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Mobile batting (2 Viewers)

Yes, there are two calls. But the fork-like "main element" (which looks similar to that of other pipistrelle species) is usually followed by other, smaller elements in the Nathusius call. - To show what I mean, google for this article (pdf): "A study of the emission of social calls by Pipistrellus spp. within central Scotland; including a description of their typical social call structure".

Written by Neil E Middleton, one of the authors of the book above. On p. 3 the document shows a spectrogram titled "Social call emitted by Pipistrellus nathusii (French & Froud, 2006)". The elements marked "b" and "c" are the additional elements which are often visible in the P. n. social call.

I have added a new version of my spectrogram, the arrow indicating what might be the smaller element "c" in my recording.
 

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Amazing how much is still being discovered.. Not so long ago, the social calls were amusingly compared to as sounding like "wet farts", but of no use in identification! I wonder if the real problem Myotis species emit distinguishable social calls.. I wonder also if the "feeding buzz", again deemed as useless from an identification perspective, might differ between species?

Managed to go out last night into the New Forest.. Forest bat detecting seems pretty tough with few obvious concentration points. Unlike Lakes or Rivers where you tend you hit hotspots quite frequently.. Was pretty lucky to come home with brief snatches of Barbastelle, Serotine and Soprano Pipistrelle (Didn't see any of them). Good views of Fallow Deer too.
 
I wonder if the real problem Myotis species emit distinguishable social calls.. I wonder also if the "feeding buzz", again deemed as useless from an identification perspective, might differ between species?
Nothing on the "feeding buzz". And distinguishing Myotis acustically remains a problem. Apparently Myotis species utter social calls almost exclusively in the vicinity of their roosts. These calls differ strongly among the species. But, if the results of the book are any hint, Myotis seems less inclined than other bats to mix social calls with echolocation in flight. - Exception: Daubenton's bat with its "downward hook" call, considered a social call in the new book. Plus another M. d. social call, "recorded from a bat foraging and coming into close contact with another bat" (p. 64).

Since I live close to a river, Daubenton's bat seemed to be a low-hanging fruit. But so far I have not been able to find it. Maybe a walk in the other direction (upstream) is the solution, we'll see.

Congratulations to meeting a Barbastelle. In December 2013 the species was found in a railway tunnel in Baden-Württemberg, and the connection was put out of service. Barbastelle was also the culprit for a delayed expansion of the airport Frankfurt-Hahn. If I ever meet a Barbastelle here, it could make the headlines in our papers.
 
Pity the Barbastelle is rare there.. it is a very characteristic call on the bat detector.. Always a highlight, but difficult to actually see in flight.

For Daubenten's you need calm water, so a large pond, canal, or flat lake is your best bet.. they can show amazingly close along canals.
 
Some more questions regarding recording:

Finally I did get one Transcend MP330 and I have been trying it this night.

I selected the option of high quality recording in the MP330 wich seems to correspond to a sampling rate of 32.000 Hz (In low quality recording is 8.000 Hz). However, if I record directly from de Micro Trio to the PC, the sampling rate is 44.100 Hz (or whatever I choose in audacity). In Stefans recordings I see a sampling rate of 16.000 (Which will be medium quality recording in transcend). Does this have any influence at all?. To Batexplorer it seems so.

Secondly I can not open a transcend file directly with Batexplorer. First I have to open it with audacity, save it and then I can open it. ¿?

Finally and surprisingly Audacity removes all noise from my broken micro trio ¿¿??

I upload the same bat call, one is recorded with the MP330 and the other directly to PC.

The info that batexplorer gets from the two different recording methods is not the same. (Ex Max frequency is 43,4 or 46,6).

Ricardo
 

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Hi Ricardo,

peak frequencies in both recordings seem about the same. The "PC directly.wav" file shows more echoes, which influences BatExplorer's measures. Measures offered by BatExplorer often have to be manually adjusted. - About the sampling rate etc: As a dilettante in matters electronics or physics, I have just relied on the advice given by Al Milano in his review ( http://batdetecting.blogspot.de/2014/06/review-micro-trio-from-ciel-new-x05.html ) of the micro trio:

As for your recorder, one of the lower quality settings (i.e. 16-bit/44.1kHz) is all that is needed. And, will provide even better results in some cases than higher quality settings. This is also true, when using lower-quality (inexpensive) digital voice recorders. However, you should feel free to experiment.
Therefore, I chose the following settings for the MP330:
- source: line-in
- quality: medium (of three options; resulting in ~500 KB files; the highest produces > 1MB files)
- volume: I chose the 2nd lowest of the eight options. More about that below: (*)

Feeded with *.wav based on these settings, Audacity produces sound files in 16-bit/44.1kHz quality. The 16-bit seems a bit of a waste, as the micro trio gives us only 8-bit sound. Anyway, I was happy to follow Milano's hint. According to its manual, the micro trio is using a sample rate of 120 kHz (8 bit) in time-expansion mode. Does it improve our results to put the MP330's recording quality on "high" instead of "medium"? I have tried, but wasn't impressed - so I just kept preferring "medium".

