Establishing breeding requirements of Whimbrel

Breeding Whimbrel may be associated with wet heaths but chicks need small pools and ditches too

header

One of the advantages for waders (shorebirds) is that parents can lead their chicks to suitable feeding areas almost as soon as they are hatched. This means that the habitat in which parents choose to secrete their nests can be very different to the habitat in which their youngsters will later forage.

ad-for-blogAs part of a study into the potential impacts of a large wind farm proposal on Shetland, a team from Alba Ecology Ltd and Natural Research Projects Ltd collected data on the habitat associations of wader species, particularly Whimbrel, on Mainland Shetland. A new paper, in the BTO journal Bird Study shows that habitats used by Whimbrel chicks for feeding are significantly different to those used by adults for feeding and nesting.

Habitat characteristics of breeding Eurasian Whimbrel Numenius phaeopus on Mainland Shetland, Scotland, UK by Kate Massey, Peter Cosgrove, Fergus Massey, Digger Jackson & Mark Chapman

Fourteen sites across Mainland Shetland were studied, in order to identify the three main requirements of Whimbrel – adult territorial and foraging habitats, nest site habitats and chick feeding habitats. The sites were spread across central and west Mainland Shetland, focusing on areas regularly used by breeding Whimbrel. Between them, these held between 90 and 100 pairs, out of a local total of 150 local pairs.

chick-for-blogWhilst adult Whimbrels used blanket bog, dominated by ling heather, cottongrass and other species associated with wet heath, when both nesting and feeding, the structure of habitats used by chicks was very different. These were characterized by small, wet and often linear features, with plenty of mosses and plants such as purple moor-grass and bulbous rush. The presence of these flashes, ditches and former peat-cuttings may be crucial to the successful breeding of Whimbrels.

Sad times for the Curlew family

curlew IUCN

Based on IUCN BirdLife assessments

As outlined in the blog Is the Curlew really near-threatened? we have probably already lost 2 out of 8 of the members of the curlew family – definitely Eskimo Curlew and possibly Slender-billed Curlew. Although Whimbrels are not currently causing official concern, there is certainly a need to be watchful. This paper is therefore an important addition to the written information about the habitat requirements of the species. The conclusions reached by the authors may well be of interest to scientists tackling tricky issues relating to the conservation of European Curlew. Across Wales and Ireland, breeding populations have been decimated (literally).

 Providing the right habitat for Shetland’s Whimbrel

 For Shetland’s Whimbrel, the habitat differences between adult feeding/nesting locations and chick foraging locations were very striking and suggest that the presence of both types of habitat may be of importance. Chicks move out of the heavily grazed open heather areas, in which nests are often made, and into wetter and taller, mixed, and structurally-diverse vegetation, where it is easier to hide from predators such as gulls, corvids and skuas, and to find food. If suitable habitat for Whimbrel chick foraging is limited, then chick growth and survival may be compromised. This paper suggests that management aimed at benefiting breeding Whimbrel needs to address the habitat needs of chicks, in terms of wet features, as well as the habitat needs of adults for foraging and nesting. You can read more in the paper.

habitat-for-blog

Grazed heather areas (left) are favoured by feeding and nesting adults, while chicks prefer wet flashes (right). Photos: Peter Cosgrove

 Work on other upland wader species has shown that food availability, vegetation structure and cover from predators may at least partly explain habitat preferences of chicks. When tracking Golden Plover families in northern England, Mark Whittingham and colleagues found that chicks selected the edges of marshy habitats. They recommended that drainage ditches should be blocked, in order to provide more suitable feeding habitat. An added benefit of this sort of measure is that more water is held on moorland, which helps to reduce flooding downstream.

Lowland wet grasslands in Broads

Shallow ditches increase Lapwing productivity: Mike Page/RSPB

As Peter Cosgrove, one of the authors of the new paper has commented, “The more I read and discover about wader chicks, the more I see the importance of small, wet flushes with cover – maybe this is a general feature of many species?” As you can read in A helping hand for Lapwings, the provision of wet features, particularly foot-drains, is crucial to the successful fledging of species in a more open landscape.

A matter of scale?

Creating the right habitat mosaic for adults and chicks will depend upon the scale of the movements of family parties of the wader species that is causing conservation concerns. Tómas Gunnarsson reports that family groups of Icelandic Black-tailed Godwits can cover large distances. One brood of small chicks (less than five days old) was found a week later 3 km away. Whimbrels may be able to select areas with suitable nesting and nearby chick-rearing potential or perhaps they can also move their chicks longer distances, if necessary? Research into the movements of family parties might tell us whether moving chicks for a kilometre or more could have adverse consequences, in terms of growth or survival. Presumably, adults would prefer to find the right mix of habitats within relatively close proximity, which suggests that managing grazed heath to provide a suitable mosaic of cover for nests, areas of short vegetation and wet features may be a sensible conservation prescription for Whimbrel.

