The Scottish Crossbill – Endemic to Scotland

With the spectacular pine forests of the Scottish Highlands as their home, Scottish crossbills are the only known endemic bird species in the whole of the United Kingdom. In fact, they are believed to be the only endemic vertebrates in the UK, and were identified as being a unique species in August 2006 based on their distinctive birdsong. The population of Scottish crossbills is estimated at around 6,800 breeding pairs and they are considered to be of ‘least concern’ by the IUCN from a conservation standpoint, while having ‘amber’ status with the RSPB.

Scottish crossbills (Loxia scotica) are small passerine birds in the finch family Fringillidae and are very similar to red crossbills in appearance, but their manner of flight, excitement (alarm) calls and birdsong set them apart, with some birders suggesting that they have Scottish accents.

These interesting little birds appear to feed solely on pine and larch seeds and are found in the old-growth Caledonian Forest of Scotland, as well as in new commercial pine plantations. As their name suggests, the mandibles of Scottish crossbills cross over one another at the tips. This allows them to expertly extract seeds from pine and larch cones. The adult males are shades of red and orange in colour, with females being shades of yellow or green. They mix freely with other crossbills in large flocks outside breeding season, but become fairly territorial when mating.

They were first identified as a distinct species by the British Ornithologists Union in 1980, but some ornithologists at the time were of the opinion that they were likely a sub-species of the parrot crossbill or red crossbill which are also found in the Caledonian Forest, and it was only in August 2006 that it was agreed they are a distinct species. With very little visible difference between crossbill species found in the area, it is the Scottish crossbill’s call which is the deciding factor for researchers monitoring population size. To confirm the identity of the Scottish crossbill, its call is recorded and analyzed on a sonogram.

If you are visiting any remnants of the Caledonian Forest, such as the Abernethy Forest or Glenmore Forest Park, be sure to watch out for the only endemic bird in Scotland – the Scottish crossbill.