Saturday, 31 January 2015

Our place in nature

There has been much discussion over the years about our place within the natural world; are we part of nature or apart from it? Some authors have suggested that while we were once part of the natural world, closely in tune with its shifting seasons and living within the landscape, we were separated once we became a predominantly urbanised society. Apart from a handful of ‘primitive’ communities still living within nature, deep in some South American rainforest, every other one of us has become removed (to varying degrees) from the natural world.

It is this removal, this act of seeing ourselves as standing apart from nature, that has driven our over-exploitation of the Earth’s natural resources. Divorced from the natural world we cannot comprehend the damage that we are doing; even when we are told about that damage it seems remote and intangible. Typing these words on this keyboard has a cost but I cannot see that cost; all I can see is the keyboard and the benefits that it brings to my daily life.

In some senses it could be argued that we are still part of nature; that our activities and the way they have changed the world are no different from what many other organisms are doing. The difference, and the thing that potentially does set us apart, is that we can comprehend the impacts that we are having. Understanding what we are doing and what the consequences of our actions are means that we have the option to do something about it. As individual organisms we can make a conscious choice not to exploit the Earth’s resources, to return to a position where we are closer to being part of nature.

It is at the level of society that this reconnection becomes difficult – some would say impossible – because society is driven by behaviours much stronger than those of the individual. Our consumer society has spiralled to levels where we are outstripping the resources available to us; yet we continue to see these resources as infinite. Societal change is needed but if it is to come it can only come from the individual or from nature herself, imposing on us a new way of living.

Friday, 30 January 2015

Challenging times for owls

2014 proved to be a particularly good year for barn owls, their breeding success in East Anglia well above average. Most of the volunteers monitoring barn owl nest box schemes reported high levels of box occupancy and large broods, reflecting the abundance of small mammal prey available.

Just how much of this success carries through into 2015 will very much depend on the availability of mice and voles over the next few weeks – that difficult late winter period when levels of owl mortality increase as the weather bites. The long growing season last year, with grass continuing to grow well into the autumn, will have benefited the herbivorous field voles and should mean that there are plenty of voles around for owls and the other predators who feed on them. The challenge will come from the weather.

Barn owls are surprisingly light birds, soft plumaged and poorly equipped to deal with difficult winter weather. High winds and heavy rain reduce the owl’s opportunities to hunt. Even if they can get out the noise of wind and rain can limit their ability to locate small mammal prey – barn owls have sensitive hearing and use this as their main means of locating prey moving about in the grassy swards over which they hunt.

Barn owls are able to catch voles through a light covering of snow but deep snow presents a real problem. Unable to detect and capture voles still active under snow a barn owl loses weight quickly and may die from starvation within just a few days. In response to deep snow cover a barn owl may move away from its usual foraging range to seek opportunities elsewhere. It may also switch to hunting other prey, notably small birds which may be taken from their roosts. Small birds are probably more of a challenge for a hunting owl, which lacks the speed and manoeuvrability of those raptors that specialise on such prey, and any shift in hunting range may expose the bird to roads and other hazards.

Daylight hunting may also become more evident at this time of the year, benefiting those of us who like to see the county’s barn owls, and it is worth keeping an eye out for these enigmatic birds.

Thursday, 29 January 2015

A taste of the Orient

First reported from the wild in Britain in 1945, the Chinese water deer is one of those introduced species that has stayed below the radar of those calling for the control and removal of such exotic imports. The reason for this is that we have not yet seen the development of any conservation problems associated with the species. Chinese water deer to not occur at the high densities that the introduced muntjac populations sometimes reach and there has only been occasional damage to agriculture, and none to forestry. Most of the established populations are still centred on the areas into which they initially escaped from captive collections and there has been only a very modest amount of expansion into new sites.

In Norfolk this small deer is most commonly encountered in the Broads, favouring reedbeds and the surrounding grazing marshes and farmland that provide feeding opportunities. Woodland habitats are also used and there is a preference for denser vegetation, which provides cover. Over recent years we have seen a gradual extension to the Chinese water deer’s range, with increasing numbers of records coming from the grazing marshes of the North Norfolk coast. Records from Titchwell and Sculthorpe Moor in the west of the county underline the distance travelled. There are very occasional inland records from the Brecks, perhaps the result of individuals escaping from a former wildlife collection.

