Science topic

Bioacoustics - Science topic

Bioacoustics refers to the investigation of sound production, dispersion through elastic media, and reception in animals, including humans. This involves neurophysiological and anatomical basis of sound production and detection, and relation of acoustic signals to the medium they disperse through. The findings give us some evidence about the evolution of acoustic mechanisms, and from that, the evolution of animals that employ them.
Questions related to Bioacoustics
  • asked a question related to Bioacoustics
Question
2 answers
Hi Folks,
The attachments are 5 bat calls, recorded via Anabat detector, from Umluj, Tabuk Province, Kingdom of Saudi Arabia.
I analyzed them using Anabat Insight's BatClassify Plugin. On analysis, four of them are classified as Pip (precision >95% in all four cases), which means they belong to the genus Pipistrelle. However, only one out of the five recordings is classified as [NSL (96%) (1); Bbar (62%) (2)]. It is not clear as to which genera out of the Noctule, Serotine or Leisler’s they belong to. The fact that Barbastelle is not reported from this part of the globe makes it even more intriguing. Moreover, the plugin pertains to species from the UK only and therefore, I need to confirm from experts. I shall be grateful if someone working on this aspect of ecology can confirm the genera and, if possible, the species from the files attached.
Thanking in anticipation
Siraj
Relevant answer
Answer
Hello dear friend
what country and present your species sample
  • asked a question related to Bioacoustics
Question
8 answers
There are some interesting challenges for DAS systems in fields of agri-biophotonics and/or biophotonics - from vibration impact studies on the roots of growing plants to sea fauna acoustics monitoring, but researchers usually prefer array of single sensors or quasi-distributed sensors. Or maybe you know the examples with the DAS application? Thank you!
Relevant answer
Answer
There were two related talks that presented very promising results at the 2022 DCLDE workshop (see https://www.soest.hawaii.edu/ore/dclde/program/ )
Léa Bouffaut- Listening at the speed of light: baleen whale monitoring using distributed acoustic sensing
William Wilcock- A Community Test of Distributed Acoustic Sensing on the Ocean Observatories Initiative Regional Cabled Array Offshore Central Oregon
  • asked a question related to Bioacoustics
Question
3 answers
I am searching for good recordings of distress calls emitted by American crocodiles, in particular by hatchlings. The longer the better. If not, also distress call recordings of other crocodilian species are fine.
Relevant answer
Answer
Differences in distress: Variance and production of American Crocodile ( Crocodylus acutus ) distress calls in Belize
Visit to that article
  • asked a question related to Bioacoustics
Question
4 answers
I am using Audacity to analyse the presence of birds and frogs recorded with a SM4 recorder (Wildlife Acoustic). Background noise (rainfall, wind) is an important variable to consider that can affect the detection of some species. What bioacoustic variable can be taken to quantify this noise? The RMS dB is an option.
Relevant answer
Answer
Mariano Feldman, when considering the effects of background noise on detection capabilities of specific sounds, you would want to measure sound levels over the frequency range of the signal (sound) of interest. For example if frogs produce sounds from 50 Hz to 1 kHz, you may find it useful to look at background noise over that bandwidth. Filters can be used to measure the RMS levels over specific bands of frequencies, but PSD values are probably more useful as you can integrate those values over the desired frequencies. Also 1/3 Octave and Octave levels are useful for monitoring patterns in sound levels over standardized frequency ranges. I am not sure if you are familiar with R or Matlab, but I would search for a program called PamGuide by Merchant et al. if you do not want to write your own code. There is also a paper associated with that software that is useful for understanding those measurements, also by Merchant et al. Lastly, when considering background noise, you will need to be aware that the signals of interest will likely influence those background noise levels. Picking a time when those signals do not occur will give you an understanding of baseline sound levels in the absence of those sounds.
  • asked a question related to Bioacoustics
Question
2 answers
I have heard of the Plant Spikerbox from Backyard Brains and trying to acquire it. I want to study the electrophysical changes in common plants as Chilli, Tamarind, Papaya, etc due to environmental and human stimuli. But the devices I find are usually very expensive. Is there any DIY way of building such devices? What type of electrodes do I need? What type of wires to connect them to the plant? And what receptors can detect low-frequency electric signals? Also in the case of Plant bioacoustics, What device can I use to detect their ultrasonic sounds?
Relevant answer
Answer
Dear Peter,
Thank you so very much for your kind answer. I have already ordered plant spikerbox from the backyard brains. But the plants I am primarily studying are Tamarind plants (Tamarindus indicus). I am a bit worried if the plant spikerbox can pick up the low frequency signals of this plant. My Tamarind plants have shown some interesting behaviour like keeping leaves open of cold stormy nights and closing the leaves for few days even if there were ample sunlight. This behavior have been repeated for last two months. So, if I may ask this suppl8mentary question that if the spikerbox cant pick up tamarind plant signal, is there any way to tweak the device that it can pick up tamarind electric signals?
  • asked a question related to Bioacoustics
Question
4 answers
Hello friends of bioacoustic and birds conservation,
Please does anyone know anything about the effect of acoustic cannons on bird behaviour, breeding ecology etc.? I am looking for a background information about the negative effect of such equipment that is used in wetlands to shoo cormorants. The aim of my interest is to find out if there is a collision between the effort to protect fishes against cormorants by acoustic cannons and the need of general bird protection in wetlands and surrounding landscape. My questions are:
1. Has this shoo activity any negative effect on another bird or generally animal species?
2. Are acoustic cannons effective in long term cormorant frightening?
3. What about habituation on such acoustic disturbance in birds?
4. Dose we have any basic information about the long term effect of non-natural acoustic stimuli on animals especially birds?
5. Are there any effective alternatives how to deter cormorants from feeding in particular fish pond that are not invasive for another species?
Many thanks for your notes.
Pavel J.
Relevant answer
Answer
Dear Hans,
many thanks. My e-mail is pavel.jaska@nature.cz. I am looking for your articles. Now I have not so much information about all this cannon methodology, efficiency etc. I will dive deep in this all and then I will make some summary about that. I will send it to you when it will be prepared.
many thakns for all
Pavel
  • asked a question related to Bioacoustics
Question
3 answers
When some of the call properties show negative correlation with temperature . Is it necessary to perform temperature correction of such properties ? What are the steps involved in the correction.
Platz and forester, 1988 gives the formula D14 = Damb - (Tamb. -14.0) (-0.0974) . Can we apply our desired temperature here (Eg. 20 °C ? Or is there any better way to perform this correction
Relevant answer
Answer
Hi Vineeth,
In the paper
Narins PM (1995) Temperature dependence of auditory function in the frog. In: Advances in Hearing Research (GA Manley, GM Klump, C Köppl, H Fastl, H Oeckinghaus eds.) World Scientific Publishers, Singapore 198-206, the authors present examples of how temperature afects frog call parameters. The following is one example from this paper of how to calculate the effect of a 10 degree C temperature change (the thermal Q10) for a frequency shift of s octaves:
In all frog species tested to date, increasing the temperature results in an upward shift in the CF and a concomitant reduction in CF-threshold of the tuning curves for fibers innervating the amphibian papilla (low- and mid-frequency fibers). In contrast, basilar papilla (high-frequency) fibers appear to have temperature-independent CFs and CF-thresholds.
Temperature induced shifts of CFs varied from 0.08 octaves/degree C for low-frequency fibers to no CF shift for high-frequency BP fibers. The frequency shift/degree C may be expressed as a thermal Q10 dB value to simplify comparisons with other temperature- dependent processes (Eatock and Manley,1981). The thermal Q10 for a frequency shift of s octaves may be calculated by:
Q1O = e**s (10/delta T)ln2 where ** means "raised to the power of."
