Olive-tree Warbler

Tiny, drab bird with a sharp bill, a dull olive-green back, and buffy yellow underparts and forehead. Found in lowland rainforest, secondary forest, and sometimes plantations, usually in the canopy. Uncommon and inconspicuous, in pairs or small flocks. Similar to Yellow Penduline-Tit, but much duller and found in different habitat. Could be confused with Tit-Hylia, but duller overall, without streaking on the head and breast. Could also be confused with some dull sunbirds, but has a shorter, deeper-based, and sharper bill. The vocalizations are very high-pitched “sit” notes that are easily missed.

Elegant slim gull with long legs, and narrow wings. Adults have a light grey body with a paler white head. The wings are light gray with black tips, lacking conspicuous white spots. Legs are dark gray and the bill is dark red. Eyes are dark. Juveniles are similar to Lesser Black-backed Gull, with strongly barred underwings and a U-shaped white rump patch and dark tail. In their 1st winter they develop a gray-brown mantle and in their second winter the head is already white; the tail and secondaries have a black band.

Small earthcreeper with long tail and curved bill. Inhabits the ground and low vegetation in dense Chaco spiny woodlands and shrubby slopes, where it generally forages alone. Both sexes have uniform orangish-brown plumage. Note the white throat and the dark supercilium. Feeds on small insects and caterpillars gleaned out of the ground. Voice is a series of 5–10 loud notes increasing in volume.