My dear Professor Newton

I have no definite information to give on the point about which you write.¹ I agree with you that the destruction of eggs is of subordinate, tho’ of course of some importance, as I believe all birds will lay a second time. Have we not evidence how little the taking of the eggs lessens the numbers of a species, on some of the Northern islands where the eggs of sea-fowl are annually collected?² From my own observations here I infer that occasional severe winters are by far the most important check; & this must apply to the adults.

In St John’s Tour in Sutherlandshire Vol 2 1849 p 178–179 you will find some particulars (if not already known to you) of the recent increase of certain birds, by the destruction of vermin.³ (Misseltoe Thrushes compete in my garden with thrushes & blackbirds for yew-berries)⁴ The famous horticulturist Rivers, now an old man, & whose father & grandfather have kept the same garden, told me that birds have increased greatly, so that he is now obliged to protect almost every thing by nets, which was not the case in his father’s time.⁵

I fear this letter will be of very little use—

I cannot remember about the Fulmar—⁶

yours very sincerely | Ch. Darwin