Finally proof that storm petrels breed in Caithness – on the island of Stroma
Wildlife Sightings by Rob Hughes
July and August are often seen as a quiet time of the year for birds, with minimal bird song and autumn migration hasn’t kicked in fully yet, but there has still been a lot happening.
Failed breeding waders head south from their northern breeding grounds, many still in their stunning breeding plumage, whilst the calls of recently fledged terns and gulls echo around the bays.
Early in July there was also still the occasional rose-coloured starling lingering in Thurso and Wick gardens.
Most of my attention goes to storm petrels in July. European storm petrels are a burrow-nesting seabird that are most active at night. Sometimes in more rougher seas, they can be seen from boats in the Pentland Firth and in much stronger winds sheltering in bays.
These birds have been shown to spend their winters off places like South Africa, which is a massive migration for a bird weighing approximately 25 grams, similar to a house sparrow.
During early August, the Caithness Bird Group visited Stroma to find breeding storm petrels, a species which has long been suspected of breeding on Stroma but had not been proven. The way to find them is to play a standardised petrel call/song in suitable habitat in the hope that one responds.
Luckily, we found 10 active burrows during our visit, finally proving that they breed in the county. They were nesting in tiny crevices in rocks and mouse sized holes in the ground. They could also possibly breed on some of Caithness’s offshore stacks, away from mammalian predators.
During July and August, a small team of us catch non-breeding storm petrels at night using a specialist mist net, tape lure and relevant bird ringing licences. When we catch a storm petrel, we attach a small metal ring to one of its leg with a numeric code so that the individual can be identified should it be recaptured.
We also collect data on their weights and wing lengths. From this we have had some very interesting re-sightings of our ringed birds and recoveries of birds ringed elsewhere that we have recaught.
Most recently, one ringed on the Caithness coastline was caught 29 days later, 415km away on Streymoy, Faroe Islands. Last year, one of our ringed birds was caught at Rogaland, Norway, just six days later, and we caught two of their petrels from Farsund and Rogaland. The idea is that these young, non-breeding birds forage over large distances and investigate potential breeding colonies before they choose a colony to breed in.
Other seabirds seen offshore in the last two months include Manx and sooty shearwaters in the Pentland Firth. There was also a movement of gulls in early August which brought in Mediterranean and little gulls into St John’s Pool and Dunnet Bay.
Over the next few weeks, expect to see the first flocks of geese heading south and enjoy the remaining swallows before they head back to Africa. Notice the swifts have already left Thurso and Wick.
- To report any sightings, email Rob at: xema_sabini@hotmail.co.uk