Counting for conservation

It is at this time of the year that I get a chance to catch up with my field notes and pull together the records of birds, invertebrates and other creatures that need to be submitted to county recorders. Sharing wildlife notes in this way is an important task. Extracting records from notebooks that would otherwise sit on a bookshelf to make them available for researchers and conservationists helps turn a hobby into something with greater worth and purpose. Some of my records have already gone into recording systems that allow the data to flow straight through to the county recorders. My bird records, for example, are recorded through BirdTrack (www.birdtrack.net), a free online system operated by the BTO that I can use in the field through a smartphone app.

The winter months also provide an opportunity to reflect on the season and to place my observations into a wider context. 2014 was, for example, a year in which the breeding season started particularly early for many resident birds, but which was a poor year for many migrants, who returned in smaller numbers than usual. My records of nesting birds underline this, with many early clutches of blackbird, song thrush and (in particular) woodpigeon. In fact, I monitored more woodpigeon nests this year than I have ever done before, with the majority of these encountered much earlier in the season than I would normally find them.

In the case of insects, it is a more complicated story and it is clear that while spring and early summer were good, the late summer and autumn weather conditions rather curtailed the season for many species. It was noticeable, for example, that my late summer garden was rather lacking in both ladybirds and hoverflies this year, a pattern now being reported by other observers.

As well as looking back over the season just gone, I like to use the turning of the year to look forward. I can think about the projects that I want to focus on during the coming year and identify particular sites or species that I want to spend time looking at. It is also a good time to be making resolutions and there is plenty of opportunity for doing more for the natural world.

A reedbed for the night

The reeds jostle in the breeze, their dry stalks pale against the darker alders that fringe these lagoons. Stripped of the vibrant greens of summer the reedbeds appear lifeless. This, however, is a deception and instead they shelter many thousands of overwintering insects and a few still active flies, beetles and spiders. A scolding wren, one of several dozen heard here this morning, underlines the invertebrate life that remains available to insectivorous birds at this otherwise difficult time of the year.

While some of these wrens are local birds that have bred on the site, others have arrived from elsewhere. Being small, wrens lose body heat quickly and are unable to build up stores of fat to see them through the challenging winter months. This prompts them to move to those sites and habitats, such a reedbeds, where invertebrate food remains available throughout the winter.

So important is this access to food that the wrens establish winter territories, smaller than those used in the breeding season but still defended against other individuals. Many wrens will remain on these territories through into March when, with the approach of the breeding season, they will return to their former haunts. Holding a small territory at this time of the year secures access to both feeding and roosting opportunities, the wren becoming increasingly familiar with the resources available within its small patch of East Anglian reedbed. Competition for territories can be fierce and research has demonstrated that birds which fail to secure a winter territory tend to suffer increased levels of overwinter mortality.

Despite maintaining a winter territory, individual wrens may come together in late afternoon to share a roosting site. Communal roosting enables these small birds to share their warmth and reduce the amount of body heat lost during the long winter nights. Several dozen wrens may cram themselves into a nest box or other cavity, and I wonder to what extent the wrens wintering around these pools make use of the nest boxes we have erected here over the years. The mild start to the winter will certainly have benefitted the wrens but if it turns significantly colder then even here they are likely to struggle.

  

Spreading its wings

A familiar silhouette catches my eye as we drive down the muddy track that winds between the pools. ‘Harrier’ I call but Dave doesn’t quite catch the bird before it drops back below the treeline. He’s not sure; it could be something else and we stop the car to check. The bird soon reappears, drifting towards us in the early morning light, its wings held in a shallow ‘v’. It is a marsh harrier, long-winged and pale-headed, a young bird and one of only a handful of sightings from this inland site.

The presence of the harrier is an encouraging sign, reflecting a species whose population is increasing and whose breeding range now expanding. There are now more breeding marsh harriers in England than at any other time during the last two centuries but their history has been a mixed one. The marsh harrier seems to have been a familiar sight to the Norfolk naturalists writing in the mid-1800s. Lubbock, for example, writing in 1845, noted how every Norfolk pool of any extent had its pair, but numbers declined rapidly to leave just a single English pair at Horsey in 1911. The following decades saw a small recovery, but it was not until the 1980s that the breeding population began to grow and reached a size where the bird’s future as a breeding species no longer looked precarious.

The return of the marsh harrier to East Anglia has been dramatic, the increasing number of breeding pairs year on year revealing a remarkable change in fortunes. East Anglia has become the stronghold for the species within Britain and it is the Broads and north Norfolk’s coastal grazing marshes that support the greatest numbers. The harriers favour reedbed sites for nesting but have also taken to arable crops, such as wheat and oilseed rape, a preference that has opened up new opportunities for these birds.

I suspect that there might not be a sufficiently large reedbed to attract breeding harriers to the site we work but it is just possible that a pair might give it a go. We know that they breed not far from here and if nothing else we’d expect to see more harriers here over the coming years.

