MIGEATION. 115 



LETTEE XXXIY. 



TO THOMAS PENKANT, ESQ. 



Selborne, May 12, 1770. 

 Deae SiE, — 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 appear- 

 ance of the sammer birds, was much interrupted. Some did 

 not show 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 yet, 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 appeal 

 about this time ; and yet, amidst all this meteorous strife 

 and war of the elements, two swallows discovered themselves 

 IS long ago as the eleventh of April, in frost and snow : but 

 chey ^-ithdrew quickly, and were not visible again for many 

 days.* House-martins, 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. AVhen the house-sparrows deprive my 

 martins 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.f 



I have lvno^^^l a dove-house infested by a pair of white 

 owls, which made great havoc among the young pigeons : 



* It is certain that swallows re-migrate ; that is, if on some of them 

 arriving in this country the weather is ungenial, they leave it again for a short 

 time. So in the autumnal migrations, swallows, after their flight, will return 

 again to this country if they meet in their passage with adverse winds or 

 •terms. An observant naturalist residing near Liverpool has assured me of 

 this fnct. — Ed. 



t The celerity with which birds find mates after a male or female has been 

 elifit, is very extraordinary. 1 have observed this among pigeons more pur- 

 ticulail- , — Ed. 



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