The Karoo complex bill shape Bill length varies within and between plumage A key plumage feature to investigate is the the songs apart; concentrate particularly on the pitch species, depending on sex ( 's bill up to 20% longer), intensity and extent of the streaking on the underparts; and the number of introductory clicks. Both sexes have The Karoo, Barlow's, Dune and Red together as well as region and habitat: on sandy soils often note the colour and breadth of the streaks, and how far a number of other calls, used in different contexts. constitute the so-called 'Karoo Lark complex' and are have longer bills, while those on harder substrata they extend down onto the flanks. Also consider the sometimes collectively referred to as 'red-backed larks'. have shorter, sturdier bills. On average, Karoo has the colour of the mantle, but keep in mind that this varies 6 Red These 4 species are so similar in structure, plumage, shortest, finest and most delicate bill, which usually even within a relatively small area, to match the colour voice, habitat and behaviour that their has looks clearly decurved. Barlow's has the longest bill of the sand on which the birds occur. The amount of 4 been the subject of lengthy investigations; historical of the group. Many Dune Larks show long but slender streaking on the mantle should also be verified (most 2 classifications proposed anything between a single and decurved bills. Red has a short but robust bill. streaked in Karoo), as should the intensity of the facial Karoo variable species and up to 6 species. Modern insights size and shape Subtle structural differences can markings. The pattern of the tail and tertial feathers kHz 1s 1s 2s 3s S are mainly from vocal and genetic evidence. provide further clues. Red Lark is the largest of the 4, can be informative: for example, around Aus and the Karoo and Red Lark songs. Song composition varies con­ distribution Fortunately the distribution ranges of with big looking almost thrush-sized; it has a long Koichab River, Barlow's can be distinguished from the siderably but on average Karoo has the shortest and highest song these 4 larks are mostly exclusive. Care should be taken tail and bulky head that is empha­sised by its deep, almost identical Dune by the dark central streaks on its of the 4 species, with only 1-2 introductory clicks. Red Lark has a lower-pitched, rounder and more powerful song which may where neighbouring species occur in close proximity, heavy bill. Karoo is the smallest of the group (especially tertials and central tail feathers. include complex motifs and often ends with a full, trilling rattle. such as along the Red/Karoo border, and in particular, , which is only slightly larger than a sparrow). Dune voice utter monotonous territorial songs year- in the restricted Barlow's/Karoo hybridisation zone in and Barlow's fall between these extremes. Karoo round. The exact song composition varies regionally, 6 the coastal strip between Port Nolloth and the Orange looks small-headed and rather delicate in the field, in and may have several song types in their repertoires. River (see specimens, right). Barlow's also comes into contrast to the big-headed, strong-billed and thick- The songs of all 4 are similar in basic structure, and also 4 close contact with Dune inland from Lüderitz towards necked ('bull-necked') Barlow's. always recall the jangle of Fawn-coloured Lark (p. 69), another Aus in Namibia (birds in the Koichab River valley and appears long-legged, and is capable of long strides (up member of the genus . Typical song 2 Dune Barlow's northwards are presumed to be Dune Larks). to 19 cm) as it runs across hot sand dunes. phrases are introduced by a number of short, staccato, kHz frog-like clicks (sometimes accelerating) that run into a S 1s 2s 1s 2s high whistle which ends in a stuttered trill. Each phrase Dune and Barlow's Lark songs. Dune has a slightly longer and higher song than Barlow's, with a long series of introductory Swakopmund Windhoek Gobabis Dune Lark lasts 1-3 s and consecutive phrases are repeated at 2-5 s clicks. Compared to Karoo, the song of Barlow's is longer, slower, Walvis Bay NA intervals. A practiced ear is required to confidently tell lower-pitched and features more initial clicking sounds. BOTSWANA Barlow's Lark Kuiseb River NAMIBIA Karoo Lark Red Lark larger and more typically paler, greyish or indistinctly mottled on robust than Karoo, peach-coloured above mantle and crown Dune Lark bill longer Barlow's Lark barlowi Gaborone with big head and (variable) and deeper Matches sand: Pale and rather plain; very similar to thick neck than Karoo's yellow, orange neighbouring Dune Larks, but not or pale red known to occur N of Koichab River

Mafikeng

Koichab River Keetmanshoop Aus Red Lark Lüderitz Debatable 'subspecies' overlap and interbreed locally: Barlow's Lark cavei • Plain-backed red 'burra' on Rufous-brown, pinkish or Barlow's patae NW dunes around Aggenys. face pattern and reddish above; inland of patae Pale coastal form; Streaky-backed brown 'harei' size of head and bill • barlow s lark patae unmarked overlaps with Karoo on central alluvial plains.  ' intermediate Upington Near mouth of Orange River, SA flanks Lark S of Orange River • Plain dark red 'aridula' on dunes around Van Wyksvlei. Karoo x Barlow's hybridisation Pofadder Bloemfontein zone between Port Nolloth P. Nolloth Aggenys and Orange River (see p. 63) Prieska Springbok SOUTH AFRICA Karoo Lark codea Van Wyksvlei Brandvlei Pale greyish or sandy brown; less head rather heavily streaked than S albescens Colesberg small in relation hybrid some streaking on to body Between Port Nolloth upper flanks Karoo Lark guttata and Alexander Bay, NC Rufous-brown above (some very red) Graaff-Reinet Cradock Karoo Lark 'saldanhae' is rufous Sutherland Beaufort West or pink above; probably guttata x small, decurved bill codea/albescens hybrids Saldanha

Grahamstown Karoo Lark albescens Oudtshoorn Occasional pairing of Dull grey to sandy above, heavily Worcester (usually) Barlow's patae streaked; from just N of Cape Town Cape Town George Karoo Lark karruensis Swellendam and Karoo codea produces Darker, browner, less red and hybrid offspring with inter­ shorter-billed than guttata thinner streaks clearly bold, broad Note: borders of subspecies are not clearly defined karoo lark codea extend onto flanks and blackish mediate proportions and 15 km N of Port Nolloth, NC even undertail coverts blotches weak flank streaking.

62  LARKS LARKS  63