A Swift, Where?

At this time of year I am looking to see the first swallow returning from the wintering grounds in Africa.  I find these brave little birds amazing and always look forward to their return.  The funny thing is I almost always hear the first swallow before I see it, they seem to delight in sitting on a roof top or electricity line and chattering their joy at coming home.  Though I don't consciously try I find my ears are tuned to any sound that approximates the chatter of a swallow, twice in the last few days I have started searching as a sound similar that of a swallow has caught my attention.  But that isn't what I want to tell of, I was in Carlton store unloading my truck when a bird sound caught my attention and it wasn't a swallow, it was the scream of a swift.  I couldn't believe my ears and started searching the sky for the author of the scream fully expecting to see the earliest arriving swift I have ever seen.  The scream was repeated, then repeated again, I finally located the source of the sound.  Just across the road sitting on a wire was a starling and as well as its usual song it was occasionally throwing in the scream of a swift  as a variation.  This isn't the first time I've been fooled by a starling but I've never heard one mimic a swift before, a duck and a magpie but never a swift.  I suspect that the bird was raised in a nest in close proximity to nesting swifts and had copied the sound as only a starling can.