Possible range expansion of the Karoo Prinia Prinia maculosa into the range of the Drakensberg Prinia Prinia hypoxantha in the eastern Free State

Free

Both prinia species occur in the Free State Province of South Africa. In the Free State, the Karoo Prinia ranges from central eastern Free State and adjacent Lesotho and north-east to Golden Gate Highlands National Park and Phuthaditjhaba (Dean 2005a, de Swardt et al. 2018. The Drakensberg Prinia ranges from north-eastern Free State and adjacent KwaZulu-Natal Province and Lesotho escarpment, northwards to Mpumalanga (Dean 2005b, de Swardt et al. 2018). In the Free State both species have been recorded in Leucosidea sericea habitat on mountain slopes. The Drakensberg Prinia is known to prefer bracken vegetation on forest margins in the eastern Free State whereas Karoo Prinias have been recorded in scrubby "fynbos" type vegetation in the Ladybrand-Zastron areas (pers. obs).
In contrast, along the KwaZulu-Natal/Lesotho escarpment, in the Royal Natal National Park and the Sani Pass areas, I found considerable overlap in their distributions and captured possible hybrids during mistnetting , de Swardt et al. 2018).
The current SABAP2 distribution map (Figure 1) of Karoo Prinia was of interest to me when I noticed SABAP2 records of this species within the range of the Drakensberg Prinia in areas north of Harrismith, Free State. My first thought was that these records could be incorrect because of their overlap within the range of the Drakensberg Prinia (for example the Drakensberg Prinia records in the range of Karoo Prinia at Golden Gate, pers. obs).
This note confirms the occurrence of Karoo Prinias within the range of Drakensberg Prinias in the eastern Free State based on SABAP2 records and discusses the possible reasons for this range expansion towards the north-eastern Free State.
During a field trip to Mount Everest Nature Reserve, Harrismith (28°1 0'S; 29°10'E) from 2-5 November 2021 birds were captured and ringed for research purposes. The site is known for three inselberg mountains: Mooihoekkop, Mount Everest, and Glen Paul (Figure 2). During the first two days of the trip mistnetting was carried out on the lower hillside slope of Mooihoekkop which is dominated with Leocisidea sericea bush where Drakensberg Prinias were abundant. This site had been used as a research site for a previous project on the prinias (de Swardt et al. 2018). On 3 November 2021, a prinia was captured at this site and ringed (Safring AS28327) (Figure 3). It was first thought to be a Drakensberg Prinia, but after carefully examining the bird (and later back at office comparing photos) it was confirmed to be a Karoo Prinia captured within the range of Drakensberg Prinia. On 4 November 2021, the nets were moved to another site on the northern aspect of Mount Everest. A Drakensberg Prinia was captured on a slope with scattered low bushes (Safring AS28339) ( Figure  4). After examining the Karoo Prinia distribution range on the SABAP2 website, I noticed that Karoo Prinias had already been recorded as sight records in areas north of Harrismith (within the Drakensberg Prinia range) (Figure 1). This ringing record was the first confirmed record of Karoo Prinia within the Free State range of the Drakensberg Prinia. Three photographs of both birds were uploaded    to the BirdPix section of Virtual Museum (BirdPix Virtual Museum records 191970 and 191971).
The Karoo Prinia's most eastern Free State distribution limit is in the Golden Gate areas towards Phuthaditjhaba and on the Lesotho escarp towards the KwaZulu-Natal where its range overlaps with Drakensberg Prinia (de Swardt 2018). In these areas from Phuthaditjhaba towards Sterkfontein Dam Nature Reserve, south of Harrismith (where Drakensberg Prinias occur in high altitude areas) they are mainly separated by unsuitable grassland habitats (no shrub or Leucosidea habitat). Therefore, it is possible that the Karoo Prinia has expanded its range northeastwards from the Lesotho escarpment, possibly moving along rivers and streams to within the range of Drakensberg Prinias north of Harrismith as shown by SABAP2 distribution map (Figure 1). The bird ringing record of Karoo Prinia at Mount Everest Nature Reserve confirms the occurrence of Karoo Prinia populations in these areas.
I recommend that more atlasing for SABAP2 be undertaken in areas where Karoo Prinia and Drakensberg Prinia overlap in range and that atlasers take photographs to enable the records to be vetted. Photographic records should be submitted to the BirdPix section of the Virtual Museum for curation.