An Eagle and a Shrew interrupt alfresco meals
Thursday 9 April 2020 was our first noticeably warm day this year in Assynt with light winds and temperatures around 16ᵒC. Given the lockdown situation due to the Covid-19 pandemic, Avril and I spent most of the day outside the house upping our vitamin D production.
The outdoor morning coffee break had been interrupted by a slow fly-past from a young White-tailed Eagle, Haliaeetus albicilla. Always an amazing sight, but this one was in no hurry and was quite low, no more than 30 metres up.
It gave me plenty of time to get back in the house for the camera and to grab a few frames as it drifted over the neighbour’s house. Job done, coffee break resumed.
Next alfresco meal was about 12.30pm. Once again being enjoyed while we were sitting on the doorstep listening to the bird song surrounding us, and the waves gently giving up the last of their energy around Loch Dhrombaig below us.
Very relaxing. Then it was there! Running along the road at some sort of mad speed was a small brown mammal. Definitely a shrew from the long and pointed snout, but was it a Common Shrew, Sorex araneus, or a Pygmy Shrew, Sorex minutus?
Back in to the house for the camera, with very little expectation of the little brown job still being anywhere to be seen. Amazingly it had actually stopped! When I came out again it was sitting against the grass verge almost directly below me.
It then spent probably less than a minute foraging before running off towards longer vegetation in its never-ending search for food. Of course, a minute to a shrew is a long time as Ian Evans will now explain, as he also confirms the identification of this doorstep picnic interrupter.
The facts and figures
Fortunately, one of David’s pictures was a perfect side view, so I was able to print it out and lay a ruler on it. This gave a ratio of tail to head and body of 58%, which is within the range of 50-60% typical of the Common Shrew. Pygmy Shrews, although smaller overall, have a proportionately longer tail, at 65-70%. There is also a difference in the length of the hind feet, one of which is visible, but short of asking David to locate the precise place where the picture was taken and measure a specific stone, no way of calculating that. Common Shrews do also look chunkier than Pygmy Shrews, but that’s not readily quantifiable either.
An interesting feature of this side view is the dark line through the fur about two-thirds of the way along the body. This is where the spring moult has reached on this individual, with the shorter summer coat (3.5mm long) replacing the longer winter coat (7mm long). The moult starts on the head and works backwards and it must involve a major investment of energy and other resources.
(Note from David, the last photo of the shrew is not sharp but it is fun as the shrew has no feet on the ground. It also helps to show quite clearly around the front leg the difference in length between the new and the old coat).
As David implies, shrews have an energetic life style. They are born between May and September, overwinter as immatures, after an autumn moult (tail to head) into a warmer coat, mature rapidly in March-April, breed (the females producing two or more litters of as many as eleven young, sired by up to six males) and die from late June onwards. They are voracious feeders, predating a wide variety of invertebrates, particularly earthworms, and requiring 80-90% of their body weight in food daily. A short life, but a merry one!
David Haines/Ian M. Evans
All photographs D. Haines