We all know that Christmas is a time for feasting and fattening up and the same is true for our garden birds.
But, as with any dinner guest, it's essential to adhere to their dietary requirements - and that doesn't include turkey fat!
Keeping warm for winter
In winter, birds need high-energy food to keep themselves warm. And with insects and natural food sources in short supply, laying on a festive spread for your feathered residents is a great idea.
Your birds will happily polish off leftover Christmas cake or crumbs of biscuit and mince pie, but cooked turkey fat and anything too salty can be dangerous.
The fat in roasting tins can quickly go rancid if it’s left in a warm kitchen before being put outside. This forms the ideal breeding ground for salmonella and other food poisoning bacteria and, just like people, this can be fatal to birds.
Plus, cooled fat can easily smear onto birds' feathers and interfere with their waterproofing and insulation. Birds need to keep their feathers clean and dry if they are to survive the cold winter weather, but a layer of grease would make this virtually impossible.
No to turkey fat!
Charlotte Ambrose, who works in our Wildlife Enquiries team, says: “Many people wrongly believe that leaving cooked turkey fat outside is beneficial for birds, but in fact it can have disastrous effects. Only pure fats such as lard and suet should be used to make homemade fat balls which will give birds’ the energy and nutrients to survive the cold winter months.”
“Putting out some of the recommended festive treats will encourage birds such as blackbirds, robins and wrens into the garden just in time for the Big Garden Birdwatch in January.”
Treat your birds
If you'd like to treat your garden birds to their own Christmas cake, mix bird seed, nuts and raisins together with lard, squash it into an upturned yoghurt pot, then hang it with string from a suitable tree. Here’s the recipe.
So the message is to lay on a festive feed for your garden birds, but avoid the fat.
For more on our science, check out the RSPB Centre for Conservation Science web pages.