In all matters of seeds and nuts, we'd best leave it to the birds

... During winter, populations of blue tits were left unfed, given plain fat balls or given fat balls enriched with vitamin E a vitamin commonly present in bird food such as nuts and seeds. Nest boxes and bird feeders were distributed around the ...

http://www.thisisexeter.co.uk/matters-seeds-nuts-d-best-leave-birds/story-19516135-detail/story.html