Thursday 6 October 2011

Red and Yellow Barbets and duets

Male Red and Yellow Barbet, Manyara, Jan 2011
There's nothing like a Red and Yellow Barbet to brighten up your morning! Even the most casual of observers wants to have a second look at this fairly common species, and well they might. Both males and females are impressively bright, you have to look past the red and yellow to the black on the throat and cap to identify the sex - male with black cap and throat (as on the right here), female just with black speckles on an orange cap (as below). And when you see one, you often find several as they tend to stick about in pairs and family groups most of the time.

Female Red and Yellow Barbet, Manyara NP, Jan 2011
Such strong pair bonds are re-inforced by their other obvious trait - the crazy duetting or even group singing in this species are thought to be mainly designed to build the pair bond, and less advertise territory occupancy to neighbours (though obviously it does that too). (If you've not heard the song, check it out half-way through this recording - crazy! I remember it when confused, because they're saying "RED (and yellow), RED (and yellow)", etc.) Evidence suggests that the calls of the two birds are so closely aligned there simply isn't sufficient reaction time for one bird to be listening and responding to the other when they do this, rather they both have some internal rhythm that they stick to, keeping each other in time together.

Dueting is actually surprisingly common in birds - at least 120 species of some 32 families are known to duet, but we don't really know why. The main features loosly associated with it are (a) it's mostly tropical birds that do it - so many visitors here won't be familiar with the concept except, perhaps, in owls, (b) it's mostly species that show rather little sexual dimorphism (like the barbets here) and (c) most of them live in rather dense habitats - though I think this species is one of the exceptions here. Certainly it's an impressive sight and sound!
Female Red and Yellow Barbet, Manyara NP, Nov 2010

Another thing you might notice about this species andthe closely related D'Arnauld's and Usambiro Barbets are their association with termites. Like so many things, these two ground barbets are rather partial to a snack on termites, given the chance, but they also rather like to nest within termite mounds - they dig a hole in the side and the termites will eventually wall their nest up, within the mound - giving lots of the benefits of termite-controlled air-conditioning to ther barbets too. Very handy. Though it might well make them vulnerable to brood parasitism from Greater Honeyguides - a species known to favour barbets and often searching termite nests for nests to parasitise.

Finally, check the toes on the top picture - classic zygodactyly (two toes forward, two backwards), perhaps an indication of their shared ancestry with woodpeckers? (Woodpeckers, Barbets and Honeyguides are all fairly closely related, within the order Piciformes - together with Toucans, but not hornbills which are more closely related to trogons and rollers, etc...).

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