What to Feed Them
Now, it's important to remember the significance of the breeding season. Over winter you can throw out whatever food you like and the birds will merrily peck it up, but in the spring there are children to think of!
Usually, birds will frequent feeders less as long as there are plenty of invertebrates lounging around for feeding. They'll be able to sustain themselves easily and return to the nest to feed their children. Now, if the weather turns and creates a food shortage you may find yourself seeing many more visits from mature birds. The risk is they'll not only use the feeder for themselves, but take food back to the nest. Fat, bread hunks, and large dry foods like peanuts can easily choke an infant bird.
Hand out high protein foods, including grated cheese, black sunflower seeds, mealworms and raisins. Sliced fruit such as apples and pears also respond well.
Keep One Eye on the Weather
At least in the winter you know what you're getting. It's going to be cold, and birds will need feeding. In the spring weather varies a lot more. For the most part food will be abundant and you can leave out minimal amounts, but a change in the weather can quickly result in food shortages. For insect-eaters, a bout of extremely wet weather will cut down their food source substantially, and you might want to leave out a few snacks appropriate to the species. A lengthy drought will harden the ground, and remove access to earthworms, a sizable loss for birds attempting to feed their young.
It's incredibly different for humans to detect a food shortage. Rather than adjusting your feeding practices dramatically just keep track of your local visitors' frequency. If they're coming with regularity it may indicate an immediate food shortage, so be sure you're not leaving out feed inappropriate for their young.
Keep it Clean
Unlike the winter, you're likely to see a much slower turnover of feed. Keep your unused seed in a metal container to keep it from spoiling, and consider investing in a covered feeder for the garden. The combination of rain and heat can quickly create mould and disease in your seed, and you don't want to be responsible for any health problems.
There'll be more wastage, so try to keep the amount of feed out at any one time to a minimum. Clear up the debris left on the feeder or grass, as well. Hardily shelled black-oil sunflower seeds will slowly kill your grass, though fruit and sunflower chips will spoil extremely quickly. Try and give the feeder a healthy scrub around once a week, perhaps more.