Patagonian Forest Earthcreeper Upucerthia saturatior Scientific name definitions

Up until recently, Patagonian Forest Earthcreeper was considered merely a dark subspecies of Scale-throated Earthcreeper (Upucerthia dumetaria). It turns out that the truth is much more interesting than this. Although similar in appearance to Scale-throated, Patagonian Forest Earthcreeper is quite different in its ecology. Overall the differences in plumage are subtle, but Patagonian Forest Earthcreeper is distinctly darker. It also shows a shorter and blacker bill. But where it differs substantially is in its requirement of taller shrubs, open forest, or forest edge; in contrast, Scale-throated Earthcreeper is a species of open habitats. The breeding distribution of Patagonian Forest Earthcreeper still is being determined, but it appears to breed in both the Argentine and Chilean sides in the temperate forest zone. Increasing evidence suggests that it may breed quite far north in Chile, nearly to the north edge of the forest zone, not all that far south of Santiago. Patagonian Forest Earthcreeper is a strong migrant and it appears that most migrate north into Chile during the winter. Here it is found in low elevations, even to sea level in areas of shrubby forest edge. Most winter records of earthcreepers in central Chile may actually pertain to this species, not to Scale-throated which tends to head lower in elevation but still remains in the mountains during the winter. The vocalizations of these earthcreepers also are distinctly different, with Patagonian Forest having a slower, lower pitched song that is more piping in its nature.

20–22 cm. Compared to formerly conspecific U. dumetaria, adult is much darker above and below than any race of the latter species, the upperparts having an olivaceous tinge, while the central rectrices are dusky brown without any rufous tinge, the tail is shorter, there are no pale tips to wing-coverts , it is greyer and less buffy below, with broader, often brown (not black) scaling, usually restricted to the upper breast, creating a more diffuse and less conspicuous scaled pattern, and the bill is slightly shorter and less strongly decurved. Previous reports of intergradation between U. dumetaria and the present species (then treated as a race of the latter) have proven erroneous. Sexes alike. Juvenile has even shorter bill.

C Chile (S from Concepción to Valdivia) and SW Argentina (W Neuquén S to W Chubut).

Inhabits forest borders, usually near waterbodies, especially patches of Nothofagus forest, sometimes around clearings well inside large blocks of forest, or at the edges of densely wooded mosaics of rivers and pools with introduced Salix and other trees (some possibly native) but without Nothofagus. Suspected to winter, mainly or exclusively (see Movements), in dry deciduous forest and matorral along the coast of C Chile, with records (presumably of migrants) even in the city of Santiago. Elevational range 250–1800 m.

Poorly known, but rather than simply moving further N during the austral winter, as often mapped in the literature, the species is suspected to be a trans-Andean migrant, given that all specimens and sight records in Argentina are from Sept to Mar, and most specimens from Chile are from late Mar to Aug. If this pattern of migration is confirmed then the species might be unknown as a breeder in Chile.

Diet undescribed, but presumably arthropods and their larvae. Forages alone or in loose pairs. Feeds exclusively on ground near tall trees, around small bushes in sandy soils, on boggy ground near forest edge, and in forest clearings, vigorously and rapidly probing its bill into the ground obliquely, and occasionally by removing large clumps of earth and stones using the feet or bill. Regularly perches in trees between bouts of foraging, and occasionally takes prey to perch above ground.

Song  (can be given from perch up to 7 m above ground) consists of 1–2 sharp, short and lower-pitched initial notes followed by either a syncopated or a continuously delivered series of triplets, at rate of three per second, each of which starts with one fast metallic, abrupt and almost vertical note followed by two shorter, flatter, longer V-shaped or shallowly U-shaped notes, rendered “p-p-tirik-tirik-tirik-tirik-tirik-tiruk”; occasionally, ends with a distinct triplet including a lower-pitched final note. Song becomes faster in response to playback, sometimes also with an additional end note. Contact call a hollow “pep”, peaking at just above 4 kHz, uttered singly or as a series of notes at intervals of c. 1·5–3 seconds.

Not globally threatened (Least Concern). Very few data on abundance, but generally considered to be reasonably numerous within its overall known range of c. 184,000 km²; apparently declining. Known from several protected areas, among them Reserva Turístico Forestal Lagunas de Epulauquén and Parque Nacional Nahuel Huapi, in Argentina, and Parque Nacional Fray Jorge, in Chile.