Caithness CWS - Caithness Field Club - Annual Bulletins - 2008

Ranger Wildlife Notes 2017 (by Paul Castle)

My first surprising find of the year was on 24th January while walking on the beach at Dunnet at lunchtime. Within about 30 minutes I had collected 102 spotted ray egg cases, 96 catshark (formerly dogfish) egg cases and 5 cuckoo ray egg cases. All the egg cases were found in a section of the beach about 100metres long near the mid-sand burn area. Similar quantities were also discovered by Donald Mitchell my Ranger colleague in north-west Sutherland. The tides must have been working in such a way that all the egg cases once broken free from the sea bottom were gathered together in a similar location.

The very next day I actually witnessed an otter on the beach at Dunnet in broad daylight something I’ve not seen for a very long time. Otters regularly use the beach at night and it’s not uncommon for them to approach very close while you are fishing in the dark. I’ve even hear stories of otters running off with fish caught by anglers and left on the sand close by them.

I recorded five dead stranding’s of cetaceans in 2017. Casualties included two porpoises at Dunnet Beach and one at Thurso beach, a young male common dolphin at Armadale beach and a dead Risso’s dolphin at Dunnet beach. Measurements and some samples were taken for analysis to try and determine cause of death.

Not all cetacean I discovered were dead fortunately and porpoise, Minke whale, Risso’s dolphins, white-beaked dolphins and even pilot whales were seen in various locations. One stunning sighting in September was of a pod of about 30 pilot whales being harassed by a group of about ten Risso’s dolphins for hours in Dunnet Bay.

I first noticed lots of splashing out towards Claredon Head by Murkle and using the telescope I could see pilot whale dorsal fins which are very distinctive. This amount of splashing and movement is quite unusual for this species. Looking closer I could see other fins which turned out to be Risso’s dolphins following the pilot whales. For several hours the Risso’s dolphins continued to harass the pilot whales as they moved around Dunnet Bay. They eventually ended up very close to shore by Castlehill Harbour. The pilot whales were spy-hopping in a tight group with the Risso’s dolphin circling like sharks in a movie. Fortunately no animals stranded which was our concern and eventually they moved back out of the bay in the later evening.

Watching two young white-tailed eagles out near Whiten Head in north Sutherland was another treat enjoyed by a group of folk on a walk with us in 2017. We watched the birds flying out from the coast and being mobbed by virtually every other bird in the area. I briefly saw one adult bird up on the hill as we approached the site on the coast were the young birds were sitting. That certainly was a special treat for the people attending our walk that day.

Great yellow bumblebees were very few and far between in 2017 and I only saw about four individuals all season, either at Farr Glebe in Bettyhill or in the Dunes at Dunnet Bay. Hopefully 2018 will prove a better bumblebee season.

The decline in numbers of the once common small tortoiseshell butterfly continued in 2017. This was previously one of the most common butterfly species but very few individuals were seen in the spring and very few seen going in to hibernation in the autumn.

Red admiral butterflies although mainly an immigrant species, it appears small numbers are now overwintering in Caithness on a regular basis. Large numbers of immigrants were seen in late August. I personally witnessed over twenty during a guided walk in north Sutherland on the 28th August.

Small blue butterflies did very well in 2017 with the first being seen on the wing in the last week of May as usual. The peak flying period is around the middle of June and by the first week of July they are no longer to be seen. Further south there can be a second hatch in late August but not here in the cooler far north.

Common blue butterflies (often mistaken for small blue) do not emerge until late June/early July and is on the wing until the end of August. If the butterfly you seen is very blue coloured then it will be common blue not a small blue butterfly. This is a very common species in Caithness and seen in good numbers all around the county.

The green veined white is often mistaken for the ‘cabbage white’ but it is not and if first white species appearing in early May and seen until late August. This species usually avoids cabbages and was again very common in 2017.

Speckled wood butterflies are now well established in Caithness but appear later in Caithness so early records are rare. Later records were common in 2017 and good sites to see this species are woodland edges such as Dunnet Forest or Achvarasdal Wood.

Species folk should be on the look-out for are small pearl-bordered fritillary sometimes found at Broubster Forest and Borgie Forest. It is probably found at other locations but is under-recorded in this area.

The pearl-bordered fritillary should be found in sunny glades in coniferous woodland in Caithness but there are too few outdoor naturalists recording them here.

If you should wish to get involved looking for these and other species then records can be sent to caithnessbutterflies@gmail.com

Philip Wright, the Butterfly Recorder for the Dunnet and Castletown area, contributed the section on butterflies. Philip also records moths, dragonflies and damselflies.