All Ireland Daubenton s Bat Waterway Survey. All-Ireland Bat Monitoring Programme is funded by

Transcription

1 All Ireland Daubenton s Bat Waterway Survey All-Ireland Bat Monitoring Programme is funded by

2 This is what you are setting up a walking transect.. Survey Spot 2 Survey Spot 1 Walk 100m You survey your local river or canal Survey Spot 3 Survey Spot 5 Survey Spot 4 Survey Spot 6 Survey Spot 7 Survey Spot 8 Survey Spot 9 Survey Spot 10 Your walking transect will have 10 spots, approx. 100m apart. You are looking for 10 survey spots that give you a good view of the water surface in order to see the skimming bat. The aim of this survey is to walk a route along a 1km stretch of river/canal. We do not survey lakes or ponds. The activity of Daubenton s bats is recorded at 10 stopping points (4 minutes per point) along the route on two evenings between the 1 st and 31 st August (you choose the dates).

3 Daubenton s bat Myotis daubentonii (Kuhl, 1817) Why survey waterways for this bat species? Daubenton s bat is known as the water bat due to its preference: to hunt close to waterbodies, to roost adjacent to water often in stone mason bridges or mature trees. Photo: Daubenton s bats roosting in stone mason bridge crevice Tina Aughney

4 Typical foraging habitat indicated by blue lines On windy, cold or rainy nights, the Daubenton s bat will seek shelter and may be absent from the water surface. So we survey on dry, calm nights. During calm dry nights, the Daubenton s bat flies over water. This is when we aim to survey our river or canal transect.

5 Daubenton s bat Myotis daubentonii (Kuhl, 1817) Why survey waterways for this bat species? Typically forages 30cm above the water surface catching insects by trawling from the water surface gaffing with its big feet or tail membrane aerial hawking: taking insects directly from the air Daubenton s bats are the only Irish bat species that flies consistently over the surface of the water. This survey takes advantage of this and means that it is easily identified.

6 Daubenton s bat Myotis daubentonii (Kuhl, 1817) Why survey waterways for this bat species? Typically flies continuously back and forth along a regular flight path. Typically flies along a straight path before turning sharply at the end of one flight path in preparation to begin another flight run. It is good to have a trial survey night to see the bats. Also watch the training video to see what I mean about flying close to the water surface.

7 Bats nocturnal mammals Insectivorous bats produce rapidly repeated sound pulses and use their returning echoes to create a sound picture of their surroundings = ECHOLOCATION. They are not blind. Bats will produce other sounds: communication, territorial behaviour, etc.. Echolocation calls are produced more frequently i.e. when bats are in flight = reveal bat s activities. Echolocation calls tend to be in the ultrasonic range i.e. >20kHz need an aid to listen bat detector.

8 All European bats use echolocation i.e. rapidly repeated bursts of sound pulses, when flying. Bats emit short, high frequency sounds and use the echoes to make a sound image of their environment. Echolocation

9 Heterodyne Bat Detectors Grabs a small range of frequencies what you have your dial tuned to. Range of frequency heard depends on the position of the dial. Cannot survey for all species/frequencies simultaneously as a consequence. BUT the resultant sound allows us to identify the repetition rate and rhythm of the call. On heterodyne, the Daubenton s bat can be described as a rapid series of click similar to a machine gun. (Please listen to the Daubenton s bat call in our call library).

10 Repetition Rate & Rhythm Daubenton s could be described as having a fast Repetition Rate because it produces a large number of pulses per seccond. Pulse rate number of pulses per second Rhythm, the overall pattern of the sounds and can be described as: Constant / Irregular / Slightly irregular / Very irregular Rhythm tells us about the constancy of a bat s wingbeat & flight style: constant wingbeat & regular rhythmic calls indicate straight line flight i.e. A Daubenton s bat Daubenton s bats on a heterodyne bat detector it sounds like rapid dry clicks with a very regular beat. When you see it flying, it is flying in straight lines (hence the regular beat or rhythm).

11 Daubenton s bat Detector Turn the dial on your detector to 35kHz Direct it over the water surface. Listen for rapid dry clicks. Torch Have your torch waiting, when you hear rapid dry clicks, turn on your torch light and if it is a Daubenton s bat, you will if flying CONSISTENTLY low over the water. Watch the training video to see this in action. NB if you are seeing bats swooping up from the water and above your head, you are more than likely listening to pipistrelles. Change the frequency on your detector moving it up to 50Khz if the sound changes to a bubbly sound this is a pipistrelle.

12 Survey Methodology In Summary, Volunteers must have the use of a heterodyne bat detector (if you don t have one, you can borrow one from BCIreland). Check out the list of waterway sites choose one that is suitable. If there is none in your local area, contact us about a local site that may be suitable for you. Chooses a site that is easy to access, safe and convenient During the daytime you will need to map ten points, approximately 100m apart along a 1km stretch of waterway with the Grid Reference located at one of the ten points visit the site on two evenings in August (40 mins after sunset) records Daubenton s bat activity at each of the ten spots for 4 minutes using the bat detector and the aid of a torch

13 BCT UK Daubenton s Bat Waterway Survey Methodology takes advantage of the following characteristics of the Daubenton s Bat Dependency on waterways to forage Unique flight pattern while foraging along waterways Characteristic echolocation call as heard through a heterodyne bat detector tuned to 35 khz

14 ( ) Myotis species echolocation calls 100 F 90 R E80 Q U70 E 60 N C50 Y 40 Hold the torch and detector like this. Don t have too bright of a torch as bats are light sensitive and will fly away from bright light. 30 k H20 z 10 0 Daubenton's bat Natterer's bat Whiskered bat Your TORCH is really important. All Myotis bats sound the same but the Daubenton s Bat is the only one the CONSISTENLY flies close to the water surface. So your torch allows you to CONFIRM that you are listening to Daubenton s bat.

