Eight Things You Can Do to Help Bats - Part 3

The Third Step You Can Take to Help Your Local Bats

                        

                         Make Your Yard Bat Friendly!

Bats eat insects, so anything you can do to increase the number of night-flying insects will improve habitat for bats. When you are planting “big” elements in your garden, such as trees or shrubs, try to incorporate species that are native to your area. Native plants, trees and shrubs are more likely to support native insect fauna; native species may also be more tolerant of the climatic conditions in your area and use less water than exotic shrub and tree species. Deciduous trees provide better habitat for insects (such as moths and beetles that may be eaten by bats) than coniferous trees (such as pine and spruce).

Numerous North American studies have shown that pesticide spraying, both agricultural and residential, can lead to toxic effects on various insectivorous bat species. Pollutants (such as PCBs, heavy metals, and cyanide and other compounds) that settle into pond, wetland and lake sediments can be taken up by larval forms of insects that eventually emerge and become prey for flying bats. These pollutants can be traced in bat hair and organ tissues, they can accumulate in the fat tissue of bats and may cross the placenta into developing bat embryos. The effects of pesticides are biggest on the weakest and the youngest bats that rely most heavily on stored fat reserves.

Fringed Myotis (Myotis thysanodes) captured in William's Lake, B.C. (with wingband). Photo by: Gina Roberts.

Water is also important. Breeding females who are nursing young bats are very thirsty after spending their day in a hot roost (temperatures can reach 37°C and higher). The first thing most bats do when they leave their roost in summer is to head for water to drink. A study of insectivorous bats in dry areas in Europe found that home range sizes for bats were very large and this was thought to be primarily due to the distances travelled to water sources. Another study in western North America found that reduced availability of water, especially to breeding female bats will reduce their ability to successfully raise young bats.

Ponds should be clear of vegetation to allow for straight flight-paths of bats skimming the water to drink.

Lines of shrubs or trees can also provide security cover for flying bats. Bats leave their roosts at dusk, usually flying from a day roost directly to a water source for a drink or then along routes to favoured foraging areas (possibly wetlands or other areas with abundant night-flying insect life). Birds of prey may hunt just at dusk, picking off commuting bats. Owls also will hunt flying bats. For this reason, bats like to fly along edges of forests in the shadows where they may be less visible to predators (it is also for this reason that bats seem to avoid flying as much on nights with a full moon, a behaviour referred to as “lunaphobia”). Some bat species will avoid crossing open areas and in the UK, studies found some bat species will avoid gaps as small as 10 metres across.

Providing roosting habitat for bats is also important. Trees with cavities, buildings and bat houses are all options for providing bat roosting habitat. This is a big topic though, and I will make that the focus of my next blog entry!

To create your own bat-friendly property:

• Reduce or eliminate the use of pesticides on your property.
• Provide a pond with clean and open water for drinking bats.
• Plant shrubs and plants that support night-flying moth species eaten by bats.
• Plant shrubs and trees along fence lines or between forested areas and wet areas (such as wetlands, ponds or river areas) to provide safe cover for bats flying between day-roosting areas and foraging and drinking habitat. Many bats prefer not to fly across open areas because of the risk of being preyed upon by night-flying hunters such as owls or dusk-flying hunters such as falcons and hawks. Lines of trees and shrubs provide a shadowy cover for flying and commuting bats.
•  Keep your back yard dark at night. If you need lights on for security, use lights that are activated by a motion-sensor. Urban lighting has been shown to not be beneficial to bats. Although lights may attract insect prey, bright lights impair bat vision (yes they can see – but prefer dim lighting) and research has shown that most bat species do not benefit from lights. Don’t point lighting at a bat house or a roost.

Deciduous trees and shrubs provide leafy forage for moth caterpillars. Native and local species are great planting choices for your backyard. In particular moths and butterflies benefit from the presence of:

·         Oaks (Genus Quercus); on the prairies, this includes bur oak, elsewhere red and white oaks provide great habitat for Lepidoptera (moths and butterflies).

Oak tree (Quercus spp.)

·         Cherry trees (Genus Prunus); includes pin cherry, chokecherry and plum among others.

Pin Cherry (Prunus spp.)

·         Willows (Genus Salix); willows are a diverse group, check which species is local and try to find a native one to plant; size varies from full trees to low shrubs.

·         Birch (Genus Betula); birches are widespread across Canada and the US but species vary depending on locality and habitat; again look for a native species to plant, it will be hardier and may support a greater variety of moth species.

·         Poplars (Genus Populus); includes aspen, poplar and cottonwoods; trees vary greatly in size and shape within this Genus, usually these are fairly fast-growing wherever they are grown.

