Field vole photo Tom Marland
Childwall Woods & Fields is teeming with mammals! We know this from our recent survey using footprint tunnels (more on this below). But you are unlikely to see most of these animals. Small mammals are naturally wary of people and dogs, and are keen to avoid being eaten by birds of prey or foxes. So they hide in tall grass and bushes, or they are active mainly at night.
We also have a healthy population of bats on site but as these appear at nightfall you are unlikely to see these either!
The mammals we have identified so far are: field vole, bank vole, wood mouse, common shrew, grey squirrel, hedgehog and fox. Using bat detectors during our night walks we have identified three species of bats – pipistrelle, soprano pipistrelle and noctule.
In addition, we suspect that weasels are present because they have been found in nearby gardens. Have you seen one of these at Childwall Woods & Fields? If so can you let us know? Given rats are found everywhere, it would also be no surprise if they were resident here.
Voles
Photo Andrew Scott
Field voles are the dominant rodent in grasslands where they create networks of shallow runs or tunnels in or under the grass. They are active day and night and feed on vegetation. They are the main prey of owls and kestrels. This dead field vole was found by a path.
Bank voles are found mainly in woodlands. They are active day and night and are agile climbers in bushes and brambles seeking seeds, fruit and insects. They nest in logs or tree roots.
Wood Mouse
The wood mouse or long tailed field mouse has larger eyes and ears, and a longer tail, than its house mouse cousin. They are the dominant rodent of woodlands and are very agile climbers. They are mainly nocturnal and feed on seeds such as acorns and beech mast, fruit and insects.
Shrews
Photo Izzie Hurdle
Photo Brenda Cameron
Shrews are tiny, barely the size of your finger, as these photos of a common shrew show. The Wildlife Trust describes the common shrew as “a small, insectivorous mammal, with tiny eyes and a large nose giving it keen sense of smell. Shrews snuffle through the undergrowth for their prey, which includes earthworms, spiders and insect chrysalises. They can be found in most habitats, but prefer woodland and grassland. Active by day and night, they are very territorial and aggressive for their size and can sometimes be heard fighting, their high-pitched squeaks particularly noticeable during the summer”. They are also a staple food for birds of prey.
We suspect that the equally widespread and even smaller pygmy shrew is also present at Childwall Woods & Fields.
Grey Squirrel
Photo Danny Carmichael
Grey squirrels need no introduction – they can be found throughout the Childwall Woods & Fields nature reserve, and in most surrounding gardens where their antics and ingenuity in raiding bird feeders are legendary.
What is less known is that they can be very destructive in woodlands because they strip the bark from young trees.
Fox
Photo John McCombs
Another well known animal needing no introduction, the fox is increasingly seen wandering the streets of this area or even lying in the sun in a garden. They are generally solitary and very versatile in their diet. Mostly they eat small rodents but they will also eat seeds, berries and worms – and whatever they can scavenge in bins or on the street.
Hedgehog
Photo Brenda Cameron
Here is a familiar animal that we should see far more than we do, both in our gardens and in CWF. This hedgehog was seen in November 2019 in the woods near Childwall Abbey Road but we have seen none since.
Hedgehogs are surprisingly mobile and can wander several miles in an evening as they snuffle around at night munching on snails and slugs. And maybe this is the problem and part of the reason for their decline?
Our gardens are now so sealed off, like cells, and there are so few gaps in or under the fences to allow hedgehogs to roam freely as they like to do. Even a site like Childwall Woods and Fields may not be large enough for them.
Hedgehogs hibernate overwinter in piles of leaves so please don’t make your gardens too tidy. These animals like some wildness.
Bats
Our common pipistrelle, soprano pipistrelle, and noctule bats are all nighttime insect eaters that find their prey in flight by echo location. They rest by day, or hibernate over winter, in crevices in hollow trees and a site such as Childwall Woods & Fields with its numerous old veteran trees is therefore ideal.
Pipistrelles are tiny, one can fit in a matchbox, but this doesn’t stop them eating up to 3000 insects a night. Bats are almost impossible to identify in flight. We have identified them using hand held bat detectors that convert the bats’ distinctive ultrasonic calls into sounds we can hear and recognise. A good place we have found to glimpse them is on the top field near the ponds.
Mammals in the food chain
I said above that we are generally unlikely to see most of our mammals – except for the squirrel – they are so wary they hide. Sometimes we might get lucky and see a kestrel devouring a field vole, as Mike Barlow did here.
Kestrel eating a field vole. Photo Mike Barlow
Another way of identifying mammals is by looking at the remains contained in owl pellets. Our resident tawny owls feed mainly on rodents. The bones that they can’t digest they regurgitate as pellets (below) which can be found below the trees where they roost. The owl pellets are up to 5cm in length.
Tawny owl pellet. Photo Brenda Cameron
For some time trustee Brenda Cameron has been collecting and analysing these owl pellets with the help of Merseyside Biobank.
The jaw bones (below) are particularly useful in identifying what the owls have been eating. These are vole and mouse jaws.
Shrew teeth are particularly distinctive because of their red or dark tips (below).
Mouse and vole jaw bones from tawny owl pellet.
Shrew jaw bones from tawny owl pellet. Photos Brenda Cameron
Surveying mammals using footprint tunnels
Another way of identifying shy animals such as small mammals is to use footprint tunnels. These are 40cm sections of drainpipe with a slat of wood inside, on which is a piece of white card with ink pads either side. Like us, rodents are inquisitive and like to explore. When they find the tunnels they wander through leaving a trail of inky footprints on the card.
Footprint tunnel suspended in hazel tree. Photo Brenda Cameron.
Wood mouse footprints. Photo Brenda Cameron
Brenda made and placed 20 footprint tunnels at different heights in Childwall Woods between June and August. In the woods Brenda suspended the tunnels in bushes or shrubs or, as here, in a hazel tree.
Woodland mammals are usually agile climbers.
Andrew Scott made a further 20 footprint tunnels and placed these at ground level in Childwall Fields during August. These were sited in the open fields and in the plantations, usually near possible food sources such as elder, bramble and rowans.
This is a tunnel sited at the base of an apple tree in the orchard on the middle field.
Tunnel at base of apple tree in middle field orchard. Photo Andrew Scott.
These are shrew and vole footprints from one of the tunnels in Childwall Fields.
Locations of footprint tunnels on Childwall Fields
Locations of footprint tunnels in Childwall Woods.
Small mammal footprints have been found in all 40 tunnels placed across the reserve.
It is this extensive survey across the CWF site, in different habitats and vegetation types, that enables us to say confidently that the reserve is teeming with mammals.
Andrew Scott