Vol. XVII. No. 429. 



THE AGRICULTURAL NEWS. 



317 



THE CROW, AND ITS RELATION 



TO MAN. 



In Bulletin No. 621, United States Department ul 

 Agriculture, is published a paper giving an account and the 

 results of an investigation as to the economic status of the 

 common Crow (Con'us brachyrynchos) in relation to its 

 value or otherwise to man, undertaken by E. R. Kalmbach, 

 Assistant Biologist, in response to the many urgent requests 

 for a number of years for information touching the habits 

 of this bird. 



Some idea of the amount ot labour involved, and the 

 completeness of the investigations undertaken, may be 

 gathered from the fact that no fewer than 2,118 stomachs of 

 crows, both old and young, became available for examination. 

 Effort was made also by means of 3,000 letters of enquiry, 

 to secure reliable information as to the good or harm done 

 by the crow, based on actual field observation. The data 

 obtained have made it possible to present considerable trust- 

 worthy testimony, whichj it is claimed, distincly reflects 

 present conditions; the quantity and character of the com- 

 bined evidence secured seems to justify the final conclusion 

 reached as to the economic status of the crow in the United 

 States. 



Although not native to the West Indies, and confined 

 in its distribution practically exclusively to America, yet the 

 crow is of so world-wide reputation, that any available liter- 

 ature concerning its life-history and food habits, should be of 

 interest to the general reader. For that reason, the informa- 

 tion given below is abstracted from the source above-men- 

 tioned. 



Practically omnivorous, the crow is capable of surviving 

 in widely diversified environments. In its diet may be found 

 everything from the choicest poultry and the tenderest shoots 

 of sprouting grain to carrion and weed seeds. The fact that 

 no less than 6.56 specifically different items were identified in 

 the stomachs examined in course of this investigation, give 

 some idea of the bird's resourcefulness, its potentialities for 

 good or harm, and the complexity of the problem of deter- 

 mining its worth. Many complaints against the bird are 

 well nigh traditional, while some of its beneficial habits have 

 been matters of common knowledge for generations. 



A brief summary of decisions reached, respecting each of 

 the more economic problems that have arisen in this investi- 

 gation, makes it possible to review, with some degree of 

 thoroughness, the many-sided question of the value of the 

 crow. 



As regards its food habits, it is seen that the crow's 

 destruction of insects presents the strongest argument in the 

 bird's favour. Nearly one-fifth of the adult crow's yearly 

 sustenance comes from such sources. That injurious insects 

 greatly outnumber beneficial insects in the diet of the crow, is 

 seen from a review of the four most important orders: beetles, 

 grasshoppers, caterpillars, and true bugs. The crow's relation 

 to beetles is all that the frugal agriculturist could desire. 

 Foremost amongst these in its food are May beetles, and thevr 

 destructive larvae, white grubs. In its consumption of grass- 

 hoppers, however, the crow renders man its most important 

 service; in regions where these decidedly injurious insects are 

 abundant, their nymphs form the principal insect-food of 

 nestlings. In its consumption of caterpillars the nestling 

 crow exceeds its parent in effectiveness in the ratio of 4 to 1 . 

 This food, found in over a third of the stomachs of young 

 crows, is all in the bird's favour, especially since cut-worms 

 constitute the major portion, .^mone the true bugs, only 

 Pentatomidae, and the periodical cicida, are considered 

 worthy of mention in the summary. The consumption of 



crustaceans is classed among the minor benefits conferred by 

 the crow, while its feeding on the smaller snakes and lizards, 

 and its destruction of the highly insectivorous amphibians, 

 especially toads and frogs, are to be deplored, as such work- 

 is opposed to the best interests of man The crow's destruc- 

 tion of wild birds and their eggs is a noxious trait of no 

 small importance. It is somewhat mitigated, however, by the 

 fact that most of the depredations on eggs occur early, 

 enough in the season to permit the raising of a second 

 brood, at a time when there is little or no danger from crows. 



As regards crops, corn is the principal food of the adult 

 crow: ii is eaten in every month of the year, and from October 

 to January forms over half the bird's diet. Damage to wheat 

 and oats is confined to sowing and sprouting time, and is by 

 no means so serious as the pilfering of sprouting corn. 



As a distributor of disease the crow, along with the 

 turkey buzzard, has been a target for much unjust criticism. 

 While the crow may be an agent in the transmission of live- 

 stock diseases, it does not follow, it is argued, that even the 

 extermination of this species would materially lessen the dan- 

 ger of infection. The crow's consumption of wild fruit in 

 itself involves nothing of economic interest, as the embryos 

 of the seeds eaten are seldom destroyed, and as this material 

 is regurgitated after the digestible portion has been assimi- 

 lated, it is apparent that the crow thereby becomes an agent 

 in the dispersal of seeds. 



In the following conclusion reached, the author appears 

 to have fairly and accurately stated the position as regards 

 the economic status of the crow in relation to its valvie to 

 man: — 



'When feeding on injurious insects, crustaceans, rodents, 

 and carion, and when dispersing seeds of beneficial plants, 

 the crow is working largely for the best interest of mm; 

 when destroying small reptiles, amphibians, wild birds, 

 poultry, corn and some other crops, when molesting live 

 stock and distributing their diseases, and when spreading 

 seeds of noxious plants, the bird is one of the farmer's 

 enemies; when destroying spiders and molluscs, however, 

 its work appears in the main to have a neutral effect. The 

 misdeeds of which the crow has been convicted greatly 

 outnumber its virtues, but these ate not necessarily equal 

 in importance. Much of its damage to crops and poultry 

 can be prevented, while the bird's services in the control of 

 insect pests can ill be spared. At the same time no policy 

 can be recommended which would allow the crow to become 

 so numerous that its shortcomings would be greatly accen- 

 tuated. As the capabilities of the crow for both good and 

 harm are great, it is believed that an extermination of the 

 species would have ultimate consequences no less serious 

 than an overabundance. 



'Inasmuch as this investigation aimed at reaching general 

 conclusions respecting the status of the crow, in order that 

 our attitude toward the bird might be based on sound 

 economic principles, it uiay be said that the laws relating to 

 it at present in force in most States, are altogether satisfac- 

 tory. It is well that no protection be afforded the bird, and ' 

 that permission be granted for shooting it when it is actually 

 found doing damage- Bounties can not be recommended, 

 nor can a campaign of wholesale destruction where com 

 plete extermination is the object sought. However, a 

 reasonable reduction of numbers is justifiable in areas where 

 there is an overabund.mce of the birds The attitude of the 

 individual farmer toward the crow should be one of toleration 

 when no serious losses are suffered, rather than one of 

 uncompromising antagonism, resulting] in the unwarranted 

 destruction of these birds, -shich at times are most valuable 

 aids to men.' 



