Scoters on the Medway

Horrid Hill, Nov 2017

Scoters. Not rare birds at a national level by any means, but birds that brighten up a Medway day. Scouring the annual county bird reports, very few sightings have been deemed worthy of inclusion. Those that have made print indicate a smattering of birds on migration plus the odd immature in the summer. Most are winter appearances, mainly single birds for one or two days.

Of course, the reporters don't help matters when they just report as 'Grain', as so often happens; which river are they actually on? As discussed in my last blog, birds can and do enter Medway airspace.

A similar tale for the Velvet Scoter; just the odd record, indicative of wayward migration:

Just one single bird single day record in the five years back for me, so just think of Velvets as the close cousin that behaves in a much similar way, but never, ever needs to move as far from home.

Best we concentrate on Common. They have never been seen in the estuary in number, and have been nowhere near annual. Low observer coverage and limited shoreline access have probably hidden the true picture to date. Though still not in any number, they are most certainly annual.

While Scoters will feed on the most commonly available favoured shellfish, they have a preference for sandy substrates. The Medway does have a sandy element, but is much muddier than found in their usual Greater Thames hotspots. In such favoured wintering areas, numbers can vary wildly year-to-year, thought to be a response to prey availability. Such yo-yo-ing is harder to detect in the data now peak years are so much lower.

Migratory volumes may also be down, but migratory timings are still fairly similar Common Scoter Channel numbers build through July into August (immatures?), second peak mid-September- early October (females/immatures?) and a third short peak early November (more males?) Spring migration peak is late-March/early-April.

Half Acre, December 2016

To understand what we see, we need to forget the political boundaries. Wood's 'Birds of Essex' gave a status of 'common passage migrant and winter visitor with a small non-breeding population in summer. Common? Yes- on the shallow waters over and around offshore sandbanks in the mouth of the Thames. Land-based observers have always faced a difficulty picking up a true reflection of numbers present. A screengrab from the excellent visitmyharbour.com shows the vast offshore mudflats (green) not always shown on a land-based OS map.

Wood makes particular reference to flocks off of Maplin Sands, and, just north, off of Dengie; 7,000 off Maplin in February 1976. Those days are gone. Present nos in the UK are estimated to be much lower around the Thames. "Although small flocks occur widely around the coast, the majority of Common Scoters wintering in British waters do so in just a few large congregations. Aerial survey work in recent years has revolutionised our knowledge of the true numbers of birds present, although estimates for particular areas do tend to be relatively imprecise. The present estimate is highly dependent on the numbers assigned to Liverpool Bay (55,000), Carmarthen Bay (20,000) and Cardigan Bay (12,000), with further counts of over 1,000 off Norfolk, the Forth, Tay, North-east Scotland and the Moray Firth. Large numbers also occur on the Solway but mostly in spring and autumn, presumably en route to/from areas farther south."

Year to year numbers do fluctuate (any cold weather displacement of even a small part of the 80,000 wintering off the Dutch coast will quickly paint a different picture). A screengrab from wheresthepath shows these banks, plus smaller ones a little further east. And the way the wind farms have been built away from them. The windfarm bird concerns have always been more about the pelagic species, such as Red-throated Diver; 'seaducks' are not as much at home out on deep water, being happier feeding at depths of up to around ten metres. Bird factoids often confirm that Scoters will dive up to 30 metres, but in reality most feeding takes place below ten- fifteen metres, much at one to three metres. Such areas are not often found for long periods in the Medway away from the shipping channels.

Defining the coastal zone. Looking at the map there may be a lot of open water, but the shipping channels are there, and studies have shown larger flocks (roosting, which break into smaller feeding flocks) tend to flush at the greatest distances, usually around the one kilometre mark. Nor are Scoter pelagic, avoiding the deepest waters (why spend time away from the easiest feeding?) explaining why the studies for the wind farms were more concerned with the likes of Red-throated Divers.

Back to my opening speck shot here, those four Common Scoter off of Horrid. Most birders would 'meh' at both the pic and the views. You can't blame birders for sticking to honeypot reserves. All part of why Common Scoter are under-recorded. They're rare in these parts, as are birders.

