BUREAU OF BIOLOGICAL SURVEY. 663 



of the injury it does to lawns and the supposed injury it does to 

 potatoes and oilier root crops. The latter destruction is, in the vast 

 majority of cases, the work of a very different mammal, the field or 

 meadow mouse, which utilizes the tunnels made by the mole to facili- 

 tate its attacks on potatoes, bulbs, and other underground crops. 



As attempts to poison moles almost invariably fail because the 

 animal lives chiefly upon insects, experiments have been made dur- 

 ing the past year with a variety of traps. Since none of the traps 

 already on the mai'ket proved entirely satisfactory a new trap has 

 been devised, for wdiich a patent has been applied for in the name 

 of the Biological Survey, which it is believed will largely solve the 

 problem and afford farmers, lawn owners, and others the means of 

 getting rid of these little mammals easily and cheaply. 



BIRD ENEMIES OF THE ALFALFA WEEVIL. 



As is well known, the alfalfa weevil, a very destructive insect 

 probably im))orted from Europe, has become firmly established in 

 Utah, in which State it is doing much damage and from which it 

 threatens to invade contiguous States, with disastrous results to the 

 important alfalfa industry. In cooperation with the Bureau of 

 Entomology the Biological Survey is engaged in investigating the 

 relations of birds to the insect to determine what aid, if an}-, birds are 

 likelv to lend in checking the increase of the weevil and retarding its 

 spread. It is interesting to note that, although the weevil has been 

 established in its new home probably only 5 or 6 years, 31 species of 

 birds have already learned to eat it, and that during the summer it 

 forms nearly one-fifth of their food. It is of interest to note, also, 

 that the English sparrow, which in most parts of the United States 

 is a pest, heads the list as a determined foe of the weevil and feeds 

 its nestlings largely on it. Thus, 170 larvie of the weevil were found 

 in the stomacli of a single nestling. If further investigations to be 

 made in 1912 confirm these results, it may prove advantageous to 

 encourage the breeding of the English sparrow around alfalfa fields 

 by putting up boxes to serve as nesting sites. If it is possible to 

 utilize the services of the English sparrow against this formidable 

 insect foe, the alfalfa weevil, it will be part compensation for the 

 damage done by the bird in other sections. 



RELATION OF BIRDS TO THE BOIJL WEEVIL. 



Several years ago the Biological Survey made a careful examina- 

 tion in Texas of the relation of birds to the boll weevil and published 

 the results. It was shown that birds prey upon the insect while it is 

 hibernating, while on the cotton plants, and during its autumnal 

 migration flight, which is the period when the weevil chiefly extends 

 its range. Similar investigations are being carried on in the terri- 

 tory more recently infested by the boll weevil, especially in Alabama 

 and Mississippi. 



BlUnS IN RELATION TO CHESTNUT-BARK DISEASE. 



The chestnut-bark disease was introduced into the United States 

 several years ago, has spread into 10 or more States, and will prob- 

 ably continue its progress indefinitely unless means be found to check 



