Guest author, Anna Shaw, looks at the importance of insects in the diets of mammals, and what we can do to stock up our garden larder. Insects make up a lesser or greater part of the diets of many British mammals. Badgers, hedgehogs, shrews and some voles and mice, for example, consume insects as part of a wider diet of invertebrates, seeds and fruit.
Grabbing a bite
All of the 18 species of bat in the UK are insectivores. A single bat can catch and eat up to 3000 insects per night. Our native bat species not only vary in size (the smallest can fit inside a matchbox) but in the habitats in that they hunt in, from woodland to waterways and urban areas.
They employ a range of techniques too. Noctule bats, for example, fly high and fast whilst Natterer’s bats fly more slowly and Daubenton’s bats swoop down and pluck insects from the water surface with its large feet. Given the reliance bats have on insects as their main food source, it’s not surprising that a reduction in the number and variety of insects, partly due to changes in agricultural practices, has contributed to a decline in our bat populations over the last century.
Catering for wildlife
Although conservation efforts have seen populations rise again, we can help bats out in our gardens too by encouraging a range of insects for them to feed on. One way to this is by growing nectar rich plants with a variety of flower shapes, colours and flowering periods, to support a greater abundance and diversity of insect species. This wider range of insects will appeal to more bat species, which feed on different selections on insects. Night-scented flowers, such as honeysuckle and evening primrose, will appeal to insects active a night, such as moths, providing further food for bats.
Other garden features, too, are easily put in place: a pond or water feature which, however small, will attract insects and other wildlife into your garden, or a ‘bug hotel’ or log pile, which provides sites for insects to nest or overwinter in. You could plant a tree, such as beech or ash, providing bats with roost sites, additional food and even a signpost to navigate by, or put up a bat box in an building or existing tree as an alternative roost site.
It isn’t just the bee that’s busy in our gardens. Insects pollinate, recycle, control pests and feed so much of the other wildlife. They’re on the menu of hedgehogs, wood mice, shrews and bats, and by encouraging them, who knows who’ll you’ll attract in.
Did you know?
Eighteen species of bat are resident in the UK, but one, the greater mouse-eared bat, is just that – one – a solitary indivdual recorded most years since 2002. Greater mouse-eared bats are the largest bat in Britain, with a wingspan around 40 cm.
By comparison, the wingspan of pipistrelles, the smallest species, is half of that (about 22 cm). The two species of pipistrelle, common and soprano, are the most likely to be spotted in urban areas, emerging a short time after sunset and flying quickly just above head-height. They feed on midges, small flies, mosquitoes, lacewings and small moths, caught in the air.
In summer, pipistrelles will roost beneath building tiles, under roofing felt or in cracks in walls, and will also make use of bat boxes.
Bats rarely cause any damage to buildings: unlike birds, they don’t bring in nesting materials and, unlike rodents, they won’t gnaw electric cables or wood. Their droppings carry no disease and are usually odourless. Large summer roosts of pipistrelles can number several hundred individuals and they can be noisy tenants, but so important are buildings to bats that managing and renovating them appropriately is a big part of bat conservation.
Many of Britain’s mammals are in trouble. If we’re not careful, even common species can be lost before our eyes. That’s why we need your help to monitor mammals and record sightings to protect their future. If you’d like to help us monitor our wild neighbours, take part in our nationwide survey Living with Mammals today.