This is the results of challenge #20 of 2012. The ID part of the challenge was tougher than the sting! However, from the PMs I received it was patently obvious that most ‘mites enjoyed reading up about the sting-birds… Overall the challenge returned an average score of 77%
We had 21 ‘mites taking part.
The results are as follows:
One ‘mite each score 4 and 5;
Two ‘mites scored 6;
four ‘mites scored 7;
five ‘mites scored 8;
six scored 9;
and two ‘mites got all the answers right.
Thanks again to those 'mites who so diligently add explanatory notes with their IDs.
#1 – Streaky-headed seedeater 
had no real issues.The bill, eyebrow and the streaked crown are all pronounced and taken in combination points to the right ID.
#2 – Dickinson's kestrel  pantera leo
points out the salient features: Overall grey colour combined with a paler head and heavily barred tail and underwing.
#3 – White-fronted plover 
No issues here…
#4 – Horus swift 
. Common and Bradfield’s swifts were alternative suggested IDs, both of whom should be ruled out on the evidence of a white rump (a smidgen of which is visible in the picture); as well as on the contrast between under-wing and body; the common swift should be near all-black and the Bradfiel’s swift uniformly lighter, but with contrast with the darker primaries and tail.
#5 – White-starred robin (juvenile) 
Although this looks like mission impossible, once you see an image of the immature bird, the penny drops! The out-sized eye is an indication of the habitat where this bird spends its life… in the darkest forests! A very difficult subject to photograph...
#6 – Curlew sandpiper  mel123
noticed that the bird is in breeding colours which is why there is no white rump, as a lot of photos show, the lack of which was bothering me a lot. Downcurved bill, white stripe on the wings, black legs helped to nail the ID down.Bonus points:
Q#1 – African harrier-hawk 
No trouble here. barryels
writes about the peculiar traits of this genus are the double-jointed legs and the small feet allowing the bird to extract its prey from nests, holes or crevices, as well in trees as rocks or banks. It eats birds and eggs, bats, small mammals, lizards and various insects. It also hunts by slow, low flying pursuit over the ground or the vegetation.
Q#2 – Kori Bustard  adrianp
writes that the male Kori bustard weighs in at 12.5kg (female is half that). Then great white pelican 9.5kg and wandering albatross (8.3kg), cape vulture (8kg) comes close.. hilda
found more info that makes the Kori Bustard the heaviest bird capable of flight in the world. Exceptional birds may weigh over 20 kg (44 lb).
Q#3 – Arctic tern flies off as the champion long-distance migratory bird. 
. See this article
Sooty shearwater is a serious contender. In 2006 it became the holder of the long-distance title after scientists put satellite tags on 19 sooty shearwaters as part of a Pacific Pelagics Project. The Sooty Shearwater travelled 64,000km in the 8-month monitoring period.
Artic terns are tiny birds by comparison. At just over 100g, fitting them with tracking devices was a tough challenge. The development of a 1.4g “geolocator” that could be attached to the animals allowed scientists to find out exactly where they went on their polar round trip by fitting 70 terns with these devices in July 2007. The devices record light intensity. This gives an estimate of the local day length, and the times of sunrise and sunset; and from this information it is possible to work out a geographical position of the birds. A year later the retrieval of 11 of the geolocators resulted in scientists being able to plot a figure-8 route taken to utilize the prevailing winds as the tern flies more than 71,000km from pole to pole each year, with some individuals flying in excess of 80,000 km annually, twice as far as previously thought, thus the title of migratory flight champions reverted to the tern just one year after the sooty shearwater was so crowned.
On average an Arctic tern gets to be around 34 years old. By extrapolation, this means that they fly distances equivalent to three trips to the moon and back in their lifetimes!
Other notable long-distance flyers include Wandering albatrosses and bar-tailed godwits.
Q#4 – Caspian tern is the largest tern in Southern Africa  tilandi
sent me the following link on the longest migratory flight:Birds That Migrate the Longest Distance
Also some interesting tidbits on the Bar-tailed Godwit’s prowess:The longest non-stop flight – Bar-tailed Godwit 10 200km 9 days
It's the longest nonstop bird migration ever measured, according to biologists who tracked the flight using satellite tags. The bird, a wader called a bar-tailed godwit, completed the journey in nine days.
In addition to demonstrating the bird's surprising endurance, the trek confirms that godwits make the southbound trip of their annual migration directly across the vast Pacific rather than along the East Asian coast, scientists said.