One for the Road

Motney, Apr '15

The Road Goose An old name in some parts, including Kent, for the Brent Goose.'Road' being the soft English version of the Scottish name, 'Rood Goose'.

My first spring back in Kent, 2013, saw a very cold May and I found myself surprised by the number of Dark-bellied Brent calls still to be heard around the Medway (and on into June). I'm sure I'd encountered them before in numbers, but they just hadn't registered. They were only Brent, after all.

Every spring since then, Brent have been present well into May, and every year other birders have been surprised to read my comments about them via, either my now-defunct Facebook account or on my Twitterfeed. So, last year I blogged a short photo-essay on them to help explain. This spring, I'm sorry to say, comes the verbose full blogpost. You have been warned. Hit that link for the short version if you like. Otherwise, enter freely and of your own free will.


Ancient Roads

Twinney, March '17

The old county avifaunas reveal Brent, like many wildfowl,only visited in very small numbers, unless the weather was extreme:

"...in an ordinary open winter, such as we now experience, a few of these birds are always to be found..."

"...in the year 1739-40, when these birds were so abundant on the continent... they were so plentiful on the coast of Kent that they were in so starving a condition as to suffer themselves to be knocked down with stones and sticks: and were carried in carts to the neighbouring towns, where a purchaser was allowed to pick and choose for sixpence apiece..."

"...in 1803 they were innumerable around Sandwich, and were so miserably poor and debilitated as not to be able to rise after alighting, and many were taken by hand..."

"...the Rainham creeks, says Prentis, are visited by small numbers in severe winters..."

A History of the Birds of Kent, Ticehurst, 1909

Road building in the 20th century

There is no real reason to think things changed in the decade after Ticehurst. Many birders do have an inkling of what happened in the 1930s, a collapse of the world population. Just how big numbers had been before the fall was down to speculation, but a correlation was seen between the decline and the world collapse of seagrass, a favoured foodplant. Today, most accept there was a bit more to it than just the seagrass, with evidence found later for other problems such as a long-running series of annual breeding failures. A perfect storm that saw the world population continued to slide for the next two decades, down to an estimated 15,000 in the mid-1950s.

Brent were removed from the UK Quarry list in 1954, and France banned hunting them in 1966. Denmark, a vital staging area, stopping shooting them in 1972.

Organised counts in Kent started in the 1960s. Brown and Grice quote five-year averages on the Medway for 1960/61- 64/65 as just 115, 1965/66- 69/70 little better at 205. But from the 70s onwards numbers improved and by the 1990s counts of over 4,000 were being made here. Recent WeBS surveys have been lower, but published records show the Medway still routinely holds nationally important numbers during winter:

For me, this was yet another species that showed a 1990s peak on the Medway, just as many other waders and wildfowl have done. My gut feel had been this was a reflection of an observer/effort bias from that time, and that numbers may well have gone under-recorded since then. This blogpost is about my findings during the spring months in the last five years.


By- Roads

Shoregate, Apr '15

First, a need to clarify the texts found in many summaries such as 'Birds in England' and 'The Migration Atlas'. They refer to numbers remaining in late spring 'on the North Kent marshes'. Not strictly true. The numbers are restricted to just one of the three estuaries making up the North Kent marshes, and that is the Medway. Brent numbers for both the south Thames (to the northwest) and the Swale (to the east) mirror the national tendency of a drop from February onward to virtually none by April and May.

There is a trend to 'lump' these estuaries together as one, based on theories of a large number of intra-seasonal exchanges of waders/wildfowl during a winter, but this really is one species which shows such a lumping to be a mistake.

The Swale mirrors the Essex marshes, where seagrass species still survive and provide good feeding for late autumn and the early part of the winter. Numbers then remain relatively stable as other food sources are available after that, but the birds do move off in February:

The Thames (here referring to Kent's southern Thames foreshore) does not really draw in the Brent in the late autumn/ early winter:

So, the pattern during the past 40 odd years has been clear- it is the Medway estuary that appeals to Brent during the early spring.

Monthly average mean totals 1971-2011

The only other sites in England where Brent hold on like this are along the north Norfolk coast, in particular, the Wash:

"...the majority of the flocks move off eastwards again in March, leaving smaller parties lingering in the north coast estuaries until May..."

"...a count of the Wash in May 1996 produced  a total of 7,220 birds still present..."

'The Birds of Norfolk', Taylor et al. 1999

The Stour in Suffolk and the Beaulieu in Hampshire are two other estuaries that have started to see a few hundred birds hang on during spring in recent years. But the Medway remains second only to north Norfolk.

The road to Siberia

"The birds start to leave in late February... gathering first on the Wash, and in recent years, on the North Kent marshes, where they remain until late spring..."

'Birds in England', Brown and Grice, 2005

This simplistic map of Dark-bellied Brent Goose passage is based on 'Birds of the Western Palearctic' with timings from 'the Migration Atlas'. Adults (yellow), in general, stage in the Waddenzee off Denmark, then move to the White Sea. Their final jump is then into the eastern Palearctic to breed, with nests and eggs building in number only from around mid-June. Their journey is long, the weather window for breeding is open only for a few weeks, so it makes sense to break the journey down and stop short to wait for the weather to break. As soon as the breeding season is finished, the end of August, the main outbound migration gets underway again, essentially using the same route.

At the start of spring youngsters (green) will be disowned by their parents from February onwards as migratory urges kick in. Brent do not breed in their first summer so, although some will return to nearer the colonies, some will stop short just above the White Sea. A useful strategy seen in many slower maturing species.

Could it be that these late staging Geese on the Medway have a higher percentage of young non-breeding birds among them? The alternative would be a good percentage of adult breeders hang on among the spring birds and then make either a much longer staging flight in May, or pause for only a short while at one of the sites. That possible if milder winters are leaving them in better condition for such changes. Questions, questions.

Ageing Brent Geese at this time of year, at a distance, is really quite a job. Without boring people, you are looking for retained juvenile coverts in the wing. You can do first summer birds, and even some second summer, but never with certainty for a fair proportion of any flock. I've been trying. Armed with 'scope and working through the closer birds at places such as Bloors, or simply looking for behavioural clues (obvious 'pairs'), the Medway in April seems to give off a feel of a slightly higher number of young when compared to mid-winter flocks most years. Nowhere near a significant observation though, but an interesting idle thought getting me through these cold April days this year.


Road traffic surveys

A distant gathering at the tip of Stoke Ooze, May '15 

Could such a change in the adult/young ratio indicate some of the 'Medway winterers' being replaced by non-breeders birds from further south? Doubtful. There's no evidence of overland migration, unlike in the autumn when flocks head south/south-west from the Medway. There's no obvious westerly passage along north Kent coast, either (but then the passage would be considerably smaller, of course). Perhaps disowned youngsters could be arriving from Essex? I rarely record flights of Brent into the Medway, but then I'm not at the estuary mouth every day.

My original plan in '13 was to count the estuary waders (and wildfowl) throughout the winter through to the end of March in 10 day periods rather than just monthly. April and May were set at 15 day periods (I wanted a bit of a rest). For Brent, there is no straight line decrease as winter ends, the totals wobble. I'm no statistician, so can't say if significant levels, but this could be a hint of a Medway hub. Some Medway birds could be taking off on their long inter-continental journey while at the same time they were being replaced by more local birds planning on taking a later flight.

All highly fanciful thinking. and I'm no scientist. The main point is, as with so many species, there is still a lot to learn.

One example, there really aren't that many Brent ringed in the UK. Ringing and Migration v31 p2 dropped through the letterbox recently. In 2015 just eight Brent were ringed in the whole of the UK, bringing the grand total up to just 1,164 with 92 recoveries to date. Colour-ringing elsewhere in the UK is starting to provide more data. Perhaps here one day?


