Weigh heigh! And up she rises?

The Westmoreland was wrecked off of Hoo over on the north shore back in 1973. Another of the many old sailing barges to come a cropper. Her agony has been prolonged. The wreck was taken to Faversham, in the hopes of restoration, but time and money ran out a few years back. The owner of the Edith May then stepped in and bought her and transfered her, on a floating dock, to Halstow Creek, where she has sat out at the end of the old causeway.

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Friday, an hour before the tide covers the flats. Halstow creek is busy with Pintail and Brent. Both are up in number, even though numbers have been going down; an internal estuary movement of lowering estuary numbers as the fowl try to gain a little shelter from the increasing easterly wind.

A figure passes me. I look up and see they are carrying a shovel. Curiosity is aroused; the local Parish Council have long-since stopped bait-digging here, but one or two still flout their rules. But a bait-digger uses a fork? And has a bucket to carry the bait in. This chap clearly had a spade and a rather large spray can of compressed air. Curiosity dials up to eleven.

They cut down off the seawall and out onto the old causeway. Now overgrown with weed, and with sections of the brickwork missing, it is not a particularly nice walk. I've done it twice in five years. Both times on an ebbing tide, to follow the waders out, at a distance. I'm in no hurry to try again. On the rise? Wouldn't risk it and besides, there would be an awful lot of birds disturbed.

I think he must be an owner of one of the handful of sailboats kept out there but, no, he keeps going, going, going.. right off the end, knee-deep in the clinging mud, pausing only to retrieve.. a child's plastic sledge. And make for the Westmoreland.

All sorts of alarms go off in my head. During the past five years I'd seen enough wreckers on hulks to know there's money in old metal. Was he planning on dragging some back? I'd planned to be off to Funton by now, but it could wait a little longer. I like the Thames barges, and didn't want anything happening to this one.

He disappears inside the floating dock. Through the 'scope, every now and then I spot his head bob up, then I see I saw a camera. What was happening?

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Of course, there is absolutely nothing to stop anyone going out on the estuary at Lower Halstow, though I wouldn't advise wading through the soft mud to anyone who's never tried it under guidance from someone with experience. You don't walk as such; lift a leg for a stride and down you go and 'stickfast'. There's a technique to wlaking the mudflats, and I'm not telling you! Instead I'll save your life here by keeping you to the seawall.

Although us birders know Twinney and Halstow creeks are a spectacle, neither are protected from routine usage. Disturbance is to be expected. So, as well as watching the mystery mudskipper, I watched the birds.

It was a rising tide, early afternoon. So, not too many gulls loafing on the causeway. By the last third of February you can usually expect to find the first handful of Mediterranean Gulls back among the Black-heads. There were eight, but they were sheltering alongside Halstow Creek. The Lapwing were in fair number for here though; often resting birds disturbed from the fields overfly, with some coming down to roost safely on the causeway; a three-figure number went up, along with a handful of Oystercatchers and Turnstones.

On the mud itself, many of the larger waders and wildfowl were soon off; they never appreciate a close approach. The smaller, as usual, stayed in more numbers, but I always add a caveat to that rule. The tighter the flock, the quicker they go; all it takes is one flustered bird to set off a flush. And the wildfowl on the water in Halstow Creek near to the Westmoreland? They retreated to the far bank.

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The 'wrecker' was off ahead of the tide, just, with his sledge laden with.. well.. nothing. And he brought it all the way back to shore. Quickly noting any second phase of flighting (just double figures of Lapwing had been happy enough to land back on the causeway, but now followed the others to Barksore), I moved to a point where I could intercept the chap and strike up a conversation.

Bad news. On Monday, in poor weather, the dry dock had decided to hole; the Westmoreland was no longer afloat. For me, the penny, like the barge, dropped. The can of compressed air was for opening/closing old rusty seals or similar; letting the water out. That's why he had gone out on the rise. To close things up. Open on the drop, close on the rise. And if I had had half a brain, I'd have noted the Westmoreland had shifted when I 'scoped it. Actually, shifted was an understatement. More liked twisted (or as the chap said, 'popped'). The shovel was to clear mud, the sledge perhaps a buoyancy aide to spread weight as the soft mud sucked up water on the incoming tide? Probably still got a bit of all that wrong, but I didn't need to ask.

We chatted for a few minutes. I asked after the Westmoreland's fate, bearing in mind Lottery funding had been turned down. They hasn't given up hope yet. The owners are Lower Halstow through and through, and the Westmoreland is a part of this village's history.

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An estuary doesn't just belong to the birds. The Medway is no exception. Lower Halstow, for birders, is one of the gems of the southern shore. But for now I understand we'll be seeing more flighting, more 'necessary' disturbance to the feeding birds- and right at the start of the coldest winter weather here for five years.

Here on the blog I sometimes mention the estuary is protected by Ramsar. The Ramsar Convention on 'Wetlands of International Importance especially as Waterfowl Habitat' is an international treaty for the conservation and sustainable use of wetlands. Recreational use has to avoid a detrimental effect. This was an unfortunate incident.

