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Super Saturday

Published: 25 August 2020

I hope readers will forgive me for personalising this blog this week but Saturday was one of those days that wildlife watchers can only experience in a place as unique as Shetland. My super Saturday comprised a moth, a bird and a habitat I’d not come across in Shetland before.

Convolvulus Hawk-moth


An early morning visit to the moth light situated in the garden revealed a Convolvulus Hawk-moth. With a body the size of a thumb and its striking pink stripes this really is a beast. This is one of the largest moths to be seen in the UK but occurs here only as a migrant. They originate in Africa and some fly north to breed in Europe, and it is their offspring that arrive in the UK. One or two find their way to Shetland most autumns and some years we just about make double figures. This is one of the hawk-moths with a very long proboscis (tongue) and it can sometimes be seen hovering at flowers for nectar at dusk. Other individuals have been seen this week at Voe and on Fair Isle. If you have seen one recently or come across one in the next few weeks, then please do let us know.

Next up was a Kingfisher! Not a bird one expects to see in Shetland but this one was found by Phil Harris at the Loch of Hellister. Although Kingfishers breeding on mainland UK tend to be sedentary those breeding in parts of northern and central Europe that freeze up during the winter move south. Like many of the migrant birds that arrive in Shetland, if the wind across the North Sea is blowing from the south-east they can get caught out and arrive a few hundred miles or more from their intended destination. Just over 20 have been seen here in Shetland.

Broken off tufa found at Hellister

 

Tufa forming near the spring head

 

Tufa forming spring - notice the large mound of moss
where the water reaches the surface


While looking for the Kingfisher my attention was drawn to two flushes on the hillside opposite. On closer inspection these proved to be base rich springs with a significant build up of tufa. Tufa is formed as Calcium Carbonate is precipitated out from the spring water as it emerges at the surface where the pressure is much less. Typically such springs are associated with an array of interesting bryophytes and plants that like base rich conditions and that is the case here. The spring and seepage lines are clearly marked by the presence of Black Bog-rush which gives the vegetation a distinctly grey hue. This was the first time I have seen tufa here in Shetland and If anyone knows of any other sites where tufa is forming I’d be really interested in hearing about them.

Black bog-rush - a sure sign that the water is base rich

 

Paul Harvey, Natural Heritage Officer


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