Dr. Redzlan Abdul Rahman photographed a male Common Flameback (Dinopium javanense) perching on a rotten tree trunk probing for the larvae of wood-boring insects (above left). Because the trunk is rotten and pieces had broken off, when the bird started probing, his tongue could clearly be seen emerging from the other end of the tunnel (above right).
The woodpecker’s tongue is its most important tool when probing for larvae. It is extremely long, has specialised muscles that enable the bird to extend and retract it with ease, and the tip is covered with backward-pointing barbs. At the same time there are glands that secrete a sticky fluid. All these adaptations allow the bird to locate larvae hidden inside rotten wood and once located, to extract them.
Short, L. L. & J. F. M. Horne, 2002. Family Capitonidae (Barbets). In: del Hoyo, J., A. Elliott & J. Sargatal (eds.), Handbook of the birds of the world. Vol. 7. Jacamars to Woodpeckers. Lynx Editions, Barcelona. Pp. 140-219.