CHELIDON URBICA 187 



Observations. — The white bases of the feathers on the nape are often 

 conspicuous and have the appearance of an ill-defined white collar. 



Like the Common Swallow, the House-Martin arrives in Tunisia 

 early in the spring, and leaves again in the autumn. The bulk of the 

 birds pass on northwards for the summer, but many remain and breed 

 in the Eegency: Blanc mentions an example of this species obtained 

 at Tatahouine in South Tunisia on February 2nd, but this must 

 doubtless have been an early straggler, as the winter quarters of the 

 House-Martin are probablj' considerably further south. 



C. urhica arrives in the Eegency both in spring and autumn in 

 large flocks, and may often be seen in company with H. rustica. 

 Like that species, it feeds on the smaller winged insects, and frequents 

 towns and villages in preference to the more open country. I have, 

 however, met with it breeding in colonies far away from any human 

 dwelling. 



One of these bird-colonies remains most vividly impressed upon 

 my memory, partly from the savage grandeur of the site and its 

 surroundings, and partly from the fact of its being also the home of 

 a colony of Cijpselus affinis cjalilcejensis, the two species, indeed, 

 forming one colony, and apparently living together in the most perfect 

 harmony. The spot in question was situated in a deep gorge or pass 

 in the chain of mountains lying to the north of Metlaoui in South 

 Tunisia where the Oued Seldja, which flows through the pass, and in 

 times gone by must have been a more important river than it is at 

 the present day, had hollowed out a recess or cavern in the mountain 

 side. The sloping bank leading up to and forming the floor of the 

 cave was carpeted with a thick bed of most luxuriant Maiden-hair fern, 

 itself an unexpected and delightful surprise in this desert country, and 

 feathery creepers hung down from the vault, while the overhanging 

 cliffs and beetling crags on either side formed a fitting frame-work 

 for the picture, and enhanced still further its picturesque beauty. 

 Lining the top of the cave at the point where it commenced to arch 

 over, and forming, as it were, a frieze or cornice to its walls, were the 

 nests of both C. affinis galilcBJensis and C. urhica, placed side by side 

 and touching one another. The nests being at a height of about forty 

 feet from the ground were practically inaccessible without the aid of 

 a long ladder, an article which a travelling caravan does not usually 

 possess. I had therefore to content myself with an examination 



