Wednesday 5 August 2020

Migrants Way. Stage 14. Bridlington to Sewerby

The tide was ebbing as I got to the empty Bridlington Park&Ride at 8:30am. There was high clouds and a steady SW wind after an early morning shower. Before I start the walk, I look back to the dunes towards Fraisthorpe.
The beach is quite deserted, I walk on the promenade by South Sands. There is a large 'creche' of juvenile Herring gulls at the beach -with a few Lesser Black-backed gulls. A few adults are in attendance, presumably the others are looking for food for the hungry young. The young gulls are quite active, playing to pick and drop objects, stealing the toy from each other. One finds a crab and runs and flies with it, other starts chasing some passing Sandwich Terns. Yet another pair follow a Black-headed gull that is walking by, whistling in hope of receiving some food.
Juvenile Herring Gull chasing Sandwich Tern.
Juvenile harassing parent to be fed.
A lucky juvenile gets some food regurgitated.
'It's mine!' a lucky juvenile Herring Gull found a crab.
Gypsey Race
The stone piers in the harbour at Bridlington defend a small creek, the Gypsey race (top shot), which probably provided a safe natural harbour in ancient times, with the protection of the Flamborough cliffs from northerly winds. The Gypsey Race is an intermittent stream, of which there are several in the Wolds. Despite its small size and actual disappearance underground in some stretches its course now runs through the Great Wold Valley.
A Kittiwake nest with an adults and young, closely guarded by an odd falcon.
Town Kittiwakes
As soon as I get to the harbour I can hear the calls of Kittiwakes. I scan the buildings, there are a few nests on most old building ledges and window sills, some on sloping roofs. There are more Kittiwakes on the outer wall. Many of them have juveniles sitting on them, although many others would now have fledged.
A Kittiwake juvenile has wandered out of the nest in a sloping roof. Juveniles in cliffs cannot move much from the nest cup.

