Investigation of the damage caused by blackbirds has led to the fol- 

 lowing conclusions : 



1. Red-winged blackbirds (Agelaius phwniceus subsp.) and (Agelaius 

 tricolor), because of their greater abundance and their food habits are 

 by far the most destructive of the blackbirds. 



2. The percentage of insect food taken by Brewer blackbirds 

 (Euphagus cyanocephalus) is much greater than that taken -by red-, 

 wings. 



3. Red-winged blackbirds are destructive to barley when "in the 

 milk." Ranches within ten miles of rivers or other breeding grounds 

 are the most affected. The amount of destruction varies greatly with 

 the abundance of the birds. 



4. Red- winged blackbirds are destructive to Egyptian corn and kafir 

 corn (Fig. 2). They appear to be especially fond of this sort of grain 

 and will gather in flocks of thousands, often causing considerable 

 damage, especially near rivers where the birds are abundant. Small 

 fields of this sort of grain are often completely stripped by the 

 birds. Milo maize suffers little damage if these other grains are avail- 

 able. Protection of fields by scarecrows or by shooting has proved 

 unsuccessful. 



An investigation of the damage to almonds caused by the Lewis wood- 

 pecker (Asyndesmus lewisi) showed that this bird was destructive to 

 almonds in certain localities, in the spring of 1912. The almond 

 growers of the Capay Valley apparently suffered the most, and prob- 

 ably with good reason, for in this particular valley the birds were 

 especially abundant. Over 65 per cent of all the food eaten by the birds 

 examined was made up of small pieces of almonds. The exceptionally 

 dry year which caused a shortage in the usual food supply, was prob- 

 ably responsible for this unusual occurrence. 



STUDIES OF THE RELATION OF BIRDS TO INSECT OUTBREAKS. 



A study of these same birds at the time of an insect outbreak has 

 shown them to be important in the restoration of that balance of nature 

 most suited to mankind. In the investigation of an insect outbreak in 

 northern California during the spring and summer of 1911, when th& 

 nymphalid butterfly (Eugonia calif ornica) became abnormally abundant, 

 it was found that the Brewer blackbird was the most efficient destroyer 

 of the insects, botH on account of its numbers and its food habits, taking 

 95 per cent of all the butterflies taken by birds. Examination of the 

 stomachs of thirteen red-winged blackbirds (Agelaius pkmniceus 

 subsp.) showed that over 93 per cent of their food was of vegetable 

 matter. The Brewer blackbirds (Euphagus cyanocephalus) examined, 

 'on the other hand; had taken 83 per cent of animal food, showing the 

 vast difference in food habits. Meadowlarks were found to feed on 

 the butterflies to a small extent, as was also the western kingbird 

 (Tyrannus verticalis), the blue fronted jay (Cyanocitta stelleri fron- 

 talis), and the Say phoebe (Sayornis say us). 



