Karoo Long-billed Lark (Certhilauda subcoronata) [XC742616]
by Lynette Rudman from Aberdeen Plain (near Noagashoogte), Western District, Eastern Cape, South Africa (call, dawn song)
Karoo Long-billed Lark (Certhilauda subcoronata) [XC395376]
by Frank Lambert from Pofadder, Northern Cape, South Africa (song)
Subspecies
Certhilauda curvirostris (Sibley and Monroe 1990, 1993) has been split into Cape Long-billed Lark (Certhilauda curvirostris) (including brevirostris), Karoo Long-billed Lark (Certhilauda subcoronata) (including damarensis and benguelensis) and Eastern Long-billed Lark (Certhilauda semitorquata) by the BirdLife Taxonomic Working Group following review of museum material and the arguments presented in Ryan and Bloomer (1999). Ryan and Bloomer (1999), in addition to splitting curvirostris, subcoronata and semitorquata, propose elevating brevirostris and benguelensis to species level, but this treatment, based largely on genetic evidence, is not supported by morphological and vocal evidence from museum specimens and scientific and popular literature. There is evident ambiguity in the placement of subspecies and differences between them are slight.
All members of genus with exception of Short-clawed Lark (Certhilauda chuana) formerly treated as conspecific, but recent research indicates that they are genetically, morphologically and vocally distinct. Although genetic data suggest that present species has no close relatives within the complex, it is very similar to Benguela Long-billed Lark (Certhilauda benguelensis) in morphology and vocalizations. Range overlaps narrowly with that of Cape Long-billed Lark (Certhilauda curvirostris) in north-west, and abuts that of Eastern Long-billed Lark (Certhilauda semitorquata) at karoo-grassland interface (roughly along 24º eastern longitude). Possible overlap with Agulhas Long-billed Lark (Certhilauda brevirostris) in southern (Breede Valley). Exhibits strong north-south clines in size, colour and streaking. Subspecies damarensis possibly belongs with Benguela Long-billed Lark (Certhilauda benguelensis), but plumage and morphology suggest that it represents northern end of cline of reduction in size and streaking of present species (by comparison, southern subspecies kaokoensis of Benguela Long-billed Lark (Certhilauda benguelensis) slightly larger, darker and more streaked). This argument is supported by a gap in atlas records south of Brandberg, which approximates with geographical boundary between the two taxa. Subspecies gilli intergrades with nominate, and bradshawi with damarensis.
The following 4 subspecies are recognised:
damarensis (Sharpe, 1904) - Central Namibia. Considered by some authors to be a distinct species, Damara Long-billed Lark (Certhilauda damarensis).
bradshawi (Sharpe, 1904) - Southern Namibia and north-western South Africa (Bushmanland).
subcoronata Smith, 1843 - Western South Africa (from Kenhardt area south to central Karoo).
gilli Roberts, 1936 - Southern Karoo (from Touwsrivier east to Beaufort West).
BirdLife International Species Factsheet