The Westmoreland had 'popped' on Monday. The end of February usually sees a drop in Knot numbers as they move off to the Waddenzee, but I'd been puzzling all week over why they had so suddenly moved out of the Halstow/Twinney creeks. There were still numbers in Funton still, but Lower Halstow's rising tide flock had gone, seemingly.

But another good excuse to keep going out at the moment. An bit of an impact study of sorts. The counts would be dull, but the more you don't see, the more you understand.

An estuary weekend is always three days long

Back to Friday the 16th and those wildfowlers. It had been a sure-fire (pun intended) certainty that the island shoots would be out for marking the end of the season. To be fair, spend enough time on the estuary and you'll soon suss wildfowlers are out most Fridays. Many of the smaller sites can only accommodate a certain amount of guns. Dates are allocated. They do not overshoot, so dates themselves are at a premium, and some they try to respect each other by not shooting the same day as their neighbour. It would be senseless to overindulge on the estuary.

When I think about the number of wildfowlers I've got to chat with these past five years, I've found many of the regulars to be the same as the fowlers of a hundred years ago; local lads, often artisans, often shooting for their own pot. The brickie, the chippie, the plasterer. The guys who can plan their work around the tides. Their weekends often start on Fridays when the tides are good.

Look at other activities on the estuary, and weekend preparations become apparent. Boat preparations at their moorings; the skipper getting everything right for his weekend crew. Club races? The temporary race buoys might be moored out in readiness the day before. River traffic can be up with extra craft arriving.

On the mudflats, bait digging can be high. The amateur, wanting to get a bit of bait for his weekend, will often make a dash on the Friday. The edge of Motney can be busy. It will have been high on the Thursday as well, the 'pro' diggers collecting a bit of bait to sell to the shops and their mates often want to have their wares ready for the Friday sales. they'll be back on the Friday low as well. They'll be the ones tresspassing on the RSPB reserve to get to the best diggings.

So, the two-day Saturday birder might never notice these changes. They certainly might not notice waders switching roosts, because many have done so the day before as disturbance levels rise. They see the peak at the weekend, with the boats, the PWCs (Personal Water Craft- the jetskis and the like), the canoeists, the hovercraft, the microlights, they all reach their peaks- as do numbers of public on the shoreline, all doing their 'thing'. Recreational pressure.

Mondays are up a bit as well but, thankfully, not yet as much as a Friday.

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A Friday, the last Friday of the shooting season, with a middle of the day fair height tide with a surge attached? That'll do. The waders will be up and about.

I chose Chetney. I gambled on a few more walkers on the public footpath. Lose some win some, walkers here always flush birds from the easily viewed pools alongside the seawall, but if I can find one to walk a quarter-mile behind i won't feel too guilty about walking the path myself. Bingo!

I also gambled on a bit of a POETS day finishing for some. ('Push' off early, tomorrow's Saturday). A local was out on private land. Double whammy. No problem with that, of course, but he was on Chetney Hill, and the waders will roost around the edge of the Shade and Chetney canal. Higher-pitched shouts? Pulled off the triple, the half-term meant had a noisy young family member out as well. Then the accumulator now paid out big time; their dogs were off the lead.

At this point I should mention I have never been in a betting shop. I've never bought a lottery ticket, never been to a Bingo hall. Boring so-and-so. Never been a gambler, more of an actuary, weighing up the risks and the premiums. What came next was the pay out of one of the closest aerial displays I've been privileged to watch in years.

Of course, for the birds this is burning up energy. They aren't snowflakes, they don't fade at the first flush, but the more they get pushed around, the further from peak condition they will be. The Medway remains a big site for birds, but one where reserves are few and most managed poorly. A grand sight, but a despairing one at the same time.

If you looked inland, the story was the same as well; Lapwings and Golden Plover up everywhere; some 'natural disturbance', some not-so-much. By the time I'd walked back up to the viewpoint a long-lens birder was out in the middle of the marsh on the footpath. They certainly got much better pics than I did; at least I got three or four more goes at counting the Goldies in flight. Again, absolutely nothing wrong, but there are days when these birds have to retreat further away from view. And as numbers of path users rise, so do the flights.

Some don't understand why I don't routinely promote commoner species. They're available on the reserves, geared for big visitor numbers. Footpaths aren't.

Here the biggest increase in path users has not been birders- too long a walk. It is joggers. Again, not a major problem- yet. But you do get your biggest counts on weekdays.The Mondays, Tuesdays, Wednesdays and Thursdays that is. The three day weekend here is driven by the game shoot.

Getting that last shot in

In England and Wales, the wildfowling season starts on September 1st, ends January 31st. With an exception, because those dates are for 'inland'. Birders sometimes miss that the season 'below high water' continues until February 20th. The definition for 'below high water' is any area below the high water mark of an ordinary spring tide.

Of course, most estuaries do not have an island complex like the Medway's. With the number of breaches to the seawalls on those islands, much of the 'ground' goes under, so there are plenty of opportunities for wildfowlers to continue shooting until the 20th.

The last weekend of the season is traditionally busy, and always seems to start on the Friday. The 16th saw many of the island shooting hides manned. Very few shots heard in two hours, and the fowlers were away soon after the top of the tide, but the lack of gunfire didn't mean a complete fail; late season wildfowling trips are as much about the tradition of marking the season out. It will be over six months until the next season starts.

