tags: Cape Raven, African White-necked Raven, White-naped Raven, Corvus albicollis, birds, mystery bird, bird ID quiz
[Mystery bird] A pair of White-naped Ravens, also known as the Cape Raven or the African White-necked Raven, Corvus albicollis, photographed while playing at just under 15000 feet on Mt Kilimanjaro, Tanzania, Africa. [I will identify this bird for you in 48 hours]
Image: Dan Logen, 24 July 2006 [larger view].
Nikon D2X, 70-200 VR lens, at 200. ISO 320, 1/6000, f 3.2.
Please name at least one field mark that supports your identification.
The photographer writes;
These White-naped Ravens were playing at just under 15000 feet on Mt Kilimanjaro. They were numerous around the camps on the mountain, feeding on scraps, despite a National Park policy of not feeding wildlife.
Are those ravens? The way they're playing, their black color and body build look right.
The white patch on the nape gives it away, White-necked Raven (Corvus albicollis). Is this a courtship display or territorial defence?
It looked totally like play to me. There were a lot of ravens at this location and there were multiple episodes of play-like behavior. Could have been courtship, certainly no aggression was exhibited. I was amazed that these birds could fly so effortlessly at this altitude. There were also Alpine Swifts nesting nearby at this altitude, again flying around with no effort.
Thanks Dan, I've just visited the Kenya Birds website and they say that this bird indulges in play a lot. It also says that it is common between 1000-3000metres so a flock at 4500-5000m would seem to be unusual, although I have seen Common Ravens "thermalling" at around this height in the Himalayas and they have been recorded scavenging even higher. I think I once read somewhere that birds metabolise oxygen more efficiently at altitude than us which may explain why they appear effortless at this height.
Thnaks for the comment Adrian. They were here at 5000 meters because this is the location of the last campsite below the summit. There are a couple hundred people there every night, and even though there are rules against feeding the ravens, they seem to find plenty to eat.
Adrian, I am sure there must be some research based upon the premise that gas exchange between the embryo and the environment has an early "training effect" for high-altitude birds... (although there must be some attrition with regard to water vapor conductance also?)
I have heard of work on the Puna Teal, Anas puna, the "puna" ecoregion being situated between 4,100 and 4,800m above sea level and know that some work has been done investigating the specializations in the organ systems of the Bar-headed Goose Anser indicus which fly at altitudes up to 9,000m above sea level.