AND ROBERT MARSHAM. 291 



ther regard. At length, when I had taken a more attentive 

 survey of the physical productions of this climate, I soon dis- 

 covered these birds to be none of the common British species 

 described by authors ; & I farther found that they were never 

 seen in G. thro' the whole course of the summer ; but con- 

 stantly & invariably made their first appearance about the 18 

 & 20th, & once as early as the 12th of Octob r & remained in 

 great abundance until the beginning of March. 



" These phenomena awakened & alarmed my curiosity as 

 events entirely new & unheard of among the body of Ornitho- 

 logists, & induced me to be particularly exact & attentive in 

 my observations on every part of their conduct. Early in the 

 autumn vast multitudes of these martins congregate in all 

 parts of the town of Castillar, which is situate on the summit 

 of a precipice most singularly lofty & romantic, about 20 miles 

 north of Gibraltar. Hence it may be inferred that they build 

 & breed on the inland mountains of Andalusia & Grenada. 

 But on the approach of winter, when their summer habita- 

 tions become bleak & inhospitable, (for all those mountains 

 are then usually covered with snow) they retreat to these 

 shores, & remain there 'till the snow is gone next spring. A 

 few are always to be seen about our hill by the middle of Oc- 

 tob r , shifting round to all sides of the rock at times to avoid 

 the wind. Novem r 2, 1771, I saw several, with some young 

 ones among them sitting in groupes, on the cliffs, where the 

 old ones came & fed them." 



Tims have I, for y r amusement, according to promise, sent 

 You an extract concerning this new & unnoticed swallow, 

 which my Brother, with great propriety, in his work has 

 called Hirundo hyemalis ; & has given several particulars 

 concerning it, & a description of it, too long for the compass 

 of a letter. 



Permit me just to hint to You, that I wrote to you some 

 time ago in answer to your last letter, which gave me much 

 satisfaction. 



I forgot to mention in the extract, that these winter Swal- 

 loivs usually leave Gib. about the beginning of March, unless 

 deep snow (as is sometimes the case, and was particularly so 



u2 



