- 

 tember in some strength, reaching a maximum in the third 

 week, and thereafter records refer to small parties at widely 

 separated dates. The Swallow has been seen on passage at 

 all times of daylight, with a lull at mid-day, and seems 

 unaffected by weather. Flights have been seen late in the 

 evening flying against the wind in drifting mist and rain ; 

 hurrying westward in the still frosty days of October ; or 

 seeking a path through the gusts of a south-west gale with- 

 out pause or turning aside to feed or rest. Sometimes flights 

 pass high up, almost out of sight even with a binocular, their 

 calling drawing attention to their presence ; sometimes low 

 down, following shore line or land contour, and sometimes, 

 but not often, in wide-wheeling flocks, each wheel a little 



