June 28, 19 17] 



NATURE 



347 



out applying racing- tests is bound to lead to 

 deterioration. For this reason the continuance 

 of such racing as may be required to test the 

 value of the stallions and mares now at stud is 

 essential. J. C. Ewart. 



THE DESTRUCTION OF HOUSE- 

 SPARROWS. 

 T^HE question whether or not a particular 



J- species of wild bird is injurious or beneficial 

 is one that is diflScult to answer, but it is mani- 

 festly unfair to complicate the matter further by 

 raising issues that are foreign to the subject, or 

 by the publication of random statements which 

 are not substantiated by actual facts. 



Recently in the Times a correspondent recorded 

 ■'a plague of caterpillars such as are taken by the 

 sparrows to feed their young," and deplores the 

 action of the Board of Agriculture in issuing an 

 Order for the destruction of the house-sparrow. 

 Unfortunately, the correspondent does not men- 

 tion the species to which this caterpillar belongs ; 

 presumably it is the larva of the Winter Moth 

 Cheimatobia brumata, L.), upon which the house- 

 sparrow feeds its young during the nestling 

 period, but only to a limited extent. For years 

 past we have had plagues of caterpillars when 

 house-sparrows were free to breed and multiply, 

 and careful inquiry has shown that such outbreaks 

 are almost universally due to the omission of 

 grease-banding of the fruit trees, or, in the case 

 of other species, to the absence of the spraying 

 machine. Owing to the present scarcity of 

 labour, either of these reasons may account for 

 the plague of caterpillars, so that the demand 

 for " the immediate reversal of the orders given " 

 by the Board of Agriculture is unjustifiable. In 

 view of the above and similar statements now 

 appearing in the Press, it may be well once more 

 to state the economic position of the house-spar- 

 row as related to agriculture and horticulture. 



First, the writer would like to state that he 

 is in full agreement with the action of the Board 

 of Agriculture, believing from long exfjerience and 

 close study of the food and feeding habits of the 

 house-sparrow that, as a result of its recom- 

 mendation, great benefit will accrue to both the 

 agriculturist and the horticulturist. 



Gurney, who investigated the food of this 

 species in 1885, stated that "fully 75 per cent, of 

 ^n adult sparrow's food during its life is corn of 

 some kind. In young sparrows not more than 

 40 per cent, is corn, while about 40 per cent, con- 

 sists of caterpillars and 10 per cent, of small 

 beetles. This is up to the age of sixteen days." 

 This statement was founded upon an examina- 

 tion of 694 dissections. In igio the writer com- 

 menced to work upon this species, and by June, 

 ^914; had examined 404 adults and 329 nestlings, 

 obtained from fruit-growing, agricultural, and 

 suburban districts. Since then the work has been 

 continued, so that up to the present time upwards 

 of 750 adults and 470 nestlings have been in- 

 vestigated, and the results clearly show : — 



(i) That the house-sparrow is far too plentiful, 

 NO. 24.87. VOL. Qol 



and in agricultural and suburban districts it still 

 requires very drastic reduction. 



(ii) That, to a less extent, perhaps, it requires re- 

 ducing in number in fruit-growing districts, and 

 were this carefully carried out annually, after the 

 nesting period, the good done during that season 

 rnight probably compensate for the harm occa- 

 sioned during the remainder of the year. 



(iii) That in agricultural districts the food of 75 

 per cent, of the sparrows consists of corn. 



(iv) That, apart from the nesting season, the 

 house-sparrow does far more harm than good; 

 indeed, its depredations on cereal crops alone 

 entail a most serious loss to the farmer and the 

 country in general. 



As a result of the numbers of house-sparrows 

 that are now, very wisely, being destroyed, we 

 shall, in all probability, see a marked increase 

 in the number of truly insectivorous birds, which 

 are invaluable to the fruit-grower. 



As to the continuance of the present Order, 

 all must depend upon the number of birds 

 destroyed in fruit-growing districts; but there is 

 little fear, in the writer's opinion, of their exter- 

 mination in agricultural or suburban districts, 

 and there the Order might be wisely continued. 



From the above recorded observations and those 

 previously published, no unprejudiced mind will 

 doubt the wisdom of a drastic reduction of this 

 species. Enthusiasts and humanitarians may 

 continue to write upon the value of this bird to 

 the farmer, etc. ; but the futility of such state- 

 ments must be apparent to the most casual 

 observer, unless they are supported by trust- 

 worthy and carefully obtained facts as to the pre- 

 cise nature and quantity of the food, while such 

 investigations as have been conducted entirely 

 fail to support the popular view that the insects . 

 destroyed during the nesting season compensate 

 for the wide destruction occasioned by the species 

 generally during the remainder of the year. 



There is a very general, but entirely mistaken, 

 opinion that the house-sparrow feeds largely upon 

 insects. During the nesting season the food fed 

 to the young birds, and in all probability most 

 of that taken by the parents, consists mainly of 

 insects, worms, and slugs ; but during the re- 

 ma,inder of the year it is mainly grain of some 

 kind. 



No thinking individual wishes or advocates the 

 destruction of truly beneficial species of wild 

 birds ; on the contrary, every encouragement 

 should be offered them, provided that they are 

 not permitted to increase to such an extent that 

 a change in their feeding habits i,s forced upon 

 them by reason of their numbers. 



Whilst the majority of species of wild birds are 

 undoubtedly beneficial, no increase in their num- 

 bers will ever lead to the extermination of any 

 of our common orchard j>ests. That they aid in 

 the control of such pests is perfectly true, but 

 so long as artificial conditions prevail — i.e. the 

 association in a given area of a large number of 

 trees of a particular species — so long will it be 

 necessary to spray, grease-band, and carry out 

 clean cultivation. If the house-sparrow is the 



