Blackbirds like fruit.

There are 3 cherry trees in Granny's garden. But the cherries never get ripe because the blackbirds and crows come and eat them.
This year they let the gooseberries, blackcurrant and even the redcurrants get ripe and Granny picked quite a lot to make pies, stewed fruit and ice-cream, and fruit salad. The  berberis flowers had turned into berries, and the blackbirds were busy eating those. Then last week they decided to eat the redcurrants instead. And when Granny went out to get some they had all gone.