There is a power-point explanation online, how to set up the H2n for unattended recording with a Pettersson D240X: http://www.sonobat.com/SamsonZoomAutorecording.html . Even here, with top-notch equipment, they recommend "16-bit/44.1kHz quality". And there is the hint: "Turn on to lowest volume setting."

(*) But trying the lowest volume level was a disaster. On the other side, The "loudest" level (8) produced results similar to your files, with the kHz axis in BatExplorer going up to 160 kHz, where no bat calls can be expected. So I decided to put the volume on "two". Any idea/explanation why level 3 might be better is welcome, of course. So far I haven't tried it.

Stefan
 
Thanks again Stephan. I will try to practice a little bit more with diferent settings.

If it's any consolation, it looks like Nathusius' is a Winter visitor only to Spain, so you can get Kuhl's confidentally next Summer.

It is no that easy. There have been quite a few sightings of Nathusius in Spain, mainly in the North. A lot of bats migration new information is comming out recently in Spain but no main pattern is being defined yet. It is not like birds, there are some other factors that make them go or not depending on food I guess.

I use to go whale watching once a year in the north of Spain, and the guy that runs the boat tells me that he sees a few bats in the middle of he sea during migration in august-september.
 
Yes, there are two calls. But the fork-like "main element" (which looks similar to that of other pipistrelle species) is usually followed by other, smaller elements in the Nathusius call. - To show what I mean, google for this article (pdf): "A study of the emission of social calls by Pipistrellus spp. within central Scotland; including a description of their typical social call structure".

Written by Neil E Middleton, one of the authors of the book above. On p. 3 the document shows a spectrogram titled "Social call emitted by Pipistrellus nathusii (French & Froud, 2006)". The elements marked "b" and "c" are the additional elements which are often visible in the P. n. social call.

I have added a new version of my spectrogram, the arrow indicating what might be the smaller element "c" in my recording.

After reading the pdf, I'd be tempted to stretch your sonogram out a bit more, and see if there is any trace of call "B", it could be too faint at the moment to see. Whack up the sensitivity, and look for any sign of it. Unfortunately, there is a Common Pipistrelle in the background with a harmonic in the exact same place as you'd want "B" , but you never know.
 
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Thanks for the hint, Peter, you may well be right! There may be an element "b", see the new sonogram. |=)|

It's worth noting that Nathusius' pipistrelle was a motivating factor for the new book. From page x: "Andrew [Froud's] initial interest in social calls came about when he and Keith [French] discovered the first known Nathusius' pipistrelle advertisement roosts for Essex on their site."

Yesterday I finally found Daubenton's bats - at least I think so. More in another post. The micro trio seems to be struggling with "vertical lines"... could be a major problem when you have to do with Myotis.

Using a setting of medium quality in the MP330 reduces the sampling rate from 120 kHz to 48 kHz. Audacity opens files with its default of 44.1 kHz. So I have imported my new files with 48 kHz. Apparently a small, but visible improvement. Next I'll try to record with the "high quality" setting of the MP330 (= 68 kHz) and choose the value for the Audacity import accordingly. We'll see...
 

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It could well be.. the pipistrelle directly above it causes a bit of concern, but the pipistrelle hasn't left a harmonic on any other of the pipistrelle calls, so it could be just a horrible coincidence!
You have to be careful with the tuning of the sonograms.. you can literally make anything look like anything you want by stretching and tuning/blurring, but I think you could be onto the Nathusius' Social call there, but I have very limited knowledge here.

It might be worth making a note of the settings that give the sharpest / most accurate sonograms for a known species like Common Pipistrelle, then using the same settings for more ambiguous species, like the myotis spp in particular.
 
Daubenton's bat (Myotis daubentonii)

This file is my best bet for Daubenton's bat (Myotis daubentonii). The hiss in the background is the small river Nagold where I found the species. It was indeed an area where the water was relatively calm, just as Peter said. My source "FF2" had given another hint: Daubenton's bat was living outside the city, between Pforzheim and Dillweißenstein. And so it was.

I started too early, immediately after sunset. Later I read that daubentonii emerges ~40 minutes later, which explains why the place was empty at first. So I finally met the bat close to Pforzheim, but only when I returned from an extended walk. The flashlight showed me a bat flying low over the water. It stayed at the other shore though, 20m away, either too shy or deterred by the light. So I turned the light off and made the recordings.

My book explains that an echolocation call of Daubenton's bat can start at 90 kHz and end at 30 kHz. Higher frequencies get often lost due to physics. But I am confused by the vertical lines which seem to go beyond 30 kHZ, sometimes down to the axis. Echoes are always to the right of the original signal, or am I mistaken? Some overregulation perhaps?

