Clare Island Survey — Phanerogamia. 10 83 



Kerner's experiments regarding the condition in which birds expel 

 seeds which they eat may be quoted here. 1 Seventeen species of birds, 

 belonging to many different families (and also a few mammals), were fed 

 with seeds and fruits of 250 different species of plants, and the seeds were, 

 after ejection, examined and sown. As a result, he divides his series of 

 birds into three groups. The first, which includes, among others, the Pigeon, 

 several Finches, Titmouse, and Duck, grind up even the hardest fruits and 

 seeds in their " gastric mills." " No seed capable of germination was found 

 under ordinary circumstances in the excrement of these birds." 2 But by 

 forcibly overfeeding some of the birds, a few seeds capable of germination 

 were obtained. In the second group, which consisted of the Eaven and the 

 Jackdaw, hard-coated seeds and fruits passed through the intestine uninjured, 

 while all soft-coated ones were destroyed. The third group included the 

 Blackbird, Song-thrush, and Bobin. Of the seeds which passed through the 

 intestines of these birds (some seeds were refused, and others were thrown up 

 after having been swallowed) over 80 per cent, germinated. Kempsi, 3 again, 

 experimenting with mammals and birds with a view of determining their role 

 in weed-dispersal, finds many cases of germination, but considers that many 

 birds, such as Doves, Quails, Larks, Finches, and Sparrows, are more efficient 

 as seed-destroyers than as seed-dispersers. 



The German Government, also, is publishing* a series of papers on birds' 

 food, especially as regards insects and weed-seeds, which are a storehouse of 

 detailed information, though we cannot yet generalize from them as regards 

 our local species. 



From the above observations it would appear that many of our common 

 birds can disseminate seeds by eating them, though the list is far from 

 complete. If we knew what seeds were included in the normal diet of the 

 commoner birds of our district, we would be in a strong position as regards a 

 pronouncement on the question of the part played by the local birds in seed- 

 dispersal. But as regards the vegetable food of birds, our information is 

 still most incomplete. That certain of the more conspicuous birds eat the 

 more conspicuous fruits, such as berries, is of course a matter of common 



1 A. Keknee. : Nat. Hist, of Plants, ii, pp. 862-864. 



- This result differs from that obtained by Guppy (Science Gossip, N.S., i, p. 146, Sept., 1894, 

 and " Naturalist in Pacific," ii, pp. 369, 513), who found thit seeds of Snarganium, Potamogeton, and 

 Cyperaceae eaten by ducks germinated readily. Again, Kerner states as a result of his experiments 

 that germination is usually retarded by passage through birds, while Guppy, Barrows (loc. cit.), and 

 others find that it is hastened. 



3 E. Kempsi : Tiber endozoische Samenverbreitung und speziell die Verbreitung von Unkrauteru 

 durch Tiere auf dem "Wege des Darmkanals. Rostock, 1906. (Abstract in Justs Bot. Jahresbericht, 

 xxiiv, 3, pp. 264-265). 



4 Arbeiten aus der biologischen Abtheilung fiir Land- und Forstwirtscbaft. 



L2 



