The Cape rockjumper or rufous rockjumper (''Chaetops frenatus'') is a medium-sized insectivorous
passerine
A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by th ...
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
endemic to the mountain
Fynbos of southernmost
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
.
Taxonomy
The Cape and Drakensberg rockjumpers were split into separate species in the 1980s. The Latin epithet ''frenatus'' refers to the "bridled" or black-and-white head pattern. When the Drakensberg rockjumper was split it was given the Latin ''aurantius'' meaning 'orange'. Initial taxonomy placed rockjumpers in the thrush family
Turdidae
The thrushes are a passerine bird family, Turdidae, with a worldwide distribution. The family was once much larger before biologists reclassified the former subfamily Saxicolinae, which includes the chats and European robins, as Old World fl ...
in 1867. They were then moved to the babblers
Timaliidae in the 1980s, before genetic work in the 1990s placed them in their own family
Chaetopidae. See the main page on the
rockjumper
The rockjumpers are medium-sized insectivorous or omnivorous birds in the genus ''Chaetops'', which constitutes the entire family Chaetopidae. The two species, the Cape rockjumper, ''Chaetops frenatus'', and the Drakensberg rockjumper, ''Chaeto ...
for more details.
Some authorities (notably
Dickinson and Christidis) treat the two rockjumpers as a single species, ''Chaetops frenatus'', with two subspecies.
However, for most field guides and birders, and according to the
International Ornithologists' Union
The International Ornithologists' Union, formerly known as the International Ornithological Committee, is a group of about 200 international ornithologists, and is responsible for the International Ornithological Congress and other international ...
and
The Clements Checklist of Birds of the World
''The Clements Checklist of Birds of the World'' is a book by Jim Clements which presents a list of the bird species of the world.
The most recent printed version is the sixth edition (2007), but has been updated yearly, the last version in 202 ...
, they are two species.
Climate Sensitivity
Cape rockjumpers exist only in Alpine Fynbos, a specialized habitat of 90,000 ha from Cape Town to Port Elizabeth in South Africa. These birds are alpine habitat specialists, and so used to a very specific range of temperatures. Cape rockjumper numbers are declining in warmer parts of their habitat, and birds were found to have low heat tolerance compared to other birds of the Fynbos. Juvenile Cape rockjumpers are more sensitive to the heat than adults, and perhaps cannot drink enough water to make up for the water they lose in trying to stay cool when it's hot.
Birds also struggle to continue foraging when it is hot, and produce smaller offspring at higher temperatures.
Behavior and Ecology
Diet
Birds forage on rocky slopes and scree. Insects are the major part of the diet, although small vertebrates are reported to be taken by Cape rockjumpers. A range of insects are taken, including caterpillars, moths, grasshoppers, beetles and flies. In addition to insects other prey include lizards and geckos, amphibians, scorpions, annelid worms and spiders. Their wings are proportionately small and they do not fly very often, although they will often take long gliding "flights" across valleys or downslope. They spend most of their lives running and jumping among rocks and grasses while hunting arthropods, small lizards, and amphibians.
Breeding
Family group territories near Cape Town vary in size from , but are larger out east. Typically these grounds consist of a breeding pair and one or two additional individuals, usually offspring from the preceding breeding season. These helpers participate in territorial defence and alarm calling, and in the feeding of nestlings and fledglings of the breeding pair. Both sexes help with nest building and incubation.
While an initial study from 2002 found Cape rockjumpers attempt only one nest per season, a more recent study found they will attempt up to 5 nests per season if initial nests fail, and even re-nesting when they have had a successful nest.
Nests are built on the ground under rocky overhangs, and lined with either fur from
red rock hare
The red rock hares are the four species in the genus ''Pronolagus''. They are African lagomorphs of the family Leporidae.
Taxonomic history
Species in this genus had previously been classified in the genus ''Lepus'', as done by J. E. Gray, or ...
or old and fluffy
protea
''Protea'' () is a genus of South African flowering plants, also called sugarbushes (Afrikaans: ''suikerbos'').