15 Bat passes a measure of activity We are not counting the number of bats, but the number of times a bat flies by (close to the water). It is not possible to say if it is the same bat flying up and down. So instead we count passes and this give us a bat activity level this is why we count for exactly 4 mins at each survey spot. Daubenton s bat pass Daubenton s bats are identified only if the bat is heard (typical echolocation calls) and seen skimming the water surface (with aid of torch). Unsure Daubenton s bat pass Bats that sound like Daubenton s bats (as heard through a heterodyne bat detector) but not seen skimming the water surface. Results quoted as No. of bats passes/40 minutes

16 Step by Step Step 1 Receiving your Volunteer Survey Pack (you can download forms for this from the website or us for a pack to be posted out) Daubenton s Bat Waterway Survey Instructions Description of methodology Sunset Times (will be ed) Health & Safety Guidelines Risk Assessment Form on website Daubenton s Bat Waterway Survey Form Daytime Survey Form Survey Spots Descriptions Habitat Survey Night time Survey Form Copy of O.S. Discovery Map Landowner Letter ( ed to volunteers) for private land

17 Step 3 Daytime Spot Selection Daytime visit (very NB to check your site out - set up your 1km transect - Make sure that the waterway is >2m or more wide 100 m apart You are looking for survey spots that give you a good view of the water surface. BE SAFE Spot Description describe your survey spots so that you can find them again at night time: e.g. Stand LHS of large willow tree, or 3 rd fence downstream of bridge or 2 nd lamp post No or walk 100 paces from last spot HINT On the night of the survey start at the survey spot furthest away from your parked car.

18 Step 4 Survey Equipment On the night you require the following equipment: Tuneable bat detector Stopwatch Recording sheets Pencil/pen, clip board Rough map Torch Thermometer Head torch REMEMBER You are a TEAM of at least 2 people Surveyor 1 using the detector and torch Surveyor 2 counting the 4 mins, recording the results, healthy and safety Avail of the temporary BCIreland membership to have Public Liability Insurance

19 Step 5 Surveying Be in position to begin survey approximately 40 minutes after sunset (check your sunset table for your location and date of survey). Record the following details prior to starting: Time, Temperature & Weather Conditions Surveyor 1 Scan waterway with detector tuned to 35kHz and simultaneously use a torch to verify Daubenton s bats. Surveyor 2 Time 4 minutes per/spot and record all results as counted by Surveyor 1. At the last point, record your stopping time.

20 Hold Bat Detector at a 90 o angle to waterway.

21 Scan waterway with bat detector in a 45 o arc listening to potential Daubenton s bats. Use torch light to confirm Daubenton s bats.

22 Count the bat passes at the bat passes you by. Remember it is only Daubenton s bat that you are surveying for i.e. a low flying bat skimming the water surface and on the bat detector it sounds like rapid series of clicks. Please listen to the call library and watch the training to be familiar with this Arc

23 Scenario A Scenario B Survey Spot Survey Spot Scenario A: Typical straight line flights of the Daubenton s bat. A bat pass is counted each time an individual bat passes through your Survey Spot Two bat passes are represented here by the dashed arrows. Scenario B: This represents a flight path by Daubenton s bats often seen on wide stretches of rivers. The looping (always within 30cm of the water surface) produces a continuous noise of echolocation calls on the bat detector (said to be constant activity). Therefore to count this as bat passes, pick a spot (as represented by the star) and count every time the individual bat passes this point as one bat pass. Two bat passes are represented here by the dashed circles.

24 If there is lighting within 100m of your survey spots let us know and record the colour of lighting. WHITE YELLOW ORANGE White lights: 12% less Yellow lights: 15% less Orange: 11.6% less Typical street lights = Lux Bats prefer no more than 0.5 Lux, some species can tolerate higher levels Impacts of lighting on Daubenton s bats

25 Step 6 When to survey & Survey Tips Survey one evening between August 1 st and August 15th. Repeat survey between August 16 th and August 30 th (Have at least 5 days between the survey dates) Survey on calm, dry evenings. Always survey in pairs. Always survey in the same direction/rotation of spots (i.e. if you start at one end of the transect, you start at the same place on the 2 nd night). Always use a fresh battery in bat detector.

26 Step 7 Returning your data Please return the following in your addressed envelope or to the address on the Survey Forms Spot Descriptions and Landowner Form Map with route marked on it Health & Safety Guidelines Please read guidelines prior to survey Please do not take any risks Please only survey in pairs Please survey safe and accessible stretches of river

27 Daubenton s Training Support Daubenton s Android Phone App. The app is available on google play. Just go to And search for daubentons or use the google play on your phone to search for it. It is the only Daubentons app available at the moment. You Tube Video Clips link on website

28 VIDEO CLIP YouTube training video. This will be ed to all participating volunteer teams HqlM4 You will also receive by Forms Maps Link to sound files to help you prepare ( if there is anything in particular that you are looking for and we will do our best to help)

29 Thank you for agreeing to volunteer. We hope that you enjoy the survey. All-Ireland Daubenton s Bat Waterway Survey is funded by: