136 BIRD LIFE GLIMPSES 



I have wondered if the starlings scoured, so to speak, 

 or fretted the inside of their caverns, by rapidly 

 vibrating their wings against them, so as to act like 

 a stiff brush on the soft, friable sandstone. One of 

 my notings, when watching in the sand-pits, was this : 

 " A starling appears, now, at the mouth of a hole, 

 waving his wings most vigorously. Then disappear- 

 ing into it, again, he quickly returns, still waving 

 them, and moves, so, along the face of the cliff, for 

 there is something like a little ledge below the row 

 of holes." This bird, indeed, waved its wings so 

 long and so vigorously that I began to think it 

 must have a special and peculiar fondness for so 

 doing — that here was an exaggeration, in a single 

 individual, of a habit common to the species, for 

 starlings during the nesting season are great per- 

 formers in this way. But if the wings were used as 

 suggested, they would certainly, I think, be sufficiently 

 strong, and their quill-feathers sufficiently stiff, to 

 fret away the sand ; and as their sweeps would be 

 in curves, this would help to explain the domed and 

 rounded shape of these bird cave-dwellings. Only, 

 why have I not seen them doing it ? Though many 

 of the holes were unfinished — some only just begun 

 — and though the birds were constantly in them, I 

 could never plainly see any actual excavation being 

 done by them, except that, sometimes, one, in a per- 

 functory sort of manner, would carry some nodules 

 of sand or gravel out of a hole that seemed nearly 

 finished ; yet still they grew and grew. The thing, 

 in fact, is something of a mystery to me. 



It is easier to see how, when the chambers are 

 completed, the starlings build their nests in them ; 