·         Apple or Crabapple (Genus Malus); flowering crab trees and apple trees provide habitat for a variety of butterflies and moths; spring-flowering, these are also considered ornamentals.

·         Maple (Genus Acer); another diverse group of trees, garden centres carry numerous species that are not native to North America; stick to native species for best effect.

·         Blueberry (Genus Vaccinium); includes serviceberry (Saskatoon), cranberry, bilberry and huckleberry (among others).

·         Alder (Genus Aldus); range in size from full trees to shrubs; usually fast-growing.

Garden plants that bloom late in the afternoon or at night can include:

·         Evening Primrose (Genus Oenothera), many plants in this Genus are also drought-resistant, some are pollinated by moths (which means moths are using flowers for food, either using nectar and/or pollen).

·         Phlox (Genus name is Phlox), the foliage provides larval food to a number of moth species, flowers are fragrant, species of plants within this group maybe tall or low growing, flowers may be blue, violet, pink, red or white depending on the type.

·         Nightflowering/Silene catchfly (Genus Silene), also known as campion in the Pink family; the species Silene noctiflora is considered a weed on the Canadian prairies but its night-flowering habit attracts moths that feed on copious amounts of nectar produced by the plant and in turn the moths act as a pollinators.

·         Milkweeds (Genus Asclepias), the foliage provides larval food for developing moths and butterflies, these plants are also important for Monarch butterflies and are a recommended plant for butterfly gardens. Be sure to ask for your local, native milkweed species at your garden centre.

·         Goldenrod (Genus Solidago), tall (up to a metre) with yellow flowers that bloom in late summer, this plant spreads through seed production and rhizome growth (so planting them in a buried pot or pail with the bottom cu out might be helpful if you are trying to contain them to an area of your garden); unfairly this plant is blamed for causing seasonal allergies, however it blooms at the same time as the more likely culprit, ragweed. Goldenrod pollen has been shown to not be the cause allergies (it produces very little pollen and that pollen is too heavy and sticky to be blown around). Pollen and nectar is used by insects, including moths; the plant foliage is used by moths and butterflies as larval food (which may cause the formation of galls that maybe subsequently pecked open by woodpeckers that eat the enclosed developing larva). Above-ground parts of the plant are all edible.

Goldenrod (Solidago spp.)

·         Purple coneflower (Genus Echinacea), purple flowers up to a metre in height, flowers are used by butterflies and bees and some moths will use flower heads as food for their developing larva. Drooping flowers may be a sign of moth larva in the cone head; however they likely will only affect a few of your flowers, so if you are a gardener please hold off with the pesticides. If you are trying to provide habitat for moths, congratulations! You have succeeded in providing moth breeding habitat!

·         Four o’clocks (Genus Mirabilis) as the name implies, they bloom in the late afternoon and evening, providing fragrant flowers and abundant nectar to night-flying moths such as Sphinx moths and hawk moths (Sphingidae) that act as pollinators for these multi-coloured flowers.

·         Salvia (Genus Salvia), foliage is used as food for developing larva of numerous moth and butterfly species.

·         Nicotiana (Genus Nicotiana) late afternoon, evening the flowers are very fragrant; the foliage is used by a number of moth species including the families Noctuidae and Sphingidae (hawk moths and sphinx moths).

·         Moonflowers – a varied group that includes a several groups – flowers all bloom in late-evening; provide nectar for foraging moths.

·         Aromatic herbs

Always check to see if your plant is an invasive species before you put it in the ground!

Canada Council on Invasive Species - http://canadainvasives.ca/

British Columbia Invasive Plant Council   http://bcinvasives.ca/

Alberta Invasive Plant Council https://www.abinvasives.ca/

Saskatchewan Invasive Plant Council - http://www.saskinvasives.ca/

Manitoba Invasive Plant Council - http://invasivespeciesmanitoba.com/site/

Ontario Invasive Plant Council - http://www.ontarioinvasiveplants.ca/

Prince Edward Island Invasive Species Council - http://peiinvasives.ca/  

Invasive Species Alliance of Nova Scotia - http:/ /www.invasivespeciesns.ca/

Yukon Invasive Species Council - http://www.yukoninvasives.com/

For more information on gardening to benefit wildlife see this page called “Ecosystem Gardening” http://www.ecosystemgardening.com/top-10-best-woody-plants-in-conservation-gardening.html for an excellent review. Also see “The Ultimate Guide to Gardening for Butterflies and Moths” http://nativeplantwildlifegarden.com/guide-to-butterfly-gardening/ for a list of resource books to help you with your garden planning!