GARDEN PESTS IN NEW ZEALAND 



Birds. 



It is generally recognised that birds are a very important aid in 

 "keeping destructive insects in check, though it is well-known that a 

 .great deal of damage can be done by these animals. Without a 

 systematic study of the stomach contents of birds, it is not possible to 

 decide when a species is beneficial or injurious, and in Xew Zealand no 

 such study has been made ; practically all the information we have is 

 based on field observations, which are, unfortunately, influenced largely 

 by the outlook of the observer, and are thus misleading. Though some 

 species subsist for the most part on insects,, most land-birds have a mixed 

 diet of vegetable and animal food, but they specialise on an insect diet 

 when rearing their young and when moulting. 





FIGURE 14. 



(a) An ichneumon (natural size liin) ; (b) a chalcid (natural size l-25in) ; (c) a hover- 

 fly (natural size $in) ; (d) hoverfly larva (natural size in) ; (e) a tachinid fly (natural 

 size |in) ; (f) a ladybird beetle (natural size &in) ; (g) ladybird larva (natural size iin) ; 

 (h) lacewing (natural size iin) ; (i) lacewing larva (natural size in). 



