Bird ringing course at Ouberg Nature Reserve, 10 to 16 May 2023

A cold and sometimes wet Karoo week was not the best for a ringing course, yet everyone thoroughly enjoyed the course! We caught 219 birds of 29 species at the Ouberg bird ringing course of May 2023, including lots of recaptures, enjoyed wonderful meals, and great camaraderie.

The course was part of a series of bird ringing courses run by the Biodiversity and Development Institute. The overall aim and structure of these events is described here. Future courses are listed under “Upcoming BDI Events” and you are welcome to join. The purpose of bird ringing is described here.

Ouberg Private Nature Reserve
Ouberg Private Nature Reserve. The farmhouse where we stay is on the left. The drainage line in front of the house stretches off to the right and is filled with riverine bushes and a few small reedbeds, used as night time roosting sites. Great ringing site!

The course was held in the foothills of the big mountains north of Montagu, Western Cape. For background to the Ouberg Private Nature Reserve and its objectives, listen to this conference presentation. Ouberg is a good place for birding in general, but it is the species richness we get while ringing makes it a chosen spot for courses! The drainage line in front of the farmhouse (see the drone photo above) is a highway for bird movement, and provides great mist netting sites.

An innovation on this course was to catch five Cape Spurfowl in noose traps – three males and two females (read more here). Only the males have spurs on their legs, making sexing easy. The spur lengths of the three males were 12, 18 and 21 mm and those with longest spurs were the heaviest (around 1 kg).

We were surprised at the number of mousebirds we caught. Mousebirds often escape from the nets. With a good catch, we looked at biometrics – the wing (mean 96.2 mm) of Speckled Mousebird was slightly larger and the tail (mean 206 mm) slightly shorter than these measurements for White-backed Mousebird (mean 92.7 mm and 222 mm respectively).

mousebird tails at the Ouberg bird ringing course of May 2023
Long tails of the White-backed Mousebird (top) and Speckled Mousebird (below)

There were two pairs of Rock Martins roosting on the farm house. They carefully avoided the mist nets, so one was caught by hand on the last morning at dawn, while it was roosting on the rafter of the veranda. Its partner escaped!

Rock Martin at the Ouberg Bird Ringing Course of May 2023
Rock Martin

Three Olive Thrushes were caught and a Karoo Thrush was seen.

Olive Thrush
Olive Thrush, showing the extensive orange on the flanks

We also caught a relatively large number of tit-babblers, nine Chestnut-vented Warblers and two Layard’s Tit-babblers. The two species are similar in size and plumage; the difference is the colour of the undertail coverts (the “vent”): white in Layard’s and chestnut (of course!) in Chestnut-vented! See the photos below.

Chestnut-vented Tit-babbler
Chestnut-vented Warbler, with chestnut vent
Layard's Tit-babbler at the Ouberg Bird Ringing Course of May 2023
Layard’s Warbler, with white vent

The Southern Fiscals consisted of four males and a female.

Cape Sparrows were very common around the farm house. This was the most caught species – 14 males and 24 females (two of the females were recaptured on later days, to make a capture total of 40 birds for the course).

Cape Sparrow showing no primary moult at the Ouberg Bird Ringing Course of May 2023
Cape Sparrow, one of 40 caught. This photo clearly shows the nine primary feathers on the wing of this male; they are all new, with smooth unworn ends. It has completed primary moult. Most of the birds we caught had completed this feather replacement process; birds try to avoid moulting during the cold winter.

Weavers and waxbills roosted in reeds near the farmhouse, and a good number were caught – six Cape Weavers, 37 Southern Masked Weavers and 14 Common Waxbills. But many flew out in the wrong direction; now we know where we will put mist nets next time! Two male Southern Masked Weavers were in partial breeding plumage.

Southern Masked Weave in partial breeding plumage at the Ouberg Bird Ringing Course of May 2023
Male Southern Masked Weaver in partial breeding plumage


We have had several bird ringing expeditions to Ouberg Nature Reserve. The first was in October 2020, and the most recent was in February this year! One of the most valuable aspects of repeated ringing at a place are the recaptures of previously ringed birds. These are used to estimate survival rates for species, which are a critical ingredient in discussions about bird species conservation. There were 37 recaptures. Six birds had first been ringed on our initial ringing expedition in October 2020 – Little Rush Warbler, two Cape Robin-chats, Chestnut-vented Tit-babbler, Cape Weaver and a Cape White-eye. A Southern Fiscal and a Cape Sparrow had been ringed on 24 July 2021. Five birds had been ringed in October 2022, and 12 birds had been ringed in February 2023, a few months ago. We have not yet got enough data to start survival analysis studies, but our intention is to keep returning to this really good ringing site.

One aspect of bird biology which is poorly known is the extent of local movement of the resident species. The drainage line at Ouberg provides an opportunity to investigate this. So on two mornings we ringed at little gaps in the riverine bush some distance from the farm house (see the photo near the top of this blog). At the first gap we recaptured a Chestnut-vented Tit-babbler (ringed at the farm house on 23-Oct-20) and a Long-billed Crombec (ringed at farm house on 15-Feb-23). At the second gap we recaptured a Cape Robin-chat (ringed at farm house on 22-Oct-20).

Numbers of birds caught at Ouberg, 10 to 16 May 2023

The species with links in the table below have full descriptions on the BDI website.

Sp noSpeciesCount
181Cape Spurfowl5
316Cape Turtle Dove3
390Speckled Mousebird13
391White-backed Mousebird20
432Acacia Pied Barbet3
506Rock Martin1
543Cape Bulbul17
551Sombre Greenbul1
581Cape Robin-chat10
609Little Rush Warbler3
621Long-billed Crombec1
622Bar-throated Apalis1
638Grey-backed Cisticola3
658Chestnut-vented Warbler9
659Layard’s Warbler2
665Fiscal Flycatcher3
686Cape Wagtail1
707Southern Fiscal5
760Southern Double-collared Sunbird2
784House Sparrow1
786Cape Sparrow40
799Cape Weaver6
803Southern Masked Weaver37
843Common Waxbill14
867Streaky-headed Canary1
873Cape Bunting1
1105Olive Thrush 3
1172Cape White-eye12
4139Karoo Prinia1

Grey-back of the Grey-backed Cisticola at the Ouberg bird ringing course of May 2023
Grey back of the Grey-backed Cisticola. There are many features of birds that you can only see properly when the bird is in the hand.

Thanks to Sue and Richard Gie for hosting us for Ouberg bird ringing course of May 2023! Thanks to Jon and Maite for preparing wonderful meals throughout the course!

Ouberg Private Nature Reserve
Winter sun. We had some drizzle, but there are rewards when the weather clears up and there are days “out of the box” like this. Ouberg is a beautiful place. We invite you to join the next bird ringing course. Photo: Saskia Thomas

The Ouberg bird ringing course of May 2023 was a really good event!

Dieter Oschadleus
Dieter Oschadleus
Dieter Oschadleus leads the BDI bird ringing expeditions, and is able to organise bird ringing courses (having run many courses in South Africa, and some in the Seychelles). Dieter is also a registered bird guide in South Africa, and has birded widely in Africa and the Indian Ocean islands. Dieter is able to act as a bird guide for day trips in Cape Town, and is able to customise birds tours in South Africa and beyond.