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Detecting bats in your NatureHood
Bats use echolocation - a biological form of sonar - to maneuver through the darkness and hunt for insects. To echolocate bats create a high frequency ultrasonic sound in their throat that is emitted through the open mouth. Those ultrasonic sound waves move through the air, hitting and reflecting off of each object they encounter, much like ripples of water do as they move across a pond. As the sound waves reflect or 'echo' back to the bat, it receives the sound in each ear at a slightly different time and intensity, providing important 3D information about the bat's environment. Based on the characteristics of the reflected sound, the bat can detect if an object is near or far away, if it’s moving, its shape and how big it is, and even the direction and relative speed of an object's movement. It's like having an ultrasound machine to guide you through the night sky! Bats echolocate regularly (but at different rates) as they move through the air, constantly updating their internal map keep track of their surroundings.
Although it’s not an exact science, you can get a good sense of which bat species you are hearing through one of our handheld bat detectors. These detectors are specially designed to detect bat echolocations and convert them from the ultrasonic range (i.e., higher than 20,000 Hz, beyond the normal range of human hearing) into the human audible range (i.e., between 20 Hz and 20,000 Hz). To begin monitoring for bats the detector should be tuned to 45.0 KHz; once something is detected you can use the tuning wheel to tune the detector frequency to the point where the pitch is lowest and loudest - this is the peak frequency of the bat's echolocation signals, and that's a key clue to identify the species you're hearing!
So what do bat echolocations sound like through a bat detector? Some examples can be found below.
A bat pass is the sound of a bat passing your location. The sounds should start low, get loud, then low again. This counts as a pass. Try to count how many times a particular bat passes overhead, and remember that there could be more than one at a time! Listen to the recording below for examples of multiple passes being made by at least 3 different bats representing 2 species.
Eastern Red Bat and Big Brown Bat, full spectrum heterodyne microphone (A. MacDonald)
A feeding buzz is a very distinctive sound made by bats, and won’t be confused with anything else! As a bat locates and is about to catch an insect, it sends out a series of very high pitched series of ultrasonic clicks that can be compared to running your fingernail over the teeth of a comb (listen for this at around 00:26 seconds in the recording below). By emitting these buzzes, the bat can zero in on its prey’s exact location, allowing it to scoop the insect into its mouth using its tail membrane.
Silver-haired Bat (Credit: Maryland Acoustic Call Library and Species Accounts)
Little Brown Myotis/Bat (Credit: Maryland Acoustic Call Library and Species Accounts)
Hoary Bat (Credit: New Mexico Bat Call Library, W. L. Gannon)
Ticks & Pops
"Ticks" and "pops" are very short, distinct sounds - similar to the sound of typing on a keyboard or typewriter, with a punctuated sound at the end.
Taps, putts and knocks
"Taps", "putts" and "knocks" are longer, distinct sounds that could be described as hammer taps, knocking gently on a wall or a hitting a tennis ball hitting with a racquet. You can mimic these sounds by forcing air through your lips while trying to keep them sealed.
"Chirps" sound similar to bird chirps and are typically short. There may be a change in pitch at the end of the chirp.
"Flaps" are distinct from ticks and taps and sound a lot like wings flapping. Individual flaps may be a bit less distinct from one another than with ticks and taps.
Have a listen to some examples of each of these sounds in the following video*. The description of each sound is quite subjective and it ultimately takes a bit of field practice with the same bat detector to become familiar with how they differ - and how the detector transmits them in the audible range. Once you're familiar with the texture and characteristics of each bat species' calls, you can start to discern multiple species passes while using your detector, as explained in the examples here.
Listen to the Bats in Your NatureHood!
In late June, Nature Canada held a Bat Detector Demonstration Workshop in Ottawa. This event was part of the NatureHood program where we were able to show members of the public how the devices work and why they're useful! Participants at the event were given electronic bat detectors which translate the ultrasonic echolocation of bats into sounds you can hear. Check out the video below on the event and hear the bats for yourself!
Interested in renting out a Bat Detector? Please contact Tejal Mistry, Conservation Coordinator, at firstname.lastname@example.org.
