SPECIES LIMITS AND CLINAL VARIATION IN A WIDESPREAD HIGH ANDEAN FURNARIID: THE BUFF-BREASTED EARTHCREEPER (UPUCERTHIA VALIDIROSTRIS)

ARETA JI; PEARMAN M

THE CONDOR

COOPER ORNITHOLOGICAL SOC

Año: 2013 vol. 115

0010-5422

The Buff-breasted Earthcreeper (Upucerthia validirostris) is endemic to western Argentina, andthe Plain-breasted Earthcreeper (U. jelskii, including subspecies saturata in the north and pallida in the south),ranges from northern Peru to northwestern Argentina. They have been considered subspecies, as constituents ofa superspecies, and as different species. From north to south, a morphocline, involving an increase of rustiness ofthe plumage and of ~15% in bill length, 10% in wing length, and 20% in tail length, links jelskii to validirostris.The cline linking jelskii and pallida is gradual, over ~1800 km; that between pallida and validirostris is steep, over~80 km. The northernmost record of validirostris is from the northern Calchaquies Valley, Salta, northwesternArgentina, a valley surrounded by mountains of up to ~6300 m above sea level through which the lowest pass isat over 4900 m, forming a barrier between validirostris and the southernmost record of pallida to the north. Thesong, continuous song, duet, and call of validirostris are structurally indistinguishable from those of jelskii/pallidaand from the single available recorded song of saturata. In all playback experiments, validirostris answered byapproaching and vocalizing to voices of validirostris and jelskii/pallida and vice versa. Treatment of validirostrisas a single species is warranted, and three subspecies can be tentatively recognized: southern validirostris (large,rufescent birds with buff bellies restricted to Argentina), central and northern jelskii (small, pale birds rangingfrom northwestern Argentina to central Peru), and northern saturata (small, dark, and brownish birds in northerncentral Peru).