The local Road network

During the first half of April this year Brent numbers have been spread throughout the estuary, from Folly Point to Cockleshell beach, some eleven kilometres apart as the Brent flies. The google earth map shows the main favoured areas. Their usual pattern. Not many groups are close to shore for any length of time, other than at freshwater inlets such as Bloors wharf.  The shoreline birds at Cockleshell beach on Grain seem to be an exception, they often commute to and from Deadman's island. But the vast majority of the Brent enjoy the relative peace mid-estuary, scattered around the relatively undisturbed islands.

All this makes getting any realistic count problematic. Hard enough with a group of birders co-ordinating efforts, pretty mad for someone operating alone. There really is nowhere from which to count both halves of the estuary at the same time; a series of mad dashes from west to east are needed to prove the birds quite lazy and staying to their discreet groups on certain parts of the estuary (yes, I am that strange birdwatcher who stands on the bench at the tip of Horrid Hill to get any height advantage he can.) Thankfully the eastern basin, Oakham to Cockleshell, can be scanned in one go from high ground, such as at Tiptree Hill. I still have yet to see another birder there, perhaps because the birds are now distant specks. Not many birders enjoy something akin to Napoleon watching battlefield troop movements(!) Of course, the counts are relative, some will undoubtedly be missed, especially among those up on the saltings. By putting up with such challenges, it is possible to show there are more than a thousand birds present this April (keeping the estuary at a nationally important level and continuing in line with counts the past few springs).


Road fuel

Frog farm, Mar '17

The special geography of the Medway clearly offers safe refuge. What about food?

Brent are vegetarian. Many texts highlight their reliance on seagrass, in particular eelgrass (why they love Foulness in Essex in the autumn).

There's not enough eelgrass to get by on. As winter sets in Brent make a second movement (why those large Essex flocks move, some into Kent) and will next take a great deal of green algae where available, chiefly sea lettuces.

Still not enough. From the 1970s onwards improved grasslands have played a much more important role in Brent diet, particularly crops; autumn-grown cereals (wheat and barley), and sometimes oil-seed rape.

But still not enough. Brent will take Glassworts and 'wild' grasses including salt grasses, fescues and cordgrasses. Arrow-grass and sea aster are also taken. These higher salt-marsh plants will have been first taken alongside the algae, and exhausted quickly but, come the start of spring and fresh regrowth, the Brent are back for seconds.

So, where a good enough mix of food types is available, good numbers of Brent can remain all winter and on into spring.

Eelgrass deserves a special mention at this point. Here in Kent it went extinct in the mid-1930s. A close relative, Narrow-leaved Eelgrass, hung on and is still found at the eastern end of the Swale and on the south Thames around the mouth of the Yantlet but within the Medway, Narrow-leaved Eelgrass was only recorded for the latest Kent Flora atlas from around the mouth of Otterham creek. Now the author of the atlas admits it being 'probably under-recorded through difficulty of access', which was down to his insistence on not relying on the reports of others and having to see every less common specimen at each site for himself during his many years of exhaustive fieldwork.

Here I admit I struggle to recall ever knowingly seeing eelgrass. It favours mudflats close to the low-water mark, or grows, floating, below the low-water mark in estuary channels, somewhere pretty much impossible to get to view from the shore here. The author also failed to find any examples of a third species, Dwarf Eelgrass, on the Medway, even though it is found in similar areas to Narrow-leaved on both the Thames and the Swale. So, what is the true picture for eelgrass species on the Medway? Watching the Brent in the autumn, many seem to be feeding on algae. Bearing in mind this single-minded approach to recording for the flora atlas, there is certainly room for someone to check matters out. If anyone knows, I'd love to hear. (And, yes, eelgrass is on my bucket list.)

Along the southern shore suitable grassland is available at Ham Green, Barksore, and on large areas of Chetney. This is in the main is 'permanent' standing grass. Over on the north shore, cereals can be important; the fewer such crops sown on the south-facing slopes of Hoo, the fewer the Brent in the western basin during a winter.

So, the spring. If Brent were relying on eelgrass regrowth in April and May, surely birds would also be on the Thames and Swale? There are saltings on both these other estuaries, but mostly are on the shoreline meaning, perhaps, too much disturbance? Algal regrowth is often greater, earlier, in the relatively sheltered Medway, so might well play some part in the choice. Crops and grass appear to be rarely touched in spring.

