One of the great delights of walking with wildlife in mind is the expectation of the unexpected. It’s a continual treasure hunt filled with familiarity of the regular encounters, the reassurance of seasonal returns and then, every now and again, something unexpected: a little find that rewards and, of course, reinvigorates the hunt (and the hunter!).

This winter, perhaps because of its mildness, I have encountered one of those little treasures so often that I have almost come to expect it. The treasure in question is a little bird called the stonechat - not much bigger than a wren but closer in lineage and behaviour to a robin. These little birds visit us in the winter and while they have very occasionally bred in Herts they are more often found in moorland and coastal scrub.

Unsurprisingly the birds that I have come across this winter have all been in areas of rough grassland and weed, with thick hedges and bramble patches not too far away for cover. My most recent encounter was of three birds as I cycled along a track next to the M25 near London Colney.

The grassy embankment below the motorway above me extended into a strip of rough grass and scrub that immediately had me scanning for stonechats. However it was not until I had got to the end of the section that I looked back and saw a little bird fly up onto a bush. I knew immediately it was a stonechat - even before raising my binoculars - simply because that is what stonechats do.

These little birds are a constant movement of short forays down to the ground followed by a quick flutter up to the nearest most prominent stalk or bush. Fences are ideal and stonechats will work their way along, down and up, down and up, snatching a grub or two off the ground and then returning to the fence post or wire. Their whole world exists in an imaginary four-foot high layer of airspace just above the ground - in this they will feed, breed and rest.

Only in the spring have I seen stonechats break this invisible ceiling and perch high on telegraph wires to sing their rattling but never the less musical tunes. The rest of the year they live up to their name, only issuing worried contact calls that sound just like two stones being scraped and tapped together - perhaps reminiscent of slipping scree on their moorland breeding grounds.

Stonechats, despite their size, are easy to see thanks to their constant movement and while they are wary of danger it is not the fear-filled panic of some birds. Rather, they maintain a measured adherence to a set distance from the observer of about 15 to 20 yards. Watching them you know they have clocked your presence but their down-and-up feeding routine does not miss a beat.

I am always reluctant to anthropomorphize but these little birds are cute and give off a friendly vibe. However many times I chance upon them I shall never tire of them. To me, they embody that subtle, unassuming part of nature that we can so easily overlook. They are little birds that have learnt to survive in the margins of our tidy world. If the M25 embankment had been mown they would not be there but as it is, the noisy motorway verge is too unattractive to us humans for it to warrant more than a cursory level of management.

As with so much of our wildlife, finding stonechats often requires that we first find a place that we, as humans, have overlooked or forgotten about. A place were, what the author Benedict Macdonald calls, our "ecological tidiness disorder" has not wreaked havoc. Maybe in the areas that we ourselves have control over, however small, we would do well to exercise an "ecological untidiness order" and ease the reins on mowing, flailing and tidying!

It should come as no surprise that areas where 'untidiness' has been deliberately maintained you have the best chance of finding stonechats - Heartwood Forest and Ellenbrook Fields are perhaps the best examples. In these places, treasure is still to be found, not least, stonechats!