1. Species Spotlight – Building Resilience for Bats

    Species Spotlight – Building Resilience for Bats


    Photo of Little Brown Bat by Erin Low

    Bats are an important part of the ecosystem in Waterton Biosphere Reserve (WBR). Unfortunately, bats in North America are threatened by white-nose syndrome (WNS), a fungal disease that has killed millions of bats since first noted in the eastern United States in 2006. 

    WNS is a threat for certain bat species, particularly the little brown bat and big brown bat that occur in Waterton Biosphere Reserve.

    Improving stewardship for bats was identified as a priority in the Species at Risk Action Plan for Waterton Biosphere Reserve. Their continued presence in WBR is important for both the environment and the economy.

    In the face of population-level challenges, WBR began the Building Resilience for Bats project in 2019 to work with local landowners to build resiliency for bats, in particular little brown myotis (or little brown bat). A resilient bat population will be quicker to recover from disturbances like WNS or severe weather through adapting to stresses, better resisting disease, and/or sustaining fewer mortalities.

    For more information on what WBRA is doing and how you can help by improving habitat stewardship for bats and participating in bat monitoring please see the Stewardship Opportunities section of this page. For a more in-depth view you can read the Bat Conservation Plan for Waterton Biosphere Reserve (2020) here.

    Sights and Sounds

    This short 14 second video shows the output from a Echo Meter Touch 2 bat detector that plugs into a mobile phone or tablet and translates a bat’s ultrasonic sounds to something humans can hear. The big brown bat sounds in the recording show the bat emitting ‘chirps’ while searching for insects (where bars are more spaced out) as well as a feeding buzz when it detected and emitted faster sounds to lock onto the insect before capturing it (where bars become closely spaced). This clip was recorded right here in Waterton Biosphere Reserve in May of 2020.



    The clip below is of “Little Brown Bat calls recorded using a home-made detector (heterodyne downconverter) coupled with a Tascam Porta II cassette tape unit. The background noise is mostly insects that issue sounds near 23 KHz. The chirps and pops are bats echo-locating. The ‘fart’ sounds are them catching prey. The rapid chirps are them landing (roosting) in the trees.”


    Photo of bat guano by Julia Palmer

    Why Bats Are Important

    Bats make up roughly 20% of all mammalian species around the world and contribute vital ecological and economic values to many ecosystems through pollination, seed dispersal, and pest control. 

    They are an important part of the ecosystem in Waterton Biosphere Reserve. Bats are the primary consumers of night-time insects, including mosquitoes and agricultural or forest pests: a single individual can consume 100 times its own weight in insects each year. Their continued presence in WBR is important for both the environment and the economy.



    Movements and Migration

    Visit the ACBP bat profile page (click image) for a description of Alberta’s bat species and their ranges

    Migratory bat species typically arrive in Alberta during April and May for their reproductive season. The southward migration begins after pups are weaned with bats leaving the province in August through to early October. Overwintering locations for these migratory bats are thought to include areas in the southern United States and Mexico, California, the Pacific Northwest, and possibly warmer locales in  British Columbia. Long distance migrants include:

    • Hoary Bat
    • Silver Haired Bat
    • Eastern Red Bat

    ‘Resident’ species may undergo seasonal movements of up to several hundred kilometres but likely remain in or close to the province. Overwintering locations (hibernacula) for most resident bats in Alberta also remain largely a mystery. Suspected habitats include abandoned caves, mine shafts, deep rock crevices, and buildings but the few identified hibernaculum areas account for only a small proportion of our bat population. Local migrants include:

    • Big Brown Bat
    • Little Brown Bat
    • Northern Myotis
    • Long-eared Myotis
    • Long-legged Myotis
    • Western Small-footed Myotis

    The Western Small-footed Myotis is the only resident species not confirmed in WBR.




  2. Diet and Foraging Habitat

    Diet and Foraging Habitat


    Alberta bats are all insectivorous, pursuing prey items by hawking (catching flying insects while in flight) or by gleaning (gathering insects off foliage or the ground), and the importance of their insect consumption cannot be understated. Lactating little brown bats can consume their own body weight each night in prey. Annual consumption rates of big brown bats can total in the millions of insects a year at a colony level. Though no similar analysis has been conducted in Canada, pest control services provided by bats represent an average $23 billion value to the U.S. agricultural sector each year.

