Happy St Patrick's Day! My dad sent me a little badge with a living piece of shamrock which I'll be wearing all day. Afterwards I'll pot it up and encourage it to grow in a pot on my kitchen windowsill. It'll make me think of my dad in Co. Limerick whenever I look at it.
My sister, Steph, showed me how to make these bird feeders. You make holes in monkey nuts then thread string through. The blue tits in particular like to hang on them and peck holes in the shells to extract the nuts. I thought the grey squirrels would probably just steal the whole thing and run off with it, but oddly I haven't seen them bother with it at all. If you use natural string (rather than nylon or something) then when it is empty you can just fling the whole thing on the compost heap.
Feeding birds encourages biodiversity in the garden. If you tempt them in for a lunch of peanuts, they might decide to finish off with a dessert of caterpillars and slugs. Site your birdfeeder carefully because bird droppings will accumulate underneath it. These add fertility over time but may be too strong for some plants (and are unwelcome on e.g. lettuce). It occurs to me that if you had a layer of some sort of mulch under the birdfeeder you could change it once in a while and put the mulch plus droppings on your compost heap. Or you could fix the feeder directly above the heap and collect the frtility directly. But to tell the truth I don't feed the birds because it's good permaculture practice. I just feed the birds because I love watching them.