The Food of Birds. 633 



have to co-operate before any satisfactory results can be 

 obtained. 



The Hungarian Central Office for Ornithology studies not 

 only the species, which are already protected by law, but also 

 those which have hitherto been considered as harmful, 

 because a rectification of the views held respecting particular 

 species is not impossible. For instance, a lecturer on one 

 occasion spoke of the usefulness of the Buzzard (Buteo 

 vulgaris), the indifference of the Black Kite (Milvus migrans), 

 and the great harmfulness of the Hooded Crow (Gorvus 

 comix) in regard to game, but when the birds were examined, 

 in the stomach of the Buzzard was found a young hare, in 

 that of the Kite two chickens, while in the Crow's stomach 

 was nothing but an abundance of reed-seed. 



According to the principles laid down above, the seed or 

 plant-eating species were studied separately and the results 

 published in a paper by L. de Thaisz, entitled "Kritische 

 Bestimmung der Nützlichkeit oder Schädlichkeit der pflan- 

 zenfressenden Vögel auf Grund des Kropfinhaltes " (Aquila 

 6, p. 133, 1899). 



In particular the Partridge (Per dix fer dix L.) was carefully 

 studied and the results published in an article by J. de Losy : 

 " Positive Daten zur Lebensweise des Rebhuhns (Perdix perdix 

 L.") (Aquila 10, p. 231, 1903). 



The study of the following species has been commenced 

 and partially completed by Ernst Csiki, keeper of the Hun- 

 garian National Museum. 



(1) Lanius excubitor L. is generally considered harmful 

 though its usefulness is undeniable. 



(2) Lanius minor Gm. A useful bird. There is no proof 

 that it does harm to young birds. 



(3) Lanius collurio L. A useful bird whose food consists 

 of insects. There is no proof that it destroys small verte- 

 brates also. 



(4) Oriolus galbula L. feeds until middle of June exclu- 

 sively on insects, afterwards on various fruits. 



(5) Micropus apus (L.). Useful. 



(6) Cotile riparia (L.) is unquestionably useful. 



(7) Ghelidon urbica (L.) is useful, though a large part of 

 its food consists of indifferent insects, 



