238 SLAXEY, Birds and the Caterpillar Pest. Pi'l^fa^ 



Economic Sedion 



BIRDS AND THE CATERPILLAR PEST 



lly 11. V,. SLAXEY, R.A.O.U., Moorooduc (Vic.j. 



How U) c(jmbat, or insure against, future raids of caterpillars 

 is a jjrobleni exercising the minds of farmers all over X'ictoria 

 at the present time. To the scientist the answer is a simple one, 

 for he would tell us that the most economical and obvious means 

 of protection is through the agency of the caterpillars' natural 

 enemies — tlie birds. But the man on the land wants to know 

 where the birds are to come from in sufficient numbers to be of 

 any use in checking the devastation such as they have recently 

 suffered. In addition to the Starlings, whose numbers seem woe- 

 fully inadequate at a time such as this, birds preying upon the 

 caterpillars include Stubble (Juail, Horsfield's I^ush L,ark, 

 Ground Lark, Silver-eye, Magpie, Magpie-lark, Black-faced 

 Cuckoo Shrike, Pallid Cuckoo, and the Fantailed Cuckoo, and 

 even the much despised Sparrow has been doing its bit. 



In the Mornington Peninsula I have noted all these birds at 

 work upon the grubs, each performing wonders in proportion to 

 its size, but without stemming the voracious horde m the least. 



The caterpillars are hatched from eggs laid in the early spring 

 by a medium-sized dark-brown moth, well known as the Bogong 

 Moth. Like the female blowfly, the moth uses much discrimina- 

 tion, as to where the eggs are laid. They are placed where Nature 

 tells her the young caterpillars stand the best chance, not only 

 of hatching, but also of reaching maturity. Therefore she 

 chooses the damp spots in a field of luxuriant growth, such as 

 -a crop of oats. Like the poor, the moths are always with us — 

 a fact not known to most farmers — but we are not pestered 

 w^th them annually, for in normal seasons 90 per cent, of the 

 eggs laid fail to hatch because climatic conditions are not favour- 

 able to their incubation. Warm showery days extending well 

 through November seem to be the ideal conditions needed for 

 their {)ropagation, and when it comes to weather conditions, the 

 average farmer is a fatalist. After all their presence is but one 

 more instance of "Polarity." The rain and the temperature 

 favour a suberabundance of food, and also caterpillais to de- 

 vour it. Action and reaction is Nature's law, and will remain so 

 to the end of time. Man creates artificial conditions in his well- 

 tilled fields of cereals, and needs must use artificial means for 

 their i)rotection. It is a ])opular fallacy that cateri)illars are able 

 to cover great distances in search of fresh fields. Experiments 

 upon travelling caterpillars marked with flour dusted upon them 

 lead (jne to doubt if they are capable of averaging a chain in 24 

 hours, and since their life is very brief (from 10 to II days), 

 they must cjuickly ])erish unless suitable food is soon forthcoming 

 on the way. I have also noted their objection to hot sunlight, 

 which stimulates them to unwonted activity. Almost invariably 



