- Order: Passeriformes
- Family: Furnariidae
The White-browed Tit-Spinetail is a small-bodied but medium-sized, dark furnariid, with a long, dark and strongly graduated tail. Individuals have a characteristic uniform bright rufous and prominent white supercilium. The dull greyish-brown back has prominent narrow white streaks that are outlined in black. The dark wings have pale prominent markings giving the appearance of two pale ‘wing panels’. The throat is whitish, with distinctive coarse black mottling, which strongly contrasts with the uniform (unstreaked) grey-brown underparts. Both sexes are alike.
Throughout most of its narrow geographic range, the White-browed Tit-Spinetail overlaps with Tawny Tit-Spinetail (Leptasthenura yanacensis), but this latter species is very different, being completely tawny brown overall. Confusion is more likely with the Andean Tit-Spinetail (Leptasthenura andicola), which White-browed Tit-Spinetail only rarely overlaps with in the higher elevational Polylepis forest patches (> 4,300 m) in the Cordillera Vilcanota (Lloyd 2008b). Andean Tit-Spinetail has a streaked crown, more prominent and wider supercilium, a white throat with conspicuous broad white streaks on the underparts, and prominent broad ‘tear-drop’ shaped white streaking along the back.
The White-browed Tit-Spinetail is highly vocal, often singing whilst acrobatically foraging from the outer-most branches of Polylepis trees.
Vocalisation #1: The song is a rapid, dry descending trill, sometimes with some 1-4 shorter introductory notes ‘tjit tjit trrrrrrreeeeeeeeuuu’ and lasting two seconds (e.g. Hesse: XC 10649) but sometimes longer when agitated (Parker and O'Neill 1980, Fjeldså and Krabbe 1990). A series of other similar trilling notes and dry rattles also are known (see Fjeldså and Krabbe 1990).
Vocalisation #2: Contact call is a ‘check’ or ‘tjit’ note - similar to other members of the genus Leptasthenura (Parker and O'Neill 1980, Fjeldså and Krabbe 1990). Pairs also emit a similar series of these notes when defending a nest (Lloyd 2006).
Voclaisation #3: Other agitated calls include a series of 'tleet' notes.
Vocalisation #4: Juvenile contact call when foraging with parents is a series of constant, high-pitched and buzzy ‘tzziit’ notes (Lloyd unpublished data).
Detailed Description (appearance)
The White-browed Tit-Spinetail is a small-bodied but medium-sized, slender, long-tailed furnariid.
Adult: Both sexes are alike. The crown is uniform bright rufous. Individuals have a white supercilium, with a narrow black border above. The face is streaked blackish and whitish. The bright rufous crown is highly contrasting with generally dull greyish-brown upperparts. The back has prominent narrow white streaks which are outlined in black and continue (and become more prominent) to the lower back. The streaks become much fainter on the rump but the uppertail coverts have prominent pale streaks. The wings are dark fuscous, with dull rufescent edging on the wing coverts, and a pale tawny patch across the flight feathers, giving the appearance of two pale ‘wing panels’. The tail is long and strongly graduated and mainly dark fuscous to black. The central retrices have thickened shafts and progressively narrower barbs, which are also greatly reduced on the distal part. The throat and upper breast is whitish, coarsely mottled with black and deeply contrasting with uniform pale grey-brown underparts.
Juvenile: Currently there are no specimens in museum collections. Observations from the Cordillera Vilcanota, southern Perú, describe juveniles as being similar to the adults except for conspicuous yellow bill flanges and the tail-length approximately two-thirds that of the adults (Lloyd 2006).
Iris: Brown to blackish grey
Mandible: Pinkish base becoming black toward tip
Tarsi and toes: Black.
Length: 16-18 cm
Mass: 13 g
There is no known geographic variation in plumage.
The above summary and detailed description of the identification of White-browed Tit-Spinetail draws on the discussions in standard field guides and other recent literature: Fjeldså and Krabbe (1990), Ridgely and Tudor (1994), Remsen (2003), Walker and Fjeldså (2005), Lloyd (2006) and Schulenberg et al. (2007).
The White-browed Tit-Spinetail is now considered to form a superspecies with Rusty-crowned Tit-Spinetail (Leptasthenura pileata), with which it was formerly considered as being conspecific (e.g. Vaurie 1980). Together with this species, they are both probably more closely related to Streaked Tit-Spinetail (Leptasthenura striata – Remsen 2003).
Lloyd, Huw. 2009. White-browed Tit-Spinetail (Leptasthenura xenothorax), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=43100