Monarchs & Nighthawks – Day 1 of our July NatureBlitz (Part 1 of 3)
During one of the hottest weekends in July, Nature Canada beat the heat with a NatureBlitz held in Ottawa’s Carlington Woods area. The 24-hour event on July 18th & 19th (see the schedule here) was a great success and featured guided walks with local plant and wildlife experts, children’s activities, fun with ultrasonic bat detectors, and a live amphibian demonstration by the Ontario-based group, Save the Salamanders. On behalf of Nature Canada, we would like to thank our volunteers, our experts and the public on coming out!
[caption id="attachment_21907" align="alignleft" width="300"] The NatureBlitz featured a number of guided group walks, each exploring a different set of organisms at the site. Photo: Susanne Ure[/caption]
So what is a NatureBlitz? It’s very much like a BioBlitz, i.e., an effort to inventory as many living things as possible in a given area during a given time, usually 24 hours). However, our NatureBlitz events are more focused on building awareness and educating the public – by helping urban residents explore and experience nearby nature right in their communities. These events are one of the public engagement tools used in our NatureHood program. Like a traditional BioBlitz, our NatureBlitzes take place over 24 hours, include a tally of all the species we observe, and are open to anyone – especially nature-newbies! While we carefully record all of the species we observe throughout the event and during each walk, we also address two important barriers to nature engagement for many people: knowledge and the ‘intimidation factor’. We do this by sharing fun facts, encouraging appropriate hands-on exploration and experiences of nature, and by interpreting the plants, wildlife and local environment for participants. Sound like fun?
We chose Carlington Woods for this summer’s NatureBlitz given its mature trees, the large diversity of birds it is known to host, and the unique ecological setting of the NCC owned property. The entire forest is surrounded by busy streets and dense urban neighborhoods, and that is exactly what piqued our interest. We wondered, can this island of forest hold any species that we would not expect to find within a bustling city?
We’re happy to report that the NatureBlitz showcased just how important isolated pockets of urban forest can be. Not surprisingly they’re safe-havens for wildlife, including species at risk!
[caption id="attachment_21908" align="alignright" width="300"] Local plant expert, Owen Clarkin, shows participants the tricks for identifying a Bitternut Hickory during his Trees & Shrubs walk on Saturday. Photo: Susanne Ure[/caption]
Our first event on the Saturday was a trees & shrubs walk, led by local plant expert, Owen Clarkin. A species of interest was the Butternut tree (Juglans cinerea), which is found peppered throughout this NCC-owned property. Currently, the tree is being attacked by a fungal disease, Butternut canker, and is being wiped out of much of its native range in Ontario, Quebec and New Brunswick. The butternut is a nationally and provincially endangered species, protected by law.
Nature Canada’s own Alex MacDonald hosted two back-to-back events on Saturday: an insect walk and a children’s scavenger hunt. With a large crowd, Alex led visitors out with butterfly nets and temporary sampling containers to catch what they could find. Beetles, butterflies, bees and grasshoppers seemed to be the stars of the walk. After the insect walk, the scavenger hunt attracted even more people, and as a reward, the kids got to exchange their sightings cards for our NatureHood species at risk trading card. The cards highlight 26 local species that are legally protected as special concern, threatened, or endangered, including the Butternut tree and the monarch butterfly – each of which was observed during the walks!
The evening bird walk had some interesting finds. Led again by Alex MacDonald, the group saw (and heard) lots of Grey Catbirds, some Black-crowned Night Herons flying over, and even a Brown Thrasher. The group even spotted a provincially and nationally threatened species: the Common Nighthawk (Chordeiles minor). This nocturnal species’ main food source is flying insects. With the large-scale use of pesticides, and the resulting pollution of downstream waterways where many flying insects breed, coupled again with habitat loss and the perils of migration, there has been a widespread decline in Common Nighthawks across Canada. The species considered at-risk with a "special concern" designation in Ontario.
