News for January 2001

Bird On! News
1st January 2001

DAVD TOMLINSON

• 25 years of Sea Eagles
• Hen harriers in trouble
• Floods across Britian

Could red kites be the commonest raptor in Britain by the middle of the 21st century? Ian Carter of English Nature made this somewhat remarkable prediction to me a few years ago. As Ian is the man co-ordinating the reintroduction of red kites to England he is in a better position than anyone to make such a statement, but even so such a forecast seemed improbable, to say the least. It no longer does so.

Last year, red kites reached their highest numbers in Britain for 150 years. There were 429 breeding pairs in England, Scotland and Wales. The Welsh population remains the largest, with 259 pairs, but England is fast catching up, with 131, while Scotland now has 39. Add in a considerable number of young, non-breeding birds and you can get some idea of the red kite's comeback. Just 12 years ago, there were a mere 54 breeding pairs of kites in Wales, and none in England or Scotland.

The first re-introduction attempts began in both England and Scotland in 1989, with the former using nestlings from Spain, the latter young birds from Sweden. The original introduction site in England was the Chilterns, and here the birds soon found conditions to their liking and started nesting. Average brood size was almost twice the size of the native Welsh kites, a reflection of the much better feeding conditions available in the Chilterns compared to the bleak Welsh uplands.

At first the existence of the kites in the Chilterns was kept quiet, and when I was first taken to the release site in 1991, I was sworn to secrecy. However, such was the success of the project that word soon got out, as red kites are among the most obvious of birds. Observant motorists spotted kites flying over the M40 motorway. Now it is almost impossible to travel along the Chilterns stretch of the M40 without seeing kites: I counted no fewer than 18 different birds the last time I drove along the road.

Following the success of the original introductions, further release sites have been used in the East Midlands, Yorkshire and Central Scotland. All have proved successful, for the red kite is a remarkably adaptable bird, which, if less unmolested, is able to flourish in the British countryside. However, kites are remarkably faithful to the area where they were hatched (or first released), so there is a trend for large populations to build up in these areas, and expansion and natural range extension into new regions to be rather slow.

However, though the kite reintroduction has been an unprecedented success, it has not been without its problems. During 2000, at least nine kites were found illegally poisoned, and it is estimated that well over 100 birds have suffered a similar fate during the last 10 years. Red kites are mainly carrion eaters, so are extremely vulnerable to poison baits, which are often put down (illegally) to kill foxes or crows. In addition, kites are vulnerable to secondary poisoning from scavenging rats that have been poisoned, and at least six nestlings died from secondary poisoning in 2000.

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25 years of Sea Eagles

While success came quickly to the red kite reintroduction project, the equally ambitious scheme to re-establish sea eagles in Scotland has had far more problems. It was in 1975 that the project began, with young birds taken from their eyries in Norway (where there is a healthy sea eagle population) and moved to the island of Rhum, in the Western Isles, for eventual release. This was traditional sea eagle country, for the last native birds had been shot on Skye in 1916.

It wasn't until 1985, 10 years after the project began, that the first wild-bred sea eagle chick fledged, though eggs had been laid two years before. Sea eagles are slow to mature, seldom breeding before they are six years old, while in a natural population, inexperienced young birds invariably mate with more experienced older birds that have bred before. It was this lack of experience in the released population that hampered the early breeding attempts.

There were other problems, too. Several eagles died from eating poisoned baits, while egg collectors also targeted the eagles. A further 59 young birds were imported from Norway during the period 1993-1998 to bolster the small numbers that had been established in the wild.

Now, at long last, it seems that sea eagle is firmly re-established in the Highlands. The first pair of wild-bred Scottish sea eagles reared a chick in 1995, while last spring there was an established population of 19 territorial pairs of eagles. Of these, 8 pairs successfully reared 12 young, bringing the total number of chicks to fledge since 1985 to exactly 100.

Visitors to the Western Isles now stand a very good chance of seeing a sea eagle, while last spring, a nesting pair on Skye could be viewed on CCTV at the nearby Aros Centre on the island. The nest was successful, and the chicks' maiden flight was even captured on film. On nearby Mull, viewing facilities were also set up at an eyrie, enabling visitors to watch the eagles at their nest from a hide.

The sea eagles is an impressive bird. The largest eagle to occur in Europe, it is the fourth biggest of the world's eagles, with a wingspan of up to 2.5m. An adult can be easily told from a golden eagle by its distinctive white tail, though this does not become pure white until the bird is at least six years old. In certain light the white tail gives a flying sea eagle an almost tail-less appearance.

For many years sea eagles were subject everywhere to intense persecution, and it is only recently that populations throughout northern Europe have started to expand. Sea eagles now breed once again in Denmark, and there are growing populations in Germany and Poland. Some of these birds wander west during the winter, and in recent years a few individuals have crossing the North Sea to reach southern England. This appears to be an increasing trend, so it might not be long before these impressive birds are regular wintering birds in southern East Anglia and Kent.

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Hen harriers in trouble

While prospect look good for both red kites and sea eagles, another of our native birds of prey is in trouble. According to the RSPB, the hen harrier looks likely to become extinct as a breeding bird in England. Last year, just five pairs nested successfully in England, though the Game Conservancy Trust believes that the English Uplands could support as many as 230 nesting pairs.

