ABOVE: An apparent hybrid between a Karoo Prinia and Black-chested Prinia, photographed by Chris Cheetham in the Northern Cape. The bird has the angry scowl of Black-chested, due to the dark lores and reddish mask behind the eye. Also characteristic of Black-chested is the distinct yellowish wash below.
ABOVE: This Karoo x Black-chested Prinia hybrid’s breast streaks are concentrated in a dark band on the upper chest. But there are also thin black streaks continuing down along the breast-sides and flanks; these areas are unmarked in normal Black-chesteds. Notice also the very worn tail. Photo by Chris Cheetham.
ABOVE: I hope the ADU and all the observers who contributed their sightings data to the SABAP2 project will forgive me for appropriating this map. This is the first time I’ve tried making a GIF (by the way, is it “giff” or “jiff”?). Karoo Prinia occurs throughout much of the south-western parts of South Africa, extending along the western coastal regions and Namaqualand and just making it across the border into far southern Namibia. It also occurs eastwards to about Bloemfontein in the Free State, and occurs in the interior of Lesotho (more detail below). Black-chested Prinia’s distribution is centered on the Kalahari. As you can see, the ranges of the two species are actually almost perfect mutually exclusive puzzle pieces – with the exception of the overlap zone in a part of the Northern Cape. And this is where Chris photographed his hybrid. Black-chested also has a rather isolated population southwards towards Port Elizabeth. This pattern is also shown by e.g. Great Spotted Cuckoo, Sabota Lark, Desert Cisticola, Cape Glossy Starling, White-browed Sparrow-Weaver, Scaly-feathered Finch, Red-billed Firefinch and a few other odds and ends. You can see the original maps on the SABAP website.
which you can read here. In short, and with a bit of self-plagiarism, it depends to a large extent on your definition of what is a species. According to the Biological Species Concept (BSC), perhaps these two prinias could be the same species, yes. The BSC deals well with populations of animals that live in the same places (sympatry) or habitats (syntopy). If two respective populations can live together without interbreeding and watering down their phenotypic (physical) or genotypic (genetic) integrity, then they represent different species, otherwise they wouldn’t exist. For example, Yellow-billed and Red-billed hornbills are often found directly alongside each other, with plenty of opportunity to interbreed. Yet they don’t. Otherwise, over time, the two discreet species would be replaced by a different, single species – perhaps the Orange-billed Hornbill.ybridization between Karoo and Black-chested Prinias is nothing new. As you can see in the map here, their ranges overlap extensively in parts of the Northern Cape, in the broad ecotone between the Nama Karoo and Kalahari. But if inbreeding between these two taxa is so rampant, would this not be evidence that they are the same species? That is a very complicated question to answer – I go into quite a lot of detail on this topic in my Harry Potter-themed book review,
One of the main problems with the BSC is that hybridization is actually far more common than one might think, with some estimates suggesting that at least 9% of all bird species have interbred in the wild – these prinias being a case in point. More modern species concepts, apparently counter-intuitively, treat hybridization as an argument against treating two taxa as the same species – quite the opposite of the BSC. The theory is that if two species hybridize, even frequently, but still retain their genomic and phenotypic integrity, without their genomes merging completely, they really are two different species.
ABOVE: A Karoo Prinia that I photographed in West Coast National Park. This species is likely the one parent of the hybrid, as suggested by its boldly streaked underparts. Unlike the hybrid bird, it has a whiter background to the breast, broader streaks that cover the central chest/belly and extend up the throat. It also lacks the red mask and dark lores of Black-chested.
ABOVE: This Karoo Prinia was photographed in Langebaan town, only a few kilometres from the previous one, and at the same time of year. However, it has a slightly more prominent yellow cast below, and thinner streaks. This is unlikely to be related to feather wear, but it may be an age- or sex-related character?
ABOVE: Black-chested Prinia (the other parent), is creamy yellow to bright sulphur yellow below, throughout the year. The black breast band is usually only present in summer breeding plumage though (but see comments below). Note the red mask and dark lores, giving it an angry look. Photo by Dylan Vasapolli.
ABOVE: Richard and Eileen Flack, please forgive me for stealing this off your website, but this Black-chested Prinia immediately caught my eye. It is a summer breeding bird, photographed in the bushveld north of Pretoria. Looks a bit streaky doesn’t it? That’s because its plumage is wet, causing the black feathers that form the breast band to shrivel into little points. Be aware!
ABOVE: A Black-chested Prinia in so-called transitional plumage – with the black breast-band just becoming visible. Interestingly, Black-chested Prinias apparently undergo two body moults each year, one resulting in the black breast-band, and another resulting in the plain non-breeding plumage, as in the next photo. However, because of the variability and unpredictability of rainfall in their arid habitat, their moult sometimes overlaps with breeding (which is unusual in most birds). Also, when they breed aseasonally, they may skip the non-breeding phase altogether and moult from one breeding plumage directly into a new breeding plumage. Photo by Richard and Eileen Flack.