Hope this is useful,
Peter
PS- If you want just want to compare frog calls recorded at different temperatures, then it is useful to shift all the temporal parameters to a common temperature (say 20 degrees C) for a valid comparison.
  • asked a question related to Bioacoustics
Question
5 answers
Hi guys,
is there any option in AVISOFT SASLab Pro software which enables you to eliminate unwanted noise from digital recording without effecting your original sound? In my case, sounds are recorded in the experimental tanks with a hydrophone connected to the digital audio recorder. The lab is full of low-frequency noise, which in some proportions, disrupts my sound of interest. If I high-pass filter recording, there is still noise which is not eliminated and it is overlapping with the sound frequency spectra.
Any advise would be helpful.
Relevant answer
Answer
Avisoft SasLab Pro 5.2 software has got inbuilt lowpass, highpass, notchpass and bandpass filters critical in elimination of unwanted noise. Open the Avisoft SasLab Pro 5.2 software, the choose the edit menu. Under edit menu select Filter. Under filter, choose the Time domain IIR or FIR Filter. If its the background noise, then you may record the room tone and filter it out. Similarly the Avisoft UltraSound Gate allows you to attenuate unwanted signals.
  • asked a question related to Bioacoustics
Question
9 answers
Excluding harmonics.
Excluding also echolocation which I know exist in some South American apodidae or caprimulgidae.
Relevant answer
Answer
Hi Jacques,
In fact, we did just these kind of playback experiments as part of a project in which we demonstrated that the Concave-eared torrent frog, Odorrana tormota, from China produces ultrasonic call components and behaviorally responds to the US components alone. See:
Feng AS, Narins PM, Xu C-H, Lin W-Y, Yu Z-L, Qiu Q, Xu Z-M and Shen J-X (2006) Ultrasonic
communication in frogs. Nature 440: 333-336.
Hope this helps-
Peter
  • asked a question related to Bioacoustics
Question
8 answers
While working on squirrel calls, I found that the frequency of the sound produced by individuals from mean sea level is quite more than the same from an elevation of about 2000 metres. Does the frequency depends upon the elevation of habitat and changes with change in the height or their is something else behind the aforesaid phenomenon.
Relevant answer
Answer
Hi Anish,
It is interesting that vocalization frequency tends to get lower as one proceeds up an altitudinal gradient. Moreover, dominant frequency also decreases with increasing body size. For many animals, body size also increases as one proceeds up an altitudinal gradient, due to harsher conditions at higher altitudes. Harsher conditions favor larger animals with smaller surface area-to-volume ratios.
In a study (refernce below) we did on hearing in tropical treefrogs found along an altitudinal gradient in Puerto Rico, we concluded:
"We suggest that the animal’s body size determines the frequency particulars of the call apparatus and the inner ear."
Meenderink SWF, Kits M and Narins PM (2010) Frequency matching of vocalizations to inner-ear sensitivity along an altitudinal gradient in the coqui frog. Biol Letters 6: 278-281. doi:101098/rsbl20090763.
I hope this helps,
Peter
  • asked a question related to Bioacoustics
Question
5 answers
Hi all,
I'm currently working on a soundscape ecology study in which the entire acoustic community is of interest. I have been reading up about the Fast Fourier Transform (FFT), and the trade-off between the time and frequency resolution, which is determined by the choice of window length.
I have however failed to find any resources which explain which temporal/frequency resolution is required for the sounds of interest.
I understand that if only one/a few species with known vocalizations are of interest, this choice can be justified easily, but what if you're dealing with an unknown acoustic community? Studies of the acoustic community which use only the audible spectrum (with a sampling rate of 44.1 kHz) often use a frequency resolution of 172 Hz, but don't offer a justification why they chose this. And what if you're also looking at the ultrasonic part of the acoustic community - how would the required frequency resolution change to capture both sonic and ultrasonic signals?
I appreciate any insights you might have.
Relevant answer
Answer
Hi Thomas Luypaert , The window size in a FFT analysis represents a number of samples, and a duration. To set the size you would need to look at the fundamental frequency in your system, its intensity and any changes it may experience in time. The window size expressed in samples along with your sampling rate (samples/second) would give you information to calculate the window duration.
Also, from the spectraplus page: " The frequency resolution of each spectral line is equal to the Sampling Rate divided by the FFT size. For instance, if the FFT size is 1024 and the Sampling Rate is 8192, the resolution of each spectral line will be: 8192 / 1024 = 8 Hz. Larger FFT sizes provide higher spectral resolution but take longer to compute."
Hope this helps!
  • asked a question related to Bioacoustics
Question
4 answers
I'd like to understand what is the typical bandwidth of bioacoustic signals and if they counld bbe revealed from radio satellites
Relevant answer
Answer
Abel has it! :-) Jim Des Lauriers
  • asked a question related to Bioacoustics
Question
2 answers
I'm a Dutch student who is working on a project to investigate the possibility of estimating the number of calling Spadefoot toads (Pelobates fuscus) on a recording by using Avisoft SASlab pro. I'm using sound recordings of calling Spadefoot toad's and I'm trying to detect every single call with Avisoft. I have used a Bandpass and Sampling Rate Conversion to filter the recording and focus on the frequencies used by the Spadefoot toad. Thereafter I used the Automatic Parameter Measurements Setup.
Avisoft detects most calls but also misses some and make some false counts. These false negatives en false positives have a lot of impact on the data. For example: I have counted 12 calls on a recording but when I analyse the data with avisoft it counts 24 calls. Is this the disadvantage of using bioacoustics or am I missing something? I hope you have some suggestions for me. 
Kind regards, 
Valentijn Jeronimus
Relevant answer
Answer
Hi Valentijn,
Ben zelf geïnteresseerd om geluidsopnames te maken van knoflookpad in Vlaanderen.
Kan je me mailen op lily.gora@vlaanderen.be, aub?
  • asked a question related to Bioacoustics
Question
3 answers
should the reflectance data be resampled to a sensor?
Relevant answer
Answer
By asd device you will get .asd file and you can convert that ascii asd file to txt file with help of viewspcpro software. Then import that data into excel sheet.then you can calculate any SVI.
  • asked a question related to Bioacoustics
Question
3 answers
I am researching about the use of bioacoustics for mammal species, and there are quite a bit of studies that use bioacoustics for mammals, but they tend to analyse the data manually. How feasible would it be to carry out machine learning for all 11 primate species in Peru?
Relevant answer
Answer
Russell Gray I think she is asking more if machine learning is feasible? My immediate answer is yes. We work on multi-species assemblages, we might have as much as 6-7 species calling within just a few seconds, it challenges the algorithms a a bit. Especially as the data is from omni-directional microphones so there's a lot of background noise. Not impossible though, just need to ensure the training is done thoroughly. Have a look at the papers by Bedoya 2014 (Automatic Recognition of Anuran Species based on Syllable identification). We are also working on implementing deep learning on our data - they've done it for bats in our lab (I think the paper is in review) and there was just a paper released on using it on birds I think? (I can't find it or remember the author off the top of my head, might have been in Methods in Ecology). Birds are in my experience a pretty good model species though as their calls are quite complex so easy for the algorithms to identify, we have more issues with the frogs as the call itself is often quite "simple" in it's pattern (then put together into a more complex call series), I don't know how primate calls look like in spectrograms though.
  • asked a question related to Bioacoustics
Question
5 answers
According to Gagliano et al 2012 (Towards understanding plant bioacoustics published in Trend in Plant Science, 17: 323-325, 2012) maize seeds emit clics during germination. When recorded and played back these clics can influence the direction of the growth of roots (in aquaculture). The response occurs at a frequence of 200 - 300 Hz.-
Questions: do plants have receptors for sounds? Do we know anything about the signal transduction leading to this phenomenon?