There is one reason for the harriers' demise - persecution. Hen harriers eat red grouse, which makes them unpopular with grouse-moor managers and gamekeepers. There is little doubt that it is the illegal, systematic shooting of adult birds and the destruction of nests that is responsible for the tiny nesting population of hen harriers in England. Hen harriers are simple to shoot, as they are bold in the defence of their nests. As the latter are built on the ground, they are easy to destroy, too.

However, the situation is highly complicated, and the answer is not straightforward. Upland conservation depends on the continuation of moor management for grouse shooting. Grouse moors are a valuable habitat for a number of other species, ranging from golden plovers and dunlins to merlins and short-eared owls. Once the shooting stops, moorland management invariably ceases, and the ground is either given over to sheep or forestry, neither of which support much diversity of nesting birds.

Thus it is essential to persuade grouse moor managers to tolerate a small population of nesting harriers. Quite how this can be achieved is the difficult question: it could be through grants, subsidies or some other financial incentives. It should also be acceptable for a quota of a certain number of pairs of harriers to be tolerated on a moor, and if the population rises above that, then the surplus birds to be persuaded to move elsewhere. Such an approach requires a radical rethink by both conservationists and shooting interests, but many people believe that such a compromise is the only way forward.

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Floods across Britain

Though floods spell disaster for man and his livestock, wildlife can cope with extremes of weather. The extensive floods that affected so much of Britain during October, November and December will certainly have had their impact on a small number of species, but the gains greatly outweigh the losses.

Deaths of birds and animals from storms are surprisingly rarely recorded. On Boxing Day last year, hurricane Lothar caused devastation on mainland Europe, destroying millions of trees on an extraordinarily broad front. Softwoods were snapped in half like matchsticks, while hard woods were blown out of the ground. There were parallels with own Great Storm of October 1987, but the damage to both property and forestry was far greater.

I visited France shortly after the storm. In the wooded hills of the Argonne (where the famous beech woods suffered as much as 98% destruction), I was told an interesting story. Shortly before the storm struck, local people noticed roe, red deer and wild boar moving out of the forests into the surrounding fields, as if they had some premonition of the disaster that was about to strike. We do know that animals are sensitive to atmospheric pressure. Presumably these animals sensed danger, and instinctively moved out of the woods, saving many from certain death. Relatively few large animals were found killed by fallen trees.

There were no similar stories from Britain during the recent storms, but nor were there any reports of significant wildlife casualties. All our wild animals are capable swimmers, even such unlikely species as hedgehogs, and while sudden rises in water level must affect (and probably drown) ground-dwelling species such as voles and mice, the majority do survive.

According to Alasdair Bright of the RSPB, "the Society does not see autumn and winter floods as a threat to birds". The only species thought likely to have been inconvenienced by the recent floods was the barn owl, as low-lying pastures and water meadows are a favourite hunting ground of this species. However, barn owls are sufficiently adaptable to move to higher ground, where it is likely that hunting displaced rodents is made easier.

All of our wintering wildfowl and waders appreciate floods, as it opens up new feeding areas. The RSPB struggles to keep many of its reserves (such as West Sedgemoor, on the Somerset Levels) wet, or flooded, throughout the winter, so the early flooding has been a bonus that has been widely appreciated by the flocks of teal, wigeon, golden plover and lapwing.

It is only in the last two or three decades that our wintering wild swans started feeding on agricultural land. They like nothing better than flooded pastures, and relish cleaning up rotting potatoes or other abandoned crops, so the floods will have helped them, too.

If future flooding is to be avoided, then it is vital that we adopt a new approach to flood control that does not, in the RSPB's words, depend on driving every drop of rain down the drains and out to sea as quickly as possible. According to Sarah Fowler, the Society's head of water policy, the solution is the creation of permanent wetlands in rural floodplains, created and designed to capture rainfall. Such wetlands would not only help reduce flooding, but also filter out pollutants to clean up water, and recharge underground acquifers. They would also make fine wildlife habitat all year round.

Similar systems are already employed on the Continent. Historically, Paris was highly vulnerable to flooding following heavy rainfall in the headwaters of the rivers Marne and Seine. The solution was the creation, some 30 years ago, of two enormous water-storage reservoirs in Champagne, the Lac de Der-Chantecoq, which takes flood water from the Marne, and the Lac de La Foret d'Orient, which takes flood water from the Seine.

These two reservoirs have become extremely important for migratory birds. In early November, some 40,000 cranes pause at Chantecoq before continuing their migration to Spain, and the same birds call in again on their spring passage. As many as 4,000 cranes now winter in the area, something that was unheard of before the reservoirs were constructed. Both reservoirs attract important numbers of wintering wildfowl, while white-tailed eagles over-winter.

In late autumn the water levels are extremely low, but as soon as the Marne or Seine threaten to flood, the excess water is siphoned off into the reservoirs. Spring water levels are usually high, and this water is retained during the summer, for these lakes are as popular with holidaymakers in the summer as they are with birds in the winter. At the end of the summer the water levels are allowed to fall once again, to allow for the winter floods.

Flood prevention schemes may be expensive, but the cost of flooding is considerably greater. If we want to prevent future floods, then we should be planning our flood-plain reservoirs now. Ironically, an EU-funded project, the Wise Use of Floodplains, is currently working in five areas across Britain, investigating how the creation of rural wetlands will help prevent flooding. Recent weeks have shown that this project should be given the highest priority.