THE CEOW BLACKBIRD. 67 



Kansas was found to contain fossil remains of corals, crinoid stems, 

 shells, etc. 



As previously stated, 466 nestlings are included in the 2,346 birds 

 whose food has been already discussed. A separate study was made 

 of these, in order to ascertain in what respect, if any, their food dif- 

 fered from that of the adults. It would have given more satisfactory 

 results if it had been possible to separate the younger nestlings — say 

 those under 1 week of age — from the older ones, for it was noticed 

 that as the young approach maturity and get readj^ to fl}^, their food 

 becomes m.ore like that of their parents. The young were collected 

 from May 22 to June 30, inclusive, and represent every age, from the 

 newly hatched to those about to leave the nest. The whole food, 

 when separated into its two principal components, was found to be as 

 follows: Animal matter, 74.4 percent; vegetable, 25.6 percent. The 

 much higher percentage of animal food in the young as compared 

 with the adults (30.3 percent) is at once noticeable, although it may 

 be insisted that the food of the young should be compared with that 

 of the adults in the corresponding season; that is, in the months of 

 May and June. If this view be taken, the difference is not so great. 

 The percentage of mineral matter in the stomachs is also a little 

 greater than in the case of adults. 



The animal food is practically the same as that of the parent birds, 

 and likewise consists chiefly of insects. These amount to 70 percent, 

 43 percent more than in the adults. The animal food other than 

 insects, amounting to less than 5 percent, is not important enough to 

 merit attention. The insect food is made up of about the same kinds 

 as are eaten by the old birds, but in somewhat different proportions. 

 Adult beetles, on account of their hard shells, are not fed to very 

 young birds, but a few are given to the older ones. Grubworms (the 

 larvae of scarabseids) are fed freely after the first or second day. A 

 little more than 19 percent of the food of the nestlings consists of 

 this family of beetles, and for the most part in the form of the larv» 

 or grubs. Predaceous beetles (carabids) constitute about 10 percent 

 of the food, weevils a little more than 3 percent, and there were 

 traces of five or six other families, none of which reached 1 percent. 



Grasshoppers and crickets, the former predominating, are a favorite 

 food for the 3"oung, being softer and more easily digested than beetles. 

 They constitute more than 21 percent of the total food. This is nearly 

 as much as the parent birds consume in August, and three times as much 

 as they eat in May and June, when they are feeding the young. This 

 shows that they select the grasshoppers and other soft insects for their 

 offspring, while they eat beetles and other hard things themselves. 



Caterpillars constitute 6 percent of the food of the young birds, 

 which is not as much as might be expected when we consider how soft 

 and apparently well adapted they are for this purpose. 