Relevant answer
Answer
Hello the right sounds can produce tremendous improvements in growth, and the wrong sounds can do just the opposite. Plants are more aware of their surroundings than we think, probably much more so than us!
  • asked a question related to Bioacoustics
Question
4 answers
I have used RAVEN software auto detect filters to identify (label) the notes of a single bird species that imitates other birds. Thus I'm working with a large data set (hundreds of thousands of notes within thousands of songs) and am attempting to label all the sounds (notes, syllables, phrases) accurately within the songs of
a bird species and found:
1) it is very time consuming to tweak the parameters to even get it to 'work'
2) when it is 'working' it returns with numerous false positive and negative results
I'm curious if those interested in identifying (labeling) large data sets of animal sounds have found a software that will sift through the spectrograms with accurate identification (labeling) of sounds?
Currently I'm using visual and aural inspection (human) of spectrograms to do this, which amazingly seems to be the only way to achieve accuracy in this task. It's incredibly time-consuming but I appear to be quicker at doing it 'old school' than by using automated (computer based) methods.
Cheers!
Brandi Gartland
M.S., Doctoral candidate in Animal Behavior
University of California, Davis
Relevant answer
Answer
There is a highly instructive user manual on the site. The reference for the initial publication is:
Tchernichovski, O., Nottebohm, F., Ho, C. E., Pesaran, B., & Mitra, P. P. (2000). A procedure for an automated measurement of song similarity. Animal behaviour, 59(6), 1167-1176.
I have studied with Olga Fehér who was herself a PhD student of the first author on the paper. I have learned a few things the hard way. First off, the initial setting of this software is designed for the analysis of zebra finch song. If you are working with a different species you may need to adjust them. Also, the detection and classification algorithms are good, but by no means perfect. Therefore I strongly advise that you keep the results by eye!
Greetings from the UK!
Tarandeep
  • asked a question related to Bioacoustics
Question
5 answers
Hello, I currently work on rainbow lorikeets vocal individuality. The problem is that parrots are very loud and the audio signals are clipping. I use directional mic Senheizer ME 66 and recorder Tascam DR 100 MK III with limiter on. Is there any solution to solve this issue? I know it is possible to fix clipping in audio programs, but is it ok to use fixed signals in my analysis or it is better to eliminate them?
Relevant answer
Answer
For most analyses, the biggest problem with clipped recordings is not the loss of reliable information about relative amplitude ("dynamics"); it's the corruption of the spectral content of the recording. Clipping introduces spurious energy into the recording at frequencies that are harmonics of the true signal. In some cases, sounds that are purely tonal (no harmonic content) will end up having strong harmonics in the clipped recording. Sounds that truly do have harmonics (like many parrot vocalizations) will be recorded with distorted relative powers in different harmonics. Most kinds of analysis that aim to classify sounds or measure their relative similarity (e.g., spectrogram cross-correlation, dynamic time warping, etc.) may be severely affected by such distortions.
What about "fixing" a clipped recording? Many digital audio editing programs (e.g., Audacity, Audition) include tools for "fixing" clipping. However, these tools are not intended to provide a perfect reconstruction of what the unclipped signal would have looked like. They're meant for rendering the harmonic distortions of brief periods of clipping in music or speech recordings inaudible to the human ear. This is very different from what would be needed for a quantitative measurement and classification analysis.
Although there may be some kinds of analysis that could tolerate clipping (e.g., analyses focused on temporal patterning of sounds that don't measure spectral content), in general I recommend against using clipped recordings for pattern analysis and classification. You're likely to get quite different results from what you would obtain using unclipped recordings of the same signals.
  • asked a question related to Bioacoustics
Question
12 answers
Dear all,
As a bioacoustics researcher I need an operational definition of communication. I have been using Weaver's (1949) definition, in which communication is the process in which one mind affects another. I have recently received some critics by reviewers that questioned the age of such definition. Even though I disagree age to be a factor by which we judge definitions, I reviewed the the theme and did not like any of the new approaches. So I ask, is there any new, better, and operational definition of communication?
Kind regards,
Carlos.
Relevant answer
Answer
I think that Polajnar and Maynard-Smith have it about right. I would say simply that communication occurs when the behavior of one organism produces a stimulus that changes the behavior of another organism. That includes both behavior due to phylogeny and due to ontogeny. In particular, it includes verbal behavior. Disagreeing with Butler, I also would argue that an organism may communicate inadvertently. Think of Clever Hans the horse, for example. It's owner communicated inadvertently.
  • asked a question related to Bioacoustics
Question
3 answers
Can someone recommend me reliable and reasonably priced speakers for playback experiments in the range of 100-15000Hz?
Relevant answer
Answer
Hey Cristian,
I've found that devices marketed specifically for playing music are often manufactured with a "curved" frequency response. Some set of frequencies within the range you provided will likely be reproduced at a lower volume than others.
The device with the "flattest" frequency response I've used is a predator caller. They range in quality along with price, but depending on your needs I'm sure there's something that will work for you. The brand I'm familiar with is FoxPro, specifically the Inferno model, which is a single horn type speaker. Worked great for producing reliable sounds between 1-7 kHz at 100dB. Have a look at some of their user manuals for more specifications.
Hope to help!
-Andrew
  • asked a question related to Bioacoustics
Question
4 answers
Unsupervised recognition and classification of bird calls and songs is a target for many researchers, however even simple sound recognizers could be useful.
I'm searching programs able to easily set a "song template" and then search for its occurrences thorough a long series of recordings. I'm willing to compare them and score them according to efficacy, speed and ease of use.
The work is within the themes of bioacoustics and ecoacoustics applied to environmental monitoring.
Relevant answer
Answer
At present we are working with MonitoR in R. It looks promising for a basic sound pattern search across multiple files of unattended recordings.
The only one interactive software we found is X-Bat, a toolbox developed for Matlab but not maintained anymore. Any hint for finding something similar ?
  • asked a question related to Bioacoustics
Question
26 answers
 What are best open source software available for the bioacoustic database management and for the cleaning and cutting of the raw recordings of animal sounds from the field? I have previously used PRAAT and now trying out Luscinia. Any other options out there? 
Relevant answer
Answer
Hi Adwait!
Have you checked warbleR ? This is a free R code developed by Marcelo Araya-Salas to streamline analysis of animal acoustic signals. 
Probably this is what you are looking for, although you must have some knowledge of R to use.
All the best!
  • asked a question related to Bioacoustics
Question
8 answers
I need a recommendation, thanks
Relevant answer
Answer
Muchas gracias Gian, you work is very interesting!
Update; I buy an used Olympus LS-100, after reading helpful reviews in birds pages and bioacoustics forums in general. And my microphone is a shotgun Sennheiser (the pic is attached to this reply, i don't know the model). Thanks to all!
  • asked a question related to Bioacoustics
Question
5 answers
This analysis is part of a bioacoustics study attempting to identify changes in chickadee alarm calls in response to traffic noise.  Our main response variable is change in peak frequency, but I am having trouble consistently identifying this using Raven Software.  It appears that when we highlight the top and bottom Spectrogram views, the peak frequencies that we identify oftentimes differ.  
On a side note, we've noticed that all of our peak frequencies are multiples of 173.  I'm fairly sure that this is the default 'frequency bin size' of Raven Software. Can anyone offer an opinion whether this is sufficient resolution for a study comparing peak frequencies of alarm calls?  If not, is there a bin size that is more standard/preferable?  Thanks!
Relevant answer
Answer
Thank you all for the excellent feedback and information - I will attempt to implement the suggestions in the coming months and be in touch if further question arise. 
