448 Un iversity of California Publications in Zoology [VOL. 11 



on insects. It would seem, therefore, that there is a certain 

 preference for insect food shown at this time of the year. It is 

 a well-known fact that many adult birds which feed on weed 

 seeds feed their young almost entirely on insects. It seems safe 

 to say, therefore, that the western meadowlark, when feeding 

 the young, turns its attention to insects. 



The accompanying table (Table V, p. 445) gives a comparison 

 of the food of fifty juvenile and fifty adult western meadowlarks. 



VARIATION IN KIND OF FOOD 



The kind of food taken by the western meadowlark is de- 

 pendent upon two cycles, the individual cycle and the environ- 

 mental cycle. 



The individual cycle includes such factors as individual taste, 

 time of feeding, and the preference for a particular locality. 

 In fact, all of the factors which depend upon the individual tastes 

 or habits of the bird are grouped here. Whether an individual 

 bird has a particular taste for a certain insect, it is impossible 

 to determine without experiment. Since we find different indi- 

 viduals showing different characteristics, we can safely infer that 

 each individual may show a slight preference for one kind of 

 food above another. Then, too, the time during which the bird 

 feeds has some effect upon the availability of certain kinds of 

 food, so that we should naturally expect that the kind of food 

 would be governed to some extent by the time the bird chooses 

 for feeding. The particular locality frequented by the bird must 

 also influence the kind of food taken. The food of a bird feeding 

 entirely in a grain field would certainly show a slight variation 

 from that taken by one living entirely in a pasture. 



The environmental cycle takes into account the changes in 

 the availability of insects and seeds, due to seasonal and climatic 

 conditions. The maximum supply of weed seed is available dur- 

 ing September and October. The maximum supply of insects 

 is apparently available during May and June. Even the culti- 

 vation of land has much to do with the availability of certain 

 kinds of food. Many weed seeds are easily obtained during 

 September and October, which, after plowing begins, are hidden 



