Spring is a beautiful time of year, with birds often chirping away as they prepare their nests, hatch their eggs, and welcome new chicks into the world. However, as the weather warms, birds' diets change slightly, so anyone who enjoys feeding them should stop leaving out certain foods, as they can actually do more harm than good.

Clare, a gardening expert from Really Wild Birdfood, is asking people to avoid leaving out suet fat balls, a very common bird food, as they spoil very quickly in spring. She said: "These can easily go soft and rancid in the heat so should be avoided. Commercially made fat products are suitable for use in the warmer months, but may not be as popular and so any uneaten product should be discarded after three weeks."

Suet balls are often left out for robins and other small birds because they help them store the calories needed to stay warm during the cold winter months.

They provide an easy source of energy that helps birds survive harsh weather, but their need for such high-calorie foods lowers as spring approaches.

Suet balls are not simply well-suited to warmer spring weather because they can quickly go rancid, melt all over bird feeders, and encourage the spread of bacteria.

They may also develop mould, and birds that eat contaminated food can become ill or spread diseases such as trichomonosis.

Melted fat can stick to birds' feathers and leave a greasy residue that traps droppings, dirt, and soil, which can also attract pests such as ants.

Birds need more protein-rich foods instead of just fatty foods to feed their chicks, and at this time of year, fat will not provide chicks the nutrients they need to grow strong and healthy.

They will really appreciate mealworms at this time of year, as they are closer to their natural diet, as birds tend to collect insects to feed baby chicks.

Birds also like sunflower seeds, plain oats, chopped up apples and sultanas that have been soaked in water beforehand.

You can also feed birds small amounts of grated cheese and rice as long as they do not have any seasoning on them.

Just be careful and make sure to cut all the food into small pieces as large chunks are difficult for birds to swallow and can become a choking hazard for chicks.