    For more information on insect preferences of Alberta bats and influence of body size, flight speed, and habitat on bat diet, refer to our Bat Conservation Plan.










    Foraging Habitat

    Particular habitat preferences can vary among bat species and breeding status, with some preferring treed areas, others open waterbodies, and yet others selecting the interface between two habitats.

    Lactating little brown bat females typically choose to forage in close proximity to their maternity roost using airspace over open water or near shorelines and along edge habitat.

    Riparian and wetland areas (along the Old Man, Castle, Waterton, Belly, and St Mary’s river valleys and associated smaller creeks and tributaries) provide natural foraging areas for bats, as these areas typically host concentrations of insect prey.

    The importance of riparian areas, springs, open river valleys, and treed stands for foraging bats in a grassland landscape and proximity to adequate roosting habitat may increase attractiveness for some species. Treed habitat may also provide connectivity through the landscape for bats that are commuting between roosting and foraging sites but that are reluctant to cross open areas.


    Water Source for Drinking

    Most species of bats drink by skimming the surface of a waterbody with their bottom jaw while in flight. Accordingly, they need open water sources free from flight obstacles, in other words a clear ‘swoop zone’.

    Waterbodies such as ponds, lakes, dugouts, and slow-moving streams can serve as open, unobstructed drinking water sources for bats. The required size of the waterbody will depend on the size of the bat species and their maneuverability, but can range from 3 m for smaller species with short, broad wings to 30 m for larger-bodied, less maneuverable species.




  3. Roosting Habitat

    Roosting Habitat

    Bat habitat can be found in both natural areas and human-made structures. Large diameter cottonwood and poplar, especially dead or decaying trees, provide natural roosting areas.

    Farms and ranches with used or abandoned buildings may also provide significant roosting habitat for some species.

    Preferred roost type depends on the species and, in some cases, on the sex and reproductive status of the individual.

    Reproducing female little brown bats, the target of the Waterton Biosphere Reserve Building Resiliency for Bats project, select warm and safe locations to raise their pups in colonies, while males and non-reproducing females choose slightly cooler locations and typically roost alone or in small groups. The warm environment in maternity colonies helps minimize energy required to keep pups warm and maximize rapid pup growth.


    Table derived from Alberta Community Bat Program’s Bat Friendly Community Guide. Click to view larger image.

  4. Breeding and Lifespan

    Breeding and Lifespan

    Bats are long-lived mammals with low reproductive output (only 1 pup produced annually over the average 10+ year lifespan for most species), and so are unable to recover quickly from population-level impacts.

    Bats live on average 3.5 times longer than other similar-sized mammals, with the bat lifespan influenced by hibernating several months each year, producing few pups, and having a low body weight. The longest recorded lifespans for the bat species found in Alberta range from 12 to 39 years.

    Mating season occurs in the fall but females store sperm so fertilization does not occur until the spring. Pups are typically born between late May and early July. Most bat species found in Alberta produce a single litter with a single pup annually except for the long-distance migrant species that commonly produce more than one pup (thought to offset the higher risk associated with migration). Pups begin flying between three to five weeks of age, depending on the species, and are weaned by six to seven weeks.












  5. Threats


    White-nose Syndrome (WNS)

    White-nose syndrome occurrence map (Feb 19, 2021). White-nose syndrome has been moving westward over the last 15 years. Data available at:

    Bats in North America are threatened by white-nose syndrome (WNS), a fungal disease that has killed close to 7 million bats since first noted in the eastern United States in 2006. As of spring 2020, the fungus causing WNS has been detected in eastern Montana just south of Val Marie, SK as well as in Washington south of the BC border. It will likely appear in Alberta within the next five years.

    WNS affects hibernating bats and at some sites, 90 to 100 percent of bats have died. Several species are affected. Three of the hardest hit, little brown myotis (Myotis lucifugus), northern myotis (Myotis septentrionalis) and tri-colored bat (Perimyotis subflavus) are listed as Endangered under Canada’s Species at Risk Act. Click here to find out more about WNS.

