Goldie flocks

"In the Thames, and perhaps to a lesser extent the Medway, the first arrivals after a brief spell about the marshes and saltings pass on to the upland fields, whereas along the Swale they not only spend the whole winter in the marshes but regularly visit the saltings and mud-flats. This latter habit is certainly not confined merely to newly-arrived birds, but is noticeable with some of the winter population...
...Dr. J.M.Harrison, writing in the South-Eastern Bird Report for 1937, considered that the visits of the Golden Plover to the saltings and mud-flats of the north Kent coast were rare and limited to odd birds. We agree in general this is correct, but it does not apply to the same extent when they first arrive or during their stay along the Swale and a certain portion of the Medway..."

The Birds of the North Kent Marshes

E.H.Gillham & R.C.Homes, 1950

A sixty-six year old conundrum, which some texts point to now being solved. And a behaviour which certainly still happens on a 'certain portion' of the Medway.

On the mudflats

The first Goldies usually turn up late July/early August, almost always found on the undulating hard flats just south of the remaining saltings on the edge of Bedlams Bottom. The first birds are mostly adults, already showing body moult. Over the next few weeks these numbers build to just around the 200 mark, and remain about this level until the expected early winter influx. This pattern mirrors similar small arrivals at more westerly sites around the eastern Swale.

First returning birds, July 2016

What are their most probable origins? 'BWP' stated British birds to be 'partial migrants' with part of the population wintering in lowlands close to their breeding sites. The Icelandic population moves through Ireland and western Britain. The most likely source for Kent Goldies at this time is Fenno-Scandinavia/Russia, in line with the results from more extensive ringing efforts just over the Channel in the Low Countries. A bird ringed in September 1967 on the North Kent Marshes was shot whilst wintering in Spain in February 1969. The Dutch ringing scheme has a large number of Norwegian records from this time of year.

Will they continue south eventually? Well, the numbers remain level on the flats for the next couple of months, but the chances are we are seeing staging birds, small numbers staying for a few weeks then moving on. The moult strategy for flight feathers is attuned to this; a start before autumn migration, a suspension for several weeks during migration, only completing on arrival at the wintering grounds.

During these first weeks back on the Medway the birds will try to see out high tide on those small islands; if there are spring tides, they go under, so the birds make for Chetney. Otherwise they stay close to the flats. When on the mud, the birds are loafing for 95% of the time. Often it is like counting Meerkats- heads pop up from behind the mounds, and back down quickly again. The distance means they can be missed without a telescope. The rising tide, from around the 2.75 mark, does tend to force them out into view for a short while. The move to roost is more usually as one flock, but they can break into two/three groups to a pre-roost assembly on the flats just north of the islands for a short period.

Part of the flats loafing flock, viewed distantly from Raspberry Hill, November 2016

Feeding activity on the flats is just about non-existent, suggesting the mud is being used just as a safe loafing ground. After working that out slowly for myself, was pleased to see the excellent Poyser monograph quotes studies that have reached the same conclusion. Birds on the mud during the day are thought to be well-fed. It also quotes studies saying juveniles more often use mudflats, but that has not been the case with first arrivals at Bedlams in the last few years. Many species have higher mortality rates in first winter birds, but checking Golden Plover on BTO Birdfacts this is one area for which we still have insufficient data from which to draw results.

The general trend for Goldies in s-e England is for an increase in numbers after moult, often coinciding with the onset of colder winter weather. Further hard weather influxes may occur, but in recent years numbers are generally plateauing from late November.

On the fields

By this time the Medway counts are into four figures. These larger numbers stick, for the main, to the permanent grasslands of Chetney Marsh, where they also feed as well as loaf during the day. They will sometimes partly/wholly move west to the ploughed fields on north-east Barksore. Interestingly, counts of birds on the mud at low tide remain fairly consistent at between 2-300 birds, but on one date this month over the full moon period I counted just over 700.

The Chetney loafing site remains constant, west of the pylon line, with feeding there and through the grassy fields west to Stangate creek. The loafing flock is, for the main, single species; when feeding the birds are mixed in with the much larger numbers of Lapwing. The birds do not suffer close approach, and generally remain a field or so north of the Saxon shore way footpath.

The loafing flock, January 2014

Feeding at night

Perhaps there is enough feeding close to these areas- Chetney marshes are now deliberately grazed by horses to ensure a less tight sward. But it likely these birds, as elsewhere, might well have a much larger feeding area. Whilst some of the more suitable fields just inland to the south have been lost to solar farming of late, talking with some local landowners, numbers do use fields south of Funton at night. They all agree numbers in recent years have been much lower than in earlier decades.

It is easy to first speculate the Bedlams Bottom birds are birds that feed south at night, whilst the main numbers can get by quite well on Chetney feeding day and night. But peaks of birds on the mud suggest otherwise.

One important factor that affects nocturnal feeding is the state of the moon; more Lapwing and Golden Plover feed at night under a full moon than a new. the additional light aids their searching. Theoretically, the 'flats' birds might need to feed more in daylight hours, but I have not noticed any change in numbers tied to the lunar cycle. Better night feeding around the full moon might cause a few more birds to switch to the safer(?) flats to day roost.

For several years I was lucky enough to live on a farm among fields perfect for Lapwing. Birds would arrive an hour or so after the end of twilight, but often largest numbers would only be present for a couple of hours; I suspected that if feeding was good they would be in and out and back to safe loafing areas as soon as possible. Darkest nights saw lowest numbers, and birds staying longer.

Both Golden Plover and Lapwing can become active more than 50 minutes before dawn. About 20 minutes before dawn they gather together, then on dawn they disperse to continue feeding if needs be. Here, watches during twilight/dawn have confirmed large movements of Lapwing flighting back to Chetney/Barksore from farmland to the south. Goldies have featured, but never in large groups.

The more you learn, the more there is to find out.

The future

It is clear that the larger scale urbanisation/development further west along the southern estuary have removed nearly all the suitable feeding habitat; continued loss/changes in use of the farmland between the Medway Towns and Sittingbourne could well have an impact on the carrying capacity of the Estuary for both these species (plus Curlew and Snipe). In recent times changes in field usage alongside the Thames led to the decline of the Cliffe birds (that would loaf out on the Higham Bight mudflats). Just this week, between the drafting and posting of this blog I have seen twitter feeds making reference to a need for more work on nocturnal core areas in consultancy surveys, which is a heartening development.

Around the estuary

So, from data Chetney and Funton would appear to have been Gillham and Homes' 'certain portion of the Medway' more than sixty years ago. For Rainham, Prentis, in the 1880's commented that 'November is the month for the Golden Plover, their arrival is most uncertain, some years they are tolerably plentiful, others very scarce. They frequent the plough fields, fly together in company of an evening over the low hedges, where they may be intercepted and shot...'  A century later and Holloway conclusions for the Gillingham district were 'a few birds are seen on migration each year particularly in autumn but the species is surprisingly scarce during the winter when a few may be seen during hard weather...'

Looking at the published county records up until my return to Medway, Golden Plover may have been a less regular visitor until the grazing on Chetney changed to a more Plover-friendly regime. This main roost area is on a game shoot. The are still legal quarry in the UK, but it is not known if Plovers are taken regularly there- a recent article in the Shooting Times stated they are shot rarely in the UK nowadays.

Records further up the estuary remain quite scarce- the odd bird or two in autumn passing south overhead, or perhaps a displaced traveler during harder weather is really about all a watcher in the Medway Towns can hope for. Much better to get to Chetney and enjoy the distant spectacle.

Part of the Chetney flock, December 2014