At this time of the year, these small deer are readily seen around the Broads and south into the river marshes of the Yare Valley. In their thick winter coats they appear stocky but at other times of the year I think they seem rather scrawny and very different from the solid muntjac that are more commonly encountered. The adult males have a long and curving upper canine that protrudes as a ‘tusk’. Readily visible in the field it proves a useful feature for identification. These teeth are smaller in the females and do not protrude.

There are probably fewer than 5,000 of these Asian deer in England but it has been a while since the last attempt to survey their numbers. Indications of their presence mostly come from birdwatchers and from those individuals reported dead on the county’s roads, following collision with traffic.

Wednesday, 28 January 2015

A remarkable meal

Spend enough time watching wildlife and you will be guaranteed occasions that surprise, impress and delight you. Just the other day I chanced across one such occasion. Scanning across the marshes I picked out a heron struggling with an unusually large prey item. The bird was distant and the magnification of the binoculars insufficient to resolve what it was that the heron was struggling to swallow. Quickly setting up my telescope I was soon on the bird. Much to my amazement the heron was attempting to swallow a stoat, the rear two-thirds of which were hanging from the bird’s beak.

The stoat was dead, of that there was no question; the russet body and black-tipped tail hung limply, swinging pendulum-like as the heron attempted to reposition its prey. Over the following minutes the heron continued in its efforts to swallow the stoat, throwing its head back and pointing its bill skywards, as if seeking the aid of gravity to push the unfortunate mustelid further down its throat. Finally, after much effort, the last of the stoat slipped out of sight and the great bill closed.

This, however, was not the end of the struggle. The bulge of the stoat could be clearly seen in the throat and the heron again began to throw back its head. Such a large prey item was causing discomfort and the bird still had some way to go to get its meal further down the digestive tract. Moments of continued effort were followed by periods where the bird stood still, only the great bill opening and closing as if the heron was struggling to draw breath. Then, the act of swallowing still unfinished, the bird walked down the bank, into a drain and out of view.

Whether the heron had stumbled across the stoat, already dead, or whether the stoat had wandered unknowingly within range of the heron’s dagger-like beak, was unclear. I suspect the latter but whatever had happened prior to my arrival it was still a remarkable sight. Herons will take larger fish and they regularly take small birds and mammals but this was something that I’ve not seen mentioned in the literature. It was new to me and all the more astonishing for it.

Tuesday, 27 January 2015

The meadow at night

The recent weather has caused the river to overtop its banks and the depth of water now present on the meadow has greatly changed the dynamics of the site. Areas of exposed mud have been submerged and the geese that roost here are now spread over a much larger expanse of water. The higher ground remains dry, however, and the rabbits feed nervously on the short turf, ever alert to danger and to the stoats that hunt here.

The flooding has made movement around the site less easy and our nocturnal visits in search of snipe and woodcock more difficult. It is not so much the depth of the water, which is readily tackled in wellingtons, but that it has pushed these wintering waders into the tussocky swards where they are difficult to spot. Snipe are jumpy birds at the best of times and the squelchy of our approach, coupled with the agitated sounds coming from the roosting geese, prompts many to flush before we get close enough to pick them out in our torchlight.

These snipe are feeding rather than roosting, the latter a behaviour usually restricted to the daylight hours. There are two peaks in feeding activity. The first of these occurs during the early part of the night, the second just before dawn. With their long and probing bills, snipe are able to feed on a wide range of invertebrates, taking many beetle and fly larvae during the course of their nocturnal foraging. Snipe can increase their body weight by as much as 25% during the winter. This additional weight is added as a layer of fat that insulates the bird and provides a food reserve should the weather worsen and favoured feeding sites freeze over.

If the weather does deteriorate then the snipe will move south or southwest in search of more favourable conditions. Some will remain, however, seeking out the margins of streams and rivers, where the ground has yet to freeze. Vast numbers of snipe winter here, often overlooked, with many arriving from elsewhere within Europe. Wintering numbers mask conservation concerns about a declining breeding population and more research work is needed identify opportunities for improving the conservation status of these smart little birds.