30/04/15 - Voles, Mice & Owls

Over the last month we have been small mammal trapping around the NNR Base at Bank Island and more lately down on the Ings, using Longworth live traps to monitor the populations on the reserve. Small mammals are important in their own right but they are also a key dietary item for the local owls and other predators. By monitoring their populations it can help us understand the population dynamics of other key species on the reserve. From the trapping we know that there are certainly plenty of Bank Voles and Wood Mice present in the edge habitat around the NNR Base, gardens and boundary which meets the surrounding farmland – however the Wood Mice have largely dominated the catches.

 Bank Vole - 17/03/15

Voles can be easily separated from Wood Mice by their rounder heads, small beady eyes and small ears and shorter tails. The Bank Vole is longer tailed and more ginger/chestnut brown in colouration than their Field Vole cousins (of which we are yet to catch as they prefer the more open tussocky grassland of the reserve itself). Bank Voles are a common and widespread small mammal of the British countryside, and unlike the Field Vole which is largely found in grassland habitats, the Bank Vole tends to be found on the edges of such habitat, frequenting field margins and more particularly hedgerows, woodland and gardens. They eat a variety of food items from seeds, insects and berries, with typical hedgerow species such as hazelnuts and blackberries being a favourite. They will also readily take seed put out at bird feeders – so they are probably benefiting from the bird food provided at the NNR Base feeding station. 

 Bank Vole - 17/03/15

Wood Mice have also been present in the Longworth traps and have made up the majority of the catches. Wood Mice have sandy brown fur, large protruding eyes, large ears and a fairly long tail. The large eyes and ears point to the fact that they are largely nocturnal, and spend a lot of time underground in burrows. The burrows are fairly complicated and may include nest chambers and food stores. Food tends to be made up of woodland seeds and nuts, with a greater percentage of insect prey in the summer months.

Wood Mouse - 17/03/15

Wood Mice are found in a range of habitats, although they tend to favour woodland and are least found in open grassland – they are a key prey item for Tawny Owls (which hunt in woodland, hedgerows and parks/garden environments), and are rarely found in any significant number in the Barn Owls diet. Barn Owls are known to largely prefer Field Voles – we’ve been running the traps this week in areas where we thought we had a good chance of catching them, however none have been caught. With the constant sightings of day hunting owls, the lack of prey caught and five birds recently picked up dead (and found under-weight), perhaps as mentioned previously this points to the suggestion that these birds may be struggling to find food due to the lack of it. 

Wood Mouse - 17/03/15

The sight of day hunting Barn Owls in the valley lately has been a talking point over recent weeks. Volunteers, staff and visitors have had the pleasure of watching two owls hunting at Bank Island recently on a daily basis. It’s great for us to be able to see them – but worrying for the owls that they appear to be struggling to find food. Recent pellet dissection by one of our volunteers from the coast has revealed a lack of Field Vole remains, along with our trapping data this would further point to the conclusion that the population may have suddenly crashed… Hopefully things will soon take a turn for the better for our Barn Owls – this individual – a lovely dark female was captured on camera at Bank Island, seemingly undeterred by our presence, never before have we had such close views of these beautiful creatures. 

Barn Owl - 30/03/15

After watching the owls hunting at Bank Island we also came across this Brown Hare in the long grass. The sightings of Brown Hares on the Ings is something we look forward to each spring, particularly the ‘Mad-March’ hares that are known to start ‘boxing’ during the month. We are yet to witness this wildlife spectacle this year, however we have been fortunate in the past to watch as an unreceptive female tries to fend off an amorous male. It is thought that this mating ritual of sorts is also aimed at testing the strength of the male before the female decides on whether or not to carry on with the courtship. 

Hares are largely nocturnal, feeding at night and spending most of the daytime laid low amongst grass in small depressions, so this time of year is your best chance of seeing one out in the open. The only other sightings are usually if you come across one hiding in the grass whilst out walking – in this case you’ll have to be quick to see it before it bolts off into the distance – being able to run at a speed of 45mph makes them Britain’s fastest land mammal! 

 Brown Hare - 30/03/15