56 BIRDS OF SOUTH AFRICA. 



this species by observing an unusual appearance on an overhanging 

 rock photographed during the journey of H.R.H. Prince Alfred 

 through South Africa in 1860. On applying a strong magnifying 

 power to the picture, I distinctly made out that the appearance con- 

 sisted of a cluster of birds' nests. 1 at once concluded that they were 

 constructed by some species of swallow unknown to me, and requested 

 my zealous contributor, Mr. Jackson, to look well after them, if ever 

 he found himself in the neighbourhood. This he has done, and tells 

 me he counted about 20 nests, under a rock, clustered together ; he 

 also obtained the only example which I have seen. Dr. Hartlaub, to 

 whom this specimen was submitted, states that it is a young bird, of 

 the American H. Lunifrons ; a species which has of late years been 

 extending its migrations from its real habitation in a most remarkable 

 manner. 



87. Hirundo Dimidiata. 



ABOVE entirely steel-blue ; the quill- feathers of the wing and 

 tail dark brownish- black. This colour extends slightly, in 

 the form of shoulder-knots, on to the collar. Under parts 

 pearly-grey. Tail deeply forked. Total length, 6" ; wing, 

 4" ; tail, 3''. 



This swallow is very rare in the neighbourhood of Cape Town, but 

 becomes more common on the mainland. It will be as well to treat 

 the peninsula bounded by False and Table Bays as apart from the 

 continent. The vast tract of land called the " Cape Flats," together 

 with Table Bay on the one hand, and False Bay on the other, quite 

 shut it off from the mainland, so to speak ; and to aid in this isolation, 

 the mainland ends in an abrupt precipitous wall of mountains, which 

 are only to be passed in one or two places. Doubtless the peninsula 

 of Table Mountain was once an island, entirely cut off from the main- 

 land, and " Table " and " False Bays " part of a strait between. As 

 soon as the hills are reached on the opposite side of Table Bay, this 

 swallow commences ; and at Swellendam, Mr. Cairncross writes : " It is 

 very common, and builds its nest generally under the thatch of an old 

 mill or stable, where it is quieter than in a dwelling-house ; lays a small 

 white egg, and tradition says it drives the sparrow and house-swallow 

 C-ff. Capensis ?) from their nests, occupies them, and breeds therein. 

 For this reason it receives no mercy from the farmer, but its eggs and 

 young are destroyed whenever met with." 



I found it abundant all along the route as far as Joel's Poor! ; there it 

 was breeding among the rocks, and under the eaves of Mr. Jackson's 

 barn. They construct a nest of mud very similar to that of H. Capen- 

 sis, but without the elongated neck. The eggs, three or four in num- 

 ber, are pure white : axis, 7'j &am., 5'". 



]Mp&*^ Boie. 



Bill short, weak, with the gape very wide, the sides 

 gradually compressed, and the culmen curved to the tip ; the 

 nostrils basal, lateral, and rounded. Wings lengthened, with 

 the first quill the longest. Tail very long and much forked. 

 Tarsi shorter than the middle toe and scutellated. Toes long 

 and very slender, and the lateral toes unequal. 



