A singing Grasshopper Warbler
Have you heard a Grasshopper Warbler singing? Their song sounds like a fisherman's reel going out. Not everyone can hear this song, it is a high pitched sound and the whole body of the bird vibrates when it is singing.
Birds must use a lot of energy while they are singing. If they are using a lot of energy they will need to eat a lot of food, just another reason why birds are eating more from your garden during the early summer.
Do we need to feed the birds in the summer? The birds will tell you when they don't need the food they will stop coming for the food.