Published online by Cambridge University Press: 10 July 2009
The Red-billed Oxpecker, or Tick-bird, is the East African representative of a genus that has always excited interest by reason of the peculiar feeding habits of its members. They obtain the whole of their food on the bodies of the larger Herbivora, and their abnormally sharp claws permit them to travel in any direction and to visit every spot on the bodies of their hosts. It is obvious that to stock-owners birds of these habits must be of economic importance, but veterinary, ornithological and entomological literature alike have failed to provide any record of an investigation of their food.
In the absence of published data application was made to various authorities for their opinions and for any detailed information they might have. Astonishingly diverse replies were given. The head of a veterinary laboratory in one of the East African dependencies wrote as follows : “ I believe they do pick off ticks, although I doubt if they eat these ; their object being to find a wound. When they have succeeded they feed on the exposed raw tissue.” Another local veterinary authority remarked : “ They cause a great deal of damage through the sores they produce in stock.” A gamewarden said : “ I always regarded the oxpecker as an unmitigated nuisance and pest. The prevalent idea that this bird frees domestic stock of ticks appears to be entirely erroneous.… These birds feed mainly on the raw tissue of open wounds and it is by their action that the open wounds usually occur.” Other observers of wide experience are less downright.
* Thanks are due to the Director of the Imperial Institute of Entomology for interesting himself in the search for published data.
† It will be noted that by implication the last part of this extract contradicts the statement in the first sentence that the oxpecker's food consists “ entirely ” of “ insects ” (read as including ticks).
* Cf. Kenya Dept. Agric. Bull. 13 of 1931, amplified by information given by Dr. Lewis personally.
* The idea that congealed blood of this kind might be associated with partly digested ticks occurred independently to Mr. Purvis, but he has not had facilities for verifying it.
† I am indebted to Mr. M. H. French, Biochemist at the Veterinary Laboratory, Mpwapwa, for the technical particulars.
* Conclusions at this stage of our knowledge must be mainly tentative. Wide variations in the effect of oxpecker activity could doubtless be demonstrated at different places and on different dates.