[caption id="attachment_21910" align="alignleft" width="200"] One of our scavenger hunt participants checks to see if there's a lady beetle in her net. Photo: Susanne Ure[/caption]
Our bat walk at dusk proved to be quite a popular choice for people, as well! Not only did we hear these amazing flying mammals, we also saw them! Flying overhead and probably catching the mosquitoes trying to bite us, we used an array of handheld bat detectors to ‘hear’ the ultrasonic echolocation signals – similar to sonar - of the bats at frequencies audible to human ears. By tuning the detectors to different frequencies and listening to changes in the quality of the sound, it’s possible (with practice!) to get a sense of which species may be flying overhead. The species we detected included the Big Brown Bat (Eptesicus fuscus; confirmed visually) and either the endangered Little Brown Bat (Myotis lucifugus) or the Tri-coloured Bat/Eastern Pipestrelle (Perimyotis subflavus). It's a case of 'either, or' because those two species echolocate at roughly the same frequencies, both can have light undersides (which we observed) and the habitat at Carlington Woods is suitable for both. We’re conducting follow-up assessments in the area and reviewing our audio recordings from the night to reach a conclusion on the latter two.
Take a listen to what bat echolocation sounds like within our hearing range below!
Pssst! Nature Canada now offers a FREE public bat detector lending library for anyone in the National Capital Region interested in borrowing one! Contact us here to inquire.
A big thanks to Nicolas Conroy, Nature Canada's NatureHood Conservation Intern, who prepared a draft of this post!
To be continued…
Financial assistance for this project has been provided by:
Help us Find At-risk Bats in your NatureHood!
Have you ever wondered if there are bats in your neighbourhood? What about your yard? If so, Nature Canada can help you answer this question with the handheld bat detectors we have available through our lending library! If you live in the National Capital Region, you can borrow a detector - free of charge - for up to one week.
[caption id="attachment_23140" align="alignright" width="200"] The Eastern Pipistrelle is a migratory bat found in southeastern Canada and the eastern United States. It feeds on flying insects most actively during the crepuscular period at dawn and dusk.[/caption]
But we're not doing this for just any reason. Here's the scoop: Have you heard about White-noseSyndrome (WNS), an introduced fungal disease (Pseudogymnoascus destructans) that's decimating many bat populations in North America? Estimates place the death toll from WNS at over 6 million bats since it was first detected in North America in 2006 (read Ontario's response plan here). Sadly, populations of up to 7 different bat species found in and around Ottawa have been impacted by WNS, and 3 of those species currently legally designated as "endangered" by the Government of Ontario: Little brown myotis (Myotis lucifugus), Northern myotis (Myotis septentrionalis) and Eastern small-footed myotis (Myotis leibii). Given this situation we need to understand the habitats these bat species are using and how local populations are doing. That's where the bat detectors - and YOU - come in.
Members of the public can borrow one of our Magenta Bat5 handheld bat detectors to ‘hear’ the ultrasonic echolocation signals – similar to sonar – that bats make as they fly, socialize and feed. Human ears are not capable of hearing sound in the frequency ranges at which most bats echolocate - that's why the frequencies are called "ultrasonic". The bat detectors pick up these ultrasonic signals and convert them into the audible range for humans, playing them for you in real-time through a speaker in the unit. Many bats echolocate at different frequencies, though there is just enough overlap between them to make things confusing! By 'tuning' the bat detector to hone in on particular frequencies, you can get a sense of which species you may be detecting. With practice in the field, and
[caption id="attachment_23169" align="alignleft" width="300"] You can borrow the Magenta Bat5 handheld bat detector (shown here) for up to 1-week using our lending library![/caption]
following the tips we provide here, you can get pretty good at recognizing the different species.
If you're interested in helping us monitor for the presence (or absence) of at-risk bat species in the National Capital Region, you can download the sign-out sheet here. Simply submit the form by email or drop it off when you pick up the detector at our office at 75 Albert Street (third floor, suite 300). And our data submission form is available online or as a hard-copy.
You can use the detector in your backyard, in your neighbourhood or at a local park, or you might consider visiting one of the areas we're hoping to cover in our seasonal surveys (see map below).
Financial support for this project is provided by: