Clare Island Survey — Phanerogamia. 10 81 



the seeds were probably disgorged rather than excreted.' In a subsequent 

 paper 2 on the role of the American Crow in agriculture, confirmation of this 

 disgorging habit, and much further information concerning the food of the 

 crow, will be found. 



Yet, when we sift the evidence available, we find it difficult to arrive at 

 any definite conclusion regarding the actual role of birds in practically 

 effecting the local dispersal of plants. The possibilities of bird-dispersal are 

 very large indeed. While the efficacy of wind and water are strictly limited 

 by questions of seed-buoyancy, we have in the bird an ageut which is capable of 

 transporting, in one way or another, the seed of any British plant. Even the 

 Oak, one of the heaviest-seeded of native species, is spread in this way. 3 But 

 the great body of evidence necessary for definite pronouncements as to what 

 birds actually do in this direction is not yet existent, and in the meantime 

 we need to avoid the danger of using isolated instances as general facts. 



Take, for instance, the case cited by W. 0. Focke. 4 A pigeon was killed 

 by some preying animal in his garden in the winter, and in the spring from 

 among its feathers appeared a number of seedlings of Vicia Fciba. " In this 

 observation he detected the normal method of the dispersal of the 

 Leguminosae by birds." 5 One feels, on the contrary, that this was quite an 

 abnormal occurrence — that a bird which had just swallowed uncrushed a 

 number of perfect seeds should be killed, and then abandoned, on a spot 

 where the conditions (in this case wholly artificial) permitted the seedlings 

 to obtain a footing. Focke himself considered such means of dispersal quite 

 exceptional — " man entschliesst sich jedoch schwer dazu, zu glauben, dass 

 dieser Weg der Verbreitung ein normaler sei" {loo. cit.). Indeed, this observer 

 in another place draws attention to the short range of normal endozoic dispersal, 

 and considers that such dispersal is usually much more local than is often 

 asserted: — " Die meisten Arten [der Pflanzen] werden namlich viel weniger 

 weit verschleppt als man glauben sollte." 6 But it may be noted that Clement 

 Eeid observed an instance similar to that which has been just discussed. 7 



Furthermore, as a practical aid towards the solution of our particular 

 problem, it is not enough that a Teal is found, on dissection, to have eaten a 



1 W. B. Barrows : Seed-planting by Birds. Report of the Secretary of Agriculture, U.S.A., 

 1890, p. 283. 



2 W. B. Barrows and E. A. Schwakz : The Common Crow of the United States. U. S. Dept. of 

 Agriculture, Division of Ornithology, &c, Bull. no. 6, pp. 24, 72, <fec. 1895. 



3 Clement Eeid, torn, cit., p. 29 ; and Nature, liii, p. 6. Not., 1895. 



4 Naturw. Verein Bremen, Abhandl., v, p. 650. 1876. 



5 Guppy, Naturalist in Pacific, ii, p. 150. 



6 "W. 0. Focke : Die Verbreitung beerentragender Pflanzen durch die Vogel. Naturw. Verein 

 Bremen, Abhandl., x, p. 140. 1889. 



' Tom. tit., p. 30. 



R,I.A. PEOC, VOL. XXXI. L 10 