Cats and birds

The sodden remains of a blackbird make a forlorn sight on the gravel path. What is left of the carcass sits within a wider pool of damp feathers, most of which are contour feathers but here and there are wing feathers, the squared off ends to the quills revealing they have been bitten off rather than plucked. This evidence alone directs the finger of blame towards one of the neighbourhood cats, of which there are many. Throughout the course of the year I will find half a dozen or more such corpses and who knows how many other birds, amphibians and small mammals will have been taken and eaten elsewhere.

It is an odd thing that we tolerate this level of butchery of our wildlife, the nation’s cats the agents of death for many tens – or possibly hundreds – of thousands of wild creatures each year. Perhaps the excuse that ‘it is in their nature’ is one that we collectively accept. It doesn’t seem right though, that we allow our pets to decimate wildlife in this manner.

The sad thing is that we do not have the figures to properly establish the impact that cats might be having on wildlife populations already under pressure from other things. It is just possible that cat predation might not be having an impact on birds like house sparrow and blackbird, which are often taken. Birds die and are killed by many different things, some of which – like disease and starvation – may be linked to how many birds there are, through a process known as density dependence. Cat predation may simply be removing some of the birds that would die anyway but, equally, it could be adding to the problem. We do know that the level of predation by urban cats is sufficient to make some parts of our towns and cities unsustainable for small mammals like mice.

While there is a need for impartial science to tell us the real impact of cats there is an overwhelming moral case for us to accept responsibility for the actions of our cats. It might be in their nature to kill but it is we who allow it to happen by letting them have free run outside.

A Breckland flora

The soils and surface layer geology of the Breckland landscape are particularly interesting, having been shaped by the tundra-like conditions that existed here during the Devensian Glaciation. The underlying chalk is covered by varying depths of sand, and in places sand and chalk may sit alongside each other at the surface. Under the tundra-like conditions surface layers may have slid downhill, riding on a still frozen subsoil, while in other places the lower layers may have 'mushroomed' up following freezing and expansion. Add to these processes a climate that delivers high summer temperatures, low rainfall and frequent night-time frosts and you have conditions that deliver an interesting plant community.

The 'poor' Breckland soils kept agriculture at bay for many generations, the area dominated by heath and rough grazing up until fairly recently. The continuity of open habitat may have seen species like field southernwood survive here for more than 10,000 years but change did come; first with enclosure and the practise of marling  (using chalk dug locally to improve soil quality) and later with sheep, rabbit production, forestry and arable farming. The impacts of these changes have been dramatic, the area of Breckland heath and grassland declining from an estimated 29,000 hectares at the beginning of the last century to just 7,000 hectares today.

Thanks to recent funding, efforts are now underway to see the re-establishment of some of Breckland's rarest plant species. Species like the Breckland, spiked and fingered speedwells, the proliferous and maiden pinks, and Spanish catchfly may all benefit from the work that is planned. Much of this work is based around clearing the surface soil to expose the seed bank beneath, the success of this approach already being seen at sites like Cranwich Camp. While such 'landscaping' may seem heavy handed on first appearance, perhaps making site owners somewhat nervous, it is proving a powerful tool for the restoration of former plant communities. The plans to recover the lost Breckland flora should once again raise the botanical profile of this rather special area. With luck, many of those species now restricted to just a handful of sites will become a familiar sight to a new community of observers, each with a growing interest in Breckland’s botanical heritage.

A smudge of grey

A smudge of grey, ever so slightly darker than the flat tones of the fenland sky against which it moves, catches my eye above the peaty horizon. ‘Plovers’ I say but Lyn cannot pick them out at this distance; ‘I can’t see them, where are you looking?’ I point but it makes no difference. It is not until we are much closer, 30 seconds or so as the car speeds along the carriageway, that the smudge becomes a flock of individual birds and is now close enough for Lyn to see. ‘How did you manage to spot them at that distance?’ comes the question but I cannot answer. It is just something that I do; the birders sense of what is out there to be seen.

The birds are golden plovers, their identity now clear as they turn and pass through a shaft of sunlight that has forced its way between the heavy clouds. This is plover country and at this time of the year the fields provide feeding opportunities for these winter visitors. This is only a small flock, numbering fifty or so birds, but I have seen much bigger flocks out here in the fens in previous years. More often than not they may be seen feeding on the ground alongside lapwing and black-headed gulls but it is in flight that they most readily capture the imagination.

At the distance that I first spotted them they might have been a flock of one of these others species, but at the back of my mind I was already thinking ‘golden plover’. At times, when I have called distant flocks in this manner, my companions have sometimes accused me of conjuring the birds out of the air. The magic, if there is any to be found, is in knowing what might occur at a particular time and place and in being alert to the possibility of its presence. It is based on experience and is an important tool for the birdwatcher. Knowing what to look for is the starting point but familiarity with different species is what refines this base knowledge into something more tractable. If it gives the appearance of magic then it shows that I’m alert to the possibilities.