Tuesday, 26 April 2016
With Fronds Like These...
The waters around the Farne Islands are rich in marine life, and by undertaking regular surveys of the creatures found around our shores we can gain an insight into the health of this enigmatic environment.
The recent Super Moon has given us an excellent chance to do this, and we’ve had a fantastic time embarking on team rock pool adventures. A Super Moon is when the moon is closer to the earth than usual (there are 6 this year), which causes larger than usual tides. We have taken full advantage of these extremely low tides and discovered a diverse range of fauna on the Inner Farne shore. One of our highlights was a nudibranch – a Common Grey Sea Slug (Aeolidia papillosa). It’s an odd looking thing, covered in cerata, which are fleshy appendages that look like fur. This sea slug feeds on anemones, but it doesn’t stop there. The Grey Sea Slug goes the extra mile and ingeniously steals the stinging defence of its anemone prey! Rather than digesting the stinging cells, the sea slug absorbs them and moves them up to the tips of its cerata, giving the sea slug its very own stinging defence.
Common Grey Sea Slug (Aeolidia papillosa) ©Lana Blakely
Common Sunstar (Crossaster papposus) ©Lana Blakely
Velvet Swimming Crab (Necora puber): the largest swimming crab in British waters ©Lana Blakely
Orange-clubbed Sea Slug (Limacia clavigera) ©Lana Blakely
Blue-rayed Limpet (Patina pellucida) ©Lana Blakely
But it isn’t just the rock pools we’ve been keeping an eye on. The breeding season has been rapidly building momentum, and the cliffs are bustling with seabirds. The island is once again filled with a cacophony of sounds, with the distinctive calls of Kittiwakes cutting through the hum of thousands of Guillemots. Puffins are busily reaffirming pair bonds after a long winter, tapping beaks with their partners before tending to their burrows. We’ve also been busy, successfully installing cameras in four Puffin burrows; now you can get a rare glimpse of their underground behaviour on a television in our Information Centre.
But the recent stormy weather has taken a toll. Over the last few days gale force winds have driven huge waves against the island’s north rocks, forcing birds off of the cliffs, including nesting Shags. Our Sandwich Tern roost, which had been growing daily, dropped from a peak of 523 birds to around 350 in just a few days. Fortunately numbers have been building again, and counts of Common and Arctic Tern amongst them have increased to double figures, so hopefully we will soon be back to our full complement of a few thousand terns. One species that hasn’t been put off is the Eider, with new nests appearing almost daily, tucked safely against piles of vegetation on the island’s central meadow.
Eider Duck on Nest ©Tom Hibbert
As well as slowing the onset of the breeding season, these strong northerly winds have also put the brakes on spring migration. Despite an initial mini-influx of migrants, including a small fall of Chiffchaff on the 11th April (12 birds across Inner Farne), our first Willow Warbler (10th April) and some fantastic views of Black Redstart, it has been a quiet few weeks. The majority of highlights have all been at sea, with long hours of mostly unproductive seawatching resulting in the occasional island scarcity. Recent additions to the year list have included Black-throated Diver, Great Northern Diver, Tufted Duck, Velvet Scoter, Goldeneye and Gadwall. This last is a real rarity, with the pair seen flying north likely to be the only record of the year.
We’ve also had some success with our gull roost. Dragging ourselves from the warmth of the tower to stand in a freezing wind, slowly picking our way through hundreds of gulls, isn’t always easy, but it can be very rewarding. In the last few weeks we have recorded up to 4 Iceland Gull and 3 Mediterranean Gull. One Med Gull was a first-winter bird (born last year) with a red Darvic ring on one leg; by reading the unique code on this ring we were able to discover that it had been ringed as a chick in Poland in June 2015 – over 800 miles from the Farnes!
Polish-ringed Mediterranean Gull
However, the star of the year so far is a bird that none of the rangers anticipated. On the 6th April a commotion amongst the gulls drew our attention to an Egyptian Goose on the south rocks of Inner Farne. This represents the first official record of this species for the Farne Islands! There are seven previous records from the nineteenth century, but these were all classed as escapees, as the species was not yet established in Britain.