All downhill for upland waders?

 

Are targeted payments for England’s upland farmers benefiting Curlew, Lapwing, Oystercatcher, Redshank and Snipe?

The farmed land that fringes our moors provides important habitats for breeding waders (Dawn Balmer)

In the period 1995 to 2013, England lost 32% of its breeding Curlew, 31% of its Redshank, 27% of its Lapwing and 14% of its Snipe*, according to the latest Breeding Bird Survey results. The uplands are the main stronghold for Curlew and hold (or used to hold?) significant numbers of the other three declining species. Is the story one of total gloom or are there areas where sensitive farm management and agri-environment payments are successfully supporting waders and other species associated with upland farms? A new survey, funded by Defra and coordinated by BTO aims to find some answers.

* Please note that the figures for population changes have not been updated. They all relate to the period 1995 to 2013. Latest figures can be found by following the link to the BBS results (see above).

The snappily-titled Breeding Waders of English Upland Farmland survey starts in April and volunteers are still needed in many areas. Please visit the BTO website if you may be able to help.

More about the key species:

Derek Belsey

Curlew (recent 32% decline in England). The species is globally defined as near-threatened and has been added to the red list of conservation concern in the UK. Losses have been particularly severe in Ireland, Northern Ireland and Wales but the distribution is shrinking in England. There’s a WaderTales blog about Curlew here. Is the Curlew really ‘near-threatened’?

Lapwing (recent 27% decline in England). Most of the work to try to understand recent declines in Lapwing numbers has been undertaken on lowland wet grassland, where cooperative mobbing of predators is an important part of the daily routine for parents. In the uplands, where breeding densities are lower, it would not be surprising if predation pressures could be impeding species recovery. There are two WaderTales blogs about these issues. A helping hand for Lapwings and How well do Lapwings and Redshanks grow?

Jill Pakenham

Redshank (recent 31% decline in England). The situation for Redshank is very similar to that for Lapwing, the presence of which may help in predator defence. There is a WaderTales blog about the special issues in the Uists (NW Scotland), where introduced hedgehogs are causing huge problems in this key wader hot-spot. Prickly problems for breeding waders

Snipe (recent 14% decline in England). The survey methods used in the new BWEUF survey are not designed to detect Snipe, which are mostly active at dusk, but the visits should provide useful count and distribution data for an under-researched species.

Nigel Clark

Oystercatcher (recent increase of 56% in England). Much of the increase may well be occurring in river valleys and newly created wetlands and gravel pits, rather than in the uplands. We know from the recent Moorland Forum report Understanding Predation that there have been changes in Oystercatcher abundance in much of upland Scotland between 1990 and 2010, potentially linked to predation pressure. It would not be surprising if similar processes operate in the English uplands.

How the BWEUF survey will work

Breeding wader populations in the UK have been a major conservation priority for some years. Declines continue despite the implementation of conservation measures that are designed to deliver appropriate habitats, some of which are supported through agri-environment schemes (AES). While enhanced monitoring of many upland and lowland habitats would be valuable, a particular gap is evident for in-bye farmland. This habitat can be defined as juncus/rush pastures, semi-improved pastures and meadows below the moorland line, although it technically includes all enclosed farmland. Using Defra funding, Natural England has commissioned BTO to run a volunteer-based survey, with RSPB field-staff filling gaps in less accessible areas.

Photo: Dawn Balmer

This project will assess the importance of in-bye land for waders, by estimating the total numbers present in these habitats, relative to national estimates measured from Bird Atlas 2007-11 data. More importantly, it will set a baseline against which to measure future change in breeding numbers.  This will be used to assess the success of Environmental Stewardship management, as well as to measure differences in numbers between AES and non-scheme habitats for waders that nest and/or forage on in-bye farmland. The survey will use 2×2km grid squares (tetrads), as in Bird Atlas 2007-11. Volunteers are asked to make two morning visits to each tetrad, one between early April and mid-May and a second before mid-July, with a minimum of a two-week gap between visits. On each visit, volunteers will be asked to survey as many as possible of the fields in this in-bye buffer of 1km below the moorland line. They will walk to within 100m of every part of each field to which they have access, recording all birds seen and heard, noting any display or territorial behaviour and mapping the locations of target wader species.

There’s an opportunity to record other species of conservation concer, such as this red-listed Yellow Wagtail (Jill Pakenham)

The key features of grassland management and structure, along with other land use, which dictate suitability for waders, will be recorded.  Predation has been identified as one potential driver of population decline – or an impediment to species recovery – so observers will be asked to record avian and non-avian predators.

Birdwatchers do not normally spend much time in this in-bye habitat so here’s an opportunity to capture as much information as possible, especially for any other waders and gamebirds (Black Grouse, Grey Partridge, Pheasant, and Red-legged Partridge). Valuable information can be data can be collected for Cuckoo, Linnet, Meadow Pipit, Reed Bunting, Ring Ouzel, Skylark, Stonechat, Twite, Wheatear, Whinchat and Yellow Wagtail, many of which are red-listed species of conservation concern (and bonus birds on a day’s birdwatching). To view further information on survey methodology follow this link.