  • asked a question related to Bioacoustics
Question
9 answers
Hi everyone,
I am writing my MSc thesis about vocal communication in woolly monkeys and I want to make a general description of their different types of calls. I want to obtain various acoustic parameters such as duration, frequency range, low frequency, high frequency, maximum amplitude, average frequency, initial frequency, and final frequency. Hence, I have to analyse my recordings using SoundRuler, but I've never used this software before. I've read the instructions but I have some questions anyway.
- I recorded in stereo, so when I introduce the recording in the software, it asks me if I want to analyse left or right channel. Can I analyse both separately and then calculate the mean of both channels?
- Also, when I introduce the recording, I mark the section that I want to analyse using green bars. Once this section is marked, I proceed to do the analysis. Is it as easy as clicking the "manual" button? When I do it, it appears a table with the different values of the parameters, but I don't know if it is as "simple" as that.
That's all at the moment. Thank you for your answers!
Laura.
Relevant answer
Hi Laura,
I agree with Pavel regarding the channels and amplitude. I also don't use SoundRuler (sorry!) but I thought it might be useful to add that you need to be sure there is no background noise overlapping your calls of interest. If for example these recordings were made at a zoo, there may be visitors chatting, or in the field there could be other animals calling etc. on your recordings. If there is, then you can either need to filter it (if it does not overlap in frequency with the monkey calls), or if that's not possible, you could manually extract the frequency measures, or simply eliminate those calls from your analyses. It might be that you can use the read-out on all your "clean" calls (i.e. no background noise, one individual calling at a time) and in that case it could be just as simple as you say!
Good luck with your interesting project!
All the best,
Esther
  • asked a question related to Bioacoustics
Question
3 answers
Dear all,
With what coefficients are corrected each frequency for acoustic waves?
I’m looking for the coefficients which are applied between emitted sound wave and the reception for each frequency
Many thanks in advance
Elena
Relevant answer
Answer
Are you looking for the propagation transfer function between the acoustic source and the acoustic receiver?
That transfer function is often called the "propagation loss" or "transmission loss". It depends on the the kind of acoustic source you are dealing with, such as a point source or a plane-wave source for instance. And it depends on the medium through which the sound is propagating, such as through homogeneous air or other fluid like water, or perhaps through layered media in earth sciences (the ocean in oceanography).  And it generally depends on the frequency as well, as you say.
If it is the propagation transfer function that you want, then you must describe your propagation scenario in more detail, including a description of the source, the propagation medium, and source-receiver separation distances that are of interest.
Ronald
  • asked a question related to Bioacoustics
Question
8 answers
I am studying species-specific hearing ability across taxa in order to better understand the effects of anthropogenic noise on animals. I don't have a background in acoustics or audiology, and I'm looking for something that can get me up to speed on the major structures and differences across all taxa that have ears or other airborne-based-sound hearing structures.
Relevant answer
Answer
  • asked a question related to Bioacoustics
Question
4 answers
I happened on one today and was able to get it to make some croaking sounds, is there any literature on the sound production mechanism?
Relevant answer
Answer
HI, you might want to check with Phil Lobel and David Mann, they would be the most likely to have recorded the species.
  • asked a question related to Bioacoustics
Question
4 answers
With an affordable rate (good price-quality ratio) please. The main purpose is to record marine mammals sounds and foraging activities at night in coral reef ecosystems but if it would be great if it could also pick up waves breaking for an artistic personal project. It has to be easily handled manualy (for snorkelling). Thank you for all advice.
Relevant answer
Answer
Thank you everyone, it really helps! I will soon let you know my choice and how does it sound.
  • asked a question related to Bioacoustics
Question
2 answers
I was monitoring a lobster and noticed it was clearly resonating through its carapace (just ahead of its tail section in the spot they're easily held). Everything on the web seems to focus on them using their antennae and file, is this a common communication mechanism as well? attached is a snippet where he seemed to "tell me off" before walking back into his mangrove.
Relevant answer
  • asked a question related to Bioacoustics
Question
10 answers
It seems reasonable that fish can measure intensity if they have a lateral line and a swim bladder. I am asking if anyone has tested their ability to measure complex intensity rather than time as averaged, e.g. only real intensity?
Relevant answer
Answer
Dear fellows,
I've been watching your discussion related to "Do fish measure reactive intensity?" and found it interesting when talking about "total sound intensity from a pure acoustic point of view". When it comes to sound reception/sensing in fish you've forgot the "most" important sensor beside the swim bladder and the lateral line, i.e. the otoliths, which act like an accelerometer. There is some literature related to this which may clarify/elucidate sound reception in fish in relation to total sound intensity. I'll like to see you++ continue with this discussion.
  • asked a question related to Bioacoustics
Question
2 answers
I recorded ten minutes and followed Rodney rountrees expert 101 on how to collect... That was when I thought it was a mutton grouper. Then a friend pointed out it was a squirrelfish. Has anyone checked them for speech?
Relevant answer
Answer
Squirrelfish are a classic group for study of sound production. My old major prof Howard Winn and students did some of the classic work, and it has recently been taken up by the Parmentier establishment. Be careful about using common names when asking an international audience about a fish. I can come up with at least 10 names of the oyster toadfish.
  • asked a question related to Bioacoustics
Question
17 answers
I am looking for a way to estimate particle acceleration of an underwater sound produced by aquatic animals, per e.g. Something easy to use in the field and reliable. Like a vector sensor or an underwater geophone?
Relevant answer
Answer
Some of the Wilcoxon sensors were developed with the US Gov't, and have ITAR restrictions associated with them.  They are not available internationally.  Applied Physical Sciences also has some sensors, but they too have ITAR restrictions.  The Microflown/Hydroflown sensors (from the Netherlands) have never been proven to be effective in underwater applications. 
My recommendation would be to get several good pressure sensors and build your own vector sensor based on pressure gradient measurements.  (I believe that's really what the PAS is.)
  • asked a question related to Bioacoustics
Question
2 answers
For detecting vocalizations of beluga from large acoustic recordings data set - used to determine presence/absence of species, so would need to detect both clicks and whistles.
Relevant answer
Answer
sure, if you send me a template file I will take a crack at it and send you a set of m-files. I would consider it a fair trade, I haven't had a chance to work with whale song much lately.
  • asked a question related to Bioacoustics
Question
14 answers
I am looking for a user-friendly software for analysing bioacoustic recordings (underwater sounds) with students. I am so far interested by Raven Pro and Adobe Audition. Any advice? What is your favourite software ?
Thanks!
Relevant answer
Answer
Hello,
You could use the R packages seewave, tuneR, soundecology and ineq (https://www.r-project.org/). “R” is free and useful in many ways. Plus, there are numerus articles using these R packages for bioacoustic and ecoacoustic research.   
Nevertheless, for a more basic and user friendly approach, you could use Audacity (http://www.audacityteam.org/).    
Best regards,
Aggelos
  • asked a question related to Bioacoustics
Question
7 answers
I'm interested in understanding if is possible and feasible to detect and record underwater sound without touching the water, e.g. with a laser interferometer like those used to record sounds by detecting the vibrations of a surface like a glass window.
Relevant answer
Answer
Here is my dads' paper actually, turns out some of these end up archived in strange places:
  • asked a question related to Bioacoustics
Question
2 answers
I haven't matched the audio up with the file, but I don't think its necessary for the example attached. The gist is that I am using the 1st, 2nd and 3rd derivative to look at a fish vocalization. the 3-D plot on the left shows those data points (based on what I read in the manual). I took a min-max of each series as well and plotted on the right in the stem for each snapshot (its slowed down by about a factor of 10, the signal is about 2.5 seconds long. I think I am looking at a periodic non-linear signal (this makes sense since the fish is basically vocalizing with a set of sin waves so I expect continuous derivatives).
in summary, since each derivative is uniform but mean power is ~=0, the signal is non-linear periodic. if I'm wrong, can you please tell me where?
