216 MR. C. F. M. SWYNNERTON ON THE 



better relished by all and were eaten in considerable quantities, being obtain- 

 able in abundance from the sheep-sheds. Special consideration in the matter 

 of variety was oiven to those birds that were being chiefly experimented on 

 at the time, and sometimes numbers of spiders and insects in great variety, 

 including numerous Diptera, would be obtained by "sweeping" and thrown 

 in to them. 



The known tastes of the birds were always, so far as possible, consulted : 

 thus Ihe swallows bad a special boy of their own whose one business it was 

 to catch Diptera. The Barratt's bulbul {Pycnonotus flavistriatus) was specially 

 supplied with wood-lice and such other subcortical species, spiders, etc., as I 

 could obtain for it in the forest (its habitat), also with the fruits of Celtis dioica, 

 S. Moore, a fruit I have frequently taken from the stomachs of wild individuals 

 of the species. The other bulbuls received bananas, papaws, guavas, oranges, 

 and occasionally other fruits in addition to their insect-food, and occasional 

 meat-eaters, as the roller and shrikes, sometimes received a dole of meat or 

 a lizard, a mouse or a bit of snake. 



The owl received chiefly meat, but also insects, especially during periods 

 of experiment, and the buzzard-eagles both meat and insects, especially 

 quantities of migratory locusts which were abundant in their time. Naturally 

 during long periods of no experimentation my efforts in the direction of variety 

 were also relaxed — extra help was discarded, rewards were not offered, sweeping 

 and all other special methods were dropped : yet even then the bird-boy, whose 

 sole daily work it was to clean the cages, provide ample water, and catch 

 insects for the birds' food, used to bring in the latter at such times mainly (but 

 by no means entirely) Orthoptera, in great variety. I have on one or two 

 occasions (I will mention them in describing my experiments) had to re- 

 commence experimenting on a bird that had for some time previously been 

 receiving its food in this rather more limited variety. I have, I think, 

 noticed no departure at such times from its usual preferences provided it was 

 suitahly fed during the few hours preceding the experiment. 



The precaution italicized is at times an exceedingly necessary one. I have 

 known a guinea-fowl tired of grain and a bulbul tired at one time of fruit, 

 at another of insects. My drongo (since I ceased experimenting on him 

 regularly) has shown "vitiation'^ in the form of increased eagerness for 

 certain orders of which he has been largely deprived and a corresponding 

 slight repugnance to those he has been chiefly receiving. My experiment of 

 August 30th, 1913, affords a very perfect illustration of this. The drongo, 

 having been deprived of Lepidoptera for some weeks, and having developed 

 over-eagerness for them and disinclination for, in particular, Orthoptera, was 

 fed for nearly a whole day on Lepidoptera alone. This was enough to tire 

 him of them and to create a fresh eagerness for Orthoptera. The experiment 

 — to "place" the butterfly Crenis rosa — was consequently unsuccessful. 

 Similarly, my rats, and, at one period, my lemur, would be so ravenous for 



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