How do you define an ordinary spring tide? Essentially, a series of spring tides occur every 14 days when the moon is full or new; the moon and sun are lined up. It isn't as simple as that because distances between the sun and the planets change. The moon is on an elliptical orbit. Some springs are higher. The sun has a tidal effect about a third in strength of that of the moon, and as the earth travels around it on its own ellipse  the effect on tidal height will differ (if we ever did lose the moon, there would still be tides, just 66% or so low, and no springs/neaps). This is why, about every seasonal Spring and Autumn we see tidal perigee springs, three or four in each year (there are 13 lunar months in a year causing further wobbles in calculations). Every eighteen months or so we get a monster high; the proxigyean spring tide. This is on the 'super' super moon, the moon's closest perigee to earth, in the new moon phase (when the moon is between the sun and earth, making for slightly higher springs) and when we are closer to the sun.

So, in reality, February springs will be 'ordinary';  the wildfowlers can shoot over the flooded islands. The perigrees happen March/April. Once out the way, there are then three months before the next high highs. The old Kent bargemen and fishermen used to call these lower springs 'the bird tides'- the safe time for breeding on the islands.

Safe is relative. A few decades back, bird tide springs could be 5.7, 5.8 metres. This year, the tide tables are full of 6.0, 6.1 metres. And surges don't really enter into these equations. Throw in some low pressure systems and spring tides in the breeding cycle will be flooding the islands.

Last Friday there was a three centimetre surge; some the wildfowlers were had water lapping around their feet. The roosts were being moved by the tide, the wildfowl being spooked by the shooting. Of course, duck numbers were down, with many having left for the near continent to start staging towards summer breeding grounds (the wildfowlers did a good job in getting closing season dates set where they did).

The shooters got their last shots in. This coming year might see more of the Medway's breeders getting their own last shots in.

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(The waders were still in good number today, but their flights are a story for the next blogpost.)

The Sharps Green Bay Turnstone roost revisited.

Deja vu. Posted on this a couple of years back, now have a bit more knowledge of Turnstone to-ings and fro-ings.

First off, I didn't emphasise that you can't get away with counting from just one angle. This google earth pic shows the hulks at high tide:

If viewing from the east, on Horrid, you can miss birds on the boats behind. If viewing from the south, you miss the birds low on the waterline on the main hulk. But if you leave off looking from the west, from Eastcourt Meadows, you'll not pick up any birds 'in' the boats. (And today, for good measure, a couple of dozen were on the remains of the small pleasure craft in the saltings.)

Today was a mini-TTTC for me (Through the Tidal Count survey technique, count each hour) which again confirmed just how much numbers can change over the course of one tide. Although a bit of a late-runner, today's tide was a reasonable height, 5.7 metres.

This meant Rainham Saltings wasn't under at the start, and would be able to hold some birds over the tide if undisturbed. Of course, this is half-term week, the kids are all off, and the Country Park was packed.

So I was expecting numbers to change. I actually thought the main roost wouldn't last, still all-too-often flushed by dogs getting sent into the saltings to chase balls and sticks. It didn't happen; I think it was either the Brent Goose effect, the cold owner effect, or the little kid effect. The firstis based on the 150+ Brent which try to ride the tide out in the Bay, so they can continue feeding around the saltings. Some dog owners pick up on this and appreciate quite a few of the public enjoy seeing them up close and personal. The second is the owners, wrapped up warm and often jacketing their their pets as well, think the dogs won't want to be in the water "stay out, it's cold, COME HERE!". Finally, a lot more dogs are on leads when young children are about. Of course, there will always be those owners who don't care about such things but today the Turnstone were about to get away with a lack of canine concerns.

By the second count, numbers were coming off of Rainham Saltings. Again, thankfully, no real flush. Most public were walking briskly alongside, their youngsters not wanting to mess around by the water's edge (not when there were so many puddles on the path). And another of the main causes of disturbance to the RS roost, the stop-and-stare birder, was missing. The person admitting to being a  birder today didn't have their bins with them. Made the effort to tell me he never bothers birding here, everything too far out, I should go to Sheppey instead, there's plenty of good birds there.. I smiled, and mentioned yesterday's Spoonbill on the sightings board at the Visitor Centre..

I digress. The roost increase had come about in dribs and drabs as some Turnstones got their feet wet. (You know they've flushed when they arrive as a lump.)

And the increase to the actual high tide figure was lumpless as well, the majority coming in off the Saltings or from Motney Saltings where the Avocet were restless and quite a few Plover were moving off for some peace. Others came in from Nor and Friars, but none from the direction of the Gillingham Marshes roost. Perhaps they'd got away with it? (This year both this and Sharps Green were often in simultaneous use.)

The disturbance, when it did come, wasn't human. Bird of Prey. Might not have put the Turnstone up at first, but it did put up the Geese, who took the waders with them. And even though the tide had barely dropped, enough wet rocks were showing for Turnstone to disperse to try starting to feed. They didn't bother coming back.

How many are there on the southern Medway at the moment?