Relevant answer
Answer
thanks professor!
  • asked a question related to Bioacoustics
Question
10 answers
So far I have some estimates from Lotek, Holohil Systems, and ATS. I would love to hear personal experiences about these and any other company's products.
I'm also curious if anyone has some insight into tracking a species that is known to burrow in mud and how the signal might work...
Thanks :)
Relevant answer
Answer
Great question!  I have many good and bad stories about various devices on small animals, but have come to the conclusion that the traditional methods are not as fool-proof and too expensive compared to what is new and better.  And I have a (hopefully great) suggestion: use passive harmonic dipole.  These are the same things that avalanche jackets have in them and you would need to buy the whole package (including the transceiver), but the costs might be cheaper than traditional radio tracking depending on how many animals you want to track.  Check out the Herp Review article (Herpetological Review, 2011, 42(4), 522–525) by GOURRET  and others from Australia (attached) and/or just Google "animal tracking passive harmonic dipole" and see what you get.  These devices are smaller than a grain of rice and can be placed on your study animal in a variety of ways, although a thread belt might be best for your sallies.  This is so the diode will eventually just fall off and you can find it again - and re-use on another animal.  I have a few colleagues who are now swearing by these and can vouch for their effectiveness for small amphibians.  Plus, you won't need to surgically implant them - a huge bonus for you and the animals!  Please let me know if you have any questions and I can help you with contacts that might be able to give you the best vendors etc.  Also, sometimes you can buy old and used avalanche finders from ski resorts and use those for much much cheaper as well.  Hope this helps.
  • asked a question related to Bioacoustics
Question
4 answers
so I'm no biologist, but I'm trying to get a grasp on some biological elements of the model for a resonant bubble with respect to the swim bladder. if a fish pushes against the bladder with muscles to make a noise, it looks like in some of the biology book pictures that the gas is moved around during vocalization. but the center frequency seems to be pretty constant in the files I look at. so if the fish isn't frequency modulating - but there is still some modulation present - shouldn't the radius factor (usually shown in centimeters) be a function of time, from when the vocalization begins to when it ends?
Relevant answer
Answer
Ok, that's one I had not seen. I was going in with a bent based on some of Dr. Bass' work where he tested various modulations of the same tone on midshipmen, and basically the pure tone got 100% of the gravid females to come hither. the more modulation was introduced, the less interested the females got. at this point I'm wondering if a modulation effect isn't present that fades with maturity. I'll send you some stuff under separate cover.
  • asked a question related to Bioacoustics
Question
3 answers
Bioacoustics is said to analyze several recordings of sound, not only including those produced by animals but by human activity as well. How long of a process is it to analyze all of the sound recordings and assess the soundscape ecology, especially if they are factors that can constantly change the overall soundscape?
Relevant answer
Answer
Hello,
Bioacoustics is a field that deals primarily with animal vocalization, sometimes in relation to anthrophony. For example, one could conduct bird song recordings to assess the masking effect of noise in animal communication.   
Some researchers conduct their recordings using remote sensing techniques. They deploy several omni-directional sensors in multiple sampling spots across the landscape in order to simultaneously conduct recordings of all significant events taking place in the soundscape, for a long period of time.
In order to obtain a realistic portrayal of the overall soundscape, meaning to capture the majority of the acoustic events taking place in a 24-hour period, it is necessary to organize your sampling protocol accordingly.  
The duration of the analyzing procedure depends on the software you are using. “R statistics” (with the appropriate packages) is very good and free but occasionally time consuming.       
For further information on recordings conducted for Bioacoustics, Soundscape Ecology and Ecoacoustics research, refer to articles written by Bernie Krause, Almo Farina and Henrik Brumm.
  • asked a question related to Bioacoustics
Question
2 answers
Any experience in what consists of a 100% scrambled call for a control?
Relevant answer
Answer
Thanks very much for your help.
  • asked a question related to Bioacoustics
Question
4 answers
Hello all,
I'm interested in attaching a small audio recorder to large mammal radiocollars and having them record continuously for 1 month.
Minimum specifications:
1. Would need to store 750 hours on audio and run on a single charge. Ideally, it would have a sampling frequency of 22kHz (but this isn't essential and battery life trumps sampling frequency).
2. Combined recorder and battery weight < 150 grams
3. Recorder and battery price < $250
Does anyone know of any recorders that fit the bill straight out of the box, or that could be modified by someone with little electronics experience?
A previous study on chipmunks used a spy microphone (http://ts-market.com/products/models/1258/) for their project. That would also work here if there was a way to change the power input to something that would last 1 month (storage on the device is enough for 1200 hours).
Having said that, the unit cost of the above device would probably exceed my budget so if anyone is aware of something cheaper that would be great.
Thanks in advance for your help.
Kas
Relevant answer
Answer
as mentioned before there are two problems, storage and batteries. Among small digital recorders the best one is the SONY PCM-M10, unfortunately now discontinued but still available in US. Its power consumption is among the lowest: 60-70mAh, that means >30 days continuous recording with 6 or 8 D size batteries (max 18Ah at 1.5V), that brings weight and size high. As an option you could use Lithium D size batteries, expensive but with double power than alkaline (up to 19Ah at 3.6V).
As for the storage the M10 is one of the very few that is declared max 32GB but can record on a Sandisk Ultra 128GB microSDXC formatted by a PC in FAT32 mode. The max microSD size now available is 200GB but I never tested it in the SONY. Huge size available; however, to record 30 days you necessarily need to switch to MP3-320K with a bandwidth of 15 kHz, that is more than with 22k PCM sampling.
In 22kHz PCM stereo (few recorders can record in mono !) you need 228GB/month that would be possible with a standard 256GB SDXC card (these are also available up to 512GB now). But recorders are larger and more power hungry.
Solutions based on microcomputers need too much power. In any case the first feature you must check is power consumption. A recorder that would partially fit your needs is the Tascam DR22WL, it records in mono and thus 1 month could fit in a 128GB microSDXC card. Unfortunately it requires near to two times the power required by the SONY M10. If you solve the battery problem the WL 22 is the good solution.
Another option to be deeply tested before going on is to use the ZOOM H1. Smaller and lighter than the SONY, It is declared to max 32GB microSD however it can record on larger memories as the SONY (to be tested on specific memory brands and to be tested for power requirements).
Eventually write me privately for alternative options.
Gianni
  • asked a question related to Bioacoustics
Question
10 answers
Communication involves multiple individuals (at least a sender and a receiver). On the other hand natural selection will act based on the fitness value of communication for each individual involved in the communication process. In such case, when should selection affect on the receiver, and when will it act on the sender? (edited)
Relevant answer
Answer
It is not necessary that sender and receiver both benefit from a new communication process. Many signals arise by 'exploiting' the sensory system of the receiver. For example, guppy males attract more attention by females when their color matches that of the most preferred food of the females. This way, males can evolve a certain color that later plays an important role in sexual selection. The color trait (it depends on your definition from which point onward you call it a 'signal') may spread even if mating with colored males would be disadvantageous for females. A recent review article on this 'sensory exploitation hypothesis' is Ter Hofstede et al. (2015) in Current Biology.
  • asked a question related to Bioacoustics
Question
1 answer
This figure ( result from Hydroacoustic instrument Cruzpro Fishfinder ), What interpretation if you look this figure??
I have a trouble in my research , What's this figure showed no detection ? or processing data wrong ? 
