266 SCIENCE PROGRESS 



this is done, and done thoroughly, we shall still be struggling 

 with the personal opinions of people who look through glasses 

 with very different eyes. The serious question is, do the people 

 who are mentioned as witnesses know enough yet to express 

 a definite opinion ? Have we sufficient evidence as to the actual 

 food of birds at different times of the year and under varied 

 conditions ? We feel bound to answer in the negative. What 

 we want is more of such work on their food as has been 

 recorded by Mr. J. Gilmour (16). 



The present paper deals with birds from the economic point 

 of view mentioned above without expressing any personal 

 opinions whatsoever. 



Roughly speaking, we have two hundred and fifty birds 

 which we may call regular residents of, or constant migrants 

 to, these islands. A large number of these are rare or un- 

 common, and are wisely protected by law, or should be. No 

 more than sixty can be said to be of any real economic 

 importance. A number of these are almost exclusively beneficial, 

 such as the Swallow, Martin, Swift, some Warblers and 

 Waders, etc. These we may discard for present purposes. 

 Some of the remainder are of general interest, such as the 

 Hawks and Owls. Others are mainly connected with the forest, 

 such as the Woodpeckers ; yet others affect for good or evil 

 the fruit-grower, as the Bullfinch, Blackbird, and Tits ; the 

 farmer has such as the Rook, Starling, Sparrow, and Plover 

 constantly before him ; and the gardener the Finches generally. 



An interesting subject has recently become prominent, 

 namely, the change of habits in birds (i, p. 74), but it does not 

 seem that anything like sufficient evidence has been collected 

 to give any scientific status to this subject. Isolated cases 

 quoted could be reduplicated a hundredfold, and thus the 

 apparent sudden change in one district loses much of its 

 significance. 



The so-called "Birds of Prey "—the Hawks, Falcons, and 

 Owls — have always been subject to persecution at the hands 

 of gamekeepers ; fortunately a certain amount of discrimination 

 now takes place in the shooting and trapping of these Raptores. 

 Their food in this country consists mainly of small mammals 

 and birds. Any great excess of mice, voles, etc., is always 

 followed by an influx of these rapacious birds. It seems, how- 

 ever, that they come when these creatures are in such excess 