    The syndrome is caused by white fungal growth on infected bats’ muzzles and wings. The cold-loving fungus infects bats during hibernation, causing them to arouse more frequently from hibernation and burn up valuable fat reserves they need to survive the winter. The disease spreads by bat-to-bat contact in colonies or bat contact with contaminated surfaces.

    In the face of population-level challenges, WBR began this project in 2019 to work with local landowners to build resiliency for bats, in particular little brown myotis (or little brown bat). A resilient bat population will be quicker to recover from disturbances like WNS or severe weather through adapting to stresses, better resisting disease, and/or sustaining fewer mortalities.

    Photo of Little brown myotis with white-nose syndrome. The fungus is visible on their muzzles. Photo by Larisa Bishop-Boros / CC BY-SA (












    Wind Energy

    Wind energy primarily affects migrating species of bats in WBR including the hoary bat, silver-haired bat, and eastern red bat (rare but sometimes present). Fatalities are greatest during the late summer and fall migration period. Specific reasons as to why impacts are not noted in the spring migration as well are unclear but perhaps the bats take a different flight route or elevation. Fatalities occur when bats collide with the spinning turbine blades or suffer injuries due to rapid changes in air pressure near the blades (barotrauma). Wind turbines kill hundreds of thousands of bats annually in North America with Canadian fatalities projected to reach 166,000 bats/year by 2035 due to increased installations and capacity.

    Tree-roosting migratory species, such as hoary bat, silver-haired bat, and eastern red bat, account for 73% of fatalities across Canada while little brown bat and big brown bat account for another 21%. Though cumulative numbers have not been published for the WBR area, bat activity and fatalities are typically higher at turbines in southwestern Alberta than at locations further east in the province.

    Degradation/Loss of Foraging Habitat

    Riparian habitats are important foraging sites for bats, particularly females, and bat use of such habitats may be affected by disturbances that alter the tree or shrub cover. Bats also use treed riparian habitats for commuting lanes or roost sites. Although riparian areas can offer forage, water, and shelter for livestock, associated trampling of seedlings or shrubs, loss of dead or decaying trees, and a decrease in the number of plant species can degrade these important habitat areas for bats. Activities that degrade or drain wetlands can also impact habitat quality and associated insect prey for bats. Wetlands with emergent vegetation are used less by bats than open wetlands as bats may have difficulty echolocating or finding a clear swoop zone when drinking due to the vegetation. However, such vegetation does support insect prey.

    Disturbance or Loss of Roost Sites

    Disturbance of roost sites, either natural or building roosts, can impact bats relying on the sites by causing them to lose pups, breaking up large colonies, causing them to travel further to roosts or foraging habitat, and decreasing their likelihood of returning to a trusted/secure site in subsequent years. Loss of building roosts typically occurs when a landowner or resident decides to actively exclude bats (e.g., patch holes or seal entry points with spray foam), to remove structures used for roosting (e.g., demolish old barn), or when structures deteriorate and succumb to weather or age (e.g., wooden granary roof collapses). The impact to bats will depend on the method and timing of roost elimination, availability of other suitable habitat, bat species, as well as sex and reproductive status of the bats using the roost. For example, females show strong loyalty to their maternity roost, so the summer removal of the roost will disrupt both current and future generations. The impact of natural roost site loss may depend on the availability of alternate sites in the nearby area: maintaining seedling, sapling, mature, and decaying trees is necessary to ensure constant supply of potential roost trees in the future.

    Please see the Stewardship Opportunities section of this page for more information on reporting roost sites and other ways you can help bats in WBR.

    For more information on additional threats to bats in WBR than what you see here, please refer to our Bat Conservation Plan.

  6. Stewardship Opportunities

    Stewardship Opportunities

    What the WBRA is Doing to Help

    In 2015, WBRA’s Species at Risk Plan identified a need to increase public and landowner awareness of threats to bats as well as how to contribute to their conservation. With the advance of WNS and the release of the 2018 recovery strategy for little brown, northern myotis, and tri-colored bats in Canada, the need became more urgent. In response, WBRA initiated a project to aid in the conservation of bats in Alberta.

    There was no recent roost monitoring data from southwestern Alberta (check out this 2018 map) so we saw this as an opportunity to contribute missing data and to improve habitat stewardship for bats in WBR. The development of the BC and Alberta Community Bat Programs and the North American Bat Monitoring Program provided a citizen science model that we could incorporate and ensured our project contributed to the larger efforts to monitor and conserve bats.

