71^ LT.-COL. N. iMA^^DER.S ON THE 



experienced it can form an idea of its difficulty. Let any one who 

 would appreciate it, watch a blackbird or thrush in his own garden, 

 and even with the best field-glasses he will be unable in the great 

 majority of cases to name the species of insect caught, or more fre- 

 quently than not the order to which it belongs. In the tropics the 

 difficulties are increased a hundredfold : fortunately in the case of 

 butterflies the task is lightei', and it is often easy to name the species 

 owin<j to the habit some birds have of holdino- the insect in the 

 bill for a few moments before swallowing it, and the lengthy 

 time it takes others either to tear ofi' the wings after the manner 

 of Shrikes, or beat them off against the ground as is the custom of 

 the Robin family. Bee-eaters and Paradise Flycatchers nip off the 

 wings close to the body as neatly as if done by a pair of scissors. 



A certain number of birds are migi'ants, such as the Cuckoo 

 and Swallow, which pass a portion of the year in Ceylon and the 

 remainder in northern latitudes ; such birds, as pointed out by 

 Mr. Marshall, would have to learn the distastef ulness or otherwise 

 of the butterflies that inhabit such dissimilar countries, and 

 theii- influence on the butterfly population of both areas would 

 have to be taken into consideration. These are, however, few in 

 number compared with the partial migrants, which move from 

 one part of the Oriental region to another ; and the butterflies 

 there being of the same character, the lessons they have learnt in 

 one part of their distribution are valuable to them in another. 

 A great many of the resident insectivorous birds move in an 

 irregular manner fi'om one part of the island to another according 

 as their food supply varies, and as this consists of insects alone it 

 is largely dependent on the lainfall. Such a movement cannot 

 be strictly termed a migration and may be a few miles only ; for 

 instance, the i-ainfall in Colombo is about eighty inches, twenty 

 miles off it is nearly two hundred; when there is a comparative 

 paucity of insect life at Colombo the birds, or rather some of them, 

 find plentiful sustenance by moving a few miles inland. Some 

 birds again, such as the Robins, remain in and about the houses 

 and gardens year after year, and others, such as the Green Bee- 

 eater, are never found in the wet portion of the island. 



It is this slight to and fro movement which makes me sceptical 

 of any insectivoi'ous bird in Ceylon, and probably in any tropical 

 island, being evei' really hard up for food. 



Mr. Marshall quotes Dr. Franz Doflein as writing : " From the 

 observations which I made in the jungles of Ceylon, it is quite 

 incomprehensible to me how naturalists who have spent years and 

 tens of years in the tropics can deny the fact " [that butterflies 

 are frequently attacked by birds]. I had ver-y little doubt when 

 I read this passage that Dr. Doflein was speaking of the north of 

 the island, and his recorded observations confirm this ; I should, 

 however, be veiy surjarised if he could say the same of the whole 

 island, more particularly the hill districts. One point to which I 

 wish more particularly to draw attention, is his suggested 

 immunit}^ from attack of the magnificent Ornithoptera darsiiis, 