Habitat characteristics of breeding Eurasian Whimbrel Numenius phaeopus on Mainland Shetland, Scotland, UK by Kate Massey, Peter Cosgrove, Fergus Massey, Digger Jackson & Mark Chapman


GFA in Iceland

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

 

 

 

Snipe & Jack Snipe in the UK and Ireland

This blog first appeared as an article in Shooting Times and Country magazine. It has been amended to provide more web links.

snipe-header

A wisp of Common Snipe

There’s a big difference between the number of Common Snipe and Jack Snipe we see in the United Kingdom each winter, with an estimated 1,100,000 of the former and 110,000 of the latter, according to the authors of Population Estimates of Bird in Great Britain and the United Kingdom. They remind us that Jack Snipe are hard to find and identify and warn that the total of 110,000 is a contender for ‘least reliable’ of the hundreds that have been compiled for this mammoth stock-take.

size-table

Comparative measurements (summarised from work by Guy-Noel Olivier)

In theory, therefore, for every ten Common Snipe we see we ought to see one Jack Snipe. Telling them apart is mostly a matter of size (see table) and there’s a useful identification video that has been produced by the British Trust for Ornithology. Both species make good use of their striped, cryptic plumage to avoid detection but Jack Snipe take the art to the next level, hiding against or under a tussock until the last possible moment and then exploding from beneath a person’s feet. Given the closeness of approach, perhaps Jack Snipes might be more obvious and their numbers exaggerated?

jack-puddle

Jack Snipe probing in mud

In the winter months, Jack Snipe are not as closely associated with wetlands as are Common Snipe, preferring longer vegetation, such as that to be found in muddy, cow-poached rough grazing marsh, to the open edges of larger bodies of water. For the tiny Jack Snipe, a cow’s hoof-print forms an ideal pool in which to probe. One of the areas that birdwatchers go to see Jack Snipe is Glasgow. Strange though it may seem, several of the wetland areas within the city limits hold small numbers of birds, especially in autumn, when migrating Jack Snipe pass through Britain, on their way from Scandinavia to wintering areas in south-west Europe. Members of the local ringing group have focused a lot of effort on this species, catching individuals by dragging a mist-net through the rough, wet, reedy grassland and ringing birds that have jumped from the ground as the net passed over them. See blog by Gillian Dinsmore.

jack-flight

Jack Snipe are relatively long-winged

Jack Snipe are well designed for migration, with much bigger wings for the size of the body than the Snipe. Unlike Common Snipe, many of which migrate in flocks, or wisps, Jack Snipe are thought to travel mostly alone and at night. They cover long distances, with some birds from Russia crossing the Sahara and those from eastern areas of Siberia travelling to eastern Africa, India and southern coastal countries of mainland Asia. The birds that winter in the British Isles have much less far to travel than the majority of the population, therefore.

Common Snipe, which are much bigger and more common than Jack Snipe, start to appear in their wintering areas as early as August. The pioneering birds are juveniles; most adults moulting at least some of their flight feathers before flying south and west in September and October. We know this because many French hunters have provided wings to scientists studying the age and sex structure of the population in that country. Moulting is an energetically expensive part of any bird’s life, so autumn feeding conditions are presumably generally good enough for moult to have been at least started, if not finished, before birds leave the breeding areas. Not every bird manages to fit in a full moult before it’s time to move south, however, with one in six adults shot in France found to be in suspended moult, having shed and moulted some primary feathers before migration, with a view to completion in the wintering grounds. A slightly smaller number have a mixed age of secondary flight feathers and about a quarter delay completion of covert moult.

snipe-1

Common Snipe

Although most of the Common Snipe we see in Britain in the wintertime have come from Scandinavia and mainland Europe, Ireland has a strong additional connection to Iceland. A quarter of foreign-ringed Common Snipe discovered in Ireland or Northern Ireland have been found to be wearing Icelandic rings, compared to 1 out of 255 in England, none in Wales and just 10% in Scotland. This and lots of other fascinating facts about migration come to light because hunters kindly send information about ringed birds to The British Trust for Ornithology, which is ‘mission control’ for ringing in both the UK and Ireland. This information is available on-line via the BTO website.

Across Europe, although there is almost certainly a decline in the number of Common Snipe, probably linked to man’s incessant drive to drain wetlands, there is no suggestion as yet that Common Snipe should be added to the list of species of conservation concern. For British and Irish breeding birds the situation is very different, however. By the time of the first national bird surveys, some 50 years ago, we had been turning wetlands into farmland for as much as 2000 years and, since then, numbers of Common Snipe may well have fallen by a further 90% in the areas in which they are still breeding. There has been a major shrinkage of the species’ range since 1968-72. Losses are shown as downward triangles in the map from the latest Bird Atlas, published by the British Trust for Ornithology. The rate of decline across England, Wales, southern Scotland and much of Ireland in the shorter period since 1988-91 emphasises just how quickly the species is being lost. It can only be a matter of time until Common Snipe is added to the red list of species of conservation concern in the UK, in order to highlight the perilous plight of our breeding population.

picture1

drumming-snipe

Displaying Common Snipe

A displaying Common Snipe is a magical thing – flying around with real purpose, climbing into the sky and vibrating its tail feathers in a stooping descent. Our grandparents could have heard them drumming on grazing marshes anywhere in the country and just imagine what the fens of eastern England must have been like 500 years ago. These days, most people in southern Britain will have to visit a nature reserve even to have a chance to share that same magic. I am lucky enough to go to Iceland every summer, where I can still easily see a dozen Common Snipe displaying at the same time above areas of wet grassland.  If you want anything like the same sort of experience in the UK, you’ll probably need to travel to the Outer Hebrides.


GFA in Iceland

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