314 FKOM THE NIGER TO THE NILE 



but confine their flight to small areas. This is even the case 

 with the birds that are found in the open spaces ; for example, 

 fly-catchers, sun-birds and weavers, all of which use their 

 wings for little more than hovering round a tree, or up and 

 down from the tree to the ground : while the deep forest is 

 frequented by birds of the Pycnonotidce and Timeliidce groups, 

 such as chat- and bush-thrushes, which might almost be said 

 to walk their way through the undergrowth, living for the 

 most part on ants and other insects to be found in the 

 fallen leaf. 



The monotony of the twilight in the dead level of their 

 under-world existence seems to find expression in their voices 

 which are confined to cries and call-notes repeated con- 

 tinuously in unvarying tones. 



The surroundings also affect their plumage which tends 

 to assume a darker colouring. To take a few examples : 

 the beautiful red-thrush {Cossypha) that frequents the woods 

 of the bush country is represented in the forest by a more 

 sombre -coloured bird (Neocossyphus) ; and the large families 

 of gay-coloured weavers {Hyphantornis and Pyromelana) 

 by a very dark group (Malimbus), the general colouring of 

 which is black. 



The bright-plumaged shrikes (Laniarius) by a black 

 species {leucorhynchus) and another (Nicator chloris). And the 

 brilUant sun-birds by a dull-coloured group (Anthrothreptes). 



These remarks only apply to the birds that live entirely 

 in the gloom of the forest, for there are others which frequent 

 the open spots and the tops of the tall trees — like parrots, 

 black-winged orioles [Oriolus nigripennis), trogons {Hetero- 

 trorjon), and the glossy starhngs {Lamprocolius) that can, for 



