Where do Ringed Plovers come from? And go to?

ringed plover btoIn December 2018 I found a colour-ringed Ringed Plover from Germany on Hartlepool Headland, NE England.  This was the first time I had really given any thought to Ringed Plovers.  Two months later 58 on a beach North of Sunderland could not be local birds as there are so few breeding opportunities on the Durham coast.  So began a month long obsession with these plucky little birds.

The Ringed Plover (Charadrius hiaticula) nests in the Arctic and northern temperate zone. The breeding distribution is largely restricted to coastal areas but in Eastern Europe the species breeds along some of the major river systems of Poland, Belarus and Ukraine. The main wintering grounds of the species extend from the British Isles to southern Africa and to the east to the Red Sea and Persian Gulf.

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The Ringed Plover has one of the classic examples of leap-frog migration in which birds from more southerly populations winter close to the breeding grounds and those from northernmost parts of the breeding range make long flights to more distant wintering grounds.

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Fig 2 BTO ringing information.

Three subspecies are recognized C. h. hiaticula is generally larger and paler than C. h. tundrae, but this division is unsatisfactory, because the variation in distinguishing features, i.e. size and the colour of the upperparts (C. h. tundrae being smaller and darker) is rather clinal. Furthermore, C. h. tundrae from Central Siberia are again larger, approaching C. h. hiaticula in size.

The nominate subspecies C. h. hiaticula breeds in the area from the British Isles to the Baltic; around the Scandinavian coast; and in inland areas in Central and Eastern Europe. Subspecies C. h. tundrae inhabits the northern parts of Eurasia from the Scandinavian mountain range to the Chukotka peninsula. The third subspecies is C. h. psammodroma, it has breeding grounds in NE Canada, Greenland, Iceland and the Faeroes.

C. h. hiaticula moves towards W European and N African wintering grounds mainly along the coasts. C. h. tundrae is a long-distance migrant in autumn it migrates across the continental land masses of Eurasia and Africa, with wintering grounds mainly in sub-Saharan Africa as far as South Africa e.g.  (c. 70º 15’ N, 30º 40’ E) C. h. tundrae from Finnmark, NE Norway have been tracked to Mauritania; Sierra Leone; and the Gulf of Guinea.

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C. h. psammodroma is thought to winter mainly in S Europe and NW Africa. It is likely that in winter Iberia and NW Africa play host to all three subspecies.

In Central Europe, C. h. hiaticula migrate earlier, with many local breeders usually leaving the breeding grounds in mid July, and the vast majority of adults observed from the beginning of August belong to C. h. tundrae. In the case of juveniles, the proportion of these two subspecies change more gradually in August. A similar pattern was found along the Iberian Atlantic coast.

While ring recoveries link the breeding grounds of the C. h. tundrae in northernmost Europe with wintering areas in W Europe, W Africa and South Africa Much less is currently known about the migration of birds from the Asian part of Russia. Using geolocators ornithologists have tracked and described annual migration routes of Ringed Plovers breeding in Chukotka (62.53°N, 177.05°E), Russia -the north-eastern limit of the species breeding range.

The wintering grounds of five males were scattered from the Persian Gulf to the Nile Delta and south to Somalia. During the wintering period three birds made only local movements, whereas two others moved 1,100 and 3,200 km northward in the second half of March, before embarking on pre-breeding migration in April. During post-breeding migration, the birds used a ‘hopping’ strategy, following the inland West Asian–East African Flyway and making hundreds of stops of various lengths, as recorded by their geolocators’. Three main regional stopover areas during southward and northward migration were identified. These were -N and W Kazakhstan together with the neighbouring southernmost areas of W Siberia.

