During the early part of 2023 (15 January to 20 April) a total of 3,440 birds of 56 species were ringed at the Alte Kalköfen Bird Observatory in southern Namibia (26°49’S 17°21’E). The majority of the birds were ringed around the complex of buildings that form the Alte Kalköfen Lodge; two other ringing sites on the Sandverhaar farm were also visited: the farm house and the grove of date palms.
Most birds were trapped with mist nets with a few caught using a baited snap trap. All birds were fitted with uniquely numbered SAFRING metal rings.
The most commonly ringed bird species were Cape Sparrows (564 birds ringed), Red-billed Quelea (553), Namaqua Doves (363) and Scaly Feathered Weavers (353).
Other species ringed in large numbers were Ring-necked Doves (104), Lark-like Buntings (77), African Red-eyed Bulbuls (74), White-throated Canaries (70) and Pale-winged Starlings (69).
There were surprise captures of species which are rare in the area, or which have never been recorded here before: Stark’s Lark (12), Karoo Scrub Robin (3), Sclater’s Lark (2), Chestnut Weaver (2), Green Wood-hoopoe (1), Cape Penduline Tit (1), Southern Grey-headed Sparrow (1) and Lanner Falcon (1).
Watercolour : Janet Snyman
Although most species occurred in fairly large numbers during January, February and the first two weeks of March 2023, there was a dramatic drop in bird numbers later in March and by mid-April the majority of the seed-eaters such as the Yellow Canaries, White-throated Canaries, Namaqua Doves, Red-billed Queleas, Lark-like Buntings and Cape Sparrows had left the area. This was presumably in response to the lack of rain and thus food. Fast and strong flying seed-eaters such as Ring-necked Doves and Laughing Doves still occurred in large numbers around the complex because they can fly long distances daily between their food sources and watering points. It was also noticed that the mean weights of some species decreased. For example, the Cape Sparrows had an average mass of 22.8 g in February, but by mid-April this had decreased to 20.9 g. Similarly, Laughing Doves also seemed to be much leaner in April than they had been in February; only one of nine doves in April weighed more than 95 g while all 21 birds ringed in February were heavier than 95 g.
The species that mainly eat fruit and berries such as the Pale-winged Starlings, African Red-eyed Bulbuls and White-backed Mousebirds were also present in much smaller numbers during late March and April than earlier in the season. Clearly, their food resources dwindled.
To gauge the effectiveness of the ringing programme, observations were made around the bird bath, close to where Cape Sparrows were mistnetted regularly. Regular watches were kept during which the proportion of sparrows that had been ringed was estimated. By the end of March, the results showed that about 10% to 15% of the local Cape Sparrow population had been ringed.
The recaptures of many of the individuals during the period gave valuable information about the sequence and speed of primary moult. Recapture of individual birds in future will provide information about longevity and local movement of individual birds.
We also set up a colour-ringing project for Familiar Chats. This is described in the section below.
Territoriality in the Familiar Chat
The Familiar Chat is a common resident bird around the Alte Kalköfen Lodge in southern Namibia with some pairs breeding inside buildings. During the study period, 15 Familiar Chats around the lodge were fitted with a combination of colour rings in addition the metal ring to make individual recognition at a distance possible.
Three different colour rings and a metal ring provide more than enough combinations to individually mark the estimated 10 pairs of Familiar Chats around the lodge. The metal rings are always placed on the left together with one colour ring. The right leg has two colour rings, always of different colours.
The aim of the project is:
1 To generate information on the movements and interactions of individual Familiar Chats around the lodge complex.
2 To determine the mate fidelity of the breeding pairs
3 To determine the home ranges and territoriality of this population of Familiar Chats.
4 To gather data on the dispersal of young birds hatched within the study area.
Recommended citation format: Earlé RA 2025. Bird ringing at Alte Kalköfen Bird Observatory, southern Namibia : January to April 2023. Biodiversity and Development Institute, Cape Town. Available online at https://thebdi.org/2024/09/12/bird-ringing-at-alte-kalkofen-bird-observatory-january-to-april-2023/
