Here are the results of challenge #16/2013.
We had 11 ‘mites taking part.
Two ‘mites scored 6.5;
one ‘mites scored 5.5;
one ‘mites scored 4.5;
one scored 4;
one scored 3;
and we had three 2.5s and two 1s.
It looks like I put together a bit of a witches brew with this challenge. I guess I got a bit rusty with the long lay-off…
Overall the challenge returned an average score of 44.9%.
#1 – Sanderling, non-breeding 
. Joint easiest with #6. Combination of short, stout and black bill, black legs, overall pale appearance with contrasting dark wrist patches should be enough to ID this wader.
#2 – Rufous-winged cisticola 
. Ladybirder justified her choice: “Black on back and the rufous panel in wing can just be seen.” Heavily worn feathers and moulting made this one a bit more challenging to ID. It is much like a Levaillant's cisiticola in both choice of habitat and colouration, the main difference being that the rufous-winged cisiticola has a grey tail as opposed to the russet tail of a Levaillant's.
#3 – African Purple Swamphen (Gallinule) 
. Somehow davejenny got a feeling for size out of the challenge photograph: “Can't be anything else with feet that big and that colour.” Some guidebooks (incorrectly) show the American purple gallinule with red legs.
Many ‘mites chose the black crake as the owner of the challenge legs. Their feet are generally more dainty with relatively longer toes in relation to the tarsus and smaller talons than the swamphen.
#4 – African black swift 
. Statistically this was the most difficult bird to ID. The full throat pouch is an indication that the bird is hoarding food for a partner or chicks. Because common swift does not breed in SA, it could probably be discounted on that point alone. That said, the common swift is uniformly dark, not showing paler secondaries (compared to rest of the wing and the back of the bird) as well as being a more slender bird. Bradfield’s would be paler.
Interesting to note that the ABS covers 100s of kms a day foraging for food!
#5 – African rock pipit 
. Habitat and unique dark line through the eye combines to make the ID possible. Other noteable features are dark bill, stance (body close to the ground), shortish tail and yellow edges to flight feathers.
#6 – Green-backed camaroptera 
. Way too easy!
In the pic the most obvious ID feature was the olive-green tail. Grey-backed has a grey-brown tail.
#7 – Mallard x moscovy hybrid (½ a point for each of the parents) [two ½s and one full point]
an escapee form some waterfowl collection, this duck now hangs out with yellow-billed and African black ducks at Rietvlei Dam. It is known that Mallards and Moscovy ducks cross-breeds with many of our indigenous ducks, polluting the bloodlines; not a welcome situation!
#8 – Leucistic white-browed sparrow-weaver. (½ a point for the ID and ½ a point for the condition) [seven ½s and two full points]
. The reporting rate for leucistic birds is about one in 5000. That explains my preoccupation with the condition, hey!
Leucism is a rare genetic condition that causes a reduction in the pigment in the animal's feathers and skin. This can result in unusual white patches appearing on the animal, or, more rarely, completely white creatures. Unlike albinos who have characteristically red eyes, leucistic animals have normal colouring in their eyes. Although this mutation occurs naturally in the wild and crops up at times due to hidden recessive genes, white animals are thought not to survive well in the wild. They lack the tawny camouflage needed for survival - this makes them visible to hunters and predators, reducing their life expectancy and survival rates.
Maybe the toughness of this challenge scared some regulars off! I hope IMAX gets a stack more entries for his challenge…