88 PAIRING OF BIRDS. 



LETTER XXXIV. 



TO THOMAS PENNANT ESQ. 



SELBORNE, May 12, 1770. 



DEAR SIR, Last month we had such a series of cold tur 

 bulent weather, such a constant succession of frost, and snow, 

 and hail, and tempest, that the regular migration, or appearance 

 of the summer birds, was much interrupted. Some did not 

 shew themselves (at least were not heard) till weeks after 

 their usual time, as the black-cap and white-throat ; and some 

 have not been heard jet, as the grasshopper-lark and largest 

 willow-wren. As to the fly-catcher, I have not seen it ; it is 

 indeed one of the latest, but should appear about this time ; 

 and yet, amidst all this meteorous strife and war of the elements, 

 two swallows discovered themselves as long ago as the eleventh 

 of April, in frost and snow ; but they withdrew quickly, and 

 were not visible again for many days. House-martens, which 

 are always more backward than swallows, were not observed 

 till May came in. 



Among the monogamous birds, several are to be found, after 

 pairing time, single, and of each sex : but whether this state 

 of celibacy is matter of choice or necessity, is not so easily 

 discoverable. When the house-sparrows deprive my martens 

 of their nests, as soon as I cause one to be shot, the other, be 

 it cock or hen, presently procures a mate, and so for several 

 times following. * 



* The late Mr Jamieson, of Portobello, told us a remarkable circum- 

 stance of the swallow, which was equal to human sagacity. A pair of 

 these birds built a nest in the corner of one of his windows at Portobello. 

 They had scarcely finished their labour, when a pair of house-sparrows 

 took forcible possession, and drove the rightful owners from their domicile. 

 The swallows made several unsuccessful attempts to regain possession, 

 being always beaten off by the sparrows, who defended the entrance with 

 determined obstinacy. At last, finding their attempts fruitless, they 

 departed, and, in a short time, returned with a host of their companions, 

 who did not attempt to take the intruders by storm, but, in a very short 

 time, by their united efforts, built up the entrance to the nest, determined 

 seemingly to imprison, for life, the occupiers of the property which had 

 been unlawfully acquired. 



Male birds procure mates by the power of their song. Hence it has been 

 inferred, that if a confined bird had acquired the song of another species, 

 without retaining any notes of its own, and was set at liberty, the pro- 

 bability is, that it would never find a mate of its own species j and, even 



