164 The Ottawa Naturalist. [Mar. 



With the possible exception of the house wren, probably 

 no other birds so readily take advantage of artificial nesting places 

 as the Chicadees (Penthestes atricapillus and others) and Tits. 

 Their unremitting search for insects on every branch, twig and 

 leaf is a fascinating sight and the good they accomplish is diffi- 

 cult to conceive. A Blue Tit will destroy six and a half million 

 insects in a year, and in bringing up a family of about twelve to 

 sixteen young ones, about twenty-four million insects would 

 ultimately be accounted for. Especially valuable are they in the 

 destruction of the eggs of certain species of defoliating cater- 

 pillars, such as the canker worms and tent caterpillars, the moths 

 of which deposit their eggs on twigs. Graf, in Switzerland, 

 states that three blue-tits and three cole-tits consumed 8000 to 

 9000 insect eggs daily ; three marsh tits, one cole-tit, a long-tailed 

 tit and a golden crested wren consumed 600 caterpillars in 100 

 minutes. The pupae of the codling moth and the hibernating 

 forms of plant lice do not escape the sharp eye of these small 

 acrobats. The little White-breasted Nuthatch (Sitta carolin- 

 ensis) which may be seen running not only upwards but also 

 downwards on the trunks of trees, has somewhat similiar habits 

 to the Chicadees. Over 50 per cent, of its food consists of 

 insects. The House Wren (Troglodytes aedon) has suffered much 

 by the inroads of the quarrelsome English sparrow which 

 drives it out of its nesting places on every possible occasion. 

 Nevertheless, this confiding little bird which charms us so much 

 with its little bubbling song and exacts such a heavy toll on insect 

 life will gladly accept a nesting box out of which the sparrows 

 may be kept by hanging it rather low down, and having the 

 entrance hole as small as possible. 



The Purple Martin (JPrognc sitbis) formerly nested in hollow 

 trees, but the advent of man encouraged it to nest about his 

 domicile. In some parts of the country, I have noticed the fact 

 particularly in certain sections of New Brunswick, one may see 

 martin houses erected on poles and this form of encouragement 

 is very successful, although the English sparrows are a constant 

 source of trouble to the rightful owners. The value of the martins 

 and swallows around the house and buildings as insect destroy- 

 ers is appreciated by all who have encouraged them. The Tree 

 Swallow (Iridoprocne bicolor), which nests m hollow trees, is 

 not so abundant in certain sections of Ontario as formerly. 

 Reporting the success of nesting boxes during 1913, Mr. W. E. 

 Saunders, of London, Ont., writes: "Another lot of boxes which 

 were put in place on an island in 1 he Rideau Lakes were a source 

 of actual competition among the tree swallows, there being more 

 pairs than there were nests, and considering the fact thai these 



