Just as in winter, high-energy food is the key to summer feeding. Live food is also recommended as it allows the adult birds to supplement the food they can find in the wild for their chicks, and also helps replenish their own low energy levels. It's best if you can avoid foods that might melt in hot weather, such as products containing lots of fat.
Peanuts used to be the staple item on our bird feeding menu, but the increase in alternatives such as sunflower hearts means we now have a greater choice. Peanuts might spread aflatoxin, a fungal infection that can be lethal to birds. Check the pack before you buy to make sure the nuts have been tested for aflatoxin. Whatever you do, never put out nuts intended for human consumption, because they contain dangerous levels of salt.