The nesting Kittiwakes are one of the highlights of Bridlington. Others are the Turnstones and Purple Sandpipers, which feed on the harbour walls and slipways. Today I count 53 in total. Some individuals are in full adult summer plumage. I see only 2 purple sandpipers.
Turnstone.
Purple Sandpiper.
Adult male Turnstone
Juvenile Turnstone.
Great Black-backed Gull.
Another attraction from the harbour are the Great Black-backed gulls, often affording close views. One loafs on the roof of the outer harbour building with some cormorants, another sits on the marker post of a groyne.
I walk on the North Beach promenade, the arch of the Flamborough cliffs in the horizon. Sandwich terns pass by with their chirrupy calls. 
Sandwich Tern calling.
The tide is now almost low, and this is the time when the area is best enjoyed. The harbour mudflats and the rocky pools by the harbour walls become exposed, attracting waders. The rocky platform at the bottom of Sewerby cliff also are exposed, and become attractive to a range of birds.
Courting Black-headed gulls on the north beach.
After a brisk walk up the north beach I get to Sewerby cliffs. 
Here, Carrion Crows have perfected the mussel dropping technique. At low tide, they hang out with the gulls and oystercatchers, looking for mussels on the rocks. When they find one, they fly to the top of the beach, gain some height, and then they drop the mussel onto the rocks until it cracks open and they can enjoy the delicacy. Sometimes it takes a few attempts.
Carrion Crow dropping a mussel
A beach combing crow amongst the gulls.
Eating a cracked mussel.
The Last Interglacial: Yorkshire’s lost world
Today we are living in an interglacial period, the Holocene. The previous interglacial (129,000 to 116,000 years ago) is known as the Ipswichian. This period was up to 2oC warmer than today, with a higher sea level (+6 to 9 m, possibly up to 12 m higher) due to extensive melting of Greenland and Antarctic Ice Sheets. Holderness didn’t exist as we know it, the area was under a shallow sea with a coastline lapping a chalk cliff - now mostly buried by glacial till - at the foothills of the Yorkshire Wolds approximately following the 10 m OSL contour line. If you had stood on Nafferton, Beverley or Cottingham at the time, looking eastwards, you would have been watching the sea, forming a wide expanse known as Holderness Bay.
The location of the raised beach at Sewerby. 
Most fossil and other evidence for the last interglacial however, was later eroded by the last glaciation. Fortunately, pockets survived in sheltered spots. Near the Sewerby Steps, where the glacial till cliff meets the chalk cliffs, there is a raised fossil beach and wave cut platform, underneath sandy and clay deposits (above). The sand on top of the raised beach was dated to 120,000 year ago. Fossil bones were found amongst the shingle of the beach. These fossils belonged to animals now typical of the warm environments of tropical and subtropical Africa, which expanded from southern latitudes and were able to move from northern Europe and formed successful populations in Britain due to the warm climate: bear, Spotted Hyena (Crocuta crocuta), Straight-tusked Elephant (Palaeoloxodon antiquus), hippo (Hippopotamus amphibius), giant elk (Megaceros giganteus), bison, narrow-nosed rhino (Stephanorhinus hemitoechus), and water vole. Another of those pockets of Ipswichian treasure was discovered inland, at a small limestone quarry at Kirkdale (North Riding of Yorkshire). In a cave in the quarry, a Spotted Hyena’s den was found in 1821, containing the fossil bones and teeth of prey hunted or scavenged by the hyenas: straight-tusked elephant, narrow-nosed rhinoceros, hippos, cave lions (Panthera spelaea) and giant elk. In the book, 'The Hippos', Eltringham reviews the fossil evidence for hippos in the UK during the Ipswichian, concluding “It is very likely that most of the rivers in southern Britain were swarming with hippos much like the African rivers today”.
No archaeological evidence of human occupation has been found from this interglacial in the UK, despite Neandertal populations in Northern France and Belgium, possibly as Britain was an island. 
After a spot of crow and gull watching from the Sewerby steps, it is time to turn back. The much wider beach at low tide helps keep my distance, as it is becoming quite busy. A flock of 20 Redshank are now feeding on the harbour. I make it back to the car by lunch time.
Redshank at the harbour mudflats.
A male sparrow with a very large bib on the beach near the Park and Ride.
Featured bird: Kittiwake
The name 'kittiwake' alludes to the calls of these gulls in their nesting colonies. They are quite small gulls, with plain grey backs and wing tips that looked like they've been dipped in ink. Kittiwakes usually nest in the smallest ledges of sheer cliffs, where they build their nests of seaweed, grass and mud, adding to it year on year. Buildings and other human constructions are really not that different from cliffs, and some Kittiwakes are now urban birds during the summer breeding season. The colonies near Flamborough may take advantage of a large sandeel fishery in Dogger Bank. The colony at Bridlington appears to be expanding, but the species as a whole is not doing so well in the UK, as due to population declines the Kittiwake was recently moved to the Red List, likely due to changes in the marine environment partly due to climate change. Kittiwakes are not migrant birds, they are oceanic gulls that move widely outside the breeding season, wintering in the North Atlantic and reaching N America, although some overwinter in the North Sea.

Walk Information
10 km circular. Start on Park and Ride TA172649. Finish at Sewerby Steps. Public toilets at Park and Ride and several along the promenades at Bridlington. Several beach accesses through ramps and steps onto the beach.

More information
Bateman, M. D. & Catt, J. A. An absolute chronology for the raised beach and associated deposits at Sewerby, East Yorkshire, England. of Quaternary Science: (1996).

Boylan, P. J. (1967) The Pleistocene Mammalia of the Sewerby-Hessle buried cliff. Proc. Yorks. Geol. Soc. 36, 115–125.

Buckland, W. (1822) Account of an Assemblage of Fossil Teeth and Bones of Elephant, Rhinoceros, Hippopotamus, Bear, Tiger, and Hyaena, and Sixteen Other Animals; Discovered in a Cave at Kirkdale, Yorkshire, in the Year 1821: With a Comparative View of Five Similar Caverns in Various Parts of England, and Others on the Continent. Philosophical Transactions of the Royal Society of London 112, 171–236 (1822).

Eltringham, S.K. (2010) The Hippos.

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