Am Bratach No. 226
August 2010
editor@bratach.co.uk

Nature’s call
by Andy Summers

August can be a difficult month for wildlife watchers. The vegetation has grown very dense. The foliage in the trees is thick and almost impenetrable. In the bird world there are lots of grey and brown youngsters about that are hard to identify and many of the adults are moulting, losing their distinctive colour patterns. However, on the plus side, there is more wildlife now than any other month of the year. It is all a question of knowing where to go and look for it.

There are some cracking moths around at the minute. Almost everywhere on the heather you will see magpie moths, Abraxus grossulariata, laying eggs on heather bushes, which are rapidly defoliated by the voracious caterpillars. Large areas of heather moorland are still recovering from last year’s devastation. Larvae and adult have bright warning colours (black, white and orange) that birds learn to associate with the distasteful chemicals that these insects contain.

Four spot chaser dragonfly emerging from its larval skin.


In the movies a dorsal fin breaking the surface of the sea is a cue for swimmers to scream and flee in terror. If I saw a fin break the surface of the sea in August around here, it would elicit a more positive response. This is because it is likely to be a basking shark. This 10m long filter feeder is the second largest fish in the world that cruises around surface waters to take advantage of plankton blooms. On days when the sea is calm the basking shark can come very close to the shore.

One beastie that I encounter regularly with mixed feelings is the Click Beetle, Athous haemorrhoidalis. It is the adult of the notorious “wireworm” that munch little holes in our potatoes, but the adults are intriguing insects with a neat contortionists trick for escaping predators. When disturbed, the beetle pretends to be dead but then suddenly arches its back, building tension in its back that violently releases when the body straightens out, hurling the whole beetle several feet into the air with an audible click. Why not try it yourself? Lift one and hold it in the palm of your hand and watch it toss itself into the air.

If you fancy doing something a bit different, why not try a spot of crepuscular cavorting with Chiroptera? In other words why not go and look for bats? It never really gets totally dark this month so you should be able to find a bat flying somewhere near you. The best time is around dusk and then again at dawn. Some species will congregate around their day roost before finally entering as part of an activity known as “swarming”. Not only is this an amazing spectacle, it also helps you locate the roost. So if you ever wondered if you had a bat roost in your roof space this is a good way to find out. The largest roost I ever found had over 1,000 bats, but this is unusual.

I spent yesterday rockpooling in the rain. There can be no better way I can think of to entertain the children (and adults) during the summer holidays. This month, take time to search for the tough egg capsules of dog whelks. Search under rocky overhangs and in damp crevices down on the beach. They look like densely packed rows of yellow skittles. Some will have been laid during the peak breeding period in spring but it is only now they start to hatch. Each capsule contains hundreds of eggs but only a few were fertile and egg cannibalism has been going on inside for several months leaving about a dozen tiny shelled dog whelks to crawl out of each capsule. A marvellous scene if you are lucky enough to witness it.

If the rain and wind will stop for a minute you find that August is a great month for dragonfly watching. Find yourself a pair of close-focusing binoculars and head for the nearest lochan. Their speed and agility are amazing. If you watch closely you might be lucky and see one them perform what acrobatic pilots call an Immelmann turn (a half loop, with a half roll at the top almost instantly reversing the direction of flight). This was made famous by the World War One fighter pilots but was probably perfected sometime in the Carboniferous era when dragonflies were the supreme aerial predators. These guys are very territorial and it is great to sit awhile and watching the dog fights over a patchwork of sphagnum moss.

Andy is a senior Highland Council ranger, based in Lochinver.

 

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