Well, quite possible around a three figure count at Gillingham Marshes. Just as often as they've flushed to Sharp's this winter they've been equally happy to flush to Nor or Darnet, where 20 or 30 are not uncommon. Next, the Rainham Saltings roost now has to be on the saltings themselves; whereas in autumn/early winter they would most likely use the deck of the hulk PAS1511 off of Bloors, the large gulls have already started to reclaim that for breeding. Another 20 or so regular around the top of Motney/Otterham, sometimes using the caisson on a tide of today's height. So, if you went out of your way to get a high score, and actually got lucky enough to find them all, you'd have around 500 in the western basin.

The eastern basin is a little more problematic, as feeders there often come out of Ham Ooze west to become part of that 500-ish total, but Lower Halstow through Millfordhope will often have 30-50, but hard to count, either scattered in among the small groups of waders on the saltings or spread along the concrete debris of the Barksore shoreline. A similar number attempt the same around the Funton 'triangle', coming together on higher tides on the concrete barges on the Barksore side, perhaps some up around the Shade. Throw in another 20 or so off of Queenborough around Deadman's. These can be joined by flights from the Thames, from off of Grain or Sheppey; a conservative total for these commuters might be 100 on a good day. So, a hypothetical count of 650 for the south shore? Of course, this is based on good days, and I can be out every day. Bad days you won't find them. But for the estuary as a whole. adding in the north shore, where birds roost on the apron wall of Kingsnorth alongside the Oystercatchers, or the beaches of southern Grain, you could, if you set out on a mission on the covering tide, aim for 750. You wouldn't always get it. You certainly won't get near it on a multi-observer un-coordinated high tide count due to disturbance patterns. And of course, this is just my perception, my considered opinion, I could still be well out!

Seek, and ye shall find- a part of this week's Funton Turnstones, roosting at Bedlams

But it all goes some way to confirming the long-held fears the WeBS totals are under-reporting the true figures on the estuary: the Sharp's Green roost alone often passes the WeBS annual estuary peak. But the problem is those birds will often end up out around the estuary islands at weekends which have been counted during the week in recent years.

If correct, then the Medway holds nationally important numbers in winter. It also holds nationally important numbers during the autumn, but that season has not been covered fully by WeBS in recent years.

Looking back to the golden years of WeBS for the Medway, 500 often routine in the winter months. Note also count coverage was better in autumn. Recently counters have more often been out for just the core period, October to February. Yet the highest numbers on the estuary were (and are) still on passage- hovering around internationally important totals. Similarly, a spring peak evident then (and still now to a casual observer); although present for shorter periods, even the once a month official survey often detected the passage increase. (And there are, of course, several other species with similar high passage numbers not being reflected in such surveys.)

Another species where any informal counts can prove useful, especially outside of those winter months.

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Oh, and nearly forgot today's stand-out bird; in the Sharps Green roost, flitting around deep among the metal hulls, a Wren. Stupid Wren? Well, they certainly feed out on the saltings a lot outside the breeding season. Perhaps this one found it easier to spend a couple of hours over the top of the tide on the rust-buckets than going ashore and facing off with winter territory holders. Clever Wren? Perhaps, if it works. I must watch out for him again.

Ural howl

Recently treated myself to 'Bird Migration across the Himalayas'. Nice little read, focusing on how the high-altitude lakes in the mountains and on the Tibetan Plateau aid wetland non-passerine species to get over the highest mountain range on the Planet. Not huge amounts in it for passerine lovers, just one detailed chapter which concludes 'a sizeable majority of migrant passerines appear to avoid the Tibetan-Himalayan region but a large number appear nevertheless to pass through or over the mountain ranges..'

Which got me thinking about our own important but distant mountain obstacle- the Urals. (There, you thought I was going to say the North Downs, didn't you?)

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'Our' birds, on a large scale, breed mainly in one ecozone. The largest ecozone on the planet, the Palearctic, stretching from Western Europe to Kamchatka and the Bering Straights. Things like the Atlantic, the Pacific, desert chains and those Himalayas help to create hard-to-cross boundaries.

And within that Palearctic zone, one central mountain range, running north to south, creates another major boundary of sorts- yes, a little more porous, but keeping many species to each side of a biogeographic divide.

Now, those Siberian Accentors many twitched in 2016.. Yup, even though going to see one for me would have been poison, no law stops me thinking about 'em. And the latest issue of 'British Birds', with two articles related to that invasion, had got me thinking about that mountain obstacle of the Urals. Mainly because one theory pushed within had me spitting tea.

"(..refined by Kenneth Williamson into our modern understandings of migration and vagrancy) ..Siberian birds reaching Britain were, he argued, young birds on 'post juvenile dispersal', not a true, purposeful migration towards the wintering grounds as undertaken by adults but a random initial movement in all directions away from the breeding area.."

Why exactly did I spit at that? Ken Williamson himself stressed dispersal should never be confused with true migration, which are being muddled here. Let me explain.

Firstly, post-juvenile dispersal is not a good term nowadays. Newton, in NN 'Bird Migration' uses post-fledging dispersal, before going on to talk about migration.

Once fledged, no longer dependent on the parents, most young migrant passerines do leave natal area to explore in all directions of the compass for a few weeks. At the end of it they find somewhere to carry out a pre-programmed post-juvenile moult in preparedness for actual migration. If they make it back the following spring, it is often to this post-juvenile moult site. They chose it because it hit all the right buttons for their species.

