Kestrel no longer so commonplace

Writing in early 1917 and far from home, the poet Edward Thomas noted how the sight of four or five planes ‘weaving and wheeling overhead’ reminded him of the kestrels that he used to see over the Shoulder of Mutton Hill near Petersfield. Such recollections rekindle my own memories of days spent near Petersfield and of the kestrels that would haunt the skies, scanning the ground below for small mammal prey.

Throughout my childhood the kestrel was regarded as our most commonly seen bird of prey, a familiar species that I was certain to see from a car journey of any distance. Long-term monitoring data from the British Trust for Ornithology (BTO) support this, showing the kestrel population of the mid-1970s to have recovered from the effects of organochlorine pesticides and to be at a peak not since matched. This peak was, however, short-lived and there was a substantial decline over the following decade, which left numbers well below the level that had been achieved. This new decline has been driven by a period of agricultural intensification that left our farmland much changed. The loss of many thousands of miles of hedgerows and field margins brought about a decline in the numbers of small mammals and large invertebrates upon which our kestrels depend.

We are not alone in having lost so many kestrels; it is a pattern repeated more widely across Western Europe, underlining how the changing demands we have for cheap food, produced in ever increasing quantities, have changed the landscape fundamentally. With less space for wildlife it is inevitable that those species at the top of the food chain will show pronounced changes in their numbers and abundance. The pattern of change seen in our kestrel populations shows some regional variation; for example, the species benefited during the period of afforestation, where many hundreds of hectares of coniferous plantation were established. However, as these new forests developed so they shaded out the swards of rough grassland between their ranks and with this loss went the field voles and their kestrel predators. The kestrel remains common enough to remain familiar and to haunt the texts of today’s nature writers. Let’s hope it remains a living part of our countryside and not one consigned to our literary heritage.

Kestrel springs a surprise

I was a little taken aback the other morning when a Kestrel flew up from beside the gravel drive that marks the entrance to the British Trust for Ornithology’s (BTO) offices in Thetford. Although I have seen them occasionally from the BTO grounds, it has been many years since they nested here and could be seen hunting and feeding alongside the 12^th Century ruins with which we share the site.

This particular bird flew a short distance to land in one of the trees that mark the boundary of the grounds. Favouring a perch that was in part shadow, the Kestrel had something in its talons that it had clearly just taken from the ground. My immediate thought was that the bird had caught one of the Wood Mice or Bank Voles which do well here, but closer inspection through my binoculars revealed that it had, instead, caught a rather sizeable earthworm. Kestrels are opportunistic enough in their habits to take a range of prey species, from small mammals and birds through to reptiles and various invertebrates.

That Kestrels will take worms may surprise some readers; perhaps it is because these soil-dwelling invertebrates seem so inconsequential, hardly worth eating because of their small size and a belly full of decaying plant material. Yet earthworms feature in the diets of many larger birds: Common Buzzard and Tawny Owl being two species that spring to mind. Tawny Owls take earthworms on damp nights, when the worms venture from the safety of their burrows to search for a mate or for fallen leaves to be dragged back underground.

The appearance of earthworms in Kestrel diets has a strong seasonal component, with early spring the period when they are most likely to feature. In part this highlights a scarcity of the favoured small mammal prey at this time of the year but it also reflects an increase in the availability of earthworms, which tend to be more surface active when the ground is waterlogged. As you might expect, Kestrel diet varies with region. Those Kestrels breeding in the upland fringes of northern Britain take a lot of small mammals (mostly voles) with some earthworms and small birds. Those breeding in the warmer climes of southern Europe tend to take more birds, lizards and larger invertebrates. Such differences underline the adaptability of this bird, a hunter that will take whatever prey happens to be locally abundant.

It didn’t take long for the Kestrel to finish off the worm before slipping from its perch in a short glide. It was only the briefest of encounters but it was one that made an impression, one of those moments when you get a real sense of nature at work.

A winter walk

The wind has dropped but clear skies overnight mean that the air carries a sharp chill and my breath clouds as I exhale. It is a fine day for a walk; the quality of the light, filtered through a brilliant blue sky, reveals every fold in the landscape and the bare limbs and branches of trees stand strong in silhouette. Crossing fields of grazed pasture, bordered by old hedgerows and occasional twisted oaks, my passing is heralded by a pair of Egyptian geese – soon to be nesting in a suitably large cavity. A flock of fieldfares, perhaps three dozen strong, chatters quietly as it moves across the short turf in search of invertebrate prey. There has been just the merest touch of frost, so the fieldfares should still be able to probe the ground.

Leaving the farmland behind I enter an area of clear fell. Now in their second year of growth, the young conifers can be seen fighting their way up through the early successional plants quick to exploit the bare soil. As I cross diagonally through the regimented lines I disturb a roe deer – a buck in his thick winter coat. He moves away but then turns to watch me, inquisitive but alert. This seems to be a feature of the roe. This buck is in velvet, his antlers sheathed in blood-rich tissue which will remain in place through into March. In adult males this annual cycle of renewal begins late in the year (from October) but starts somewhat later in young bucks. With his curiosity satisfied the roe moves off and I am alone again, save for the solitary crow that sits calling from an isolated beech.

A little further on, and warmed by my exertions and the strengthening sun, I catch sight of a kestrel. It passes low over the trees in a neighbouring block of plantation before dipping down to work one of the snag lines of twisted root plates left in place when the last block of timber was harvested. The kestrel flushes a flock of 40 or so goldfinches but seems to take no interest in them. The goldfinches rise as one to perch in a nearby birch, their delicate calls resonant like tiny chimes. It is not that often that I see so many goldfinches together and they add a splash of colour to the brown and russet tones of the forest backdrop.

It is on mornings such as this that I really appreciate being out doors in the Norfolk landscape. It may be winter but it is a fine and bright winter, with enough of the sun’s warmth creeping through to suggest that spring is not that far away.

Front row seat for a Norfolk spectacle

The raised earthen bank at Stubb Mill, Hickling, may seem an unlikely place from which to watch for birds of prey and other wildlife. Scrub, reeds and rough grassland stretch away into the distance and on a cold winter’s afternoon it can all seem rather bleak, not to mention cold. However, at this time of the year the watchpoint provides an excellent opportunity for viewing harriers, merlin and common crane as the birds come in to roost just before dusk. With very little shelter from the elements, the watchpoint is best visited on a bright afternoon. The birds will still arrive in the rain but tend to hunker down quite quickly and, with poor light, there is not much of a spectacle. However, in the good light of a bright December afternoon, you may be spoilt by views of hunting harriers or of merlin and Sparrowhawk mobbing their larger cousins. There is even the chance of seeing a short-eared owl or peregrine.

Most observers tend to arrive an hour or so before dusk but I prefer to arrive well before this. One of the reasons for arriving so early is to be able to watch Chinese water deer in good light. This introduced species has established a sizeable population within the county, centred on the Broads, but seemingly spreading north and west to other sites. Most of the Chinese water deer that I encounter elsewhere within the county are either ones that have been killed in collision with motorcars or are brief glimpses of live individuals disappearing into thick vegetation. Stubb Mill has proved to be one of the best places to get good views of these small deer, perhaps because you are sitting on a bank looking down on the surrounding habitat. Slightly larger in size than a muntjac, the Chinese water deer reminds me of a roe deer in its posture and movements, though smaller in size. First introduced at Woburn Park in the early 1900s, several established populations occur in Bedfordshire, Cambridgeshire and Norfolk where they favour mixed reedbed and woodland habitats. They are cautious animals and if alarmed will run off, flinging up their hind legs as they go.

Perhaps I have been fortunate in my visits to Stubb Mill. Each time I have been treated to close views of the deer, followed by the spectacle of hen and marsh harriers quartering the ground or loafing about in scrub. These have been accompanied by views of kestrel, sparrowhawk and merlin on virtually every occasion, with the whole afternoon often rounded off by the arrival of the local cranes. Having so many special birds and animals in one place makes this a site that everyone interested in Norfolk’s wildlife should visit at least once.