SPECIES

Cape Rockjumper Chaetops frenatus Scientific name definitions

Krista N. Oswald
Version: 2.0 — Published May 17, 2021

Appearance

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Identification

The Cape Rockjumper is a striking ground-dwelling, medium-sized passerine. The species name refers to the black/white patterning on the head (frenatus meaning "bridled"). It has a distinctive long, glossy, black tail with increasingly broad white tips toward the tail edges (although no white tips on the two central tail feathers). The vent, thighs, bill, tarsi, and toes are all black (14). Contour feathers are soft and fluffy. Most distinctively, adult Cape Rockjumpers have a bright orange-red iris.

Similar Species

The closest relative of the Cape Rockjumper is the Drakensberg Rockjumper (Chaetops aurantius). These species are superficially similar in appearance and vocalizations. They mainly differ in appearance in that the Drakensberg Rockjumper is orange where the Cape Rockjumper is rufous. The female Drakensberg Rockjumper is slightly paler than the female Cape Rockjumper. The call of the Drakensberg Rockjumper is slightly higher in pitch, but otherwise quite similar, as each will show some response to vocalizations of the other species (KNO, personal observations).

They also differ in location and habitat. The Drakensberg Rockjumper is found in the highlands of South Africa as well as Lesotho, occupying the nearby Lesotho highlands and adjacent Great Escarpment (14). Therefore the two are allopatric, their respective distributions separated by the Great Karoo plain (ca 100 to 150 km wide) north of Grahamstown, South Africa. The Drakensberg Rockjumper's habitat is alpine grassland as opposed to the Cape Rockjumper's preference for mountain fynbos (14). Formerly considered as a subspecies of the Cape Rockjumper, the Drakensberg Rockjumper was split in the 1980s and is considered a separate species by all current authorities.

The Drakensberg Rockjumper can be found in groups of up to 12 (14), whereas the Cape Rockjumper generally is in groups of only 2–5 (15; 9; 16).

Plumages

Juvenile

Resembles adult female, but can be distinguished by a dark-brown iris and even paler malar stripe. Recently fledged individuals have a not yet fully grown tail and a remnant yellow gape.

Adult

Female. The forehead, crown, hind-neck, lores, cheek, auriculars, upper neck, mantle, scapulars, and upper back are a warm taupe or brownish-gray, finely-streaked with black. The supercilium is whitish, with a stippled submoustachial stripe that ranges from a subtle rufous to more buffy white. The throat is lighter whitish gray, with subtle streaking. The breast and underparts are a deep burgundy rufous with dark brown undertail covers. The upperwing coverts are soft black with white tips; the flight-feathers are black, the outer primaries and inner secondaries are tipped with white, and there is a white patch at base of primaries. The lower back and uppertail coverts are rufous. The tail is black with white tips on all but the central rectrices. White tips becoming more extensive on outer rectrices. Females are similar to males, but are burgundy where the male is rufous, more grayish/gray-brown where the male is black, and with the plumage generally less saturated/contrasting.

Male. The forehead, crown, hind-neck, supercilium, lores, cheek, auriculars, and lower neck side are gray finely-streaked with black. A black moustachial stripe contrasts with a bright white malar stripe, which extends to the upper breast. The mantle, scapulars, and back are silvery gray with dense black streaks. The chin to upper breast is black, with the mid-breast, belly, and rump a rich chestnut red ("rufous"). The undertail coverts are black with whitish tips. The upperwing coverts are black with white tips; the flight-feathers are black, and the outer primaries and inner secondaries are tipped with white, with a white patch at base of primaries.

Molts

Little information. Molts predominantly in the Austral autumn, but adults can be found in various stage of molt throughout the year. Tail molt recorded in birds caught and banded in March and April (unpublished banding data). Immature attains the adult plumage at 3–6 months after fledging. Has a single adult plumage.

Bare Parts

Bare parts color data from (17).

Bill

Black.

Iris and Facial Skin

In adults, the iris is a bright vermillion red . In juveniles, the iris is dark brown.

Tarsi and Toes

Black.

Measurements

Measurement data were collected from 72 individuals (29 males, 27 females, and 15 immatures) banded between 2015 and 2016 at Blue Hill Nature Reserve in South Africa.

Immature (less than 3 months post-fledge) (mean): mass 46.0 g; wing length (chord) 82.86 mm; tail length 95.0 mm; tarsus length 35.73 mm; keel 22.14 mm; culmen length 19.19 mm; head width 17.18 mm; head height 16.73 mm.

Female (means): mass 51.0 g; wing length (chord) 95.68 mm; tail length 95.68 mm; tarsus length 36.33 mm; keel 22.75 mm; culmen length 20 03 mm; head width 17.97 mm; head height 16.75 mm.

Male (means): mass 55.8 g; wing length (chord) 92.08 mm; tail length 100.42 mm; tarsus length 38.14 mm; keel 3.72 mm; culmen length 22.20 mm; head width 18.32 mm; head height 18.09 mm.

Recommended Citation

Oswald, K. N. (2021). Cape Rockjumper (Chaetops frenatus), version 2.0. In Birds of the World (T. S. Schulenberg and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.rufroc1.02