Would you agree that the commoner something is, the more likely we are to overlook it? I've often thought about that for the Starling - it is only as their numbers have declined that I have really begun to appreciate what an amazing bird it is, from its star-spangled plumage to its incredible mimicry to its mega-group murmuration displays.

Perhaps the bird that has now occupied the space of the Starling in the 'so common we don't even notice it' category is the Wood Pigeon. While so much of nature is plummeting in numbers, the Wood Pigeon keeps on going from strength to strength. There are now thought to be over 5 million pairs breeding in the UK, and its population has risen by about 150% in the last 50 years.

Its population boom in the wider countryside is thought to be due to the massive increase in the planting of winter wheat (which is sown in autumn, germinates, and so carpets many fields in green throughout the winter) and oil-seed rape. The Wood Pigeon benefits because, unlike many seed-eating birds, it can switch quite happily to eating green leaves.

However, its increase in gardens is probably in part because it has become less fearful of us humans, now realising that we rarely pose it any threat within our gardens, and indeed taking advantage of many a bird feeder, or at least the seed spilt from it. I'm indebted to my Wood Pigeons for clearing up anything that the finches and tits might drop, helping ensure that my feeding areas remain rodent-free.

But what caught my eye in my Wood Pigeon garden-world this week was this:

It is an adult Wood Pigeon in the foreground, with its bold white neck-flash and pale eye ring, and three juveniles. There was another adult nearby, and they were clearly a family party. It would be easy to mistake the youngsters for Stock Doves, but in flight they would reveal the bold white crescent across each wing that is diagnostic of the Wood Pigeon.

I estimate that the youngsters had fledged from the nest maybe a week or so previously, and they clearly weren't very sure of themelves in this big, wild world. The parents weren't feeding them at all - that would have stopped when they left the nest. But the youngsters were shadowing the parents, watching to see what they were supposed to be doing.

Working backwards, the young would have been in the nest for about a month, and the eggs would have been laid about 17 days before that, so the mother would have laid the eggs in about mid September.

This is actually not unusual for Wood Pigeons. As a species, they have a very long breeding season, starting as early as February, with some nests still active right through to December. It doesn't mean that one pair will move tirelessly from one brood to the next over a 10-month period - many pairs will only raise one brood during the year. But this extended breeding season, with different pairs nesting at different times, may also help explain their success.

While these youngsters almost certainly came from a nest in my garden, they will have been very aware of large flocks of Wood Pigeons flying overhead in the last couple of weeks. A flock of about 400 flew over my house only this morning, and down here near the southern English coast, tens of thousands pass over in late autumn.

And the interesting thing is that we still don't know where they come from or where they're going. Although Wood Pigeons are migratory across much of Europe, there is little evidence that large numbers come to the UK from Europe, nor that our flocks ever cross The Channel heding southwards. It is a reminder that there are still things we don't know about even this most seemingly familiar of birds. Nature is ever fascinating in its mysteries.