Etymology
The genus ''Protea'' was named in 1735 by Carl Linnaeus, possibly after the Greek god Proteus, who could change his form a ...
seed pods. In general, nests are built under rocks on the downward facing slope to provide protection in inclement weather.
As ground nesters, rockjumpers face large amounts of predation. Cape rockjumper nest predation comes predominantly from the
Boomslang, with this predation increasing at higher temperatures. They also experience predation from
Cape grey mongoose
The Cape grey mongoose (''Herpestes pulverulentus''), also called the small grey mongoose, is a small mammal native to South Africa, Lesotho and southern Namibia.
Appearance
It is a small species (55–69 cm long, weight range 0.5 – 1 ...
,
honey badger
The honey badger (''Mellivora capensis''), also known as the ratel ( or ), is a mammal widely distributed in Africa, Southwest Asia, and the Indian subcontinent. Because of its wide range and occurrence in a variety of habitats, it is liste ...
,
common egg-eater, and
African vlei rat.
[Oswald, KN, EF Diener, JP Diener, SJ Cunningham, B Smit, and ATK Lee (2020). Increasing temperatures increase the risk of reproductive failure in an alpine ground-nesting bird, the Cape Rockjumper Chaetops frenatus. ''Ibis'' 10.1111/ibi.1284] While parents can deter mongoose by harassing them, this is generally not successful to deter snakes. Although not recorded, it is also likely they experience predation from
chacma baboon
The chacma baboon (''Papio ursinus''), also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide vari ...
,
black-backed jackal,
white-necked raven
The white-necked raven (''Corvus albicollis'') is somewhat smaller (50–54 cm in length) than the common raven or its nearest relative, the thick-billed raven ''C. crassirostris''. It is native to eastern and southern Africa.
Descriptio ...
, and other snakes in the area (such as
Cape cobra
The Cape cobra (''Naja nivea''), also called the yellow cobra, is a moderate-sized, highly venomous species of cobra inhabiting a wide variety of biomes across southern Africa including arid savanna, fynbos, bushveld, desert and semi-desert reg ...
or
puff adder
The puff adder (''Bitis arietans'') is a viper species found in savannahs and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rainforest regions.U.S. Navy. 1991. ''Venomous Snakes of the World''. US Govt. ...
).
Nest success for Cape rockjumpers is higher in territories that had more recent fire (within 3-5 years), possibly as there were fewer predators present.
Habitat
Cape rockjumpers inhabit only mountain Fynbos, specifically that dominated by low scrubby
restio
''Restio'' is a genus of flowering plants within the family Restionaceae, described in 1772.Rottbøll, Christen Friis. 1772. Descriptiones Plantarum Rariorum 9 The entire genus is endemic to South Africa (Cape Province and KwaZulu-Natal).
In c ...
vegetation. They prefer steep slopes with plenty of large boulders from which they can perch to keep an eye out for predators. While there is an established population at sea level at
Rooi-Els (~ 80 km east of Cape Town), this area nevertheless is made up of mountain Fynbos habitat.
Description
This
rockjumper
The rockjumpers are medium-sized insectivorous or omnivorous birds in the genus ''Chaetops'', which constitutes the entire family Chaetopidae. The two species, the Cape rockjumper, ''Chaetops frenatus'', and the Drakensberg rockjumper, ''Chaeto ...
is 23–25 cm long with a long black tail and strong legs. The male has a dark grey and black head with a thin white
supercilium and a broad white moustache (malar stripe). The back and wings are dark grey, and the underparts and rump are
rufous
Rufous () is a color that may be described as reddish-brown or brownish-red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a dia ...
red. The female and juvenile have a paler grey head, upperparts and wings, a duller head pattern, an orange rump, and buff underparts. The call varies from 1-4 piercing whistles to a series of trills. Adults have bright red eyes, while juveniles have black eyes until mature.
The closely related
Drakensberg rockjumper (''Chaetops aurantius'') does not overlap in range. The male of that species has orange underparts, and the female and young are paler below than the Cape rockjumper.
References
External links
*
*
* Cape rockjumper
Species text in The Atlas of Southern African Birds
{{Taxonbar, from=Q942132
Cape rockjumper
Endemic birds of South Africa
Cape rockjumper