How RSPB conservation scientists are battling to protect our wading birds before it's too late
The UK's wading birds are in deep water.
Breeding numbers of many species have crashed in the wake of massive habitat loss. Now they face a further threat – from thriving predators.
The lapwing population fell 65 per cent between 1970 and 2013. Redshank numbers dropped 45 per cent between 1995 and 2013. Only 40 or so breeding pairs of black-tailed godwits remain. The figures make for depressing reading for anyone who values biodiversity.
“Historically, the long-term declines that we’ve seen have been largely related to habitat – the complete loss of habitat in some cases, such as grasslands and wetlands being turned into arable,” explains Dr Jennifer Smart, principal conservation scientist with the RSPB.
“More recently though, we believe that now the populations are vastly reduced what’s holding them at lower levels, even where we have conservation action in place, is high pressure from predators.
“Reduced populations are much more isolated. Even where we still have good numbers of breeding waders they are often in small pockets within a wider landscape where there isn’t much else of value to predators, so they focus on these key conservation areas during the breeding season.
“Populations of these predators have changed too. There is a big body of evidence that we’ve got increasing populations of foxes and conservation efforts for birds of prey have meant their numbers have grown.”
Conservation scientists have two challenges to meet then. We must provide the habitat required to stabilise our wader populations and protection from predation to help their numbers to recover.
Against a backdrop of rising demand for cheap food to feed a growing population, much of our natural wet grassland has disappeared to provide agricultural land and its features have been simplified to enable efficient processing with big machinery.
“In the intensification of wet grassland, you drain it and graze it so you end up with a grassland that is pretty homogenous,” says Dr Smart.
“But what we know from our studies on habitat requirements from these species is that they all need slightly different things, so you want a field that has variation in how wet it is and in its features.”
Lapwings, for example, favour fresh, short grassland with areas of bare, wet mud, while redshanks prefer taller vegetation adjacent to wet beds.
While nature reserves can provide these conditions – try visiting RSPB Frampton Marsh in The Wash for a masterclass in how that’s done – the challenge is how to do it at a landscape scale.
“We would never expect a farmer to manage his grassland in the same way as we would on a nature reserve. It’s unrealistic. But what we hope farmers will do - and agri-environment payments can help them do - is find some middle ground,” explains Dr Smart.
“Some of the work we’ve done has been trying to understand how to replicate what we do in a way that is acceptable to farmers.
“Our work in the Norfolk Broads was about understanding how wet it has to be. We asked: If we put wet features in straight, which would help farmers, does it matter? And what sort of grazing can you get away with without it being detrimental?”
Landscape features have a significant impact on the second problem of predation.
Dr Smart, who is based at the University of East Anglia and works throughout the region, has been part of a team conducting a seven-year study in the Broads on breeding lapwings and redshanks.
It found that providing areas of tall vegetation adjacent to where lapwings nest reduces predation rates. It is thought it helps reinstate habitat for the small mammals that foxes prey on all year around.
Variation in field structure provides other benefits too.
“When you’ve got a field with a series of linear wet features and some pools and some scrapes, it varies seasonally,” says Dr Smart. “We’ve found by monitoring foxes that they tend to stick to the edges of wet fields so nests in the centre do much better than those on the edges.”
Many researchers have found that predation is lower when lapwings nest at high density, as it aids their defence response, which is to take flight en masse and mob predators. This also benefits redshanks, as it acts as a warning. Their strategy, however, is to sit tight on their nests in tall vegetation and rely on camouflage.
The best scenario – a wet field, with high lapwing density and tall vegetation at the verges – can reduce the chances of nest predation for the species from 70 per cent to 50, the researchers concluded.
“We are massively helped by technology,” says Dr Smart. “When I started as a PhD student 15 years ago, we had nothing! The main thing we use is iButtons, which are tiny temperature loggers.
“You glue them to a nail and stick them in the nest beneath the eggs and they monitor the temperature. We measure the eggs to give us an estimate of when they are due to hatch. Then, if the nest gets predated, we can download the data and it will tell us the time and date that the predation occurred, as there is a sudden drop in temperature.
“We find 80-90 per cent of predation is at night. There are no bird nest predators active at night, so we know it’s all mammals.
