The Sharp's Green Bay Turnstone roost

They were back today. Nearly 250 Turnstone were spread about the rusting hulks in Sharp's Green Bay, joined by a handful of Lapwing, Redshank and Oystercatcher, a few Grey Plover and single Ringed Plover and Dunlin.

I decided to watch them out from roost to see where they intended to feed, so took off up Horrid Hill to wait. Leaving from about an hour after the full, in tens and twenties, a few swung west, but most headed for the mud reappearing in the creeks of Friars Saltings just east of Nor Marsh. From there a few would later tag on to the Dunlin flocks coming south to feed alongside Rainham Creek, but the remainder, well, remained.

These would undoubtedly be aiming to feed on the two large mid-estuary mudflats, Bishop Ooze and Bartlett Spit, which have a substantial amount of rock spread around them. This can be derived from the large amount of seaweed spread on the southern flanks of these flats (these seaweeds need a holdfast which the rubble supplies). From Roman times onward much of the estuary was reclaimed by creating seawalls, and then farmed for several centuries. The rising tides have in turn reclaimed the estuary basin over the years.

On a rising tide the Turnstone will, in the main, move back from Bishop and Bartlett to Rainham Saltings/Rainham Creek, and from there any wanting to keep feeding move to Ferol Peak, the raised flat between Copperhouse Marsh and Nor, which is one of the last areas to go under. They will then choose a safe roost site.

On quieter weekdays in the Country Park it can be entertaining to watch Turnstones take the short 'overland route' from Rainham Saltings to the Sharp's Green roost, whizzing past low at head height.

So, within the western basin of the estuary, Turnstones roost mainly either here or at the Strand. Smaller numbers also occur on Nor, Friars and sometimes Motney. In recent years smaller numbers have been recorded for the whole of the estuary on the national WeBS counts, but this could be thanks to what I term the 'weekend effect'. Sharps Green Bay falls within the Riverside Country Park, and the roost lies just 111 metres offshore from the Park's most popular walk, the Horrid Hill causeway. Whilst the wrecks are themselves very,very rarely visited by people, dogs are often allowed to swim out some distance from the causeway. I have not looked more deeply at cause and effect, but am aware my higher Turnstone counts never really happen on a Sunday(!)

(The Sharp's Green Ringed Plovers seem to do something similar- they are often on the wrecks of the smaller pleasure craft, but also go missing for days at a time. I'm still having a hard time tracking their alternate roost down.)