So, within the first seven weeks of their short lives, rapidly grown a relatively weak juvenile plumage to get them clear of the nest whilst at the same time registering their natal area, to which some (mainly of one sex) will return close-by to breed. Then imprint a second site, their post-juvenile moult site, to which some will return straight to in spring in order to breed. Bearing in mind first month of life is pre-fledging stuck around the nest, they do not really have long to find somewhere; the post-fledging dispersal period is just about three weeks or so.

Function of dispersal is about gaining a head start for following years' breeding. Return and quick start. Part of why those near continent passerine spp. are not colonising. Post-fledging dispersal flights generally too short for crossing the Channel/southern North Sea. Because they are usually only airborne for an hour, possibly two, on any given dispersal night flight. Studies on post-fledging dispersal among Blackcaps have shown an average nightly flight distance of just a handful of kilometres.

This is not going to get any Siberian waif to us.

The post-juvenile moult is something virtually all young passerines go through. It comes about mainly from internal cues (endogenous mechanisms). Vast majority replace only some feathers, and is not a full moult. They usually does not have the time, nor the resources before having to migrate or suffer the first hardships of winter. The p-j moult is mainly only covering feathers, those that will work the hardest until the first full moult a year away. Feathers grown in the nest are weaker and looser than adult feathers. New body feathers will insulate more. New coverts on the wings will act like the protective tiles on the Space Shuttle. Why, if only some greater coverts are changed, they will be the ones on top covering the other greater coverts, those that suffer most wear from sunlight through to vegetation. Also why the old name for tertials, 'shield feathers', is a great descriptive term.

At the same  time endogenous cues start to set migration proper in motion. Migratory restlessness kicks in. The bird builds muscle, puts on weight, and effectively slows and stops any short-range random movements. Pre-programmed general directions kick in.The famous experiments with Robins and Blackcaps in tippex-lined buckets to have their overnight directional flutterings recorded, have shown that change from short-period random scratchings to purposeful one-direction all night flutterings; the general migratory directions are inbuilt.

Now, all those Siberian Accentors that turned up were in post-juvenile plumage. They were no longer moving randomly. A North Sea crossing would be bloomin' tough for any post-fledging disperser. A bird under the control of those migratory drives could cross it.

They also came in October. Migration time for adult and juvenile Sibe Accentors. The p-j moult is in the month before.

The initial random dispersal may well be influenced by weather conditions. How far do Siberian Accentors travel before the post-juvenile moult? Winds might have pushed them further on these short wandering flights. But they still shouldn't be dispersing as far as to Blighty. None of the birds here were in full juvenile plumage, and post-juvenile birds are no longer dispersing. They can, of course, still be blown a long way off course, wind-drift occurs more in youngsters, but many will now be attempting to readjust flightlines in line with their internal directional drives.

Post-juvenile dispersal for flights after the post-juvenile moult is a misnomer. It is not that post-juvenile dispersal is bringing them to us, it is something 'going wrong' with/during their migration. 

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Endogenous vs exonegous migratory controls. Wind, one of the easiest influences for us 'severe migrationists' to look to for cues, is an outside influence (exogenous). Others often help develop the migratory disposition; day-length and temperature play parts. But endogenous systems are big drivers. How else do birds wintering near the equator know to start back? Day length is similar, temperature similar, angle of sunlight similar... yet off they set. And again, experiments, taking birds into closed-off labs show such cues for movement, moult, kick in even if they can't pick up on the external clues- they have built-in circannual rhythms.

Of course we birders want to know what is going on. Knowing takes time, and we're still not there completely yet. Theories come along, theories go. They fail rigorous testing. Sure, reversed migration is out of favour, big time. But what if the endogneous drive is, for whatever reason, faulty? Might there be a 'favoured' remaining direction based on a combination of prevalent endogenous/exongenous drives? There are a lot of things in play. Some causative, some correlative. Whatever plonks a lost bird over the North Sea means a coastal landing for tired waifs and strays. We just need to keep refining our understanding- and keep refining the terminologies.

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Let's look at a 'North Kent' species for a mo'. Post juvenile dispersal in Reed Warblers. An example based on a paper by eastern Europeans, but if you take your Kent Bird Reports off the shelves and look at the ringing evidence for the timing of short-distance random direction flights between, say, Dungeness and Icklesham in East Sussex to the west, it translates well.

Nocturnal, occurring up to two months after fledging, involving flights of less than 75 minutes in the last two hours of night (the time when birds can start to see 'see'). In their paper, a lot of ne/sw movements detected, because, locally, that was where the suitable habitat lay. The birds did not carry  the fuel reserves for longer-distance movements. Some individuals shown to take several movements in differing non-migratory directions. And why youngsters respond well to all tape lures birders play- a clue for a possible good spot. Why adults largely ignore, they've already found their sweet spot and won't be looking to change.

Post-juvenile dispersal is not what gets a bird from Siberia to Blighty.

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If not convinced, just a quick thought on broods. Why do first broods do better than second broods? Studies on Tits have shown second broods end up in fragmented habitats, a secondary choice. Think of a species that throws in a third brood; they might well have very little time to disperse.

