Buff-tailed Sicklebill

With a total length of 5–6 in (13–15 cm) and weighing 0.28-0.44 oz (8-12.5 g), it is a relatively large hummingbird. Males and females are virtually identical, differing only in size (especially wing measurements), with the females being some 20% smaller. Its upperparts are iridescent dull greenish, while the underparts are whitish, densely streaked with dusky. The neck-side has a relatively faint blue patch. The tips of the rectrices (tail feathers) are white, and there is a naked stripe on top of the head (but this is usually concealed). The most conspicuous features, however, are those the common name refers to: the bill is strongly decurved, and the outer three rectrices on each side are deep buff, best visible from below. Immature birds have light-tipped remiges (pinions), hardly any blue on the neck, and lack the naked crown stripe. Hatchlings have black skin and grey down. There are two subspecies which are not very distinct and almost form a continuous cline, with an extensive intergradation zone in northern Peru: Eutoxeres condamini condamini (Bourcier, 1851) – northern buff-tailed sicklebill Colombia and Ecuador. Bill longer, lower belly much streaked Eutoxeres condamini gracilis Berlepsch & Stolzmann, 1902 – southern buff-tailed sicklebill Central Peru to Bolivia. Bill shorter, lower belly less streaked The buff outer remiges are the most reliable trait for separating the buff-tailed sicklebill from the only other member of the genus Eutoxeres, the white-tipped sicklebill (E. aquila), which has a more northerly distribution. The Eutoxeres species are somewhat sympatric however, for example in the foothills of Putumayo around Mocoa, Colombia.