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The pathways of each bird were rather similar in autumn and spring in the southwestern half of the routes, while a loop migration was evident in Siberia, and although the distances covered were longer, the migration speed was faster on the northbound route than on the southbound one. The migration tracks likely reflect a historical eastward expansion of the breeding grounds of this species in the late Pleistocene. Here Ringed Plovers may have had a largely W Palearctic breeding distribution with migration south to Africa; then as the ice melted and large areas of suitable habitat became available, the breeding distribution may have expanded eastwards with eastern breeders continuing to winter in Africa. The same scenario is thought to have led to similar breeding and wintering distributions in other species, e.g. Northern Wheatear and Willow Warbler. Based on migration routes there may be other subspecies to find, but to date genetic markers confirm C. h. tundrae to be a subspecies that expanded rapidly as ice retreated.

References 

Meissner W and Chylarecki P. (2010) Ageing and sexing the Ringed Plover Charadrius hiaticula. Wader Study Group Bulletin • January 2010

Pinchuk P, Karlionova N and Meissner W (2016) Biometry indicates sexual differences in spring migration strategy in Ringed Plovers Charadrius hiaticula tundrae captured in the southern Belarus. North-Western Journal of Zoology 12 (2): 319-324.

Thies L., Tomkovich P., dos Remedios N., Lislevand T., Pinchuk P., Wallander J.,
Dänhardt J., Þórisson B., Blomqvist D. & Küpper C. 2018. Population and sub –
species differentiation in a high latitude breeding wader, the Common Ringed
Plover Charadrius hiaticula. Ardea 106: 163–176. doi:10.5253/arde.v106i2.a8

Thorisson, B., Eyjólfsson, V., Gardarsson, A., Albertsdóttir, H.B. & Gunnarsson, T.G. 2012. The non-breeding distribution of Icelandic Common Ringed Plovers. Wader Study Group Bull. 119(2): 97–101.

Tomkovich P.S., R. Porter, E.Y. Loktionov & E.E. Syroechkovskiy. 2017. Transcontinental pathways and seasonal movements of an Asian migrant, the Common Ringed Plover Charadrius hiaticula tundrae. Wader Study 124(3): 175–184.

May Bank Holidays, public beaches and the death of Ringed Plovers.

If Beatrix Potter had lived near the coast I am sure Ringed Plover would have featured in her animated tales. A small, dumpy, short-legged wading bird with dapper markings, they would easily fold into her pocket-sized children’s books. With their rock pool gazing vanity they would have fitted well amongst the neighbours she parodied in her work. Perhaps then things would be different. As it is Ringed Plovers barely even feature, even amongst birders tales. By the end of January anyone living near the coast will have it on their list as numbers are swelled by 30,000 northern birds mainly from Canada, Greenland, Iceland in the west and to a lesser extent Scandinavia. After that, apart from the odd ‘bird-racer’, it receives little attention. Even the tundrae race generates less interest than Greenland Wheatears with whom they share their summer home.

The lack of attention in the summer has seen the population drop both considerably and invisibly from 8,540 pairs (1984) to 5,438 pairs (2007) (BTO, 2007). 25% nest on the machair of the Western Isles, where nests of shorebirds are predated by the introduced Hedgehog. It is the marked increase in nest failures, at the egg stage. that has earned Ringed Plover a place on the concern list where it has recently gone from amber to red.

The RSPB draws attention to their plight ‘Red Alert: helping Ringed Plover’. They say, ‘Sadly, they were recently added to the Red List of Birds of Conservation Concern due to declines in their wintering numbers. The reasons [for the decline] are currently unknown. Breeding birds are also in decline.’

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In a cheery summary the RSPB assures us that, ‘[The RSPB are] currently pulling together all our information on ringed plover declines so that we can best plan our next steps to conserve this engaging bird. We’ll keep you updated on our next steps.

Fairly innocuous -bird X in decline, we are doing our best, they are safe on our reserves, send us some money and we will do more good work.  At face value it ends there.

