The water shrew's whole world is a bit of muddy bank under the culvert and a few metres in either direction. It is amazing to see how much it can find to eat very close by. The shrew seems to favour one spot under the culvert to eat (back left as we look at it). Sometimes it stays to eat (often with its back to the camera) but sometimes it seems to drop the food and leave to find more almost immediately. I came to the conclusion that it must be caching food there if it has a short-term surplus, and it doesn't seem to have any difficulty finding food. Then I found a paper from Austria* which describes food caches in the Eurasian water shrew, mainly consisting of caddis fly larvae and water snails. I presume the venomous bite of the water shrew will disable the prey to stop it escaping. Here is the shrew eating, first a shrimp it has just brought in, and then what looks like a larva, perhaps caddis fly, from the larder.
This water shrew first came to notice when the camera was set to record otters. Now several other things have turned up while the camera is after the water shrew. The most intriguing has been a wood mouse. Several times the camera has seen a wood mouse come to the cache and take food, either eating it on the spot or taking it away. As far as I can see it is always a caddis fly larva still in its case. The next video shows the shrew depositing food without eating it, then once coming from the nest/burrow for a snack, and then the mouse - twice it comes to take a caddis fly away and the third time it stays to eat it. I have added a short slow-motion replay to show the mouse biting the end off the casing and pulling out the larva, just like the shrew does.
The camera is still in place in the hope that it will record even more interesting behaviour.
* Haberl W. Food storage, prey remains and notes on occasional vertebrates in the diet of the Eurasian water shrew, Neomys fodiens. Folia Zool. 51(2):93-102 (2002).
No comments:
Post a Comment