For any Scoter to get here, they have to be drawn from those shrinking numbers still traveling this far south and west and not stop short for either their summer moult (immatures) or for their winter quarters (mainly immatures and females- a male is always a red-letter day).

They have to be willing to put up with the increased traffic in the shipping lanes next to their old favoured coastal zones, and they then have to have some obscure reason to then turn south into the Medway. In clear weather they'll avoid doing that a lot of the time, for sure. Why they more often arrive arrive on muckier weather, and why it sometimes takes them a few days to find their way out- feed up and leave when good conditions return.

Why always better to consider the Medway as 'inland' for such species. Why Medway estuary Scoter record patterns are a little more like inland sites such as Leybourne lakes.

Overland passage of waders and wildfowl from the main estuary (yellow) is seen often enough in the autumn, less so winter and spring. (And passage via the river mouth itself has been less well studied.) Leybourne lakes (orange circle), south of the Medway Gap through the North Downs, do get less than annual records. As with many seabirds, flights over water into headwinds are easiest observed, tailwinds see height and some missed, overland flight is even higher. And, thanks to radar studies in the Baltic, we know a lot of Scoter movement takes place at night.

(An aside, the Essex publications all speak of passage up the Thames. Some turn back, others disappear around the green line of Lower Hope Reach. Overland movement is probably a much easy subject to study there. Some birders have been working on it from both sides of the estuary for several years now, and will, hopefully, write up one day.)

The Shade, November 2013

Birding the north shore: Medway seabirds from Grain

For most birders down the years, the Ordnance Survey has been their guide to patch boundaries, and the Medway has ended somewhere between Sheerness and Grain. If you check the annual county reports, totals for birds such as Common Scoter have often just referred to counts as being at Grain. Historically, the ease of parking and the lure of adjacent bushes has dragged visitors to the north shore; very few birders have enjoyed the concrete of Sheerness- if you've made the effort to visit Sheppey for birds, then Warden, Leysdown and Shellness will always drag you to east.

When I birded Grain through the nineties, the Ordnance Survey told me of the Roas Bank and the Flats. At the time, most birders just called the whole expanse the Roas. The older OS maps had made more of the Flats, with the Roas being a small area north of the village. Depth readings today show no raised bank; it is still there, an area of much more solid mud (I have walked it once, and that was enough), but the modern navigation maps have dropped it.

The other advantage of the navigation maps is the offshore detail- excellent sites such as i-boating allow you to see what the seabirds can see; the deep water channels. Seabirds love 'em. On the screengrab you can see how the Thames has a clearly defined channel cutting close to Canvey island; why they get close silhouette views of Skuas, why Kent birders see clear but extremely distant shearwaters (and why the two county annual reports have different totals/mixes for such species most years- as one local birder always argues, the two counties really need to be talking to each other more).

But I digress. The tentacle that is the Medway deep water channel is extremely clear; for sailors, the tidal effects can felt some way offshore (the first maker buoy is highlighted above), and why, some birds moving past Sheerness can be said to be using the channel.

Politically, the boundary between Medway and Thames is an imagined line between the main bastion of the old Dockyard at Sheerness, and the church tower at Grain. It appears on the navigation maps, and is hinted at by marking the local constituency boundary through the estuary.

Zooming in on the navigation maps, Dolly is still there:

...but Roas and The Flats have made way for Grain Spit and Yantlet Flats.

Drawing the imaginary boundary line makes for a very convenient marker on the shore, just a couple of metres shy of where the boundary hits the seawall; the old concrete lookout, a shelter for many a long seawatch (circled in red).

Nowadays my visits to Grain are few. Back in the day, fair weather meant watches north of the village, overlooking the Thames. No sane birder would choose this blockhouse. Or the benches above it, just south of the Moat at a height of five metres, or atop the Moat itself, some ten metres above sea level (both good spots to listen for the wandering tit flocks to break the monotony). All a short walk from the Chapel Lane car park (blue). But if I'm there nowadays, I'll try these for their views out to the Medway Channel.

And you really have to have a sad Medway fixation to want to watch due east, when many more birds are following the Thames just north of you; this morning's clear sky beyond Sheerness would have most giving up in minutes.