Unsurprisingly, Ringed Plovers aren’t species X, they are complicated. Their issues will not be resolved by flag waving and money and there is enough literature to describe the problems:
1) Climate change –fewer birds arrive due to milder winters so we need to assess the decline in a European context; summer storms impact the beaches on which they nest; Britain is at the limit of their breeding range and warmer summers will mean the southern nests will be less productive.
2) Disturbance –most of the potential nesting habitat lies outside of nature reserves and Ringed Plover parents are sensitive to humans, particularly humans with dogs. The two May Bank Holidays right in the middle of the nesting season are when there is a big influx of people and dogs to beaches.
3) Low breeding productivity –nest failure rate at the egg stage has been steadily increasing since 1970s.
The reality does not fit with these RSPB public facing statements as these do not address the issues above:
• all of the key estuaries for Ringed Plovers are protected under national and international legislation
• RSPB teams work hard to ensure that coastal habitat is not lost or degraded.
• In particular, we seek to prevent disturbance of high tide roosts.

The reality is much less reassuring. Climate change aside, the future for Ringed Plovers will feature increasing amounts of disturbance even in the protected areas. The control of dogs off leads is not influenced by the RSPB’s good wishes.

The few studies that have investigated the effects of human disturbance on breeding densities of ground-nesting bird species, indicate that breeding density is substantially reduced by recreational disturbances. Such reduced breeding density, or lack of breeding success within otherwise potentially suitable habitat, may be the main consequence of human disturbance.

A small number of mostly observational studies suggest that responses to a walker with a dog tended to be stronger than a person approaching without one; displacement of incubating or brooding birds led to increased predation risk from opportunistic predators, especially larger gulls and corvids.

Human disturbance influences territory choice, territories were established where disturbance is relatively low. In a second study human disturbance, largely attributable to holiday makers, was especially concentrated around car parks (points of beach access) over two weekends in May (extended weekend holiday periods), and during July and August (school holidays) at the end of the plover breeding season. Disturbance came mostly from walkers (with or without dogs), sun-bathers and occasional picnickers, anglers and bait-diggers.

Highly disturbed sections of beach were avoided by most nesting pairs (with the exception of those with no prior experience of breeding on the site) despite presence of otherwise suitable habitat. Where nesting occurred, density of territories and nests was less along more disturbed sections. Of all nests found, 8.5% were lost due to people, mostly though accidental trampling of the well camouflaged eggs, with a higher proportion of losses occurring closer to footpaths.

Disturbance did not affect incubation length, proportion of nests that hatched, or chicks fledged, although only low disturbance areas were considered. Chick foraging time was reduced in areas with more people but this had no effect on growth or survival to fledging. A model was constructed that predicted that if human activity was restricted (e.g. through fencing of sections of beach with nests) then the ringed plover breeding population size would increase by about 8%, whilst if people were absent altogether the population would increase by around 85%.

10 Ringed Plover nests on the north Norfolk coast over three days (the May Bank Holiday period) on a beach which traditionally experiences high numbers of tourists. When a person approached to within 100 m most plovers reacted by leaving the nest. For long periods there were constantly people within 100 m of all 10 nests.

Earlier on Lindesfarne unintentional disturbance by visitors and their dogs was considered more serious than direct loss (e.g. through trampling) as incubating birds normally ran from nests when approached, giving opportunities for carrion crows and other avian predators, watching for plover movement, to locate and predate the eggs. It was noted that increased movement to and from nests by ringed plovers due to disturbance, left tracks on sandy substrate leading to the nest scrape, and also possibly scent trails that mammalian predators (e.g. Fox ) might exploit.

So for more than 30 years we have known of the problems that face Ringed Plovers. The RSPB do not need to wait for new data. If we want to save the Ringed Plover as a breeding bird in England we know what we have to do. Restrict people on beaches where Ringed Plovers could nest. County Durham has about 40 miles of coast about 11 miles of which would be suitable for Ringed Plover to nest.

I don’t see any organisation coming forward to take on this challenge any time soon.  Bye-bye Ringed Plover.

Say goodbye to the Ringed Plover.

The seashore between the windrows and the low water mark of the tide is a world beyond our experience. Subterranean, damp, cold and unseen live animals that drive shorebird migration. More stable than the changes in salinity and temperature of rock pools, a smooth skin of sand, pock-marked with tell-tale marks for those whose lives depend on reading them. Brutally, we can only break into this world through disruption -chemical or physical.

