Tool-kit for wader conservation

andyhayDecades of drainage and agricultural intensification have caused huge declines in numbers of breeding waders in the lowland wet-grasslands of Western Europe. Although we were already well aware of these problems by 1995, and farmland prescriptions have been used to try to arrest the declines since then, we have still lost nearly half of Britain’s breeding Lapwing in the last twenty years. Even on nature reserves and in sympathetically-managed wet-grassland, it has proved hard to boost the number of chicks produced. Why is this and what else is there that can be done?

bouThis is a summary of a presentation by Professor Jennifer Gill of the University of East Anglia and Dr Jen Smart of RSPB, delivered at the BOU’s Grassland Workshop (IOC Vancouver, 2018).

There are five key techniques in the tool-kit used by conservationists trying to support breeding waders:

  • Make the site attractive to waders
  • Manage predator numbers, particularly through lethal control
  • Manage habitat structure to make alternative prey available
  • Exclude predators, either permanently or temporarily
  • Invest in head-starting chicks, to boost productivity

Size of the problem

redshankThe decline in wader numbers in England has been happening for a very long time. In just the period 1995-2016, Lapwing numbers have fallen by a further 26% and Redshank numbers by 39%, according to Bird Trends, produced by BTO & JNCC. Within the English lowlands there has been a dramatic contraction into nature reserves, especially in the east of England.

The Breeding Waders in Wet Meadows survey showed that fields that are within nature reserves are much more likely to be occupied than other fields in wet grassland, particularly those that are included in wader-specific agri-environment schemes. The study is published in Ibis by Jen Smart et al.

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Attracting breeding waders

Lowland wet grasslands in Broads

Creating shallow ditches. Mike Page/RSPB

Reserve managers and sympathetic landowners have become very good at creating the sort of habitats that attract breeding Lapwings. Autumn and winter grazing can be manipulated to produce short swards, whilst adding in shallow pools and foot-drains (linear features running through fields) increases feeding opportunities for chicks. See Restoration of wet features for breeding waders on lowland grassland 

The RSPB has invested heavily in time and equipment to deliver these lowland west grasslands, on their own land, on other nature reserves and on commercial farmland. By working with Natural England, they have helped to shape agri-environment schemes that can be used to deliver payments to farmers who are well-placed to create habitat that suits breeding waders.

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wader pairsIn the east of England, there are now more than 3000 hectares of this attractive, well-managed wet grassland habitat, designed to be just right for species such as Lapwing. The graph alongside, drawn using RSPB data, shows the number of pairs of Lapwing (green), Redshank (red) and other waders (Oystercatcher, Avocet & Snipe: blue) in Berney Marshes RSPB reserve in eastern England for the period 1986 to 2016. There were early successes, as new areas were purchased and transformed, but growth in wader populations has not been sustained, despite ongoing improvements in land management. What is preventing further recovery?

Demographic processes

survivalIn a paper in the Journal of Ornithology, Maya Roodbergen et al  used demographic data collated across Europe to show that there had been long-term declines in nest survival and increases in nest predation rates in lowland wader species. One of the main focuses of management action at Berney Marshes is to maximise Lapwing productivity but nesting success is still below 0.6 chicks per pair in most years (see graph), which is the minimum estimated productivity for population stability (Macdonald & Bolton). Not enough chicks are being hatched, with the vast majority of egg losses being associated with fox activity.

Controlling foxes

The obvious solution for breeding waders must surely be to shoot foxes? It’s not that simple. In a multi-year, replicated experiment to assess the impact of controlling foxes and crows, RSPB scientists showed that there were no clear improvements in wader nesting success; effectiveness is very much site-specific. Much may well depend on how much fox control there is in the surrounding area.

foxIf fox impacts cannot be reduced sufficiently through lethal control, perhaps it is possible to reduce their effects on waders by understanding the ways in which foxes forage and to adapt the habitat appropriately? Work by Becky Laidlaw and others has shown that Lapwing nest predation rates are lower close to tall vegetation and in areas with complex wet features. However, Becky has also shown that management to create these features, even in areas of high wader density and effective predator mobbing, is only likely to achieve small reductions in nest predation. There is a WaderTales blog about this: Can habitat management rescue Lapwing populations?

Excluding foxes

malpasOne solution to the fox problem that does work is to exclude foxes (and badgers) from an area, by using electric fences. See paper by Lucy Malpas (now Lucy Mason). Fences may be deployed at different scales; just around individual nests, temporarily (around individual fields) or permanently (around larger areas).

  1. Nest-scale may be most appropriate for species such as Curlew, which have large territories and do not nest colonially. Finding nests is time consuming but relatively small lengths of fence could potentially be erected during the incubation period.
  2. Whole-site protection will suit semi-colonial species such as Lapwing. Although expensive to install, permanent fences can require relatively little maintenance and can potentially be powered by mains electricity. One disadvantage may be that the presence of large numbers of chicks can attract avian predators, such as birds of prey, which are themselves conservation priorities and hence difficult to manage.
  3. fence 2Field-scale fences usually rely on batteries, which need to be checked and changed, and fences need maintenance, as the grass grows and can short out the bottom strands. However, deployment at the field-level allows for dynamic use within a farming landscape and in accordance with agri-environment schemes. New research by RSPB and the University of East Anglia aims to see if fences need only to be deployed for relatively short periods. If pairs nest synchronously then groups of birds may be able to maintain the ‘fence-effect’ by mobbing predators, when a temporary fence is removed.

Head-starting

morgan 2018Although it might be possible to improve the habitat that is available for breeding waders and to reduce predation pressure, it is sometimes too late to boost numbers – simply because populations have shrunk to too low a level. At this point, head-starting (rearing chicks from eggs) may be appropriate. This blog celebrates the success of the first year of a joint initiative by RSPB and WWT (Project Godwit) to increase the local population of Black-tailed Godwits in the East Anglian fens: Head-starting Success.

In conclusion

In trying to boost breeding wader populations, land-managers and conservationists have developed techniques to increase site attractiveness and reduce predator impacts, through management, control and exclusion. The tools that are used will depend upon species, budget and conservation priorities.

This work was presented by Jennifer Gill & Jen Smart at a BOU symposium on the Conservation of Grassland Birds, in Vancouver, August 2018.

Blog adultWaderTales blogs about Lapwings and Redshanks

The work of RSPB and University of East Anglia scientists features strongly in these blogs, which focus on support for breeding wader populations in lowland wet grassland and on coastal saltings.


GFA in Iceland

WaderTales blogs are written by Graham Appleton (@grahamfappleton), who  has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.

 

 

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Head-starting success

The first year of head-started Black-tailed Godwits

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Head-started bird from 2017

As I write this, the Scientific & Technical Advisory Group of Project Godwit is meeting to review progress. They will be learning about the success of the project, which has three aims: to create the best possible habitat for the small (and threatened) population of Limosa Black-tailed Godwits breeding in the East Anglian washes, to provide protection for nesting pairs and to augment chick-production using head-starting. Head-starting involves removing first clutches and hand-rearing chicks before releasing them back to the wild. All of this is set within a rigorous scientific framework, so that the efficacy of head-starting and nest-protection can be carefully evaluated.

Success!

What a year it has been! When I wrote Special Black-tailed Godwits last year, I finished by saying, “Imagine how exciting it will be if one of this year’s head-started birds is found breeding in the Nene or Ouse Washes next year”. Amazingly, nine of the 26 head-started birds from 2017 were back this year and two females definitely had nests, with one fledging a chick, and a further two paired together are suspected to have attempted to nest. From data shared with me by Roos Kentie, this return-rate is comparable to wild-breeding Limosa Black-tailed Godwits in her Dutch study-area.

