WILD LIFE IN CALIFORNIA 



31 



some student of ant life will soon tell us 

 whether it is so or not. 



Mr. Newell, who has made some observa- 

 tions of the habits of the Iridomyrmex hu- 

 mills, or Argentine ant, says this species nests 

 both out of doors and in the woodwork and 

 masonry of houses, and the colonies which 

 may inhabit a large area have the unique 

 habit of coming together on the approach of 

 winter and uniting in one large colony which 

 may contain a large number of queens. In 

 the spring this big colony divides or splits up 

 into numerous smaller colonies, which spread 

 out and cover an extensive territory. This 

 fact suggests that the winter months are the 

 best time in which to war upon the pest. 



The presence of these ants in the United 

 States was noted eleven years ago, and it was 

 then mentioned that there was a possibility 

 of their overrunning the warmer sections of 

 the country. In all probability, they had been 

 here for a season or two, at least, before it 

 was discovered they were established. So far 

 as I can learn from enquiry and observation, 

 the pest does not seem to have extended its 

 habitat to any distance easterly beyond the 

 range of hills back of Oakland and Berkeley. 

 Therefore it would seem as if there existed 

 some conditions in the easterly section un- 

 favorable to their requirements in the matter 

 of temperature or food. Neither do they seem 

 to have extended their operations south any 

 distance beyond the bay where the frost is 

 more severe and freezing weather sometimes 

 prevails. 



Since the advent of foreign ants the number 

 of English sparrows about the City of Oak- 

 land, and some of its suburbs, have become 

 less. The decimation is more noticeable in 

 the streets and the more thickly built-up resi- 

 dent districts. Residents of fifteen years ago 

 will easily recall how numerous these birds 

 were on Broadway and Washington and the 

 central cross streets, as well as in the parks; 

 and how common it was to see the litter of 

 their nesting material hanging from all the 

 nooks and corners of building fronts. Now 



some of the streets and buildings are entirely 

 free from the large flocks of sparrows, but 

 without careful investigation and study, it 

 cannot be set down for a fact that the Argen- 

 tine ants are responsible for the change. If 

 they are to be credited with partially ridding 

 the community of the pest bird, the deed must 

 have been accomplished by the ants swarm- 

 ing into the nests of the sparrows and killing 

 the nestlings when first hatched. This idea 

 was suggested to me by the experience of a 

 resident of Piedmont, who for many years 

 has maintained an aviary in his grounds for 

 keeping and rearing canaries. Up to the last 

 three or four years, he had no trouble in 

 raising young birds, nor did he discover any 

 unusual interference in the various features 

 of the brooding of the birds until in late years. 

 Now it is quite different. Though the birds 

 build their nests and hatch their young as 

 formerly, the baby canaries all die within a 

 brief time after seeing the light of day. For 

 a while the gentleman was puzzled for a solu- 

 tion of the cause of the fatality, but finally 

 he discovered that the nests, after the hatch- 

 ing, were overrun with Argentine ants. 



The English sparrows have the habit of 

 nesting in one locality, if not disturbed, and 

 raising several broods in a season. Thus 

 creating a condition similar to the nesting in 

 the aviary, which enables the ants to locate 

 the nestlings more readily and with certainty. 

 In the case of other birds, as a rule, they 

 locate their nests in trees and shrubs away 

 from the buildings where the ants are most 

 common, and get through with their family 

 cares before the locality might be discovered 

 by the enemy ants even if some of their scouts 

 were ranging around away from human hab- 

 itations, where the ants seem to find a greater 

 supply of food to their liking. 



Should the decimation of the sparrow pest 

 prove to be due to the advent of the Argentine 

 ants, there are some people who will look 

 upon the latter with less feelings of enmity 

 than others not annoyed by the birds. 



