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Sunday 20 November 2011

Thames Boat Survey - LNHS area

Northfleet to the O2

Monday November 14th

                                                  

For some time now I have with a lot of help from the Environment Agency, London Wildlife Trust and the PLA been trying to get a boat survey arranged with the sole purpose of locating new high tide roosts, and also to identify any jetties/structures that may be suitable that can be to the benefit of London’s wader population, or indeed any other wildlife. On Monday November 14th I got the chance along with Paul Hawkins with a boat very kindly supplied by the Environment Agency with 2 boatmen, Tom Cousins and Dave Bartlett, despite the atrocious weather (very foggy) it was a success with new roosts located that I would not have found without the boat.
This coming Sunday, the 27th we have the first land based high tide count taking place which will be more accurate than the estimates given from the boat below, you can see that there are already good numbers in the Inner Thames. Thanks go to the birders who are helping out and giving up there times this coming Sunday, hopefully the weather will be a bit kinder than last Monday. The estimated counts below do not include East India Dock Basin roost or Rainham RSPB.




Bar Tailed Godwit.(P.Hawkins) click on photos to enlarge

Lapwing (P.Hawkins)

Lapwing roosting up

Sites were also noted and photographed, especially old derelict/no longer in use structures that could possibly be an enhancement to local wildlife. The potential for some of these sites is clear in that they could be converted to shingle based, to not only give waders alternative winter roosts if disturbed, but also during the Spring/Summer months they could offer breeding opportunities for specialist species. Common Tern for one, seemingly reducing as a London breeder along with numbers of nesting pairs in the Inner Docks area (E.I.D.Basin) etc…are falling away. The colony opposite Crossness (29 pairs this year) shows that structures on the Thames can be beneficial to this species.
Additionally there is also the possibility of encouraging Oystercatcher, Ringed Plover, possibly Lapwing on the larger jetties and even Little Ringed Plover to breed on these structures. Oystercatchers are under achieving in the Inner Thames as a breeding bird and eggs/young are heavily predated by the larger Gull species. This year it was noted that a pair in Barking were successful due to the fact that they nested on a Common Tern breeding jetty, in doing so they gained the protection of the colony. The Terns are extremely aggressive in the breeding season and will attack any large Gull that threatens the colony, the Oystercatchers were ignored.
The survey was conducted by boat to give maximum coverage to the area referred to above, to be in position at high tide at the Northfleet area we launched at Crossness about 12.30ish.

From Crossness we surveyed the Kent sector heading down river, staying tight to that side checking all structures/jetties right up to Tilbury Docks. At this stage in time many species had already gone to roost as most of the mud was covered, on 2 areas with high mud levels large flocks were seen feeding frantically before going to roost.




Part of the Littlebrook roost

Erith Yacht club roost (P.Hawkins)




From Tilbury Docks we kept tight to the Essex side checking the known roosts and looking for new ones also. We continued right up to the 02 before crossing to the Kent side again and then headed back to Crossness.
The most suitable mud and feeding areas for London’s wading birds has always been from West Thurrock Marshes up to Barking Outfall, consequently nearly all high tide roosts are congregated within this corridor. These areas offer large sections of exposed mud, at low tide this gives them a buffer zone from disturbance and the security they need to feed naturally. From Barking Outfall upwards there are no jetty/structures offering suitable secure roost sites, the colony of Redshank at East India Dock Basin use the Creek as a roost.



Redshank going to roost (P.Hawkins)

West Thurrock roost

Oystercatcher on one roost at West Thurrock
At the other end of the survey, downriver, the Tilbury Docks area as expected was very busy offering little in the way of roost sites, both sides of the river were checked and the results were negative. There could likely be a roost further down river past the docks but this would likely take it out of the LNHS recording area.
One area where I thought there may be a substantial roost was Greenhithe at Broadness Point, an undisturbed rural area, this never materialised and the next roost up river was at Stone Point.

New Roosts

One of the main objects of the survey was to locate any new roosts within the LNHS recording area, this was realised with the discovery of 3 new roosts, one at Erith Yacht Club, one outside Littlebrook Power Station and another just past the Dartford Bridge at Crossways. It has to be said that all 3 would have likely gone undetected but for the use of the boat as all are on wide stretches of the river on the Kent side.



Brent Geese

Brent Geese (P.Hawkins)

Peregrine Falcon


Species counts at Roost Sites

Both I and Paul undertook estimated counts on each roost site that we encountered the name of the sites and the species involved are listed below. Next Sunday’s counts will be far more accurate, one reason is that on many estimated counts we were well below the jetty/structure at river level.


Barking Bay – 7 Curlew
Barking Outfall – 60 Redshank
Crossness – 700 Dunlin, 300 Black Tailed Godwit, 100 Redshank, 30 Lapwing
Crossways (new roost) – 1000 Dunlin, 40 Lapwing
Erith Yacht Club (new roost) – 350 Redshank, 70 Lapwing
Fords Dagenham – 80 Redshank
Littlebrook Power Station (new roost) – 22 Redshank, 1 Knot. Also 18 Curlew on remaining mud, it is likely that these would have gone to roost on Rainham RSPB.
Purfleet – 100 Lapwing
Rainham Stone Barges – 180 Black Tailed Godwit, 10 Redshank
West Thurrock- Jetties – 300 Dunlin, 150 Redshank, 8 Oystercatcher. Stone Point – 3 Curlew

Totals
Black Tailed Godwit - 480
Curlew - 28
Dunlin – 2000
Knot – 1
Lapwing – 240
Redshank – 772

As you can see quite impressive totals this early in the winter given how mild it is, and the fact that there has been no cold weather movement as yet from Canvey and Coalhouse etc…

Additional Species

Bar Tailed Godwit – a single seen just after West Thurrock
Dark Bellied Brent Goose – 2 singles on the river with a further group of 4 at West Thurrock
Little Egret – 1 seen on foreshore
Peregrine Falcon – a male seen
Rock Pipit – up to 3 birds seen

A very enjoyable experience and some stunning views.






2 comments:

  1. There's sometimes a small roost on Broadness Point at the north end of Swanscombe Marshes, either on rocks or on the grassy edges. I live opposite it in Grays. It's not there every tide - I think the rocks are covered pretty much every high tide - not that I'm there in the daylight to check very often at the moment. When I last saw it there were around 40 redshank and 7 dunlins.

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  2. Parus, thanks for the info,appreciated,I will check it on Sunday.Hopefully we will get a good count like laat year.Dave

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