124 CYPSELID.E. 



wall of the New Mole Parade. Many black Swifts nested in close 

 vicinity, but from continued observation it appeared that the 

 Light-coloured Swifts nested in adjacent holes and kept apart 

 from their dark congeners. These holes being far in, it was 

 difficult to be certain, since nests and old birds were out of reach. 

 However, another colony nested in 1878 in the Patio of the 

 Convent, and I was able to watch them daily and hourly for some 

 weeks from the A.D.C.'s room which I occupied. I soon found 

 that there were not any dark Swifts, and after making sure of 

 this I inspected their nests. On the 12th June I found five nests 

 one with two eggs, three with three eggs, and one with two 

 young birds nearly fledged ; some of the eggs were fresh, others 

 much incubated. The nests (placed on the tops of rafters and on 

 a wall, and two between a rafter and the wall) were solidly built 

 of castings of insects' wings, thistledown, and bits of paja, glued 

 together by mucus so strongly as to require much force to separate 

 them from the rafters : those on the tops of the rafters were much 

 smaller than the others, and little more than a saucer-shaped 

 rampart. In all cases I caught the old birds and examined them 

 carefully before releasing them. It is curious that the black 

 Swift usually lays two eggs, rarely three, whilst three out of four 

 of the pale Swifts' nests contained three eggs." 



151. Cypselus melba, Linnaeus. White-bellied Swift, Alpine 

 Swift. 



Moorish. El namera. Spanish. Avion real, Avion de pecho 

 bianco. 



" Found near Tangier on passage, crossing the Straits from 

 March to May, returning from August to October. It is not so 

 common as C, apus" Favier. 



The White-bellied Swift breeds sparingly at Gibraltar in the 

 inaccessible crevices of the rocks on the Mediterranean side ; 

 they seem to arrive, if anything, a little later than the Common 

 Swift. The earliest dates of arrival noticed were the 24th of March 



