STATE HORTICULTURAL SOCIETY 



^33 



• 



may place the robin in the list of moderately useful birds, using every 

 opportunity to increase our knowledge, and for the time being leaving 

 him practically to himself. I propose to examine next season at least a 

 hundred stomachs of the species, to make all the field observations possible, 

 and to learn what I can of the food of the young. 



II. The Cat-bird (Mi'mus carolinensis, L.) 



This bird, scarcely less abundant than the robin, arrives a little later 

 and makes a rather shorter stay, disappearing from this latitude usually 

 in September. It also occupies a larger territory in the State in mid- 

 summer than the robin, being not at all uncommon in extreme Southern 

 Illinois in July and August. I do not know that it ever winters north- 

 ward. Its habits and habitat are so like those of the robin that one might 

 reasonably anticipate that, respecting their food, both could be treated 

 as one species \ but we shall see proof that there are specific food-charac- 

 teristics to separate them. 



How indefinite and uncertain is our knowledge of the food of this 

 especially notorious species (and a portion of birds in general) may be 

 seen by comparing my notes with the statement mad^in the recent and 

 elaborate work of Baird, Brewer and Ridgway : 



"The food of the cat-bird is almost exclusively the larvx of the larger insects. 

 For these it searches both among the bushes and the fallen leaves, as well as the 

 furrows of newly-plowed fields and cultivated gardens. The benefit it thus confers upon 

 the farmer and upon the horticulturist is very great, and can hardly be overestimated." 



My observations of this bird cover the three months of May, June 

 and July, eighteen stomachs having been examined during the first month 

 (one taken April 30th being included in these), nine in the second and 

 ten in the third. 



In the stomachs taken in May I found nothing but insects, myria- 

 pods and spiders. The principal elements at this time were ants, nine- 

 teen per cent. ; caterpillars, sixteen per cent. ; adult crane-flies, twenty- 

 three per cent., and beetles, nineteen per cent., including seven per 

 cent, of carabidcB and six per cent, of curculionidae. The latter were 

 chiefly of the two species Ithycerus noveboracensis and Epiccerus vadosus, 

 injuring fruit-trees by eating the young leaves and gnawing the twigs, 

 but not attacking the fruit. Five per cent, of the food was oethoptera, 

 including one white cricket (Orcanthus), four per cent, spiders, and nine 

 per cent, vegetarian thousand-legs {Diplopoda). 



A large number of the eggs of crane-flies (kindly determined for me 

 by Prof. C. V. Riley) were found in the stomachs of these birds. As 

 they were always found associated with fragments of the adult insects, 

 there is no proof that the cat-bird takes these eggs separately. During this 

 month, notwithstanding the number of carabidai taken, there remains 

 apparently a considerable margin of benefit in favor of the birds. 



In June the insect average falls to sixty-four per cent, as against 

 eighty-seven per cent, of the previous month. This loss is, unfortunately, 



