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Wednesday, 20 November 2013

High Tide Boat Survey

November 18th

One year I am going to get it right with the weather, Monday was awful, grey, drizzly, misty and overcast all day, much the same as in the surveys of 2011/12, nonetheless we pressed on with the now annual November boat survey.
As part of the on-going High Tide Project the Environment Agency very kindly supply a boat which they launch from Crossness, the boat takes 4 of us and is skippered by Tom Cousins of the E/A. Supporting him were Peter Gray, also E/A and Jemma Shoobridge the E/A Biodiversity Officer.

Tom about to drop the boat


The plan is to record and survey as many roosting waders on known or unknown structures/jetties from Tilbury down to Galleon’s Reach, peak tide for Tilbury was just after 1.00pm and was a relatively high one at 6.37m.A shade under 7.00m at Silvertown also meant that the whole stretch would be covered ensuring that all waders went to roost and would not be able to carrying on feeding on any exposed mud.
After launching we headed up on the Kent side to take position literally at the last port of call, Tilbury, to be more precise the old repair jetty, once a favoured roost site. Not strictly within the LNHS area which finishes at Northfleet, I check this any way every year as it was once a large roost. It was empty as other years and it now has 4 Wind Turbines overlooking it, these were not here last year, a necessary evil?

What I did not mention was that whilst we were heading out of the river at a rate of knots to get in position, we checked the odd site if it already held birds, this proved dividends and gave us 7 Turnstones on the rocks by the lighthouse at Broadness Point. Good birds for the London area and a bit of a winter rarity unless you’re lucky enough to pick one up on passage, a good start.

From Tilbury we headed up and our next stop was West Thurrock, one of the big roosts but rather surprisingly empty today, the only birds present were 2 Oystercatchers. Stone Point however held 11 Curlew and a half dozen Redshank. Scanning round I saw some Redshank heading across the river so we headed over to the Crossways Roost, this was empty but a nearby derelict jetty near Johnsons Wharf held 120 Redshank and 40 Lapwing. This jetty was a new roost site and shows the importance of having alternative sites relatively close, say if they were disturbed at West Thurrock which possibly could been the case why they were on it.
Another reason being that, close by they would not have to expend too much energy flying around looking for somewhere else to roost, in extreme cold weather for old, young or sick birds this can prove fatal.

Repair Jetty at Tilbury - old roost seemingly not used anymore?

Jemma looking at the Repair Jetty

Redshank roosting on Jetty at Johnsons Wharf

The sole occupants of the West Thurrock Roost - 2 Oystercatchers

From here we moved up to the next roost, a regular site at Littlebrook Power Station, this held 72 Redshank and 3 Lapwing, a good count so we carried on firstly shooting back across the river to record the known Purfleet roost. Another good count of 60 Lapwing greeted us, as we know, a bird in decline and quite recently added to the Red List.

Moving forward it was onwards and upwards as we passed Rainham RSPB, this year Howard had kindly agreed to record the birds going to roost on site, including the Reserve gives us a far more accurate count for the Inner Thames of the number of waders on the River.
He added a further 12 Curlew, 200 Dunlin,35 more Redshank,200 Golden Plover and 700 Lapwing, all these were recorded flying from the Thames to the Reserve when the mud disappeared..

Over then to Erith Yacht Club, this another known roost, it did not reach the figures of last year but still produced 32 Lapwing and 50 Redshank, I looked for the wintering Spotted Redshank but for not wanting to get too close and also the bad light I could not pick it out.

Redshank roosting below Gulls at Erith Yacht Club

The next stop was the Stone Barges, I had been wondering where the Black Tailed Godwits were as they hadn’t roosted at Rainham, it was likely the Barges or Fords, I had seen a good number on the way down to Tilbury on the exposed mud.

Stone Barges

Sure enough, they and a good number of Redshank were present when we arrived; this one is very hard to count due to all the different levels and unseen edge/faces of the Barges. In the end I arrived at 180 Blackwits, 12 Dunlin and 200 Redshank; it’s not an exact science and if anything most counts are always going to be under. You can only count what is on show and visible from the boat and in many cases you are below the structure jetty and cannot see the middle, which can obviously hold more birds.
As we were on the point of leaving I saw a bird in flight, with some Black Tailed Godwits coming in, first thoughts were Redshank then as it got closer I realised it was a male Ruff due to size, a good bird, talking to Howard later it has been seen before and is possibly wintering.

We pressed on, next stop was the derelict jetty at Fords, Dagenham, a particular favourite of mine and one I have been monitoring and recording since 2005, birds on show were another 12 Curlew, 40 Redshank and 60 more Lapwing. Of them all I know this roost slips away and there is a large open flat area which cannot be seen, it is also out of the wind so this roost likely held more than what was on show.

How Fords Roost looks on a better day - wall to wall Black Tailed Godwit

We moved onwards holding to the Essex side, we were going to record the Crossness roost when we docked, so on to the Barking Bay Roost, this unfortunately was empty. It is now a working Jetty and although one section has been screened to allow for roosting waders, it is fencing and completely see through. This means that nervous waders at roost are susceptible to any disturbance on the other side of the fence, the whole thing needs to be screened and covered.

Dolphin Jetty at Barking Bay - Common Tern breeding site, 20+ pairs in 2013

Disused Dolphin Jetty - haunch board round the side, pea shingled out, the perfect nest site

Another disused Dolphin again Barking Bay - perfect nest site for Terns

Next stop was the roost at Galleon’s Reach/Beckton, this has provided good numbers in the past so we were optimistic of a good count, however on arrival a ship had berthed at an adjoining jetty and we couldn’t get in there to record it. Unfortunately there was no other way to see it so that one went by the wayside, a pity.

Time now was pressing on so although it would have been good to have checked the Woolwich roost and possibly the Bow Creek roost we headed back to Crossness. On the way back as we crossed over to Margaret Ness we came across a flock of 19 Great Crested Grebes sitting and diving on the river pretty near the bank, by far the largest flock I have seen on the Inner Thames.
Tom mentioned that they are always in the same spot as he has seen them a number of times, an area worth keeping an eye on when the real cold weather comes.

I had already noted that the Crossness roost was active on the way up to Beckton and so it proved with a good number of birds present, a minimum of 600 Dunlin were present along with 100 Redshank and 9 Lapwing. This is a big Teal roost as well with around 40 birds lining the wall along with at least 8 Grey Herons.
This was the finish of the survey and Tom and Peter then hauled the boat out onto the Jetty, a very good survey despite the foul weather.

A big thanks go to Tom, Peter and Jemma, good company on the day and very educational learning about other aspects of the river.

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