    WBR began a project in 2019 to work with local landowners to build resiliency for bats, in particular little brown myotis (or little brown bat). A resilient bat population will be quicker to recover from disturbances like WNS or severe weather through adapting to stresses, better resisting disease, and/or sustaining fewer mortalities. By confirming agricultural buildings that support bat roosting (e.g., barns, shed, granaries), WBR helps landowners decide how best to protect such sites or provide alternate roosting areas if the original structures are damaged or scheduled for removal. Landowners who steward high quality roosting and foraging habitats will support successful rearing of pups and help maximize the health of adults heading into hibernation. Periodic monitoring of roosts can help detect population changes as well as identify target sites for mitigation measures currently being tested to lessen the impacts of WNS (e.g., inoculation with probiotics/anti-fungal agents, oral vaccines).

    Click image to read WBR’s Bat Conservation Plan

    In 2020, a Waterton Biosphere Reserve conservation technician helped landowners identify and monitor maternity roosts for bats, specifically by identifying entry and exit points, conducting roost counts, helping determine the particular bat species through bat detectors and guano collection, and discussing ways to maintain or improve habitat for bats on a given property. To correspond with when mother bats have flightless pups in the colony, our roost count window ran from early June to mid-July, while visits at sites with no known roosts occurred until the end of summer. Due to the COVID-19 pandemic, field visits incorporated all appropriate safety protocols and planned in-person educational events were cancelled. Read about the results of our 2020 Field Season in the WBRA Outreach & Fieldwork section of this page.

    WBRA has since prepared a Bat Conservation Plan for the Waterton Biosphere Reserve that synthesizes the knowledge and experience gained from our 2019 and 2020 work. The plan details conservation objectives and strategies, outlines stewardship activities that could be pursued, identifies required resources, and suggests potential partnerships going forward. The target areas are outreach and education, identification and monitoring of roosts/colonies, and habitat protection and enhancement.



    What You Can do to Help Bat Habitat

    Photo of pond by Robert Anderson

    You can help bats in your area by becoming a steward of good bat habitat. Landowners can help promote resilient bat populations by maintaining important roosts that help females successfully raise pups and by ensuring adequate prey and foraging locations to maximize the health of bats heading into hibernation.

    Maintaining good bat habitat goes beyond ensuring roost sites in buildings are protected wherever possible. Many bat species, including the little brown myotis, will use natural roosts such as spaces under loose bark; cavities and crevices of standing dead trees or older live trees; cracks and crevices of cliffs, rock bands, and boulders; or erosion cavities of rock or solidified mud.

    But in addition to adequate roosting sites, bats rely on accessible drinking water and sufficient insects for food. Bats drink by dipping their bottom jaw in water while flying, thus ideal drinking sites will be open, calm waterbodies that are free from thick vegetation or other flight obstacles and that are close to their summer roosts (e.g., less than two kilometres away for female little brown bats). These waterbodies, as well as streams or rivers, often support the insect populations important to foraging bats. Landowners who implement best practices to maintain healthy riparian areas, avoid drainage of wetlands or seasonal wet areas, and preserve known/potential natural and man-made roost sites will be protecting habitat for little brown bats as well as several other at-risk insectivorous species.

    Beneficial Management Practices 

    Beneficial management practices for bats maintain roosting sites or potential roosting habitat, including the recruitment of young cottonwood and poplar trees that will produce future mature and old-growth age classes conducive to roosting. This could include practices that avoid grazing riparian areas during the spring when soils and stream banks are more susceptible to damage and in the fall when woody vegetation is most vulnerable to browsing or placing salt and minerals away from waterbodies to draw cattle away from riparian areas. Similarly, practices that promote diverse vegetation composition and structure across the landscape (e.g., avoid intensive grazing; use rotational grazing with light to moderate stocking rates), particularly in treed stands and riparian areas, will positively impact insect diversity and abundance and thus promote high quality foraging habitat for bats. Ensuring water troughs, tanks, rain barrels, and other small containment devices for drinking water are covered or have escape options suitable for bats is one example of a beneficial management practice to promote safe, healthy drinking water sources for bats.

