Thousands of crows, rather smaller than our rook, keep up a constant cawing in these plantations; the curious wood-swallows (Artami), which closely resemble swallows in their habits and flight but differ much in form and structure, twitter from the tree-tops; while a lyre-tailed drongo-shrike, with brilliant black plumage and milk-white eyes, continually deceives the naturalist by the variety of its unmelodious notes.
Source: wiktionary