More confusion: Around sunset I was able to watch two kinds of bats over the water, still in the heavily populated part of the city. There were Common pips, and also a second species: longer wings, more swallow-like.
 

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I'm having the exact same struggles especially with Myotis species, where you can tune wavesurfer and get anything from tiny signal, to the whole y axis! Which is correct?!! My only hope is to get enough known bat recordings, and somehow calibrate wavesurfer. Daubenten's is a good one to start with, as you can identify by bats going low over the water. Well done for successfully finding them. They do emerge ridiculously late, but are cool to see!

No idea about your swallow like bat.. Schreiber's is often described as having Swallow like flight/wings. Not sure if they are in your region.
 
No, Schreiber's bat is not present in Germany. Northern Germany does have the Pond bat (Myotis dasycneme). It is not breeding in Baden-Württemberg. However, it is migratory (~ 300km), and is known to prefer places in the German Central Uplands for hibernation! Pforzheim would tick all the right boxes, but FF2 says, soberingly, that the species hasn't been found here. Anyway, it is an interesting question, and a main distinction between Daubenton's and Pond bat would have to be by visual observation.
 
Bat call or Dog whistle?

Hi Peter,

you are right: it is cool to see the Daubenton's. I am just back from revisiting the place where I found them. Today I was able to watch (and record) these bats for 10+ minutes, instead of only a few seconds. Probably they didn't like the flashlight, but to say that they are shy was an exaggeration. Flying so close to the water is different from the erratic journeys of a Common pipistrelle. In the future it should be pretty easy to identify a Daubenton's when I can watch it for just a few seconds. An ideal object for bat photographers, the bat which flies in only two dimensions.

From what I have read, the Pond bat flies not 5-20 centimeters above the water, but 50 cm. Both faster and more straightforward than the Daubenton's. In other words, a bit like a kingfisher. To my surprise, one of the Daubenton's today was able to fly a sharp "S curve" close to the water. Definitely not a Pond bat.

I close for today with my most shocking sonogram so far with the micro trio. The recording was on Saturday evening, in a public park, but I've opened this file in BatExplorer only today. There are Common and Nathusius' pipistrelles, but around 20 kHz, what could this be? A dog whistle? Other human noise? Social calls of a Noctule? (A bit high for the latter, says the new book.)

Stefan
 

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Lol, I've no idea about the 20KHz signal, maybe insect chatter? Many of my recordings are destroyed by insect chatter and Robins for a spell in the early evening.

Peter
 
It seems that the sound emitted by insects (grasshoppers etc) displays a broader range of frequencies. Unlike the whistle which I hear in the wav file. And the "call" starts at a somewhat higher frequency, ends at a lower frequency - not what I'd expect from insect noise.

I've found a dog whistle (offered for Euro 20.--) online, which can change the frequency. A sample of the sound can be "heard". Looking at the result (recorded via audio cable), in BatExplorer, the frequency is varied, but it is an uninterrupted sound of 8+ seconds. Other dog whistles may be different, but sounds meant to communicate with a dog are probably just like whistles in the "human range" of frequencies, only higher. So I am skeptical whether dog whistles + a human would be able to emit these very short calls, with a duration of 130-170 ms.

It might be a bat call, but my sources are not a big help.

Edit: It would be interesting to see how my set-up behaves in the presence of grasshoppers, cicadas and other >20 kHz sound emitting insects. Time to schedule a field trip on a hot day.
 
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The recording of the mysterious bat call (if it wasn't something else) was made 90 minutes after sunset. In about four minutes, I made eight recordings, five of them (the first four and the eighth) show these whistle signals around 20 kHz. For now, here are two more sonograms, maybe someone has an idea what it is. I am off to the park to research this important biological question!
 

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The Mysterious Park Bat (continued)

Another recording from Monday has four similar signals, #s 21-24 of the "bat calls". I give the sonogram and the wav file. OK, "similar" is an exaggeration: the calls are around 27 kHz, not in the 20 kHz range - quite a difference.

Knowledge on social calls is still young. Regarding the Noctule, the new British book mainly refers to Pfalzer (2002), "Inter- und intraspezifische Variabilität der Soziallaute heimischer Fledermausarten (Chiroptera: Vespertilionidae)". Available online (pdf; 275 pp.). The chapter on the Lesser Noctule has nothing like my "calls", but it was interesting to see that Pfalzer has categorized many social calls of the Lesser Noctule (Type I - Type N) based on 25 recordings or less.

The Park Bat is probably not a new species. At best I can hope for a Lesser Noctule speaking a rare local dialect.
 

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Don't know.. Another possible gotcha is electrical interference from an alarm system pulsing or similar.. I must admit, much of my recordings are skipped thru until the classic sine wave of a series of definite bat calls is found.
 
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