And please give your comment and your suggestion ,
Regards
Muhammad
Relevant answer
Answer
 
Such a  pattern can  result  from  the  error  inside  the  transducer-amplifier channel. The most  probable  the  transducer  is damaged or  not  connected correctly. The patterns are reflected the noise or  electrical disturbaces.
  • asked a question related to Bioacoustics
Question
2 answers
Attempting to create an automatic detection algorithm to scan large data sets. I want to pull out beluga vocalizations to determine spatio-temporal habitat use from several years of hydrophone recordings.
Relevant answer
Answer
Dear Karyn,
Our foundation has been funding for several years a project which has developed an automatic detection system. This has been designed to detect, extract and store in a database killer whale vocalizations but theoretically it should work with any sound event. It would be great to have one of your recordings to make a test and, if if works, we can find the way to process your  recordings, as the system stills under development and there is no a version for distribution yet.
J
  • asked a question related to Bioacoustics
Question
10 answers
I seek advice on dealing with background noise which overlaps in frequency with the signal of interest. The software I use is Avisoft SAS-Lab Pro. I have used an eraser tool (under strict predetermined criteria). Is there a more suitable method in cases where the background noise is of a similar frequency to the signal?
Recordings are made at a sample rate of 48kHz (16-bit) and resampled to 22.05kHz. Spectrogram parameters: 256 FFT, Hamming window, 100% frame size, 50% overlap. Resolution: 86Hz and 2.9ms.
Relevant answer
Answer
As suggested by Israel, if the "nature" of your noise does not change (assuming frequency remains the same as the signal but not the amplitude or phase) then a simple amplitude based filter should work. You may also try phase-based filters.
If the noise (or even if the signal) changes its characteristics then go for statistical filters which can even be adaptive! The first one to try out is Wiener filter mechanism with adaptive filter algorithms like LMS, NLMS and RLS. These are the best ones (my personal experience). See these for more information 
and
and
  • asked a question related to Bioacoustics
Question
4 answers
Should i use dBPeak values to determine underwater noise mitigation (i.e., safety zones) instead of dBrms even though the NMFS interim sound thresholds for marine mammals uses dBrms? As thresholds are considered absolute values we should not exceed (e.g., to avoid TTS and PTS), should we monitor for dBPeak values instead of dBrms? This is in relation to impulsive sound rather than continuous sounds.
Relevant answer
Answer
Thanks all.
Moving forward we will be using a dual metrics criteria that includes the interim NMFS sound thresholds as well as Southall et al. 2007 values (SPLrms and SPLpeak).
We'll be keeping an eye on the draft NOAA guidance as well to see what the final version outlines. For those interested this is the draft guidance: http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm
  • asked a question related to Bioacoustics
Question
7 answers
Whether the Software Raven pro 64 bit 1.5 (Bioacoustics Cornell Lab of Ornithology USA) is able to analyze the spectrum of dolphins with specific?
logarithms, frequency range, and the range of intensity ??
Thank You ,..
Relevant answer
Answer
Hi Russ Charif  Thank you very much for your suggestion and information to me .
i will be message you in research gate , about my problem using Raven Pro.
Regards 
Muhammad
  • asked a question related to Bioacoustics
Question
6 answers
As every rotating object creates or emits sound due to its rotational motion, so are the planets. But, do we have any research, where in which we try to figure out how the biological oscillations associated with various parts of our body are related to different sound spectrum emissions from rotating planets? If so, via resonance do they impact the functional qualities?
  • asked a question related to Bioacoustics
Question
8 answers
Respected all,
i have identified six songs on the basis of spectrams analysis in the vocalization of Indian magpie robin . how can i interpret my audio format data for a bioacoutic journal.
Relevant answer
Answer
the first step is to define what you want to demonstrate/show: their behavioral function/meaning ? their stability/stereotypy for species recognition ? their specificity versus other similar species ? their possible use for automatic species recognition ?
A basic spectrographic analysis might be enough for most of these cases, but you need a suitable sample size. You need N individuals (or N recordings of different individuals, maybe with some degree of individual replication).
According to the shapes you see on the spectrogram, and also according to your listening of the sounds, you then need to identify some measuring points that enable you to characterize the vocalizations and analyze them statistically.
that's the basic strategy, then you need to tune it according to your research goals.
Gianni
  • asked a question related to Bioacoustics
Question
9 answers
I've recently used the calls of male midwife toads played back to a restricted population of the toads in order to assess their overall population size. Has anything like this been done in the past within Europe either with midwife toads or another anuran species?
Relevant answer
Answer
Hi Steven,
Thanks Abhishek Raj for tagging my paper.
In our lab in Australia we use call playback for a wide range of Litoria species. However, there are a lot of species here that don't respond to call playback.
For our auditory surveys we estimate the number of callers prior to playback for three minutes, play calls (or imitate calls) for one minute, then record the number of answering males. We have found this to be useful as an abundance measure for calling activity, but it is always coupled with visual encounters. Our females and juveniles dont make sound so VES is needed and our males are very hard to spot in VES as they startle easily and hide (but females and juveniles don't hide). This covers us for male presence as long as we statistically account for changes in weather and change in calling as e.g. dropping temperatures reduce the amount of calling (however this cant account for changes in male energetic constraints).
There are a couple of things to consider if using call playback, I'm not sure if your interested in this side of things.
1. The number of calling males you use in playback (as previously mentioned)
2. The type of call you use (advertisement call, aggressive call, release call, unenthusiastic call) If you don't know what the calls mean, maybe choose the most common calls in good weather/breeding periods? A pilot study could help determine this and even make a neat note for call types.
3. Not all males within a chorus area actually call (satellite male behaviour)
4. We are going to modify our methods to also estimate the number of males calling during call playback. Sometimes males call during call playback but not afterwards, and kind of 'mirror' our calls, so actual response can be lost if only recording afterwards.
5. When I take volunteers out, I never rely on their ears. I have found with my species that untrained people massively overestimate the number of calling males as their calls are very loud and you feel your surrounded by 20, but its really 8
Good luck with your surveys.
  • asked a question related to Bioacoustics
Question
15 answers
I'm new to acoustics and trying to describe and analyze loud calls of red langurs. Loud calls of this species has never been studied previously, so there's no reference I can look up to. I need suggestions to determine if: (please see attached image)
  1. the loud call is tonal or non-tonal (I think they're non-tonal)?
  2. is there any predefined "names" for the shape of the spectrogram (a, b1, b2)?
  3. where (on the spectrogram) is the fundamental frequency (F0)?
Any inputs will be very appreciated. Thank you.
Relevant answer
Answer
If there is only one animal calling there, it is possible that you have a kind of nonlinear phenomena common in mammalian vocalizations (biphonation). So, you probably have two independent fundamental frequencies (as you can see in the vocal units from the middle of the call on). It seems that at the begining of the sequence the animal is producing tonal calls that the fundamental is the F0. Then you have the biphonation happening.
Please, find more about biphonation in these papers:
Riede, T., Herzel, H., Mehwald, D., Seidner, W., Trumler, E., Tembrock, G. & Bo¨hme, G. 2000: Nonlinear phenomena and their anatomical basis in the natural howling of a female dog-wolf breed. J. Acoust. Soc. Am. 108, 1435—1442
Fitch, W. T., Neubauer, J. & Herzel, H. 2002: Calls out of chaos: the adaptive significance of nonlinear phenomena in mammalian vocal production. Anim. Behav. 63, 407—418.
  • asked a question related to Bioacoustics
Question
9 answers
I am looking to record prairie dogs vocalizations paired with their behavior continuously in the field, so the device will be exposed to the elements.
