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.

  

Island Life

There is something romantic about island life and about being cut-off from the mainland and its ways. It is a feeling that is hard to describe, not least in terms of its origins, but I wonder if the feeling stems from having to look inward rather than outward. By focussing on the routine of island living you are freed from the unnecessary adornments of a globalised society, able to concentrate on the local and the present.

I find the feeling strongest on small, barely habited, islands, particularly those scattered along our western seaboard: from the Hebrides in the north to Flat Holm in the south. Even Flat Holm, a ten-minute sprint by rib from Cardiff Bay, shares the sense of comfortable isolation. Situated in the middle of the Bristol Channel and barely 500m wide at its longest point, the island and its scatter of buildings has a long history of use. In this time of economic belt-tightening, Flat Holm’s future has become uncertain; the council landowners allegedly keen to jettison their responsibilities for the island and its heritage. The ruins of a cholera hospital, of a naval garrison and of a Victorian rainwater collection system are testament to changing uses down through the years. Like many of our marginal islands, Flat Holm has been both protector and nurse to previous generations.

It is also a seabird island. Too far up the Bristol Channel to attract nesting auks or shags, the island is instead home to a colony of some 4,000 lesser black-backed gulls, fewer herring gulls, a pair of ravens and a pair of cliff nesting peregrines. A few pairs of woodpigeons breed in some low elder woodland, but these get hammered by the peregrines, while blackbird, dunnock, wren and two species of pipit just about make up the avian community.

Other islands may differ in their communities – Steep Holm, the neighbouring island to Flat Holm, has cormorants and, bizarrely, muntjac deer (an introduction) – but they share the same sense of ease. Of course, the realities of living year-round on a small island will be very different from the few days I get to spend on my trips. Even so, I suspect it would prove to be a rewarding way in which to live.

A flurry of brown

With a whir of rust-coloured wings, a small bundle of brown can be seen flying between a scruffy, moss-covered stump and a thick column of ivy that clings to the trunk of a nearby Sycamore. The bird makes the trip several times, each time returning from the stump with a beak full of moss. This is a male Wren and he is busy building a nest to which he hopes to attract a mate.

The nest itself is soon discovered by watching the bird, a growing pile of moss pressed against the trunk and held in place by the mass of ivy tendrils and leaves within which it is placed. It looks as if much of the main structure has been completed, the bird now working on the top of what will become a neatly domed structure. The material around the entrance hole will be particularly tightly woven, allowing the bird to create a slight overhang, which affords the nest contents that little bit extra in the way of protection.

This is unlikely to be the only nest that this male will build over the coming weeks, since males construct a number of ‘cock’ nests, only one of which will secure the female’s approval. The favoured nest will be finished off with a lining of feathers. Some cock nests can appear a little rushed and are poorly constructed, giving the impression that the male is simply going through the motions – or it might be that the female has already selected another nest and he abandons the attempt mid-build. Most, however, are well built and look just like a finished and occupied nest, meaning that you cannot tell if a nest is active until you place a finger (or endoscope) inside and discover the soft lining. Even those nests that appear unused later into the season may suddenly come good, perhaps used for a second clutch or, in some instances, where the male takes on another mate.

Like most birds, it is during the period when building that Wrens are sensitive to disturbance. At this stage they have invested little in the breeding attempt and the cost of starting again somewhere else is low. For this reason, I will simply note the location of this nest from a distance, returning in a few weeks time to make a proper check. In the meantime I will return over the coming days to see if I can spot this particular male building other nests within his territory. He should be obvious enough, although this piece of damp woodland supports many male Wrens and it is not always that easy to work out where one breeding territory stops and the next begins.