Sibe Accs leave late September to late October (in southern part of range). Post-juvenile dispersal starts earlier, but these birds will develop a migratory condition- build muscle, put on fat; p-j dispersal is over, endogenous and exogenous migratory systems are in control. Again, the post-fledging dispersal may have moved some birds a shortish distance, usually in all directions, and it might be strong winds influence the number that move in one direction in a particular year, but by the time these birds were reaching us, they were no longer dispersing.

Whilst the article gushed over their being 'Sibes' (and yes, that's in the name), it should be noted the species breeds in the Western Palearctic. Not huge numbers, but some make it over the Urals each year.These birds cross that mountainous boundary to reach their Chinese/Korean wintering grounds, but the geographical definition of Siberia has the western boundary as the Urals; hence not all Siberian Accentors breed in Siberia. Now, those Urals aren't the Himalayas by any standards, but how easy is it to carry out post-fledging dispersal over them? Like other divides, say like our English Channel, only a really small percentage of post-fledging dispersers will make it over easily, before true migratory urges take hold and enable more to cross a divide.

Although some of the references available are a little sketchy, another 'sibe', the Yellow-browed Warbler has, in recent decades, expanded breeding range and numbers on the Western Palearctic side of the Urals, which could help explain the increase in recent autumn numbers here. It could be the constant easterly airflows experienced in 2016 caused problems for Accentors this side of that divide. We just don't know until such time ringing, or similar, tracks individuals.

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Of course, this is a local blog, for local birds. Let's apply these theories to Nightingale dispersal and Chattenden Woods.

Their habitat is now fragmented. How easy is it for post-fledging dispersers to find a decent spot in that month following breaking the bonds to the natal area? The argument for the Nightingales over near the north shore is that their breeding grounds can be lost to development if suitable replacement habitat is provided within their dispersal area. The talk has been of over the Thames. Some might find it, only if they can readily cross that ever-widening estuary in time to set about their post-juvenile moult. Of course, it is much more likely that Essex dispersers will benefit. The Hoo birds will lose out, unless efforts at other reserves such as Northward Hill succeed in creating the correct habitat. A key feature is closed scrub, allowing favoured feeding on bare ground beneath bushes. And scrub remains a habitat grossly undervalued. As the closed low scrub is out-competed by maturing woodland numbers decrease (part of why the peak at Chattenden has been passed).

Here on the south shore our scattered numbers are dropping fast. Half-a-dozen breeding pairs lost their scrub to housing clearance last winter. Their last youngsters would have been struggling to find suitable habitat in the area. Scrub tidying by Council and private landowners knocked out another three or four pairs, and necessary improvement to reed-bed water levels drove back other birds in the couple of years before that. At other sites, pathway improvements are fragmenting scrub habitat and I'm putting money on their numbers falling.

Habitat. Build it, they will come. If they can find locally it in that fortnight after leaving the nest that is.

A Reed Warbler ringing encounter

Reed Warbler (Acrocephalus scirpaceus) Scheme: ESI Ring no: 2L29368
Ringed as an adult, April 28th, 2013, La Veguilla, Codorba, Córdoba, Spain

Retrapped on the south Medway, July 2nd, 2014.
Duration: 430 days. Distance: 1559 km (16deg NNE)

And retrapped again on the 3rd.

Just a Mipit

Yup, this post is on Meadow Pipits. No groaning back there. You've been warned enough times this blog focuses on common species, you know, the ones we know loads about.

Or not. The BTO's Migration atlas points out there are major gaps in our knowledge of the winter ecology of Meadow Pipits. First 'whaaaaaa?' moment. At the time of publication the data was clear; no evidence to date for foreign Meadow Pipits wintering in Britain and Ireland. This is just another of those species, like the Robin, where the zugunruhe is strong in autumn, and the birds we count coasting are not arriving to join us here, they moving much further south. The vast majority of subsequent encounters of birds ringed in UK during winter have also been in the UK.

So another urban myth gets put to bed for the moment- all those County Reports saying 'winter visitor' really need to qualify that statement; most birders will read that as foreign birds, whereas we are more likely getting some visitors from other parts of Blighty. And no real idea of distances yet, either. Sites where numbers increase could just be a readjustment from, say, inland to the coast. Open minds are needed. Brit breeders do move to the coast, and do leave, down to places such as Iberia, but how much is partial migration? Just some of the local population involved? The last Migration Atlas relative abundance maps make you ask questions; a clear shift from north of the Watford Gap, to a spread south of the Watford Gap in winter. No ringing evidence of cold-weather movements within a winter, everything saying site faithful.

Tabulated Mipit records in the County Reports add little information. Often winter counts equate to a number similar to a breeding population plus surviving young. Do all the southern birds make for the south and are all our wintering birds narfeners? Is it a partial migrant? We just really don't know enough to answer with confidence. Yet some in this county are saying with certainty Mipits in the hand can be identified as birds from the Western Isles, or further. 'Showing characteristics of..', maybe. 'Having the whiff of a clinal appearance found in a slightly larger percentage elsewhere', maybe more so. But nothing is proven. Don't believe all you are told.

Mipits! So much to find out. So much to challenge.