    Considerations in Using Bat Boxes

    Bat boxes or bat houses are often viewed as an easy conservation or habitat enhancement tool to help local bats, and indeed they are sometimes used by little brown or big brown bats or occasionally long-legged myotis. But bat houses also frequently sit unused by bats or have been the location of mass mortality events due to overheating. Research is ongoing to determine whether bat boxes are beneficial or detrimental to local bats in light of climate change and to identify what features of bat boxes provide the greatest likelihood of supporting healthy bat populations. 

    Maintaining natural roost habitat is a proven method of supporting local bat populations. Natural roosts offer characteristics appealing to a broader range of species (by including those species that will not use boxes). In addition, natural roosts provide options for bats to move sites based on their current needs (e.g., different sun orientation/cooler temperatures during hot spells, lower parasite levels in roost).

    Accordingly, consider these factors if you choose to install bat boxes on your property:

    • Multiple boxes at multiple orientations will provide more microclimate options for bats, akin to a forest with a cluster of roost options.
    • Multi-chamber designs with passages between chambers will better allow females with dependent pups to move within the box based on thermal needs. 
    • Regular maintenance should factor into your installation. The box(es) should be checked annually to clean out any unwanted visitors (e.g., wasp nests) and ensure weathertightness.
    • Monitoring of your bat box(es) can help provide valuable data to current research, even if the box is not used by bats! Information on your bat box can be submitted to the Canada-wide bat box project

     See What You Can Do To Help Monitor Bats below on how to monitor bat numbers in active bat boxes and submit roost count data.

    If you want to learn more about ensuring your property has high-quality natural habitat to support local bats, check out Alberta Community Bat Program’s Building Bat Friendly Communities Program Guide by clicking here. If you want to learn more about bat boxes, designs, and installation, check out Alberta Community Bat Program’s Building Homes for Bats guidelines by clicking here.

    What You Can do to Help Monitor Bats

    A great way to make sure bats are getting the help they need is to report a suspected roost to the Waterton Biosphere Reserve Association by emailing

    Landowners who suspect building-roosting bats on their land can contact us to discuss how to confirm the roost and how to monitor the colony size. We can help you better understand the habitat features supporting local bats and understand how to best manage that habitat.

    Reporting maternity roost locations to Waterton Biosphere Reserve (or the Alberta Community Bat Program) also helps identify target locations for novel techniques to combat WNS (e.g., inoculation of bats with probiotic bacteria cultures to decrease mortality or application of vaccines) as they are tested and become more widely available.

    Once a suspected roost is found and reported, landowners can monitor the roosts and conduct roost emergence counts when bats return in the spring. Ideally, two roost emergence counts should be conducted before pups are able to fly, and two counts afterwards to see if your bat numbers are changing. But any level of counting can help provide valuable data. WBR can provide guidance on how to conduct a roost count as well as how to collect and submit guano to identify the species. For this information you can contact us at When handling guano, be sure to wear gloves and a mask. Wild bats in either natural or man-made roosts have very little chance of transmitting diseases to humans, unless handled without proper protection.

    Bats at overwintering sites are sensitive to disturbance as premature awakening can use valuable energy and lower their chance of surviving the winter. Avoid disturbing known overwintering sites if at all possible, but report any potentially new or previously unknown sites as there is a shortage of information on overwintering bats in WBR and elsewhere.



  7. WBRA Outreach & Fieldwork

    WBRA Outreach & Fieldwork

    2020 Field Season

    Photo by Elizabeth Anderson

    Waterton Biosphere Reserve Association’s Building Resilience for Bats project was created in a collaborative effort to help bats provincially. Together, our data is helping raise awareness of bat conservation and is contributing important information on known roost sites in southwestern Alberta.

    During WBR’s 2020 project field season, our conservation technician helped landowners to identify and monitor maternity roosts for bats. To correspond with when mother bats have flightless pups in the colony, our survey window for roost counts ran from early June to mid-July. Maternity roost counts followed the Alberta Community Bat Program protocol where participants (i.e., technician, landowner, other volunteers) counted bats leaving the suspected roost exit for one hour after sunset. Where guano (bat poop) was accessible, we collected a sample for lab analysis of the bat species using the roost. We were sometimes able to get a sense of bat species in the area using bat detectors like the one shown to the left.