This Question has been answered, I appreciate all feedback, thank you!
Relevant answer
Answer
It sounds like an interesting project, however it will be much easier for people to help if you tell us: what frequency and duration of sampling will you need, in order to address your research questions?
In favourable conditions you can get good video and sound recording with almost any compact digital camera, even with older models as Tessa mentioned. And you can easily mount a compact camera on a low tripod or other stand and add a rain-proof cover (or choose a waterproof model), place it near your study animals, turn on video mode, walk away and leave the camera to run continuously...
...until the battery runs down or memory card fills up... maybe half an hour, maybe an hour or two, depending on camera, memory and video settings.
Much more challenging if you want to record continuously all day, day after day. You will need external power and high capacity data storage... and afterwards you will need to spend many days watching/listening in order to extract the data of interest.
Some other considerations: can you work near these animals (set up equipment, change batteries, etc) without disturbing the behaviour you are studying? Can you predict fairly accurately when and where the behaviour of interest will occur?  How near and how far from the recording equipment do you expect the animals be heard/seen? Do you want the vision to be clear and close enough to identify age/sex/other characteristics? How much ambient noise from wind or road traffic or other sources? How many animals do you want to record concurrently?
  • asked a question related to Bioacoustics
Question
7 answers
I would like to study if Vespa velutina in their nests produce a particular sound.
If yes, is this sound detectable from long dinstances? (up to 1 km)
Do there are already studies like this?
Thanks
Filippo
Relevant answer
Answer
Muchas gracias Juan Josè
  • asked a question related to Bioacoustics
Question
7 answers
I am searching for good song recordings of African Reed Warblers. The longer the better. Or maybe somebody works near the habitat of these birds and it's not a big deal to record several minutes for me :)
There are some recordings on xeno-canto.org, but they are way too short for the analysis :(
Relevant answer
Answer
In Yellowhammer Dialects project, I am exploiting many sources of recordings:) Surprisingly, some yellowhammer song are also on Flicker, however I bet this is not the case of African warblers.
The best would be to contact British library - they have about 47 songs: http://cadensa.bl.uk/uhtbin/cgisirsi/?ps=jvO7LMNQhB/WORKS-FILE/325200049/123 I will send you a contact to a responsible person through email, Nika:-)
  • asked a question related to Bioacoustics
Question
10 answers
It is a stridulatory apparatus which sound has never been heard in the larval stages. On the other hand the sound is audible on the adults. Does anyone has a biological idea or explanation of this phenomenon?
Relevant answer
Answer
Dear Nahid, they're manca stages of terrestrial isopods.
  • asked a question related to Bioacoustics
Question
6 answers
I am currently trying to assess the population size of a non-native species here in England, the midwife toad (Alytes obstetricans). So far I have only found what I think are males (as they call) but I have noticed a difference in the kind of calls that are made by the toads.When I have looked at the calls using sonogram analysis software two different calls are distinguished. I was wondering if one could be from a male and the other from a female.
I have attached a sonogram which shows a short section of one of my recordings. Am I right in thinking that individual A is a male and individual B is a female returning his call?
Relevant answer
Answer
This is for A. cisternasii but you may find similar papers for A. obstetricans:
Female Courtship Call of the Iberian Midwife Toad (Alytes cisternasii)
Jaime Bosch and Rafael Márquez
Journal of Herpetology
Vol. 35, No. 4 (Dec., 2001), pp. 647-652
  • asked a question related to Bioacoustics
Question
11 answers
I study the riches of song complexes (dialects, sub-dialects etc) of Chaffinch (Fringilla coelebs) in Ukraine. But I did not found studies of numerical separation of these complexes and numerical description of their riches.
Relevant answer
Answer
You may use Shannon entropy measurements to calculate note disorder within the song. Please take o look in:
SILVA, M. L. ; VIELLIARD, Jacques Marie Edme ; PIQUEIRA, J. R. C. 2000. Using shannon entropy on measuring the individual variability in the Rufous-bellied Thrush Turdus rufiventris vocal communication. Journal of Theoretical Biology, 207(1): 57-64, 
  • asked a question related to Bioacoustics
Question
5 answers
I am curious about the idea if it is possible that non-echolocating bat species may be affected by extreme noise. Since most of the studies published deals with echolocating species. Thanks in advance! 
Relevant answer
Answer
 While much of the literature on anthropogenic noise impacts on bats is focused on foraging and use of echolocation, I think the general  body of literature on noise impacts on wildlife in general is just a pertinent. My point being, regardless of whether the noise is impacting their echolocation abilities (or how much the species is using echolocation), extreme noise would still likely impact their behavior.
You have probably seen this, but here fairly recent literature review that might be helpful: 
[Francis and Barber 2013. A framework for understanding noise impacts on wildlife: an urgent conservation priority. Frontiers in Ecology and the Environment 11: 305–313.]
  • asked a question related to Bioacoustics
Question
9 answers
I am working on avian acoustic adaptations in urban habitats. I use Avisoft SAS LabPro and Raven Pro1.4 software. These software do give amplitude levels of sound but are exceptionally too high in comparison to measurement made by Sound Level Meter SVAN 957. What measurement setting should I do in the software for getting accurate SPL( dB) from the .wav files?
Relevant answer
Answer
Your question requires a bit of clarification. When you talk about estimating SPL of bird calls, do you mean the received level (RL) of the calls at your microphone, or the source level (SL) as the bird produced the sound? SLs are typically given in dB SPL (or dB re 1 µPa) at a distance of 1 m from a source.
If you want SLs you first need to measure (or estimate) the RL and then apply an adjustment for the distance between the bird and your microphone, since RL falls off logarithmically with distance from the source.
In order to get actual RLs from a recording, you need to have calibrated (or more properly “characterized”) recording equipment so that you know the scaling relationship between the digital sample values in the audio recording and actual sound pressure at the microphone, measured in micropascals (µPa). There are two approaches commonly used to obtain this calibration info. The first “stepwise” calibration approach relies on knowing the way in which the signal is transformed at three stages: (1) the microphone, which converts pressure variations into voltage variations, (2) the preamplifier, which amplifies the weak electrical signal from the mic, and (3) the digitizer (analog-to-digital converter) which converts the continuous voltage waveform into a series of digital audio samples (typically 16- or 24-bit integers).
The second approach is to treat the entire recording system (mic + preamp + digitizer) as a “black box” and just determine what the scaling relationship is between the audio sample values and the sound pressure (in µPa) at the microphone. Usually this is done by making a recording of one or more calibration signals (usually pure tones) while also measuring the level at the microphone with a sound level meter.
These approaches are summarized in the attached Powerpoint slides.
Beginning in Raven Pro 1.5 (currently in a beta version) you can enter calibration information if you have it available to get true SPL values out from the measurements. Without that calibration info, dB measurements in Raven can be used for making relative comparisons between sounds in the same recording (or in different recordings if they were made with the same equipment and gain settings), but not to infer actual dB SPL.
One caveat to keep in mind is that if you change gain settings during a recording or between recordings, you need to know what the gain setting was at every time, and what this gain setting corresponds to in terms of dB of amplification.
  • asked a question related to Bioacoustics
Question
3 answers
I’m working on an automated frog call detection problem. I’m trying to determine a good way to estimate the number of true negatives within a given sample. The true and false positives, and the false negative are easy, but to perform some of the more sophisticated analyses, one needs a value for the true negatives. True negatives in this context can be defined as the sample space within which the automated classifier could have made an incorrect classification, but did not.
My thought was to sum the time taken up by the true and false positives then add the time taken by the false negatives (determined by multiplying the number of false negatives by the mean time of a true positive). Then subtract that value from the overall time, leaving the time that was “at risk” of incorrect classification. Then divide the remaining time by the mean time of a false negative (with the logic that if it did make a hit, it would have been incorrect) to get the number of true negatives.
