February, 1912.] 



127 



Plant Sanitation. 



It is especially at the breeding season, 

 when their nests are full of clamouring; 

 youngsters, that such birds turn their 

 attention to insects. 



I have recently read a note describing 

 how, in one of the European countries 

 (Hungary, I belive), the sparrows and 

 other small birds had been exterminated 

 under the mistaken idea that they did 

 more harm than good. As a result, insect 

 pests increased to such an alarming 

 extent that measures are now being 

 adopted, at vast expenses, to reinstate 

 the feathered friends of the farmers. 



With the possible exception of the 

 pigeon tribe nearly all frugivorous and 

 graminivorous birds vary their diet 

 with insects. The caee against the much- 

 abused sparrow is still an open one. 

 There is no doubt that the vast flocks 

 of sparrows that abound in England do 

 an euormous amouut of harm in the 

 harvest fields, and still more — indirectly 

 —by their pugnaceous habits which tend 

 to drive away the more strictly insecti- 

 vorous birds. The sparrow may be 

 of great value in countries where grain 

 crops are not cultivated, or where there 

 may be an insufficient natural provision 

 of more useful species. But in Ceylon, 

 where Passer domesticus is an alien and 

 we are blessed with many insectivorous 

 birds, its increase should be sternly dis- 

 couraged. I suppose there is no country 

 in the world to which the common spar- 

 row has not been introduced— usually 

 unintentionally. It makes itself at home 

 on shipping and travels freely from 

 port to port. The date of its original 

 appearance in Ceylon is lost in obscurity. 

 It probably came over ' with the Con- 

 queror' — or one of them. Our local 

 race is believed by Legge to have in- 

 vaded us from the Indian Continent. 

 Considering the number of years that 

 it must have been with us, it does not 

 appear to have increased so rapidly as 

 might have been expected- Possibly 

 beasts and birds of prey may find it more 

 easy of capture than are the indigenous 

 birds that have learnt the ways of their 

 enemies by the experience of countless 

 generations. I am inclined to think, 

 however, that the sparrow shows siens 

 of decided increase in parts of the Uva 

 Province. I have noticed comparatively 

 large flocks of them, when coaching from 

 Bandarawela to Badulla. The multipli- 

 cation of a new introduction may be very 

 slow at first but, with an inherently 

 dominant species, a stage may arrive 

 when the p^oliQcness of the species 

 exceeds the wastage and there is then 

 no efficient check to its rapid increase. 

 If tins should happen in Ceylon, the 

 sparrow might become a serious menace 



to rice cultivation. With this view, it 

 would be wise to check the further in- 

 crease of these birds, by destroying their 

 nests at every opportunity. 



I should not advise such action in the 

 case of a truly iudigeuous species, how- 

 ever obnoxious it might appear. In mat- 

 ters of the distribution of fauna, nature 

 knows her own business better than we 

 do, and artificial interference with her 

 methods is often followed by unexpected 

 and disastrous consequences. The whole- 

 sale destruction of hawks and owls has 

 been known to result in a devastating 

 plague of field mice, 



The introduction of new birds, how- 

 ever innocent they may appear to be, 

 should not be permitted without careful 

 consideration by experts, and should 

 certainly not be left to the caprice of 

 the individual. A notable instance of 

 mistaken action of this nature occurred 

 in the Seychelles, within comparatively 

 recent years. At one time, rice and 

 grain of various kinds — sufficient to sup- 

 port the population— were grown in the 1 

 Islands. Birds, especially pretty birds, 

 were somewhat scarce; so some aestheti- 

 cally inclined individual thought that he 

 was conferring a benefit upon the commu- 

 nity by importing and liberating a small 

 flock of ' Cardinal finches ' from Mada- 

 gascar. This beautiful flame-coloured 

 bird flourished exceedingly in its new 

 home and increased enormously in num- 

 bers. Being exclusively a grain feeder, 

 it soon worked such havoc that, for many 

 years, the cultivation of rice has been 

 completely abandoned. Formerly, the 

 Islands were self-supporting in the 

 matter of rice. Now; every bushel of 

 rice that is consumed in the place has to 

 be imported. 



To return to beneficial birds, fresh 

 kuowledge of insectivorous habits is con- 

 stantly being accumulated. The British 

 Grouse, at one time believed to feed 

 exclusively upon heather, is now known 

 to consume enormous numbers of insects 

 during the summer months. Young 

 grouse are said to live almost entirely 

 upon insect food. Even the smaller 

 hawks and owls are large consumers of 

 insects, especially of beetles and cater- 

 pillars, In Ceylon, every bird that 

 flies takes toll of the winged termites 

 which appear, at times, in such pro- 

 digious numbers. Kestrels have been 

 observed catching the large cockcha- 

 fers whose larvae are sometimes so 

 destructive to the roots of plants. 

 When investigating an outbreak of the 

 ' Spotted Locust,'-an animal that, from 

 its brilliant colouriug and evil smell, 

 might be expected to be most nauseous, 



