Homeowners who enjoy seeing and feeding birds in their gardens are being cautioned about the potential dangers of putting out a seemingly harmless common type of food, particularly during the summer months. The Royal Society for the Protection of Birds (RSPB) has issued a stark warning to bird lovers, advising them to think twice before offering fat balls or suet balls to birds during the hotter periods.

It comes as the Met Office predicts a rise in temperatures in the days ahead. As the first yellow heat-health alert of 2025 has been announced for four English regions, caution is paramount. The alert covers the East of England, East Midlands, London, and South East regions.

While winter bird feeding is encouraged to aid their survival in the cold winter months, the RSPB urges garden owners to be mindful of their offerings in warm weather. Those who are used to putting out fat balls should be particularly mindful of this advice, reports Wales Online.

In the warmer spring and summer seasons, the RSPB says that "birds require high-protein foods, especially while they’re moulting. Be careful with peanuts, fat and bread during spring and summer. If you want to feed peanuts, only do so in rigid mesh feeders that will not allow sizeable pieces to be removed, since these could be a choking hazard to chicks."

The organisation warns against using homemade fat balls in bird feeders. It adds: "Home-made fat balls can melt in warm summer weather, and should be avoided."

Instead, it suggests suet-based substitutes that can better withstand heat. Fat balls can be a fantastic energy boost for our feathered friends, but they're not without their perils, particularly during hot weather.

Fatty treats, especially homemade, are known for turning into a greasy mess when temperatures rise. This can leave birds in an awful sticky situation, as the fat can get stuck in their feathers, causing them issues when flying.

Fat balls can pose a danger to birds during the summer months because of the risk of spoilage and the potential harm they can cause. In hot weather, these fat balls may melt, turn rancid, and serve as breeding grounds for harmful bacteria, which can lead to illness in birds.

Research shows that while certain birds thrive on fatty snacks, others might actually find their reproductive success compromised by such readily available feasts. Fat balls can inadvertently act as a choking hazard for the unsuspecting chicks, especially during nesting season.

As temperatures climb during summer, fat balls are prone to spoiling and playing host to all manner of unwelcome guests – including unwanted pests. When fat is melted or softened, it can turn into a breeding ground for bacteria, potentially leading to illness in birds.

There is also the risk of the Usutu virus. First detected on British shores in 2020, this mosquito-transferred disease has been wreaking havoc among blackbirds, leading to notable dips in their numbers. On the watchlist of worrying wildlife illnesses, Usutu is flagged as 'notifiable', which indicates that although it is not a specific virus name, it represents a virus of concern, similar to various other diseases affecting animals or humans.

It's recommended to restrict the use of fat balls during warmer months, as they're more likely to melt. Opt for high-quality fat balls made with premium ingredients that can withstand outdoor conditions.

To attract a wider variety of bird species, it's best to offer an assortment of food options, such as seeds, nuts, berries, and insects.

What do birds eat?

The RSPB suggests that many birds will happily consume a diverse range of foods. Here are some of the organisation's top tips for feeding birds:

• Blackbirds primarily feed on the ground and will consume a wide variety of foods, from suet pellets to mealworms.
• Blue Tits and Great Tits utilise a feeder, eating seeds as well as suet and peanuts.
• Finches, including Chaffinches and Greenfinches, also use a feeder, and they have a particular fondness for sunflower hearts.
• If you're eager to attract Goldfinches or Siskins, try Nyjer seeds as they both seem to adore them. Nyjer seed is also popular with Greenfinches and Redpolls.
• House Sparrows, Dunnocks and Collared Doves prefer to feed on the ground and will be attracted by small seeds.
• Suet balls and other fat-based food bars are excellent sources of high energy for winter and are popular with a wide range of birds.
• Mealworms are especially favoured by Robins and Blue Tits and may attract other insect-eating birds such as Pied Wagtails.

Ensure to look for good quality bird food – those that don't include 'fillers' such as dried peas, beans, and whole wheat that birds rarely eat.

Leftovers such as dried fruit, apples and pears can be put out for birds, but avoid anything mouldy or salty. If you have a dog, refrain from putting out dried fruit – vine fruits like raisins can be toxic to them.

Where should bird feeders be placed?

Bird feeders can be set up in various locations, but it's best to choose a quiet spot where birds won't feel disturbed. Aim for an area away from bushes where predators might hide, yet close enough to cover for birds to quickly escape if needed, as they prefer to eat with a clear view of their surroundings.

Try to position feeders in sheltered areas protected from strong winds. Regardless of where you hang your feeder, ensure it's visible from indoors so you can enjoy watching the birds.

Remember, it may take some time for birds to get used to a new feeder, so don't be disheartened if you don't see many birds initially.