Visiting nightjar a difficult bird to spot
The predominantly east and south-east winds brought a substantial fall of migrants this week. They included nationally rare species such as the lesser scaup, now moved to the Loch of Freester; a laughing gull at Boddam; and the Franklin’s gull, at Graven on the 12th.
Local rarities included dipper, honey buzzard, nightjar, little egret and subalpine warbler. In addition there were also very scarce passage migrants such as a garganey.
Most records of this duck are in spring when single males are most often seen, although pairs and small groups are sometimes observed on passage.
Slightly larger than a teal, the male has a purple-brown head with a bold white crescent extending from over the eye to the side of the nape. The breast is pinkish-brown with dark markings, contrasting with pale grey flanks and black and white scapulars.
Migrants are usually seen on fresh water where they feed on aquatic vegetation, supplemented by small molluscs and other invertebrates. They feed by dabbling or dipping their heads in the water, only rarely upending like teal and mallard.
Garganey is a summer visitor to Britain, breeding in very small numbers in southern parts of England with a few pairs in Scotland. Scotland is at the western limit of their range and, although breeding over most of Europe, they are scarce in the north-west region.
Like many people with trees or shrubs, we have enjoyed a variety of small migrants in the garden over the last few days – willow warbler, garden warbler, whitethroat, lesser whitethroat, spotted flycatcher, pied flycatcher and whinchat.
It is always a pleasure to see the commoner migrants, but my bird of the week was one I hadn’t seen before, and one which certainly was not easy to spot. Fortunately there were several other birders at the Sumburgh Quarry site who gave expert assistance.
Viewing the resting bird through the telescope, it was more like seeing a piece of beautifully carved, intricately coloured wood on a rocky ledge than looking at a nightjar.
The nightjar specialises on large flying insects, such as moths, and is active at dawn and dusk. It has a tiny bill with a large gape, flanked by bristles, for funnelling the insects into its throat, and large eyes for maximum light gathering.
Throughout the day it rests motionless on the ground, or stretched out along a branch. The plumage has a “dead leaf’” mottled brown, buff-white, grey and black pattern providing excellent cryptic camouflage. Nightjars were formerly scarce passage migrants to Shetland but they are now considered as rare vagrants, reaching the islands when overshooting their European breeding grounds on return from wintering in Africa.
Of the four other local rarities, the dipper, honey buzzard and subalpine warbler were on Foula, where a wryneck was also recorded. The little egret was in the Vidlin area.
There were also several records of bluethroats which are scarce migrants en route from Africa and Asia to their breeding range in north Europe.
Bluethroats are slim, long-legged birds, about the size of a robin, with brown upperparts and a distinctive pale stripe above the eye. The male has a vivid blue bib, with a thin gorget of black, bordered by white and then a broader rusty-red band on the chest. In the centre of the bib is a rusty red-patch and the sides of the black-tipped tail are also rusty-red.
Other migrants recorded through the week at various locations included turtle dove, robin, common redstart, black redstart, wood warbler, sedge warbler, icterine warbler, grey wagtail, yellow wagtail, house martin, sand martin, swallow, swift, mistle thrush, song thrush, greenfinch, chaffinch, crossbill, red-backed shrike, tree pipit, reed bunting and cuckoo. Waders included black-tailed godwit, knot, wood sandpiper, common sandpiper and a spotted redshank.
As well as migrants passing through, many breeding birds are hatching young now. I spent a very pleasant time one sunny evening watching a tiny lapwing chick pecking in the dried up mud at the edge of a pool. An adult was nearby, but this lone chick was several metres away, intent on discovering what was edible in the mud. If danger threatens, wader chicks crouch motionless, relying on camouflage.
Shelduck ducklings were also reported in the South Mainland this week, while starling chicks are calling vociferously from drystane dykes and house sparrows are also feeding young.
There have also been some records of sea mammals this week with a pod of six to eight killer whales seen 35 miles off Sumburgh Head on the 14th, and seven killer whales seen in Weisdale Voe on the 15th.
Joyce JM Garden