“In a much smaller sample of nests, we use nest cameras to identify the predators. The temperature logger and nest camera data corroborate each other. From our nest cameras, we’ve found 70 per cent of nest predation is foxes, 12 per cent is badgers and then a much smaller percentage of everything else.”
Changes in the landscape and greater access to food sources – including in urban environments, at rubbish tips and the release of 55 million pheasants a year in the countryside – are thought to be helping foxes thrive. The hunting ban is not thought to be significant – given that data shows a steadily increasing number of foxes have been shot on estates that control them since the 1960s.
Fencing can significantly reduce their impact in specific areas, like nature reserves, but is an expensive solution and unsuitable in many locations.
“Where we’ve created really good habitat conditions for waders or ground predator-free environments by putting up fences to exclude foxes and badgers, we see big population of waders being very successful at the nest stage – but this creates a massive hotspot effect for avian predators.
“We’ve got increasing populations of raptors in this country, which is a fantastic conservation success story, but that also brings some pressures on other species we’re trying to preserve.
“The only real option is to provide them with other food so they don’t need to eat the waders,” says Dr Smart. “We did this with kestrels to stop them eating little terns, which was very successful.
“The trial we’re doing now is with red kites in Oxfordshire, where they are everywhere, which is great but they were having a big predatory effect on one of our reserves. Diversionary feeding has proved very successful, reduced the hunting pressure and improved nest productivity.”
While the trial involved putting food out for red kites, the big question is how to create the landscape conditions that will naturally provide alternative sources of prey.
“This is where the patches of tall vegetation are again very attractive. It can impact on stoats, weasels and raptors to provide a sustainable solution,” says Dr Smart.
Likewise restoring some of our hay meadows, which teemed with small mammals, could help.
“Intensive solutions are fine in nature reserve settings but they are not going to fix the wider problems. We need these longer-term solutions that we can employ at landscape scale.”
While we can’t wind the clock back, managing the landscape better to provide some of the variety and complexity that it once featured must be part of the answer.
Saving our black-tailed godwits
Dr Jennifer Smart has been part of Project Godwit, the intensive effort to save one of our most vulnerable waders in the Ouse Washes and Nene Washes.
This year, only 40 breeding pairs of black-tailed godwits were recorded in the country - 35 at the RSPB’s Nene Washes reserve in Cambridgeshire, three at Welney, the Wildfowl and Wetland Trust (WWT) reserve in Norfolk, and two at WWT Slimbridge in Gloucestershire.
The small population that called the Ouse Washes home were hit by increased flooding in the Nineties and Noughties. Adjacent land was purchased to help them but the process was to slow to save most.
While the population in the Nene Washes grew during the period, it’s now on the wane due to poor productivity – and predation is again the main problem.
Dr Smart says: “We’re just at the beginning of a five-year project largely funded by EU Life and HSBC, Natural England and others to save black-tailed godwits in the UK.
“The main objective is to manage the 1,500 hectares that we’ve got in an exemplary way for the species. The second objectivity is to increase productivity in the remaining population, so we need to put in predator management actions, like control and exclusion, to make them fledge more young.”
As reported by the Cambridge Independent, conservation experts from the RSPB and WWT have been ‘headstarting’ godwits this year. This involves removing the earliest eggs of the season from nests in the first week of incubation, rearing the chicks in captivity, then releasing them into the wild once they are strong enough to fly around. It is an intensive, but effective, method of helping them survive the most vulnerable period and encourages the parents to lay more eggs – which happened in five of the eight pairs whose eggs were taken this year.
“We’re releasing the chicks in the Ouse Washes, so hopefully they will have imprinted that area and if they survive, they will come back to the area to breed.
“The idea is we’ll fix the problem at Nene Washes and hopefully get that population more productive and we’ll have this new population in the Ouse Washes, growing off the headstarting.
“Overall we’ve got more young godwits flying around so it’s been a big success so far,” says Dr Smart.
Some 26 chicks were released at Welney, in the Ouse Washes, hatched from eggs taken in the Nene Washes. If licensing can be achieved, the researchers hope to take eggs from bigger populations in Europe in future years and double the number reared in captivity.
The precocial godwit chicks survived well away from their parents and began foraging for food shortly after hatching. Once released they met up with flocks of adult godwits, with whom they will hopefully migrate.
Dr Smart warns: “We’ve got to fix this problem in the next five years - or we’re going to lose them.”
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