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But for this note, let's look at winter roosting. Searching Google Scolar provides little to update the old statement in Birds of the Western Palearctic: 'Roosting. Little information. Nocturnal and probably communal outside breeding season.On ground under plants and amongst grass in the open, also in young plantations, base of osiers and hedges used mainly in bad weather..'

Here on the southern Medway, reedbed roosting does occur in the midwinter, but needs qualifing. Opened areas of reedbed, where dry. AKA the autumn's netrides. It may be they prefer the unimproved pasture alongside the  reedbeds, with double figure counts routine here. Brownfield wasteground goes down a treat. Similar numbers can be found in one open areas among the stalks of umbellifers, teasels. Then there's my local site, rank grassland with the double figure counts on a brownfield site reseeded c. 15 years ago, and cut each autumn.

They do like it. It is some little way off their feeding areas, as there is a clear urban flightline. As long as I can remember for the three decades I have lived on the edge of the medway Towns, Meadow Pipits have moved eastwards in the morning over Rainham, between the main A2 and the B2004 Lower Rainham Road. In the first winters back from working away in Sussex, the old landfill was surefire. This past winter, although from the boundary fence nothing appears to have changed, the site has been largely deserted. The birds now turn north towards Ham Green. What is most odd is that it is a turn once they overfly the old roost- prior to that, they are have still moved east over lower Rainham. It is almost as if they have added a dog-leg extension onto the old flightpath. And where do they go to during the day? How far do they travel?

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We ignore them as common birds at our peril. The species is amber-listed thanks to a downward trend in numbers since the 1970s. Although many texts state a common species on coastal marshes, texts specific to North Kent point at times when it was anything but. How many would be noteworthy this time of year along the southern shore of the Medway? We certainly have fewer than the more 'coastal' north Kent marshes. Say within the more-developed western basin? Any number noteworthy up and including the Country Park. Double figures around the central Peninsulas, then 20+ worth recording when you reach the flatlands of Barksore and Chetney. And details of any roost, of course.

Main thing is, don't ignore 'em.

You'd best practise some more..

Returning to yesterday's post on the problems with counting the Medway Islands on a spring, look at a wader, for a completely different, historic problem.

To explain, let's focus on Curlew. They love central/east Greenborough on a neap tide. Offshore, safe. They love it so much they'll shrink their core area on a 'norm' but they do have to change on a spring. They'll chop and change their refuge, dependent on onshore disturbance. Today, for many the unimproved pasture elsewhere was deemed unsafe so they were on the flooded wet fields of Barksore (that green circle on yesterday's screengrab map). And the majority had been since the tide had been on the rise, liking to roost earlier than many other wader spp., way before the rib turned up. So, unless they take flight, they are hidden from waterborne observers by a high sea wall.

This is one reason why Curlew can be under-represented on old WeBS counts. If the land-based counters are out on a neap, they will not have such large numbers present- they'll be out on Greenborough. If, hypothetically, that boat had been doing a WeBS, they'd have missed them (and others) ashore. And here's the problem when counts are out by a several days: the two nearest WeBS dates are highlighted on this tide-table snapshot. Much lower tides than today's.

http://www.visitmyharbour.com/tides/395/uk-tables/sheerness-river-medway-tide-tables

The Medway estuary has a unique situation of a large island network within a man-made basin estuary (the Victorian brick industry shaped it) but counters on other estuaries shouldn't be complacent. Here, 'Thames' waders will use the Medway roosts under certain conditions. So even if (and I don't know) the Thames does manage to follow the BTO direction of 'estuary co-ordination imperative', if they are on a different day to the Medway, there could be a chunk missing that may not even be picked up when the Medway counters are out.

Some will claim this to be a favourite sermon of mine of course, heard here before, and they'll be right: it remains worth repeating for any newer readers who might be WeBS counters elsewhere. Here the BTO spent time puzzling over the lack of waders on the Medway some years back, without questioning the data itself. More recently, this past couple of years Natural England have been puzzling over the relatively low numbers in relation to habitat available. It is all too easy to take WeBS as Gospel where it has been incomplete and executed poorly.

I know this is probably just how us 'soft sarfeners' don't like talking to neighbours, but a good example why it is worth any estuary WeBS counter chatting with their seawall count neighbour; to see if peaks and troughs on the ebbs and floods mirror. Or just to see if they're out and about at the same time. Putting in place those best practices the BTO promote.

You'd best practise more..

A high 6.4m spring tide. Most first choice roost sites would be going under under. For a couple of days now the forecast had been for a .2, .3 surge on top, with a fair old wind action thrown in.  The birds were going to be hard pushed over the tide. So I'd promised myself a trip up Tiptree Hill to monitor.

Tiptree has long been known as one of the very best viewpoints for the estuary, featuring in just about every 'Where to watch..' guidebook published over the last fifty years, yet has fallen out of favour with birders. I've not bumped into one up there in the five years I've been going. One local does visit about once a fortnight, but usually at a set time, meaning my tide chases rarely match. Solitude is still possible in the over-crowded south-east. Why don't birders like it? Well, the views are never going to be close! Viewing the spectacle seems to be out of favour nowadays, with most chasing the money shots. And, when I've asked birders, the answer I get is that they either don't like the walk (450 yards up an incline), or don't like to leave their car on the lonely backroad below, admittedly a favourite site for break-ins. Safest parking is in Lower Halstow a whole mile away.