The old bastion in Sheerness docks is just left of centre, with the mid-river Grain Tower far left; slap in the Medway, despite the owner claiming the address as 'No 1, The Thames'. If a bird has gone south past the Tower, it's in the Medway, physically, politically, geographically, list-ethically.

All good reasons not just to keep lists. Take Common Scoter. Today a small group were picked up high off of Jacob's Bank (north and west of Sheerness). Clearly following the shoreline. As the reached the Medway deep water channel they dropped low and turned south-west, in and past the Tower. And they used it like a race marker, arcing behind it and heading back out north-east down the Channel, to put down out around the Great Nore. (More on that species in my next blogpost.)

So, what lists could those Scoter have ended up on today? Grain? Tick. Sheerness? Tick. Thames? Tick. Medway? Tick. None of which tell the story of how this dog-legged narrow Channel puts off seabirds from venturing further into the Medway estuary. All helping confirm the Medway's rare position of 'inland estuary', ornithologically speaking.

to 

A final postscript; the Grain warm water outflow steams once more! Certainly the gas-fired flow and temperature may be somewhat lower than the old oil-fired station, and not likely to bring a repeat of the glory years of Tern attractions but it was enough to lure Cormorants and a Shag into the mist this morning. Who needs Dunge, eh?

Up and down the Stangate Strip

During the winter months a rising spring tide from the Chetney sea wall provides one of the best wader spectacles on the estuary. Make the walk out from Raspberry Hill to close where the path cuts east over the Peninsula, and watch towards Slaughterhouse Point. As the waters keep rising to cover the neap roost sites, more and more lines of birds head past you towards Barksore saltings. At first, small groups of Grey Plovers, Godwits, Curlews- then a procession, chains of waders large and small coming off of Greenborough, Burntwick and the Chetney saltings. As the tide tops, large flights of Oystercatcher and Curlew may take to the sky just north of you, joined by big numbers of Lapwing, sometimes pulling the Golden Plover up with them. From then until the safer roosts uncover, wheeling flights of aerial roosters keep tripping overhead. All the excitement of the Stangate Creek complex- without actually viewing very much of Stangate Creek.

Historically, for the birdwatcher Stangate has always been difficult to view from land. Certainly there's a distant sight-line from the right lay-by at Funton, while further away, the panorama from up on the Saxon Shore Way, but as most birders are not content with counting specks these days, few bother (40 months back, still not bumped into a birder up on Tiptree Hill). Searching the various local birding guides very few authors have touched on the importance of the creek.

Starting from the mouth, working clockwise, the eastern flats opposite Burntwick, Sharfleet Creek and the north-east corner of Greenborough run into an unnamed (on the charts I have seen at least) large serpentine creek (A) that cuts into Chetney marshes for nearly a kilometre from low mark to seawall. For my purposes I've called it Chetney Creek (but if anyone can put me right...).

From the angles available up on Tiptree Hill the Creek appears to be a pool. It certainly has a good deal of standing water nearby in the form of dykes and reed-fringed fleets. Flights of duck are up and about as the raptors pass over.

On low waters, many resting wildfowl mainly line these flats, while the majority of the 'local' waders will have moved just north and east along the main channel by Blackstakes (B). Come the rise a number, of these waders move into Chetney Creek, more with any northern/eastern element to the wind. Many Shelduck and geese (wild and feral) will be either side of the wall here throughout the tidal cycle.

As you continue south south relatively little mud is exposed until you reach (the impressively named) Chetney Hill, The old Blackstump Creek (C) is still in good shape and is used by many birds over the tide, even though the sea wall has cut the creek off. Some excellent habitat around the Creek has been further improved with a pool/scrape, sadly obscured from the Chetney footpath (yellow) but is viewable, distantly, from the Saxon Shore way on Tiptree Hill.

The low mound of Chetney Hill is made into a round island by the Chetney canal that surrounds it. To the south and east the canal holds few birds at roost (due in part to the proximity of the public footpath and farm buildings), but the west and north are relatively undisturbed over the tide. The western edge is the site of the Oystercatcher roost birders can scan from the lay-by on the Funton road. Loafing Brent often use the roost (with birds still using it now in Mid-May). The late winter Knot flock, which more usually favour Greenborough or Chetney Creek, sometimes crams itself on here; this past winter the Knot actually usurped the Oystercatchers for a while, who retreated en masse to the old dock by the footpath.