In Summary

The wader declines quoted in this article use Breeding Bird Survey data from 1995 but there is evidence of longer-term falls for Curlew (55% since 1975), Lapwing (65%), Redshank (65%) and Snipe (90%). These are worrying numbers and it is to be hoped that the BTO can find enough volunteers for BWEUF, despite the fact that many of the survey squares are a long way from the flat-lands in which most English birdwatchers live. Curlews, Lapwings, Oystercatchers, Redshanks and Snipe are counting on us to count them.

---

 

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton

Spring moult in Black-tailed Godwits

Black-tailed Godwits will look and smell different by the end of May

A spring flock of Black-tailed Godwits at Cley (Pat Wileman)

Before they return to Iceland in April or early May, wintering Black-tailed Godwits have got a lot of extra feeding to do, both to fuel their journeys north and to undertake a complete change of body feathers. The grey plumage that has protected them since the autumn is discarded, to be replaced by summer finery. Although more colourful, these feathers provide cryptic camouflage in the habitats in which the birds nest – and they have less odour too.

There is a lot of individual variation but the timing of the spring moult of Icelandic Black-tailed Godwits seems to differ depending on the wintering area used by individuals. Many Icelandic birds that enjoy the sun in Portugal, for instance, can start to change colour before the turn of the year, but there is little red to be seen in British flocks until February or even March. We have the impression that there might be enough variation across Britain & Ireland to potentially pick up differences at this scale but we have yet to establish if this is true.

Full summer plumage in Iceland (Tómas Gunnarsson)

Some godwit observers have been scoring the moult of spring flocks of Black-tailed Godwits for years, especially for ringed individuals. This has given us quite a lot of data from a few sites, but spread over a number of years and a range of spring conditions.

We thought that we may be able to look at the regional differences more effectively if we could collect images from as many flocks as possible over one weekend. We chose Easter weekend 2016 to try this out, as we thought that this should give us as much variation as possible, with birds at several different stages of moult. Birds were scored from 1 (full winter) to 7 (full summer), according to the table below and images at the bottom of the blog, but all we needed was pictures from birdwatchers that we could then score. We had not reckoned on Storm Katie, which seriously affected opportunities to take photographs!

This was very much a pilot project. We know that we can score most birds when they are seen moving around, so that each bird gives a view of chest side and back. Could we capture this information from a sample of birds in two-dimensional pictures? If this worked, potentially we could have run a season-long project.

Spring moult

Cameras at the ready (Graham Catley)

There is a big difference between the winter and summer plumage of Black-tailed Godwits. Over the course of a few weeks, a grey individual turns into a thing of beauty. Camera shutters start to click in bird hides when a flock of birds sweeps back and forth, flashing white as the sun shines on bellies and underwings and then russet red as it catches their backs. It would be easy to think that these summer colours make Black-tailed Godwits more obvious, when they are nesting, but that’s not the case. In rusty-orange sedge-edged pools and when creeping their way through the red stems of dwarf willow on their way to a carefully hidden nest, they are very well camouflaged.

Plumage 6 (left) and 5 (right). Photo: Dennis Swaby

Most wading birds moult into a summer plumage in spring. For Black-tailed Godwits, this process involves body feathers, some of the small coverts on the wings, scapulars and a variable number of tertials. Their individuality is apparent from the richness of colour, the mixture of red, black and white feathers in the body and of grey and red feathers in the back. When the moult has been completed, male birds tend to be redder in the chest and neck and they have fewer grey feathers in the back than females, but there is an overlap. When sexing methods were checked against DNA samples it was shown that experienced observers could correctly assign sex to 82% of marked breeding birds in the field for which the sex was also determined by DNA. There’s an interesting paper about this in Bird Study. 

By mid-April Black-tailed Godwits in the UK are in virtually full summer plumage (Graham Catley)

Breeding waders don’t just look different – it has been suggested that they smell different too. Birds of a range of species, including Black-tailed Godwits, have been shown to produce a different preen gland oil with which to groom their summer plumage feathers, with monoesters replaced by diesters as winter feathers are discarded and pre-nuptial moult progresses. This was something that was first shown for Knot by Jeroen Reneerkens and colleagues and then for another eighteen species, breeding in both high Arctic and temperate conditions. In nesting birds, secretion of diester waxes continues through to egg-hatching, with the lowest occurrence of diester production in male Ruff and male Curlew Sandpipers. Given that these are the only two species in the sample under consideration in which males don’t incubate eggs, Jeroen et al suggest that diester preen waxes are harder for predators to detect using a sense of smell. You can read more here. When this theory was tested, using a sniffer dog, Jeroen showed that less volatile diesters were harder to detect. (paper)

Did it work?

This plumage 3 bird will soon be a plumage 4 – lots of new feathers are growing through on the breast (Pat Wileman)

Although we received fewer images than had been hoped (thanks Storm Katie!) we discovered that pictures are not enough. The clue may well have been in the protocol; we had asked for pictures of 25 to 50 birds so as to show the chest and back of each individual, and that was too tough an ask.

However, it’s still really helpful to receive plumage scores alongside colour-ring sightings so please keep those coming. Black-tailed Godwit colour-ring sightings can be sent to any of the scheme organisers. If you are not sure who your Black-tailed Godwit belongs to, Jenny Gill (j.gill@uea.ac.uk) is happy to act as a clearing house. There are some sample scores below.

Scoring Black-tailed Godwit moult

---

WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton