Friday, July 31, 2009

Ashy-throated Bush-Tanager in Santa Fe, a report by Jan Axel Cubilla

Location: Altos de Piedra—Guabal Road, second ridge, near the new facilities of Santa Fe National Park, still on the Pacific slope. Around 600–800 meters above sea level.

Time: Saturday, july 18. Around 10:30 a.m. Cloudy.
Habitat: Montane very humid forest border.
Description: During a stop in the road, we detected a mixed flock about 7 to 10 meters away. Most of them were Dusky-faced Tanagers. But also presents were a pair of Flame-colored Tangers and one Crimson-collared Tanager. They were working along some Melastomes when someone noticed a different bird accompanying the flock. It was a little bit smaller and chunkier than the Dusky-faced Tanagers, with a big-eyed appearance. We (with Rosabel Miró) recognized it almost immediately as a Bush-Tanager (and we were aware of the presence of Yellow-throated Bush-Tanagers in the area). I got a view of the bird without obstructions during approximately 10 seconds with my 10x42 Leica Trinovid against a dark background (a mossy trunk). Dull olive upperparts, including crown, with dark gray face and throat. Black eye without eyebrows, dots or any other mark. Dull yellow breast band, not bright but contrasting with the whitish gray underparts. Black legs and bill. It didn’t vocalize. It foraged actively, specially on the Melastomes.
Discussion: The bird was identified almost immediately as a Bush-Tanager. It had a black eye, but didn’t have any yellow in the throat, nor white in the head, separating it from all the others Bush-Tanagers recorded in Panama (I have seen them all in Panama—except Pirre—including the Yellow-throated Bush-Tanager). Carmiol’s Tanagers are more uniformly olive, always in groups with a constant chattering. The euphonias and manakins (females) are all smaller and with a different colour pattern. Females Tachyphonus tanagers are more uniformly brown (Tawny-crested, White-lined), with no olive at all or have white in the bill or are totally yellow below (White-shouldered). Usually are accompanied by males. Female Ant-Tanagers have no gray. The Schiffornis of the foothills also has a big-eyed appearance, but is more uniform in color (with no yellow) and has more skulking habits.

The Ashy-throated Bush-Tanager is known (in Panama) only from the Bocas foothills along the Oleoducto road (where it is rare), with only one record from the pacific side in Quebrada Arena, Fortuna. It is also known mainly from the Caribbean slope in Costa Rica. The habitat and elevation are right for this species (a little low for Panama, but in Costa Rica it has been recorded from 400 to 1200 m). Taking into account that its preferred habitat (humid Caribbean foothills) is barely visited by birders, except in Bocas del Toro, is not surprising to find it above Santa Fe, a place long known by the occurrence of Caribbean species into the Pacific slope.

One last thing. After checking all the illustrations that I have available (Ridgely & Gwynne, Stiles & Skutch, Garrigues & Dean, Hilty & Brown, Ridgely & Greenfield), by far, the one that best matches is that of the plate 48 of Ridgely & Gwynne. All the others illustrations show much brighter birds, the South American guides showing completely gray-headed birds.

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