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Where did the chicks go?

The left-hand map below shows the finding locations of chicks in the period June to September 2017, before they headed south for the winter. There had been a major publicity campaign, asking birdwatchers to look out for these special godwits in East Anglia. The Project Godwit team were pleased to receive news of six birds in Norfolk, Suffolk and Essex. The bird that turned up at Steart Marshes, in Somerset, came as more of a surprise.

headstarted map

Most limosa Black-tailed Godwits spend the winter in Africa, south of the Sahara, but an increasing number now stay in Portugal and Spain. There is a WaderTales blog about some of the costs and benefits of this new strategy: Should Black-tailed Godwits cross the Sahara? There were no winter sightings of the head-started birds but several popped up again in the spring of 2018, as shown in the right-hand map above. Four birds were seen in Portugal, two in France and one in Belgium. The Belgian sighting was the only unexpected sighting, as discussed in Site-fidelity in Black-tailed Godwits.

What about ‘wild’ birds?

wild mapRSPB scientists have been using colour-rings to follow the movements of Nene and Ouse Washes Black-tailed Godwits since 1999. As you can see, from the map alongside, the pattern of sightings is very similar to the one for the head-started birds, the only difference being a couple of winter reports in Senegal of the same individual and a bird that spends each winter in Portugal. August and September sightings have been in East Anglia, Spain and Portugal, with February and March sightings in Portugal, Spain, France and East Anglia.

As Black-tailed Godwits move north in February and March, they mix with birds of the islandica race which are preparing for the journey to Iceland. There’s a blog about the two subspecies here: Godwits in, Godwits out: Spring-time on the Washes.

Using geolocators

One of the outstanding questions is ‘Do head-started birds migrate in same way and spend the winter in the same places as birds that were raised naturally’. Given that released chicks have generally behaved just like other youngsters, they probably do, but it would be nice to have proof. To provide an answer, geolocators have been attached to the flag-type ring on each of 22 head-started chicks and 20 wild godwits. When they return (and if they can be caught on their nests) these geolocators will be taken off and the data will be downloaded. Keep an eye on the Project Godwit website for new information.

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Newly-tagged adult is released

Geolocators do not only reveal the final destinations of migratory birds, they also provide information about stop-over sites. Given that the limosa species is in serious decline (there’s a blog about the 75% drop in the Dutch population), it is important to understand the habitat requirements and timing of movements during migration. Two adult birds from the Nene have been tracked using geolocators, both of which spent the winter in Senegal.

The class of 2018

morgan 2018

‘Morgan’ is one of the class of 2018. This chick has already been seen in Hampshire and hopefully the geolocator (attached to green flag) will reveal where it spends the winter.

And so to the second year… As you can read here, 2018 was a strange breeding season. It started with a flood and ended with a drought. A total of 55 eggs were taken from the Nene Washes, including early eggs that had to be rescued from a waterlogged wheat field. Despite the muddy state of many of the eggs, 38 chicks were reared successfully and the first five were spotted away from the Welney and Nene release areas before the end of July – four on the North Norfolk coast and one at Titchfield Haven, in Hampshire.

These sightings and all the others that will hopefully be reported in August and September, are really valuable. They confirm which birds have survived their first few weeks and months in the wild and give a good clue as to which birds the team might see next spring. If you see one of the young birds, which carry a lime E ring on the right leg, please report it via this website.

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Funding

Project Godwit is a partnership between RSPB and WWT, with major funding from the EU Life Nature Programme, The HSBC 150th Anniversary Fund, Natural England, the Heritage Lottery Fund, through the Back from the Brink Programme and Leica UK.


GFA in Iceland

Graham (@grahamfappleton) has studied waders for over 40 years and is currently involved in wader research in the UK and in Iceland.  He was Director of Communications at The British Trust for Ornithology until 2013 and is now a freelance writer and broadcaster.