I expected to be alone, but the bleaching snow lifted. From the monotone a lone bait-digger broke the surface with his spade. The small spoil heaps he created attracted Sanderling and Redshank. They walked around his feet as though he was as much beach as they were. The birds picked at things that would not be of interest to a fisherman. To us the sand is a physical substrate on which to walk. To them the sand is a larder of hidden treasures.

Bait Digger

Coastal wetlands are among the most productive of ecosystems holding dense populations of invertebrates. Many of these invertebrates spend much of their time deep in the substrate, either because of their physiological or feeding requirements. This attracts shorebirds, locating to temperate coastal wetlands in the non-breeding season, to feed on this invertebrate bonanza.

The digger left and the Sanderling increased to six. They fought and bickered to establish their pecking order. They had changed their behaviour. No longer the familiar clockwork toys, running in and out with each wave, they were fixed on this place until the waves returned the heap to the sea. The birds became the familiar wave-chasers again.

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Further North the chunky shapes of Ringed Plovers held court on a damp patch of sand. They waited for their chance in between the lead-less dogs that moved them back to the rockpools. Here they could sometimes be caught gazing as though admiring their beauty. Jonsson captured this look, but it was though I was seeing this for the first time.

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683AD36E-2D37-445E-BB08-01A533762825A fruitless search for Knot brought me to a beach shrinking on an incoming tide. Here Sanderling behaved as they should, but Dunlin were also chasing the waves. A Bar-tailed Godwit plunged its head under as water lapped onto the beach. A Grey Plover with a limp stayed higher up but was still regularly able to pull worms from under its feet.

By now dog walkers could not reach the preferred Ringed Plover playground as it too was now cut off by the water. 58 birds played out their strategic power games like pocket yodas. This was truly fascinating and only ceased as the water stole their dance floor.

I wanted to know more about the running staring chess game, but it appears that no-one has studied the winter arrangement. The only paper I can find is one by Pienkowski (1980). he was interested in the economics of feeding and the birds he studied were at Lindisfarne and had a huge area of foreshore to hunt.

In looking for an answer I found more questions. Ringed Plovers have recently become red listed. Unhelpfully, the RSPB on their ‘Help us to help the Ringed Plover’ page provide little information as to what my contribution would be going towards as,

‘Sadly, they were recently added to the Red List of Birds of Conservation Concern due to declines in their wintering numbers. The reasons are currently unknown. All of the key estuaries for ringed plovers are protected under national and international legislation and RSPB teams work hard to ensure that coastal habitat is not lost or degraded. In particular, we seek to prevent disturbance of high tide roosts.

Breeding birds are also in decline, although to a lesser extent than wintering birds.’

My voxpop of my County Durham 58 is that their winter feeding and roosting are regularly disturbed by dogs not on leads and people using the beach more generally. My suspicions were supported by a depressing report from the North West Norfolk Ringing Group. In 1994 60-65 pairs in their study area and by 2009 they had to give up their study. The reduction being so great, largely blamed on predation and disturbance has left Norfolk with about 160 pairs in total.

So how do they fair in Northumberland and County Durham. Ring plovers feature in both Biodiversity action plans, but with Councils strapped for cash it is not clear that these remain priorities. In 2016 there were less than 10 pairs in County Durhamm and many of those will not have produced young due to the high disturbance on our beaches. And we do nothing.

As birders we complain on Twitter and FB about this new breed of birders -toggers who with their need to get close to the birds for the best photo. Some do disturb the bird -feed migrant wheatears so they no longer migrate and become easy prey to BOPs, some individual birds will die. Perhaps though it is the slow decline and disappearance of a species we don’t notice as it is not glamorous species happening on our watch that should cause us more concern. But we don’t notice those birds that pad out a list in early January. I would challenge the RSPB to change their statement, we know exactly why Ringed Plovers are declining. It’s just too difficult to reverse the trend.