Science Questions

How do birds recognise fat balls as food?

During the winter I’ve put blocks of suet with seeds in them out for the birds. It only takes a few minutes for the birds to find them and dig in but increasingly I’ve become very disturbed by the whole thing. Suet is animal fat so apart from the fact I’m promoting carnivorous behaviour in chickadees it raises the much more fundamental question which is, how do birds recognise fat balls as food when they don’t look like their natural food at all? Melissa

Birds are quite adaptive when it comes to people and the kinds of foods we give them. Here in the UK there’s a wonderful phenomenon that happened. Since 1921 a thing which we no-longer have, glass bottles of milk sitting on our doorsteps with milk that wasn’t homogenised, had this wonderful creamy chunks floating up to the top. For the first time in 1921 someone saw a blue tit pecking at that top, the silver foil top of the milk bottle to drink the cream. If that isn’t a more unnatural food-source for birds, I don’t know what is. What actually happened, and people studied how this behaviour spread around England, by the 50s and 60s birds all the way around England had learned how to do it. It always seems like it came to a new area and all the birds in that area would learn how to do it. It’s this phenomenon that spread around. I think birds do know how to adapt very much to different types of food that we give them. Suet, I think, is actually meant to be a very good type of food for birds, especially in winter. The RSPB here in the UK – the Royal Society for the Protection of Birds – on their website they do recommend putting out suet. I don’t think that’s a problem. I think birds can eat other animals, it’s all right but I understand your concern. I think birds really are quite adaptable. They’ll have a go and if it tastes good they’ll realise it’s got nutrients and energy in it then they’ll take it and they’ll eat it.

May 2008