What's in a name

I have been leafing through the new edition of my favoured bird guide, a publication that will accompany me on my birdwatching trips around the county. I hope that it will serve me as well as the battered copy of the first edition that it is now replacing. The book contains new information and so recognises new species, created where previously recognised races have been split into two. So now, for example, I have Yellow-legged and Caspian Gull. Annoyingly, for me at least, the guide contains some of the creeping changes in bird names that seems to come from an increasing Americanisation of our language. Gone are the Red-throated, Black-throated and Great Northern Divers, the ‘Diver’ now replaced by ‘Loon’. I cannot imagine any birdwatcher I know referring to the ‘Great Northern Loon’ at Whittlingham Country Park. At least the authors have not gone as far as those of a bird list that I saw recently; they’d replaced Common Gull with ‘Mew Gull’ and the term ‘Skua’ with ‘Jaeger’!

Somebody suggested that standardising the English names in this way is a sensible approach, enabling our New World cousins to understand which species we are writing or talking about. My natural response to this is that we already have names in place that enable those working on birds, in whichever country, to understand which species we mean. These are the Scientific names, based on the binomial system devised by Linnaeus.

Of course, such changes are not new and if you browse through bird guides from generations past, you will see many other examples of bird names that have changed. The Yellow Bunting of 1943 is now the Yellowhammer, the Hedge Sparrow is now Dunnock or Hedge Accentor and, going back further, the Red-breast is now the Robin. This last change of name is particularly interesting as the ‘Robin’ bit in ‘Robin Red-breast’ was a sort of country or folk name, in much the same way as some people refer to ‘Jenny Wren’. Imagine if we started calling the Wren, the ‘Jenny’!

I am often struck by how much more charm there is in the local names of birds than in many of the common names that we use at the national level. The ‘bee bird’ for Spotted Flycatcher is one of my favourite local Norfolk names but there are others: Bunt Lark (Corn Bunting), Blood Olp (Bullfinch – derived from ‘alpe’, the oldest known name for this bird and used by Chaucer) and the Sea Dotterel (Turnstone) are just three of many.

Whatever your views, names remain important because they enable us to communicate about these creatures and share our passions for the natural world.

Has the cold weather hit our Wrens?

There is a chill to these bright mornings, the clear skies overnight allowing the mercury to dip below zero and delivering a brushstroke of silver frost to the short heathland turf. Even so, such bright mornings bring with them the hope of spring, lifting my spirits, and it feels good to be out at such an hour. The change of season appears to be having a similar effect on many of the woodland creatures, including the birds, and the ranks of conifers echo with bird song. The Robins have been singing right through the bleak days of winter but now their wistful song has a more strident tone. Blackbirds too, are delivering a purposeful chorus and many pairs will have already started to build nests or lay eggs.

There are other singers; the thrice-repeated call of the Song Thrush strongly sung, the ‘teacher-teacher’ of the Great Tit and, here and there, the less often heard songs of Siskin and Crossbill. What is missing, however, is one particular component of this early season orchestra – that delivered by one of our smallest songsters. In recent years, this part of the forest has been alive with the metallic ringing trills of the Wren. This species has fared well over recent years because of a run of mild winters and I fear that this year’s cold snap may have hit the Wren hard.

The Wren is one of our most numerous breeding birds but its numbers can fluctuate quite dramatically from one year to the next if the winter weather goes against it. The severe winter of 1962/63, for instance, resulted in an 80% decline in the breeding population nationally the following year. Another study, carried out in a Nottinghamshire woodland, saw virtually the entire adult breeding population lost after the very cold winter of 1985/86. In both cases, it took several years for the breeding population to recover to former levels.

While the most recent winter may not have been as severe or long-lasting as these, it might have been sufficient to reduce the number of Wren territories locally. One other characteristic impact of a cold winter on the Wren population is a noticeable change in habitat preferences. In the year that follows a cold winter, breeding Wrens are often absent from formerly favoured hedgerow and garden habitats. Those territories that remain occupied tend to be in woodland or alongside riparian habitats, suggesting that woodland is a high quality habitat, while hedgerows and gardens are less suitable and the last to be filled with breeding birds. We will have to see what long-term monitoring programmes, such as the BTO’s Breeding Bird Survey, reveal later in the year. Have our Wrens been hit by the cold?