Here are the answers to challenge #4.
The average score was 5.52/8 or 69%. Well done to adrianp and Ladybirder for getting full marks
1. Black-backed Puffback (immature)

This one caused quite a few problems. I think the orange wash underneath threw a lot of people off. The shape, black cap and white-tipped wing feathers all point towards Puffback. The females and youngsters have a grey, not black back, and it's more grey in the young birds. I think the orange is what confused everyone here, as none of our field guides really illustrate this feature properly (or at all). Roberts describes the immature as having orange-buff underparts. This was the most orange I've ever seen on an immature Puffback though. (picture taken: Tuli Block, Botswana)
2. Black-throated Canary (male)

Not too many problems here. The shape, size and bill shape puts this as a seed-eater. The shape, and colouring are wrong for most other seed-eaters, except the Canaries. This is a nice male which shows the distinct black throat where this bird gets its name from. (photo taken: Marievale Bird Snactuary, Gauteng)
3. Sabota Lark

I tried to maybe catch some of you out by showing it uncharacteristically sitting on the floor, as 90% of the time Sabotas perch on trees or shrubs. Most of you never fell for it and got it. Almost everyone put it in the Lark family, and the well-marked back, well-defined white supercilium and malar stripe, and the breast streaking make this Sabota. Dusky would have a much more plainly marked back, and Large-billed would have a yellow base to the bill and much more streaking underneath going all the way to the flanks. (Photo taken: S44, Kruger National Park)
4. Red-billed Quelea (non-br Male)

Quite a straight-forward ID here. The only other candidates with a heavy red bill include Pin-tailed and Shaft-tailed Whydah, and Village Indigobird. All three of those have more markings on the head than this. (Photo taken: Moremi Game Reserve, Botswana)
5. Buff-streaked Chat (female)

This was quite a tricky one, and I was impressed by how many of you got it! I think a big clue here was the habitat, as boulder-strewn slopes is typical habitat for this species. Most of our field guides don't illustrate female Buff-streaked Chat so accurately. The buff underparts and rump, dark tail with no traces of white, very faintly streaked breast and greyish supercilium all point to female Buff-streaked Chat. (Photo taken: Dullstroom)
6. Golden-tailed Woodpecker (male)

This one's not too tough if you just put all the pieces together. It can't be Knysna, Bennett's, Speckle-throated, or Green-backed as those are all have spotted, not streaked underparts. Bearded can be eliminated for several reasons, including grey underparts and broad black malar stripes and cheeks. This leaves Cardinal and Golden-tailed. I think everyone said one of these two species. It can't be Cardinal as that has a a more distinct malar stripe which is also black, not red, and Cardinal also has a plainer face than this . This leaves Golden-tailed, which fits with everything: Small red malar stripe, fully red head, streaked breast and streaked face. (Photo taken: Tshokwane, Kruger National Park)
7. Ovambo Sparrowhawk (female, sub-adult, pale form)

Accipiters are usually quite tough, especially when dealing with young birds, but the combination of the barring going all the way up to the throat, orange-ish cere, dark red-brown eye all point towards Ovambo Sparrowhawk. (Photo taken: Vlaklaagte, MP)
8. Bushveld Pipit

I though this one would be tough, but most of you nailed it! I'm impressed. A small compact pipit, with basically no facial markings or supercilium, and not streaked enough to be Striped, Tree or Short-tailed. Not the right shape or colouring to be any of the larger Pipits. (Photo taken: North-eastern Gauteng)
Hope you all had fun, and maybe even learned a thing or two
Regards
Matt