For the purposes of this note I'll stick mainly to the middle distance.  The screengrab below details the main areas mentioned. About a mile to Barksore's roost. Just under a mile and a half to Slaughterhouse Point on Greenborough, a similar distance to Millfordhope.

I use a favourite mapping website at the moment as it has a set of googlemap images that were taken at high tide, around a 5.9 metre height. They show how the old sea walls have given way in places to allow the once enclosed, once farmed island, to revert to salt marsh. The dark green colour is no trick photography; at this tidal height the ground is saturated. On tides over these heights, much goes under to leave a broken framework of sea walls. In the photographs that follow, the seawall of the southeast corner of Greenborough, Slaughterhouse Point (lined in green, above) features.

On a day like today not many pleasure-boaters venture far out in the estuary, and are rarely holed up among the islands. In the summer, north and east of Greenborough are popular areas to hole up. Yet for much of top of today's tide, there was only boat out there. Birders on a rib, sadly, pushing the birds around.

Does it matter?

Well, let's take one goose: the Brent. Often on lower tides loafs closer to countable areas along the shoreline. The islands are regularly shot by wildfowlers. On Higher tides? Into those islands, tentatively, now they have been deserted by the gunners. The lure of saltmarsh feeding. On these, the highest tides? With the ground flooded, any remaining saltmarsh seed floats. New easy access food sources become available, often gathered in lea of any sea walls above water on the islands, or floating above the plant stems rising from the shallow inundation. Of course, this late in the season, the amount of such food available is already depleted, but any surge will give a chance at picking up a little. So many wildfowl will be floating over the islands, trying to feed. Even if not that hungry, the duck and geese will float over the islands themselves, as much less choppy, with less chance of getting disturbance by any river traffic.

Studies have shown disturbance to Brent causes a time-delay of around twenty minutres before normal behaviours are resumed- by that we're talking about the easily observable (feeding), the subtle (the vast majority of the disturbed flock coming off alert mode) and the unobservable to the field worker, stress rates, etc.

So, at the time of the pictures, even though a skipper might argue they were a fair distance, the clue you should pick up on that tells you you're disturbing the birds is their flighting.

The Slaughterhouse Brent made for Millfordhope. No great problems then? Here's the rub. The spooked Brent arrived, spooking the Brent already present. Feeding stopped. Only for fifteen, twenty minutes, but right at the point of today's high tide, when those areas least inundated over a season were wet open food bars for their picking. Denied Slaughterhouse, they doubled up on Millfordhope, putting all the wildfowl over that island on guard as well.

(If you can't see the clicks, zoom in, they're there, over the island.)

Instead of feeding the geese, in the main, floated over what would usually be the centre of the island, safest from any further boats. The only other active boat was the Harbourmaster who, on spotting the rib from Lower Halstow, made a sortie via Shepherd's Creek to give the occupants the once-over (never mind safety concerns, illegal landings can and do happen around the south shore). So, as well as pushing the birds themselves, by their very presence the rib-birders had inadvertently created a second disturbance.

Of course, that's the story of one species; all the other wildfowl spp. present were disturbed similarly, albeit all with subtle differences in behaviour. So too were the waders, but I'll save that for a second post. I will just mention today's birders and their silhouette effect. The temptation for observers on a rib is to remain standing when drifting. And why not? Birders on small fishing boats do the same. But they are often riding higher in the water, with a walkable deck and seating in the centre, so birders tend to step back a bit, or mill. Appear as if not totally focused on the birds. Essentially, not do an impression of poor seawall fieldcraft for long periods as these guys did. You first stand up, birds will alert. You stand up and stare at wildfowl, they will be on guard. And if you're too close, they'll flight.

Best practices.

We birders often believe we hold the higher moral ground. We expect other users, the seaplanes, hovercraft, microlights, drone users, kayakers island visitors to adopt best practices around the estuary to keep disturbance down and help meet the legal international obligations to protect the estuary. Actually, that's polite, many birders would call out for tougher rules in place based on the levels of disturbance evidenced. So why not best practices for birders?

There already exist best methods for breeding species that can be adopted. Sadly, in many recent years, they have been ignored. Two years ago, a collapse in colony numbers in the days following landings to count. Last year, many failed to return.

Best practices for shoreline roosts are already adopted elsewhere in the county. Here, we still lack even basic signage on our reserves. Adopting best practices has never been more needed, and never likely to have a better chance at a time County and Local Councils set up an initiative to reduce disturbance around this area.

If you flush birds 'on' the islands, you're too close. Move away. Don't keep pushing the birds around as these guys did today. Even if you're counting, as these guys were today (of course I had recognised that rib). One thing also clear from up on Tiptree; certain flights moved from the first counted areas to later counted areas, often via circuitous routes (Sharpness to Greenborough via Slayhills a good example today). The argument that the islands cannot be counted well from shore remains one worth exploring; on any day neither their counts, nor mine, will be both accurate and precise. On a high spring, in late winter, my count doesn't stop the birds from a rare feeding opportunity.