(For any local historians, there is also the interesting story of the Chetney Hill Lazaret.)

Stangate Creek now has a dog-leg to the west. This borders the eastern end of Barksore (G), which has a remnant area of saltings now mainly covered by spartina; larger waders like Curlew can retreat here during a spring tide, and many Little Egret and Grey Heron will also gather, but the biggest numbers are now found at the end of Stangate; on our clockwise journey we now swing north onto Greenborough at the three-way junction with Millfordhope and Halstow Creeks (H) a substantial pre-roost gathering of waders and wildfowl builds, which can hold out spread along the old sea wall as far as Slaughterhouse point on a neap. This is an important shelter when certain winds, or disturbance, hit the Funton complex, and is where some/all of the 'Funton' Avocets will usually be found when reported as 'missing' from their main roost.

For the remaining journey back north out of Stangate Creek the western sea walls are covered by gulleries in the summer months. In winter, many waders are spread along the same walls. On the low tide these birds move, in the main, west to the larger flats such as Ham Ooze. As far up as Sharfleet Creek (I) resting duck and especially Geese will be sat on the western mudflats. The Greenborough shoreline is the more routinely fowled, when the birds drop east to Chetney. It is a similar usage picture for Sharfleet Saltings (J) and on up to the mouth at Stangate Spit (K).

That is Stangate circumvented; within that outline, the waters of the creek keep a good depth over the low tide period, and can be a magnet for birds. In winters when a local notable such as, say, a Long-tailed Duck or Common Scoter take up residence, over the high tide they try to keep to a good feeding depth of water, so move into Funton or Halstow with the tide, but then back out into Stangate on the drop. Any number of Goldeneyes and Mergansers present will follow the same routine, as do the smaller Grebes and the odd Diver. Stangate is a safer haven than the wide open waters of the main river channel along Saltpan Reach.

The distant waters of Stangate Creek at mid-tide
(foreground Barksore and the flats of Funton Creek).

(An aside. I still deliberately remain on land for my birding; the various boat excursions for bird/seal watching nearly always end up in Stangate Creek, invariably turning up a good record or two around there. The birders that travel out on them swear by them. Whilst I can't personally vouch for any, a trawl around Queenborough quayside, Riverside Country Park {and even the 'floating tea room' at Lower Halstow} will find details of several different owners offering sailings.)

So, that's birds around Stangate, birds on Stangate, and now birds over Stangate. The mouth of the Stangate is the preferred arrival/departure for many of the breeding Terns that, in the main, prefer to head out to the open waters of the Greater Thames to fish. The southern end of the creek is directly below the flight-paths from Millfordhope/Halstow for waders/wildfowl en route to safe roosts. All the time birds are switching east to west to east over the rest of the creek. When breeding, the gulls routinely follow Stangate out south for feeding, or simply 'hop over' onto the Chetney fields to loaf/feed. The Marshes here are also used, pre-breeding, as gathering sites for returning birds, a time when counts of Mediterranean Gulls can reach three figures just inside the Creek.

Meds 'n' Black-heads, Chetney, April 2015

Human usage is, in the main, as an overnight mooring for small craft during the summer months, mainly along the western edge of the deep water channel. More than a dozen boats can be anchored at a busy weekend, in the main seen as little threat by the roosters/nesters (it is the smaller craft, sailing close to colonies on the high tide, that cause most disturbance (landings are mainly limited to the unsigned Burntwick island, but most going ashore soon realise not to go near the colonies).

Of course, this guide is for the benefit of anyone seeing the seaplane playing on the 'runway' designated by Peel Ports; it is easy to appreciate the disturbance caused when on the strip, but disturbance to birds alongside, beyond the seawall as the plane banks low will be apparent to any observer.

One lives in hope Peel Ports may yet see the problems for this internationally protected and internationally important area.

Coming into land in south-west Stangate, over Chetney Hill, July 2015