Gobi Bat Project and Acoustic Detection of Bats Cori Lausen Birchdale Ecological Ltd. www.batsRus.ca

Great Gobi Strictly Protected Area Bat Project Main Goals of Project: To determine what species of bats are in the GGSPA using mistnets and bat detectors. To record echolocation (bat ultrasound) from each species to know what each bat sounds like for identification without mistnet capture. To teach Mongolian biologists about bat acoustics and how to use the bat detectors to learn more about bats in Mongolia.

Great Gobi Strictly Protected Area Bat Project May 2011 BAT DETECTORS: ANABAT and SM2BAT

Bat Detectors and Software Donated to Mongolia: Titley Scientific (Australia) - Anabat Wildlife Acoustics (USA) - SM2BAT Joe Szewczak (USA) – Sonobat (analysis software)

Two Types of Detectors Full spectrum Zero-crossing Wildlife Acoustics SM2BAT Full spectrum Zero-crossing Titley Scientific Anabat

Species of bats captured in Gobi Vespertilio murinus

Species of bats captured in Gobi Eptesicus gobiensis

Species of bats captured in Gobi Hypsugo alashanicus

Species of bats captured in Gobi Myotis mystacinus

Species Differences at a Glance Myotis mystacinus Hypsugo alashanicus Eptesicus gobiensis Vespertilio murinus MINIMUM FREQUENCIES OF PULSES

Species Previously Known from Great Gobi Strictly Protected Area Recorded but not captured May 2011 Photo: Ariunbold Plecotus kozlovi

Water as a Limiting Factor Studies in the Southwest USA (Rick Adams) have shown that bats do not move when their water source dries out, they just stop reproducing each year. This means we need to keep checking for reproduction in dry areas with ephemeral water. Enhancing Gobi’s water sources would be good for bats… it is currently being considered for bears (e.g. at Baran Tooroi).

Khulan Holes -keeping water open for bats

Making Bat-Friendly Water Troughs A way for them to crawl out of water (or they will drown) Appropriate size for all species of bats to benefit

Understanding bat echolocation We can’t hear bats. Frequency of sound: Humans hear <20kHz Speech is <5 kHz Most bats echolocate >20kHz (ultrasound). We therefore need to transform ultrasound into a lower frequency using bat detectors.

Sound Sound is a wave. Sound bounces off of objects providing echoes. Object must be larger than one wavelength to reflect sound.

Sound Sound is a wave. Sound bounces off of objects providing echoes. Object must be larger than one wavelength to reflect sound. A 35 kHz frequency has a wavelength of ~1 cm, and would therefore best detect this size of object.

Wave Length Wave length Increases as frequency decreases 35kHz wave length = 10 mm 70kHz wave length = 5 mm Shorter wavelengths (Higher Frequencies) Can detect smaller objects Provide finer detail Longer wavelengths (Lower Frequencies) Travel further (Less absorbed by the air) Objects have to be larger or about the same size as a wave length to be detecter Shorter wave lengths/higher frequencies provide more detail and can detect finer texture So why wouldn’t all bats use really short wavelengths (high frequencies)? Higher frequencies travel less distance because of Atmospheric Attenuation So there is a battle for bats to produce the optimal calls to detect their environment and their prey items. 18

Example of ultrasound from Gobi Bats…. 35 kHz allows bat to detect objects 1 cm. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. Clutter: -trees -grass -ground -other bats -detector -insect prey etc. Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. Clutter: -trees -grass -ground -other bats -detector -insect prey etc. Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. Clutter: -trees -grass -ground -other bats -detector -insect prey etc. Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. Clutter: -trees -grass -ground -other bats -detector -insect prey etc. Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

Frequency (kHz) Time (s) Properties of bat echolocation. Clutter: -trees -grass -ground -other bats -detector -insect prey etc. Properties of bat echolocation. The effect of CLUTTER. Frequency (kHz) Time (s)

In High Clutter: Species/genera/families often converge High slope Short duration Long frequency sweeps Raised frequency

Clutter … makes identification of some species challenging Northern Myotis (a bat that tends to stay in high clutter) Little Brown in low clutter Little Brown in high clutter

Search-phase Continuum Two species of different families Produced at different levels of clutter Variation within an individual is much greater than between families! Big Brown Bat Different voices… CLUTTER!!!! Introduce topic here Mexican Freetail Bat

Frequency (kHz) Time (s)

Feeding Buzz Short, steep pulses give better distance resolution because they are more sharply defined in time Long flat pulses can detect objects from further away Flat calls can also be used to measure relative velocity between the bat and the prey item (ie. horse shoe bats)

Search-phase Continuum Eptesicus fuscus Two species of different families Produced at different levels of clutter Variation within an individual is much greater than between families! Different voices… CLUTTER!!!! Introduce topic here Tadarida brasiliensis SLIDE BY C. CORBEN, ANABAT WORKSHOPS

To Understand Species Diversity in Mongolia Collect reference calls from captured bats -bat distributions can then be determined using bat detectors -capture may not be required in many places of the country if a good reference call collection is established -to evaluate whether taxonomic classifications are accurate, recording ultrasound from potentially cryptic species is important (e.g. Soprano vs Commom Pipistrelles in Europe)

Obtaining Reference Calls from Captures Hand-released * Zip-lining Bat-kiting *Try to obtain ‘free-flying’ calls so wait until the bat has flown out of the hand but is still within recording distance of microphone. Ideal if they circle back over you, or you can run after them!

Reference Calls from Bats Tethering Techniques Zip-line Bat-kite

Effects of Releasing a Bat

Analook View Unknown and Reference Files

Sonobat View Unknown and Reference Files