Complex sentence: They are small, slender passerines from the Old World, with long, usually decurved bills; some species have long tail; many are brightly coloured, most with some iridescence, particularly in the male.
Split into simpler sentences: They are small, slender passerines from the Old World, usually with downward-curved bills. Some species have especially long tail feathers, many are brightly coloured, most with some iridescence, particularly in the male.