Friday 26 July 2019

A Good Tern 24th July 2019

I was watching a couple of Mediterranean Gulls, preening on a muddy shore, the cares and stresses of breeding forgotten and their focus now directed to sorting moulting feathers as they acquired their new winter plumage, their heads already beginning to become grizzled as the black is replaced by white. Can it be so soon that it is all over for another year and the ever so  gentle, long decline into autumn and then winter is upon us? The gull's behaviour told me it was indeed so.

Mediterranean Gull - adult
Two Greater Black-backed Gulls, dwarfing the other gulls nearby, were 'dismantling' a large crab, leg by leg. Stabbing and tearing the still live crab to pieces with their formidable bills. Totally pitiless. killers of the tideline, ever ready to seize anything showing weakness or vulnerability.

Greater Black-backed Gulls
Two large terns, a parent and its offspring flew in with the incoming tide, as I stood on the mud and seaweed, watching the seawater creeping inexorably from Weymouth Bay into the Fleet Lagoon that lies between the huge shingle spit of Chesil Bank and where I stood under the seawall. This is a place called Ferrybridge, near Portland in Dorset, and is now a nature reserve. It was still early enough in the morning for the light to be benign, only later would it be harsh and bright on a day predicted to be one of the hottest of the year.

The Fleet Lagoon at Ferrybridge which forms part of the nature reserve
A southwest wind blew hard enough to keep the temperature on the cool side for now but that would change in the next hour or two. The two terns in question were Sandwich Terns. They had noticed the small group of Black headed and Mediterranean Gulls that were idling away time on a spit of shingle and decided to join them. Gulls and terns are sociable birds for virtually their whole lives, having an affinity with each other and will always seek company if it is available. 

Sandwich Terns are Britain's largest breeding tern, similar in size to Black headed Gulls, but their shorter legs make them appear slightly smaller and their profile is slimmer and more elongated compared to the gulls, the long wings, especially those of the parent bird creating an impression of elegance and no little grace. 

The gulls at this popular spot are used to the close presence of humans  and they showed no alarm as I edged towards them. This gave the terns a similar confidence  so I was able to move ever closer until I could advance no further, for I would be standing in the sea.

The adult tern was already beginning to moult and spent much time picking at its feathers with its long and narrow bill. A rapier and a formidable tool, black with a sulphur yellow tip. The black crown of breeding feathers was being replaced by white feathering on the forehead but the rear crown still sported a ragged halo and mane of black feathers. 

The juvenile was recently fledged and altogether more squat, with less of the elegance of its parent, lacking the extremely pointed wings and having a shorter and thicker bill. Its head was capped sooty brown while the dull white upperparts were profusely patterned with greyish brown chevrons and vermiculations, its underparts, like its parent, were pure white. In a time long past, so different was the appearance of a young Sandwich Tern from the adult, it was considered to be a separate species and given the name Striated Tern.

Sandwich Tern - adult

Sandwich Tern - juvenile
The name Sandwich Tern was first coined in 1787 by a gentleman going by the name of Latham who gave it the Latin name Sterna sandvicensis owing to it being found " in vast flocks making a screaming noise" at Sandwich in Kent. They have had many colloquial names since and now lost in history, such as Sparling, Kek and Kek Swallow, Kip and Screecher Kip, Screecher, Skrike, Pearl Gull, Cat Swallow, Great Sea Swallow and Big Sea Swallow.The origin of these names is in many cases obvious, others not so.

Once the young have fledged it is not unusual to encounter a parent bird and single youngster, such as this, wandering along our coasts in summer, the young bird still following its parent around although by now fully grown, and making a mewing call, insistent and querulous, to which the adult will occasionally respond but otherwise ignores, although seeming happy enough to endure the  young bird's persistent begging and cajoling.

All terns are noisy birds, virtually no action is performed without an accompaniment of raucous cries that are harsh and un-musical to human ears and Sandwich Terns are no exception, forever screaming with angry complaint in their breeding colonies or communicating with an excitable kirrick kirrick as they fish in the sea

These two Sandwich Terns, like all of their kind, would give vent to their feelings at the slightest provocation, the adult responding with harsh cries whenever the gulls started calling and the youngster forever begging of its parent. They stood on the spit as the sea slowly rose about their legs and as the water began to reach their underparts, the adult called harshly and repeatedly, raised its wings and lifted off, to be followed by its offspring. Still calling they departed towards the open sea and were gone although I could still hear them calling after they became invisible.

Sandwich Terns breed in scattered colonies around much of Britain and along the coast of northwest Europe and most will migrate south for the winter, following the seaboard of western Europe and Africa to as far as the Cape of Good Hope at the tip of South Africa. Sometimes they round the Cape and fly onwards into the Indian Ocean, reaching as far as Natal in eastern South Africa. In direct contrast a very small number now spend the winter around the south coast of England.

I looked at the two terns and wondered where they would be in a month or so. Still here patrolling the shores of southern England or heading southwards across the sea? Guided by an incomprehensible instinctive stimulus that points the way clearly to these feathered beings and enables them to successfully migrate to their ultimate destination off the coast of West Africa..

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