In all probability both good food supplies and safe feeding areas are needed. The volume of saltings edge available among the islands, away from disturbance, must be a win bonus.

The feeding routine is essentially diurnal, and tidal. This lends itself to the island complex. At this time of the year, many of the birds will be hidden up in the saltings over high tide then some, not all, will work a short distance over adjacent flats to continue feeding as the tide drops.

Again, this creates problems for obtaining highest counts when checking a creek or bay. Often only the Brent nearest the edges of the islands can be seen easily and often out of decent binocular range. Because only some Brent some follow the tide out, often easy to think the 100 Brent in open view on the mud, to loaf/feed on algae, are the whole group, whereas a strain of the eyes along the island edge will often double that number as the birds loafing/feeding among the salt marsh plants give themselves away.


A pothole in the Road

Bartlett Creek, May '15

"Any Brent you see in the late spring and summer have been shot, and can't migrate."

A much-chanted mantra over the years here. Believed it for decades myself, heard it again a couple of times this past winter. Since coming to understand the complexities of Brent migration a little better, I have looked for summering Brent carrying any obvious injury. Early summer sees the small numbers remaining keeping together, often flying together for short distances. The problem comes when numbers drop further and lone birds starts routinely strolling between their low- and high-tide areas. I have yet to see a shot bird. It really is time for birders to reconsider over-summering birds as perhaps not being walking wounded, but more likely lazy birds with very weak migratory urges.


Anti-Road protestors

Motney, May '15

In April and May more users are venturing out onto the estuary. Most boat owners cause little concern, but smaller craft are known to make landing on various of the islands. Brent can be pushed out of the western basin, especially over weekends, by personal watercraft such as jetskis and hovercraft.

Human encroachment on the shoreline saltings can keep birds off of feeding areas and cause damage to the salt marsh foodplants themselves, an example being the widening paths out onto one reserve on the southern shore. Vegetation disappears, the mud becomes soft and the walkers move to the side; wide paths grow through the sea-purslane and glassworts.

Bait diggers working nature reserve saltings, Mar '17

The biggest problem for the geese in the eastern basin this spring would appear to be seaplane activity, as the birds cannot tolerate the low banking turns over them when on the saltings and islands- with both of the authorised landing strips being placed adjacent to the island complex, such disturbance is routine.

Brent landing at Twinney after flighting from Ham, May '17-
the seaplane completing maneuvers in the distance over Ham Ooze

Thankfully flights have been few so far this spring, but will become more frequent as the weather improves during May. Other species are affected as well; the over-summering Curlew have already been pushed from Greenborough this spring and are proving difficult to relocate.

Road Planning Departments

Rainham Creek, May '16

The estuary is protected, but is a multi-purpose site with few actual 'reserves'. In respect of looking after the Brent, rather than bang on about the 'usual suspects' birders know about such as the EU Birds Directive, SSSI, MPA, Ramsar, etc., this time I'll big up some responsibilities listed as objectives under AEWA (The African-Eurasian Migratory Waterbird Agreement, an international treaty overseen by the United Nations Environment Programme). Yes, thankfully, political bodies and organisations do try to uphold such things. Brent are just one of the 254 species dependent on wetlands covered by the agreement, requiring action such as;-

- Population monitoring-  here in the UK mainly via data collected through WeBS.
- Minimum disturbance- potentially damaging activities having to be controlled within disturbance-free refuge zones.
- Reduction of conflicts with agriculture- a suite of policies/schemes available to landowners.

This time I'll also big up an umbrella group interested in considering such matters for here- MSEP is the Medway Swale Estuary Partnership, looking to co-ordinate and promote sustainable management and use of these two estuaries through bringing together the likes of councils, conservation bodies, wildfowlers, boating associations, fishermen, port authorities...

Getting the balance of interests right is never going to be easy, and I wish them luck in such things as keeping the Medway 'roadworthy'.

Twinney, May '16