Crossbills at large
Crossbills dominate the bird news this week, with the largest flock recorded being 45 observed at Kergord. Reports of common crossbills were widespread including Virkie, Sandwick, Cunningsburgh, Lerwick, Toft and Voe.
Most Shetland records of this species occur in the summer when crossbills arrive from the Scandinavian breeding populations. Breeding early in the year, influxes occur when there is insufficient food in their breeding grounds for the adults and their young. The high number seen at Kergord is due to the number of coniferous trees planted there, as crossbills are specialist feeders on the seeds of species such as spruce, larch and pine. However, they will also take the buds, flowers and seeds of other tree species, like sycamore, and from plants such as heather and thrift.
These thick-set, powerful-looking finches are easily recognisable, flying around in noisy flocks and spending much of their time high in the trees. The males are orange-red and the females greenish-coloured with an orange rump, while juveniles are grey-brown with bold streaks. As the name “crossbill” suggests, the mandibles of the bill are crossed at the tip. This provides an effective pair of pincers for prising apart the scales of cones to extract the seeds. When feeding on cones, they behave rather like parrots, using their feet to hold down the cones. Breeding is timed by the availability of conifer seeds.
Marsh warblers have been recorded from Virkie, Hoswick and Voe this week. Swifts have been seen at Sumburgh and Spiggie. There was a cuckoo at Kergord and a chiffchaff at Scousburgh. Long-tailed skuas have been reported offshore and a sandwich tern. There were 24 Canada geese at Eshaness, a quail was heard calling on Bressay (near our garden), a hobby was seen at Voe and the drake lesser scaup remains at the Loch of Benston.
Volker Deecke reported that the group of four killer whales, recorded off Yell last week, which then continued down Lunna Ness, were probably the same four seen off Gulberwick, and then off Cunningsburgh on the 21st as the group composition was the same: two adult females, a juvenile male and one small juvenile. On the 26th 15 Risso’s dolphins were seen near Swarta skerry at Lunna Ness. Risso’s dolphins can attain lengths of up to 10.9m and have blunt, rounded heads with a relatively tall, sickle-shaped fin. The grey back and flanks have many pencil-like scratches and scars. These dolphins are a deep water species and are only seen close to shore where the deep water contour line is close to the landmass as it is around much of Shetland. On the 27th a large pod of Atlantic white-sided dolphins were seen heading north past Noss and Bressay in the morning. On the 28th five killer whales were off the South Mainland for much of the day, being seen several times around Sumburgh Head and travelling as far north as Mousa Sound. The project team launched their boat at Cunningsburgh and followed the whales back round to the west side of Sumburgh, witnessing a seal kill at Troswick. If you see killer whales please phone the team on 07500 380524.