92 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



SWALLOWS: SOME INSTANCES OF THEIR 

 RETARDED MIGRATION. 



BY WILLIAM CRAIBB ANGUS. 



[Read 27th November, 1883.] 



That the migration of swallows is in some measure 

 dependent on the season and the weather, is well 

 known. In exceptionally wet and stormy seasons, 

 swallows have been known to leave as early as the 

 close of August ; and in seasons remarkable for their 

 mildness, when in most nests there would be second 

 broods, I have known them pack so that it would 

 be impossible to form even an approximate estimate 

 of their numbers, and roam about in sheltered 

 nooks so late as the third week in September. 

 Macgillivray records an instance of the apjDearance 

 of the sw^allow in 1839 so late as the 7th of October. 

 Mr. Harvie-Brown, in his Second Report on Scottish 

 Ornithology, published in the Society's Proceedings 

 for 1879-80,* records the ax3pearance of the martin 

 in Berwickshire on 3rd October, 1879; and in his 

 Third Report , published in the Proceedings for 1880- 

 81, t he gives 24th-27th September as the date of the 

 usual departure of the swallow, mentioning that 

 *' they stayed very late this year in some places," 

 and giving on the authority of correspondents the 

 following dates of departure, viz. : 30th September 

 and 2nd October, when martins and sand martins 

 were " numerously " seen ; one or two were seen on 

 the 5th, and several on the 10th October, the num- 

 bers diminishing with the advance of the season ; 

 at Alloa, in 1867, says Mr. Harvie-Brown, one was 

 seen by a reliable witness as late as the 13th of 

 November. Isolated instances of the appearance of 



* Proceedings, iv. 291. t Proceedings, v. 61. 



