( sn ) 



In 1908 we obtained two nestlings near Biskra, which are described in 

 Vbg. d. pal. Fatiiut i. p. 604. In 1909 we found a clutch of four eggs near Bonlj 

 Chegga, March 20, but they were so hard-set that onlj' two could be successfully 

 blown. In 1911 we were at last in time, and, after digging out an empty fresh 

 nest on March 1, we took four clutches on March 13, and nests with young birds 

 were found south of Lagliouat and near the dayats. 



The nests are built in the deserted burrows of Meriones getuliis (the "djerd " 

 of the Arabs) and other smaller mammals. The nest is often from four to five feet 

 from the entrance hole, and sometimes the burrows are curved, and branch off into 

 various arms. Tliey are mostly in tlie hillocks formed by the sand, but sometimi's 

 on a bank or even in the almost flat ground. The nest itself consists outwardly of 

 rootlets and stems of grass or other plants, and the bulk is built with sheep's wool, 

 camel's hair and other hairs, pieces of string, wool or rags, sometimes a few 

 feathers, and not rarely (in two nests out of five) with snakeskin. The full number 

 of a clutch is undoubtedly four, though three may form a full clutch sometimes ; 

 but in the one case out of five where we found three, the clutch was apparently 

 not a full one. 



In the clutch taken in 1909 and in the three full clutches of 1911 there is in 

 every case one egg distinctly paler, almost white, while the others are pale greenish 

 blue, with sometimes numerous, but generally not many small rufous spots. The 

 three eggs of the incomplete clutch of March 13, 1911, are more richly spotted 

 than the others. The measurements are: 22 x 17-1, 22 x 17, 22-5 x 17, and 

 23 X 16-6; 24-2 x 16-5, 24-5 x 16-5, 255 x 16-4, and 25-5 x 16-9; 23-5 x IS, 

 24-5 X 17'1, 24-6 x 18, and 24-9 x 17 ; 24-4 x UrO, 25 x 10-9, 25-1 x 10-7, and 

 25 2 x 16-5 ; 243 x 16, 24-3 x 16-2, and 24-3 x 16-8 mm. Thus it is seen that 

 the size varies a good deal, even in the same clutch. 



108. Oenanthe lugens halophila (Tristr.). 

 {JidX/fuld /iiye/ts lialojj/iila auct.) 



Coming by railway from the north, one first meets with this species in the plain 

 south of El Kautara, and all around Biskra, where it inhabits the low, bare, rocky 

 dills in tlie desert, without going as high up on the mountains as O. leHcura 

 sijeniticu. In the M'zab country we saw it near Berryan. It also occurs sparingly 

 in the real desert at the edges of sebchas, as far south as Touggonrt and Wargla. 

 It is a beautiful bird, the whitish cap being very consjncuous. The song is generally 

 short, but pleasant, and is mostly uttered while the bird perches on a rock. The 

 four or five eggs are of a very pale greenish blue, of a rather thick oval, spotted 

 with rufous, and measure on an overage (nine eggs) 20'16 x 15'61 mm. 



The males vary a little, the cap being more buflfish grey or more whitish, 

 and the black area of the back wider or narrower. The females, however, vary 

 considerably in the colour of the throat, which is sometimes quite black, with 

 hardly a few buffy edges to some feathers, more often blackish grey and grey, less 

 frequently almost entirely white. There is nothing to show that the black-throated 

 or white-throatud birds are older or younger. 



109. Oenanthe leucura syenitica (Heugl.). 



See Hartert, Viiy. jial. Fauna i. p. tJ'JS. 



The males of, 0. leucura leucura and V. I. .v/etiitica (the African form) are 

 very much alike in their colour; though must of the hiouth European birds aie of 



