The RSPB is reminding Christmas dinner chefs NOT to put the cooking fat from their festive roast out for garden birds as the greasy mixture can damage their feathers.

Christmas is a time for feasting and living off the fat of the land, not least for garden birds. But doing so literally for our feathered friends could prove fatal, the charity advises.

In winter, the birds do need high-energy food to keep themselves warm. With insects and natural food sources in short supply, laying on a festive spread for your feathered neighbours is a great idea. But, as with any dinner guest, it’s essential to adhere to their dietary requirements. 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 charity warns.

Cooled fat mixed with roasted meat juices 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.

In addition, fat from 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.

RSPB wildlife advisor Katie Nethercoat said: “Many people wrongly believe that leaving cooked turkey fat outside is beneficial for birds, but in fact it can have disastrous effects. The consistency of the fat makes it prone to smearing, which is detrimental for birds’ feathers, along with the fat providing perfect conditions for breeding bacteria.

"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, as well as some of our winter visitors such as fieldfare and redwing, into the garden just in time for the Big Garden Birdwatch in January.”

If you’d like to treat your garden birds to their own Christmas cake, the RSPB suggests mixing bird seed, nuts and raisins together with lard, squashing it in and around a pinecone, then hanging it with string from a suitable tree.

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