    We also met with landowners at properties known to support bats but where specific roost locations were unclear. These stewardship visits focused on exploring bat habitat in the area, discussing ways to maintain or improve habitat for bats on a given property, and using the bat detectors to identify possible species using the area.




    Results of 2020 Field Season

    We had 21 WBR landowners reach out about bats and bat habitat in WBR, resulting in 32 total contacts during site visits and roost counts and another 11 additional contacts through phone and email conversations.

    Photo by Elizabeth Anderson

    There were 7 total roost counts completed and many more great discussions about bat biology, threats, and habitat needs through the bat reproductive cycle.

    Little brown and big brown bats dominated the detections on handheld detectors at roost count locations, though long-legged bats and the occasional hoary or silver-haired bat were detected as well. At all locations where guano was collected, little brown bats were identified as the species using the roost. Big brown bats were also identified at one location with multiple roost sites in the structure.

    The largest count saw 145 bats exiting the roost, but bat numbers would be even higher if counts were conducted later as pups began to fly. Pups of little brown bats (the focus of the Building Resilience for Bats project) are typically born in late June/early July and take their first flight at 3 weeks of age. By 4 weeks of age, they are weaned, self-sufficient members of the colony and begin focusing on foraging and fattening in preparation for hibernation.

    We visited 13 landowners during roost counts and site visits in June, July, and August 2020. (see map below). Site visits typically included an initial conversation regarding bat sightings/history on the property followed by a tour to identify habitat features in the immediate area as well as a discussion about features in the surrounding landscape that may support bat needs. Landowners received printed materials relevant to their situation (i.e., different handouts for those stewarding habitat and roosts versus those desiring to exclude). As the evenings progressed, handheld bat detectors and tablets helped identify bat activity and potential species in the immediate area (i.e., within the 30 m range of the detector). The detections provided an opportunity to further discuss habitat needs, habitat management, and threats to specific species in the area.

    Refer to “2020 Activities” (page 30) in our Bat Conservation Plan for more information.

    Click image to view larger map

  8. In The News

    In The News

    CBC’s The Homestretch

    Photo courtesy of Brian Keating

    A serendipitous encounter turned into a magical night all about bats and other things nature!

    Our conservation technician, Elizabeth Anderson, was conducting a site visit and went with the rancher down to a lake on the property to discuss bats and bat habitat. Brian Keating was camping by this lake that particular night and naturally was intrigued by their conversation. They all had a wonderful time together learning about bats and the technology we use to monitor them. Brian had such a great time that he spoke about what he learned on CBC Calgary’s The Homestretch.

    WBRA wants to say a big thank you to naturalist Brian Keating and CBC Calgary’s Jenny Howe of The Homestretch for featuring the Waterton Biosphere Reserve Association and our Building Resilience for Bats Project! Click here to listen to the radio feature. 



    Land Stewardship Centre’s Grassroots News

    The WBRA received a “Stewardship Showcase” in the Land Stewardship Centre of Canada‘s Grassroots News in September 2020 for our Building Resilience for Bats project. We are honoured by this recognition. Thank you Land Stewardship Centre for this feature and for all your support with the project, it is greatly appreciated. 

    You can read the Grassroots News article here.









    Shootin’ the Breeze

    The Building Resilience For Bats Project was featured in an article by Jenaya Launstein in Pincher Creek’s Shootin’ the Breeze. Click the image to view a larger file and to read the article.

    You can read the Shootin’ the Breeze News article here.









  9. Resources


    We have compiled a few resources with more in-depth information for you . Click on the images to access the full pdf documents.























  10. Funders and Supporters

    Funders and Supporters

    We want to acknowledge and send out a huge thank you to the supporters of our Building Resilience for Bats Project, Environment and Climate Change, Land Stewardship Centre of Canada , Patagonia, Tamarack, and Parks Canada. Also, another big thank you to Alberta Community Bat Program for their collaboration in helping bats in Alberta! Together, our project data helps raise awareness of bat conservation and contributes important information on known roost sites in southwestern Alberta. Finally, many thanks to the landowners who gave access to their properties and continue to provide roosting habitat in efforts to support local bat populations.