The odd pair

[Primrose]

For over a week now a young starling has been trailing after a parenting blackbird in and around our garden. The youngster now seems capable of feeding itself and doesn't appear to be part of the two flocks of young starlings which regularly arrive to feed. For some strange reason seems to think it has to stay close to the blackbird and occasionally goes up to it begging for food. The blackbird ignores it but when it flies off with food in its beak, the starling follows. And whenever the blackbird returns to the bird table, baby starling comes too. I've never previously known a case of a bird from a different species latching on to another one like this. It's quite comical to watch but can anybody suggest why this would be happening.