News for August 2000, From Spoonbills to Flycatchers

Bird On! News
31st July 2000

David Tomlinson

• Rainham Marshes - a new reserve for London
• A bittern success
• Where are the flycatchers
• Song thrush survival

NO one knows when spoonbills stopped nesting in Britain but most experts believe that at least 400 years have passed since these attractive birds last bred in the East Anglian fens. In recent years increasing numbers of spoonbills have been seen on freshwater marshes in eastern England, while in 1989 a pair did build a nest in Suffolk but no eggs were laid.

The spoonbills that visit us are all wanderers from Holland where there are several thriving colonies. There was a time in the 1960's when their future was in doubt but not any more. The Dutch spoonbill population has been growing in recent years thanks to protection both on the breeding grounds and the migration route to West Africa. The latter takes the birds through France, into northern Spain. Here they linger on the estuaries of the rivers Guernica and Bidasoa before moving south to the marshes of southern Spain and Portugal. Their next stop is Morocco before reaching their wintering grounds in Senegal.

Spoonbills may be regular migrants in Eastern England but they are rare visitors to Scotland. Thus there was considerable surprise earlier this summer when the RSPB announced that a pair of spoonbills had settled at its Mersehead nature reserve in Dumfries and Galloway. These birds have been displaying and nest building, raising hopes that they might stay and breed. If they do so, it would be the first record ever for Scotland.

I heard the news about the spoonbills the day after I came home from a visit to the Dutch island of Texel. Here there are several spoonbill colonies and I enjoyed many fine views of the birds during my stay on the island. The birds breed on the freshwater marshes but they feed in the tidal mud creeks of the adjoining Waddenzee. I suspect that the reason they have never bred at English east-coast reserves like Minsmere is because there is nothing like the Waddenzee close by. However, Mersehead is adjacent to the rich mud-flats of the Solway estuary, an area similar in many ways to the Waddenzee. There is a real chance that if they don't nest successfully this year at Mersehead, they might do so in years to come.

The RSPB is right to be proud of attracting the spoonbills to Mersehead as this superb reserve was, until recently, farmland. The RSPB recognised its potential and has turned it into a fine wetland reserve with areas of open water and reedbeds along with damp, grazed pastures that provide ideal conditions for wintering wildfowl. I last visited Mersehead in November a couple of years ago and was richly entertained by flocks of thousands of barnacle geese along with impressive numbers of wigeon, pintail, shoveler, teal and other wildfowl.

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Rainham Marshes - a new reserve for London

Whether the RSPB will able to do a similar conjuring trick with its latest acquisition, Rainham Marshes in the east of London, remains to be seen. The Society has just bought the marshes from the Ministry of Defence for £1.1 million, a purchase made possible thanks to donations from the public and various public bodies including English Nature. In addition, the Heritage Lottery Fun is to provide 50% of the final purchase cost. It's good to see lottery money being spent on something that is certain to be more lasting than the Dome.

For almost 100 years Rainham Marshes have been an MoD firing range; the area still contains unexploded ordnance so it will be some years before the public will be able to wander over this new reserve. Despite the MoD's activities, the marshes have retained something of their wildlife value with breeding redshanks and lapwings as well as good flocks of wintering wildfowl.

Conservationists have wanted to get control over Rainham Marshes for years - I visited the area back in the late 80's when there was a previous bid to make Rainham a nature reserve. I came away less than inspired for the marshes have huge land-fill rubbish dumps on either side while burnt-out cars and piles of rubbish scar the area. It is hardly the most promising site for a nature reserve and its only real value is that it is the last remnant of the once extensive inner Thames marshes. I concluded that the conservationists would do far better to spend their money elsewhere.

However, now that the RSPB has control of the area I wish it the best of luck in its bid to make it a valuable and worthwhile wetland reserve. I will follow progress with interest. Who knows, perhaps one day it will also attract nesting spoonbills.

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A bittern success

Bitterns are another reedbed bird that the RSPB will hope to attract to Rainham in the years ahead. Though this past breeding season has not been a good one for Britain's tiny bittern population, the first young bitterns for more than 50 years have fledged on the RSPB's North Warren nature reserve near Aldeburgh in Suffolk. The last time that bitterns are thought to have bred successfully at North Warren was back in 1946.

This success was thanks to habitat management on the reserve. According to Rob Macklin, the senior warden for the site, "A young bittern is a great reward for the most comprehensive reedbed restoration ever undertaken at an RSPB reserve". Ringing showed that the young bittern's father fledged from a nest at Minsmere in 1999. Three young bitterns hatched at North Warren, of which one is known to have died, while the fate of the third bird is uncertain.

Bitterns are one of the most specialised of birds as they depend on extensive reed beds for their survival. In contrast, spotted flycatchers are far more catholic in their choice of habitat, nesting in farmland, woodland and parkland, even in gardens. They have attempted to nest in my garden several times though they have only been successful once. In some ways it is a relief not to have them nesting as we go to great lengths not to disturb them and get worried about them whenever a magpie flies over.

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Where are the flycatchers?

This year, I haven't seen a single flycatcher in my garden, nor any in the village. Their scarcity is not surprising since according to the British Trust for Ornithology numbers have crashed by about 75% in the last 25 years. A once common garden bird has now become something of a rarity. This is a tragedy: though spotted flycatchers may not have either striking plumage or a beautiful voice, they are among the most confiding and entertaining of birds.

The BTO has been investigating the decline of the spotted flycatcher and discovered that there have been no differences in the breeding success of these birds in either different habitats or different parts of the countryside. Where the birds are suffering is in the first year of life; ringing has shown that there has been a 27% decline in survival rates. But though we now know why this species is declining, we don't yet know the cause. It may be something in this country or on the birds' wintering grounds in tropical Africa. Climate change could even be to blame. More work is needed before we discover the reason.

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Song thrush survival

While the BTO has been working on flycatchers, the RSPB has been investigating the crash in song thrush numbers in the last 30 years. A four-year study has shown that thrushes living in areas dominated by intensive agriculture are struggling to find enough food.

According to Dr Will Peach, RSPB research biologist:

"The biggest single cause seems to be the loss of favoured feeding habitats such as wet ditches, woodlands and damp grazed grassland. Song thrushes like to forage on soft damp ground where their favoured prey, such as snails, are abundant. But the destruction of hedges, ditches and woodlands, coupled with the drainage of formerly damp, marginal farmland, means that these birds are having real difficulty in finding enough food, particularly later in the summer when the countryside is at its driest."

I'm pleased to say that song thrushes seem to be doing well in my village, though this reflects the fact that rural garden areas now support more than 20 times more nesting song thrushes than arable farmland. We were entertained daily by the superb singing of our local song thrush until well into June. He has now fallen silent but we look forward to hearing him singing again towards the end of the year - I usually expect to hear thrushes singing around Remembrance Day in early November.

We did have a minor tragedy this spring when a fledgling song thrush killed itself by flying into one of the windows of the house. Ironically, almost all our windows carry transfers of birds of prey in a bid to avoid such collisions. Jacobi Jayne & Company sells warning silhouette transfers, and their unique Warning Web, which will help avoid such deaths.