Thursday 21 January 2016

Redshanks on The Swale from Oare Marshes on a chilly late afternoon

Arriving at Oare, I concentrated on the Swale and the foreshore, bypassing the tempting close views of Pintail and Shoveller on the East Flood.

It must have been fairly close to Low Tide (16.25 at Southend), and the closest birds were scattered Common Redshank, Tringa totanus, on the foreshore mud. I saw a small amount of "head-jerking" as seen in the RSPB page video. The RSPB states that many of the wintering birds may be from Iceland, and one bird ringed near Kingsnorth Power station in 2001 was recovered in Iceland in 2013.   



Over-wintering birds number about 130,000, with about 25,000 breeders, mainly in NW England and Scotland.

On the RSPB page, the non-breeding plumage looks a little more scaly-edged on the greater coverts and whiter on the belly, but that scaliness doesn't fit the written descriptions as far as I can see - the winter plumage should be much plainer than the breeding.

According to BWP and general understanding, birds in winter on the foreshore tend to feed singly, and sometimes may hold feeding territories, particularly adults. It is difficult for me to see this, without individual markers! At high tide they may roost in small, occasionally large, groups, as we often see on the Radar Pool at Cliffe Pools. At neap tides may be able to continue feeding on the remaining mud even as the tides peak, but at spring tides long inactive periods in tighter flocks may occur at the roosts - I would say that I have commonly seen this at Cliffe for example. Redshank are active at night feeding by touch if it is dark, as well as during the day, when they feed by both sight and touch, and may often be crepuscular.

Both sexes mature at 1 year old, but may not actually breed until their second year. Birds are fairly monogamous and pairings may last for a typical life span, 5 years say, although one bird may have several successive partners during its life, and divorces and repairing may occur within one season on occasion. Bonds may be maintained over winter, or be reformed upon re-arrival at the breeding grounds. The sexes arrive in the area together or the males first. The males gradually start to spend time at the specific scrapes or nest sites, performing scrape displays, and then scrape ceremonies together with the females, and spend increasing time at their chosen sites. Occasionally a second female may lay in the same nest, possibly suggesting bigamy. The males seem more faithful to their particular nesting areas, while females move around areas more. Where same pairs were re-established the following season, the birds generally nested the second year within 5 m of the previous year's nest.

Pairs on breeding grounds generally night-roost fairly close together, either close to the scrape, or on the feeding areas. When not feeding, non-incubating birds generally roost within 5 m of the incubating bird. Sheltered areas and deeper vegetation often used when weather is poorer.

Ground-chasing commonly seen, males generally pursuing females, but a mutually co-ordinated activity. Frequency of ground-chases decreases as proper courtship commences. Males then perform stylised display flights, gliding down and fluttering up in a switchback sequence over the communal nesting or other areas, continuing for as much as a km, lasting for 4 minutes, perhaps mainly by young unpaired females! A successful display flight may attract a female into the air, and the birds may then land together either by the nest or in the feeding area.  As they alight they change from the display-flight song, to an alighting display, including a wing-lifting display, and a specific alighting song. This alighting display is also used when non-incubating bird lands near to incubating bird. A copulatory rattle is also characteristic.

Generally stay together during nesting, often until just around when the young fledge. Sometimes one adult leaves earlier. Fairly non-territorial and semi-colonial during breeding, groups sharing feeding areas, groundspace and airspace around the nests, possibly helping in defence against predators. Often further assisted by nesting in association with Lapwings. In grazed areas breeding density is partly determined by the distribution of suitable tussocks. On salt marshes nests often sited along the ditch sides where the grass is a bit longer.

There were two Black-bellied Brent Geese by the ferry slip, this one looking as though it was feeding on Ulva, the gelatinous Green Alga.



Lots of Shelduck on Horse Sands, and Teal by the mouth of Oare Creek, with Great Black-backed, Lesser Black-backed, Herring, Common Gull, Larus canus, and Black-headed Gulls across the area. Curlew bubbled (with no sign of Whimbrel), there were about 60 Dunlin bumbling around, Oystercatchers were feeding along the water edges, and I spotted two (I think) Grey Plover doing their frozen still act, and one Godwit on the far side of Oare Creek. There were over a score of Avocets. They sweep their bills from side to side and then having raised their bills above the water, they jerk their heads backwards and forwards as if shuffling the items in their bills. There were two Great Crested Grebe on the water. Over on Sheppey I spotted two female Marsh Harriers in the distance.

One possible Stonechat (just by shape with a hint of a white wing-bar) on a bush towards the lightly frozen back of the East Flood.

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