Brown-billed Scythebill
Campylorhamphus pusillus
The brown-billed scythebill is 20 to 25 cm (7.9 to 9.8 in) long and weighs 32 to 48 g (1.1 to 1.7 oz). It is a slim, medium-sized woodcreeper with a very long, slim, dramatically decurved bill. The sexes have the same plumage. Adults of the nominate subspecies have a face and neck streaked buff and blackish brown, with a faint buffy supercilium. Their crown and nape are dark brown, with thin deep buff streaks that extend sparsely onto the upper back. Their back and wing coverts are deep reddish brown, their rump is cinnamon-rufous, and their wings and tail are rufous-chestnut. Voice: The brown-billed scythebill sings mostly at dawn and dusk. Its song is complex and highly variable, a "series of notes lasting 2·5–5 seconds, beginning with a soft, twittering trill that continues in background during a series of loud whistles that are usually descending (sometimes ascending) and somewhat quavering, e.g.
ID text from Wikipedia, CC BY-SA 4.0

Red-billed Scythebill
Campylorhamphus trochilirostris
The red-billed scythebill is 22 to 28 cm (8.7 to 11 in) long and weighs 30 to 55 g (1.1 to 1.9 oz). It is a slim, medium-sized woodcreeper with a very long, slim, dramatically decurved bill. The sexes have the same plumage. Adults of the nominate subspecies C. t. trochilirostris have a thinly streaked face and neck with a weak supercilium. Their crown, nape, and back are reddish olive-brown, with the back being somewhat lighter. Their crown has longish whitish to ochraceous spots with narrow blackish edges; the spots narrow on the nape and become thin streaks on the upper back. Voice: Like its breeding seasons, the red-billed scythebill's songs vary widely throughout its range. One in Venezuela is "a rapid descending whinny...'we'he'he'he'he'he'he'e'e'e'e'e' ". In western Ecuador and Peru it is "a descending and gradually slowing series of fewer whistled notes, 'tuwee-tuwee-toowa-tew-tew' ".
ID text from Wikipedia, CC BY-SA 4.0

Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Brown-billed Scythebill and Red-billed Scythebill.