Darwin Correspondence Project

17 College Sqre East. | Belfast

1st Decr 1854.

My dear Mr Patterson,

The subject referred to in Mr Darwin's note is one which has long interested me, & I am glad to have the opp.y of supplying some of the details which he wishes for.— In June 1848 Mr D. wrote to Mr Thompson requesting to be informed of the result of any observations which the latter might have made relative to (amongst other things) the dispersal of fresh water productions by birds; and in Feb.y 1850 Professor E. Forbes, who was then preparing a paper for the R. I. “on the distribution of fresh water animals & plants,” made a similar application.

I have found the two letters in Mr Ts MSS. tog.r with notes of his reply to Professor Forbes & some other mema of which I enclose copies.— The Athenæum of 16th March 1850, contains a notice of the Professor's paper, in which he mentioned Mr T's views; & lest Mr Darwin shd not have the Edin. Phil. Jour. at hand, I send a copy of an extract from it which Mr T. had made.

The taxidermist alluded to in the reply to Forbes's note, is Mr Darragh the Curator of our museum, & I find that he has nothing to add to what he had formerly stated to Mr T., save that he has in sevl instances obtained the seeds of plants in the stomachs of ducks.— He mentions one specimen in particular which was shot at Lough Neagh & contained a large quantity of the seeds of an aquatic plant, abundant there.—

I venture to make the following suggestions, altho' there may not be any novelty in them:—

1st That where seeds in a vegetative condition are transported to a great distance by birds, their dispersal, in that condition, is most probably attributable to Birds of Prey, which after feeding on the seed-eating birds, cast up the seeds uninjured; or to the death of the seed-eating birds, from any cause, after reaching land, but before the seeds have been subjected to the full operation of the digestive process.— I do not mean to say that this process necessarily destroys the vegetative power in all cases, for, on the contrary, it is well known that grains of oats often pass uninjured through the stomachs of horses, especially when the animals are old; but I have never heard of any well-authenticated instance of a perfect seed having been observed in the excrement of a bird.— I can howr certify that I shot the sparrowhawk referred to in one of Mr T's. mema, after it had retired to roost in the ev.g, & that on dissection next day, I found in it the greater portion of a Grey linnet, includ.g its crop with the contents, consisting of a whole grain of wheat & some small seeds.—

The accompanying note respect.g Mr Langtry's eagles shows that they cast up entire grains of oats swallowed whilst they were feeding on small birds, & it is not therefore going too far to surmise that if my sparrowhawk had set out on migration instead of going to roost, immediately after eating the Grey linnet, the wheat & other seeds would have had a fair chance of vegetating at a distance. Various birds of prey are well known to take long & very rapid migratory flights, but even if they did not do so, they might still be the means of saving the vegetative power of seeds conveyed in the stomachs of ducks &c., by preying on the latter so soon as they arrived.—

2nd Mr Thompson seems to have thought that the Grallatores could not be instrumental in transporting seeds, “as they are not vegetable feeders ” but altho' they do not feed on seeds, some of them, for example the Curlew, Woodcock & Snipe, are in the habit of inserting their entire bills into soft boggy places in search of worms &c. & I have on different occasions procured Curlews & snipe with the feathers at the bases of their bills soiled with earthy matter.— It is quite possible that minute seeds might thus be taken up accidentally & carried to a distce—

8th Decr

(I have been obliged to lay aside this letter since 1st Inst. which will account for my apparent neglect.—)

3rd Altho' the Natatores may, as observed by Mr Thompson, usually migrate from the Sea, we know that many of the vegetable feeders are in the habit of resorting to fresh water lakes, ponds & marshy places along the coasts, every evening, and that they remain there during the greater part of the night.—

4th Within the last week, & since I commenced the present letter, I have had an opportunity of examining the contents of the stomach of a wild goose (the Beau Goose) shot at an inland locality in the Co.y of Down.—

It contained vegetable matter mixed with about a tablespoonful of sand & on separating the former I found the calyx or seed vessel (I could not with certainty say which) of a small plant— The seeds themselves may or may not have been mixed with the sand in this particular case, but the presence of any of the parts concerned in fructification shows that these birds do not merely crop the leaves or roots; & the circumstce of their swallowing so much sand ought not to be overlooked, for even if the bird should perish on a barren rock, the soil which wd be formed by its decayed body and the sand, might form a sufficient bed for seeds to grow in.—

Magillivray, altho he throws doubt upon the old & often repeated opinion that the seeds of the Misseltoe germinate after passing through the intestines of the Missel-thrush, admits that on 2 occasions he found whole seeds in the intestines of birds (See his Br. birds V. 2. p. 125) & Balfour in his Classbook of Botany says:— “The pulpy covering of some fruits renders them fit for the food of birds & other animals, and when the seeds are hard & enclosed in a stony endocarp, they may escape the action of the gastric juice & be deposited in a state fit for germination.”

Yours sinc.y | Jas R. Garrett
Robt Patterson Esq. | Belfast.