Why does some bird food leave a mess?

The BTO’s Claire Boothby explains: “Most seeds have a kernel – the bit the bird is going to eat, surrounded by a tough outer case that is discarded by the bird. In some foods, the outer case is removed during processing, resulting in less waste. Sunflower hearts (without the husk) are good, as many birds will take these and they produce less waste.” Bird expert Stephen Moss agrees: “I love kibbled sunflower hearts. You pay more, but there’s no waste. If you buy sunflower seeds that haven’t been shelled, birds use more effort to take the husk off and don’t get as much energy, which is critical in winter, and they leave a mess that can attract vermin.” CJ WildBird Foods launched Hi-Energy No Mess food in 1999. A spokeswoman says: “Birds are fierce food critics. They speak with their beaks, and discard seeds and morsels that offer no nutritional benefit. We developed ways to de-husk seeds, minimising waste, preventing growth and helping birds.” The RSPB’s Nick Turner adds: “A no-mess mix should contain foods that birds enjoy, and seeds that don’t require the breaking of shells. Our no-mess mix contains sunflower hearts, kibbled maize, husk-free oats and canary seed. We don’t use whole oats as many birds struggle to de-hull them.”