So when I spotted a smallish bird with the same colouring but without the dark feathers, sitting quite happily on a garden bench, I wondered what the hell I had found. I was worried not only about cats (we are on the end of a route taken by several neighbourhood cats and as the main road is next, they return they way they came); but also because we have lost several birds to sparrowhawks. I know raptors are glorious - but not when they take another bird in front of me. Anyway, I kept my eye on the one on the bench. He seemed to disappear about 8pm and reappear around 7 am for about a week. Sometimes two adults would join him - and appeared to be showing him how to stretch his wings..... and I still never caught on!! Then I saw the article in the paper an appeal from the RSPB (Royal Society for the Protection of Birds) - part of which I reproduce here, for interest, information, and general edification!
Just before baby birds are ready to tentatively extend a wing, wiggle a tail feather and take flight for the first time, they leave their nest - "fledge" as it's called. They then spend a couple of days on the ground and round the nest developing their final flight feathers. The fledglings will appear fully feathered, and will hop around your garden in broad daylight - hence why members of the public are convinced they need rescuing. Fledglings are extremely unlikely to be abandoned. The parent birds are either gathering food, or more probably nearby with a beady eye on their youngster waiting for you to leave. They know best about rearing their young. Removing a fledgling from the wild (or your garden) significantly reduces it's chances of long time survival, so please don't "kidnap" the baby, even in a well-meaning way. There are only a couple of situations when the public should give a helping hand. If the bird is found on a busy road or pathway, pick it up (carefully) and move it a short distance to a safer place. It must be within hearing distance of where it was found.
Similarly, if you find your cat or dog eyeing up a fledgling, keep the animal in for a couple of days (or the dog on a lead). If you find an injured fledgling, contact (in the UK) the RSPCA. You might phone your local vet as they do sometimes treat wild birds for free.
Finally, if you discover a baby bird on the ground either with no feathers or covered only with a little coat of "down", it has likely fallen out of the nest ahead of schedule. Occasionally it is possible to put these babies back in the nest, but only if you are 100% sure of the nest it fell out of.
So now you know. Why, at my age, didn't I know how fledglings behaved? We have at least two sets of nesting blackbirds in our hedges every year, and at some point there is always a lot of running up and down the grass and bobbing up and down with several of them at once. Now I know that they are using our grass for take-off practice! Keep your eyes open now, you may come across a fledgling for the first time.