ABOVE: This is a Black-chested Prinia in glorious, full and featureless non-breeding plumage. In this state, its wing feathers, coverts and tail are fresh and unabraded, and it completely lacks the black breast-band. In fact, these are quite tricky to distinguish from Tawny-flanked Prinias. The latter is on average warmer above, has a buff (not white) supercilium, has a less contrasting white throat, and has tawny flanks (duh) and a rufousy wing-panel. Their calls differ clearly, and they typically inhabit slightly different habitats (with some local overlap though). Photo by Richard and Eileen Flack. Check out their incredible photography website here. Really a great resource for birders in Africa.
ABOVE: These range maps, based on data from SABAP2, show the distributions of Karoo Prinia (large area in south-west) and Drakensberg Prinia (along the north-eastern escarpment). The map cannot be trusted 100%. For example, the yellow blocks that claim Karoo Prinia from Mpumalanga are almost certainly misidentifications or confusions arising from the fact that these two species were previously lumped. The two species overlap widely in the Eastern Cape, where great care is need to identify them.
ABOVE: Drakensberg Prinia usually has distinctly yellow-washed underparts, as implied by its scientific name. Other features include typically fine and limited streaking on the breast, and an unstreaked chin. The calls of Karoo and Drakensberg Prinias are very similar. Another gorgeous photo by Richard and Eileen Flack. I love how that inner toe on the right foot has accidentally become hooked on a snag! Birds’ feet are such complicated structures, yet so clumsy sometimes.
rakensberg Prinia also comes into play. Veteran birders will remember that this species and Karoo Prinia were once lumped, under the name Prinia maculosa (which now applies only to Karoo Prinia). At one stage the name Spotted Prinia was introduced, which could equally well describe either – I much prefer Karoo and Drakensberg. And don’t get confused by Namaqua Warbler, which was called Namaqua Prinia Prinia substriata or even Burnesia substriata in the past. Today, this enigmatic little skulker is not even in the same genus as prinias. Instead, it occupies the monospecific Phragmacia: a delightfully descriptive hint at its riverine bush habitat, i.e. a mix of reeds (Phragmites) and Acacia trees. It differs in e.g. its blue eggs and cup-shaped (instead of oval) nest, but we’re getting off track…
Drakensberg Prinia is normally distinguished from Karoo Prinia by its much richer yellow underparts – the scientific name hypoxantha means yellow below. By the way, the name of Karoo Prinia, maculosa, means spotted. And while we’re at it, the name Prinia is of Javanese origin. Drakensberg Prinia also has an unstreaked chin and throat and generally lighter streaking below compared to Karoo. But some worn birds are whiter, and some have quite heavy streaking, just to keep us birders on our toes. This species almost certainly hybridizes with Karoo Prinia in overlap zones in the Eastern Cape. In fact, I remember there was some research into this issue at one stage. If you know more, please share!
The situation in Lesotho is also questionable – in general, Karoo Prinia inhabits the western parts and mountainous interior, where it co-occurs with other scrub-loving Karoo species such as Large-billed Lark, Layard’s Warbler, Sickle-winged Chat and Black-headed Canary. Conversely, Drakensberg Prinia occurs mainly on the northern and eastern sides of Lesotho, primarily below the escarpment and on the foothills.
Another thing to keep in mind is that prinias have several subspecies or races. I’ll disregard my prejudice against the validity of many of the myriad races that have been described for southern African birds for a moment, and give you a quick summary. In both Karoo and Drakensberg Prinias, the basic clinal variation inherent in many of our birds also applies: eastern ones are darker and more heavily streaked; western ones are paler and less heavily streaked. But Black-chested Prinias from north-western Namibia (subspecies P. flavicans ansorgei) are noteworthy in that they are much paler and have a reduced or incomplete breast-band, that usually consist of only a few broken streaks. Interestingly, there are also very different-looking ansorgei races in this same Kaokoland area in two other birds: Sabota Lark Calendulauda sabota ansorgei, and Long-billed Crombec Sylvietta rufescens ansorgei. The lark’s ansorgei breaks the pattern of thick-billed forms in the west and slender-billed forms in the east, by also having a slender bill. The crombec’s ansorgei is a strange white and rufous creature.
And who knows? Perhaps Black-chested and Tawny-flanked also occasionally hybridizes in parts of their range? Perhaps a particularly adventurous prinia might even experiment with a randy Rufous-eared Warbler or a sexy cisticola. We clearly have a lot more to discover about the worlds of these tiny tinktinkies!