The problem with this method is that it does not work when there are lots of calls, frequently the summed time exceeds the recording time, which makes sense. I am going to explore the use of the median, but I was curious if anyone else has gone down this particular path with any degree of success?
Cheers,
Paul
Relevant answer
Answer
Some of the occupancy models that account for both false positives and false negatives might be useful, e.g.
Accounting for false-positive acoustic detections of bats using occupancy models
By:Clement, MJ (Clement, Matthew J.)[ 1 ] ; Rodhouse, TJ (Rodhouse, Thomas J.)[ 2 ] ; Ormsbee, PC (Ormsbee, Patricia C.); Szewczak, JM (Szewczak, Joseph M.)[ 3 ] ; Nichols, JD (Nichols, James D.)[ 1 ]
JOURNAL OF APPLIED ECOLOGY
Volume: 51
Issue: 5
Pages: 1460-1467
DOI: 10.1111/1365-2664.12303
Published: OCT 2014
  • asked a question related to Bioacoustics
Question
4 answers
I am trying to understand signal evolution in terrestrial mammals in an environment such as neotropical beach (south of Brazil, municipality of Florianópolis,Santa Catarina), humid, saline, windy versus a rural more savana like environment. I know the classical studies of Richards and Willey, Aubin and Jouventin, but I could not find any study relating saline or humidity degrees with signal funtional structure. Any possible help? Any comparison made about bird species living in coastal versus savanna environment?    
Relevant answer
Answer
Hi Patricia,
I do not have yet papers to advise you, but I would be interested in following some of your work : I try to link bioacoustic patterns to the medium where they are emitted...
Sincerely,
Hervé glotin http://sabiod.org
  • asked a question related to Bioacoustics
Question
5 answers
And more broadly, are there some good cases of bioacoustic signals being lost where the reason for the loss is well-studied?
Relevant answer
Answer
I think that was caused by the evolution and the habitat selection.
  • asked a question related to Bioacoustics
Question
4 answers
We (some Czech and Slovak ornithologists) use commercial recorders for owl monitoring (in a weatherproof box placed on the tree).
I am looking for other people who use this method or similar. 
Relevant answer
Answer
I’ve never used the Olympus DM 650. I’m using Zoom H4n, to record birds (zebra finch and great tit). I think it’s a similar product. I’m pleased with this recorder. It’s easy to use, good quality and not too expensive.
But when I have to make passive recording in field condition I’m using SongMeter 2 from Wildlife Acoustic. It’s a weatherproof system which can be programed to record for example 2 hours after sunrise each morning. The battery life is really good (several weeks or mouth depending on the program).
Hope this can help.
  • asked a question related to Bioacoustics
Question
7 answers
I’m recording great tit vocalizations around the nest during breeding. Males can use songs, alarm calls or this kind of call that I am not sure to identify (see the attached files).
Relevant answer
Answer
This sounds like a long-range communication call. These are often used while moving fast in the  dense canopy, and when pair or flock members are separated by the distance of 10-15 m at least. 
  • asked a question related to Bioacoustics
Question
8 answers
I am new to the soundscape analysis field. I am looking for a software that would allow me to analyse different metrics, from the basics (amplitude of a certain frequency band) to the advanced such as counting of specific signals (snapping shrimps snaps and fish vocalizations) and diversity indexes. I have limited experience with R and no experience at all with Matlab but I am willing to invest time in it if it is really worth it.
Relevant answer
Answer
Dear Tullio,
There is no magic bullet that will let you detect every type of signal.  For general data exploration, I'd suggest the following software packages:  xbat (Matlab program written by Harold Figueroa from Cornell - nicely done, no longer supported and documentation is supposed to be a bit on the slim side),. Cornell's Raven, Osprey (Matlab program written by Dave Mellinger at Oregon State that has some nice annotation features), or Triton (Matlab program written primarily by Sean Wiggins at Scripps Institution of Oceanography that is designed for very large datasets and has a nice compressed spectrogram function [some of the other packages have this as well]).  There are other packages out there as well.  For detecting calls, it really depends upon your soundscape and the calls you are interested in as to how easy that is to do.  The Teager energy detector was used by Kandia and Stylianou (2006) for detecting odontocete echolocation clicks and should work well for snapping shrimp; we developed it independently and while we never published as Kandia & Stylianou beat us to the punch our description can be seen in some our papers (look at Soldevilla et al. 2008 or Roch et al. 2011).  
I haven't done work on fish calls, but I would expect that for pulsed calls you would want to key in on some aspect of the frequency range and pulse rate. 
If you just want a general signal detector, you could look at the work of Erbe and King (2008), they designed a signal detector that is very easy to implement and can do a pretty nice job.
Best of luck in your research - Marie
Erbe, C., and King, A. R. (2008). "Automatic detection of marine mammals using information entropy," J. Acous. Soc. Am. 124(5), 2833-2840.
Kandia, V., and Stylianou, Y. (2006). "Detection of sperm whale clicks based on the Teager-Kaiser energy operator," Appl. Acous. 67(11-12), 1144-1163.
Roch, M. A., Klinck, H., Baumann-Pickering, S., Mellinger, D. K., Qui, S., Soldevilla, M. S., and Hildebrand, J. A. (2011). "Classification of echolocation clicks from odontocetes in the Southern California Bight," J. Acous. Soc. Am. 129(1), 467-475.
Soldevilla, M. S., Henderson, E. E., Campbell, G. S., Wiggins, S. M., Hildebrand, J. A., and Roch, M. A. (2008). "Classification of Risso's and Pacific white-sided dolphins using spectral properties of echolocation clicks," J. Acous. Soc. Am. 124(1), 609-624.
  • asked a question related to Bioacoustics
Question
10 answers
I am looking for a decibelimeter for bioacoustic research that is not as expensive as a Brüel & Kjær and that has an enough quality. Any tips?
Relevant answer
Answer
If you need sound level meter Class I as B&K but much cheaper, you can try Svantek products on page http://svantek.com/sound-meters-analysers.html. If you need usual FFT analysis SVAN 979 is your option, if you need higher frequncies 977 could be useful and if you need something small 971 is fantastic but with third-octave band analysis only (as I know). Transfer of data into PC is standard so you can use it for any usual data acquisition.
(I am not a reseller of any product :-))
  • asked a question related to Bioacoustics
Question
5 answers
Advertisement call of Pseudopaludicola species.
Relevant answer
Answer
So this way I can only wish You luck in Your further research.
       Best regards
        Chris
  • asked a question related to Bioacoustics
Question
5 answers
I usually deal with outdoor noise propagation (noise impact assessments). I use software like Cadna, Soundplan and Predictor. I'm Interested in bioacoustics (I don't do this for a job) I'd like to know if specific software (free and not) exists to study the noise effects on animals. Sometimes reading noise reports that deal with impacts on animals I noticed that usually a dB(A) is used. Is it correct that a human filter scale can study the noise effects on animals?
Relevant answer
Answer
to evaluate a possible impact of noise on animals the A curve is misleading as it is based on the human hearing sensitivity curve. No weighting, or a weighting tailored on the sensitivity curve of the target species should be used instead. However, I strongly suggest to perform full range 1/3 octave analysis and possibly consider the percentile distribution of energy vs frequencies to have an idea of the possible impacts.
Not only "levels" should be considered; the spectral structure of the noise and its distribution in time (e.g. continuous, intermittent, random, ....) are important as well.
  • asked a question related to Bioacoustics
Question
16 answers
I'm working with sound emission of Netrosoma (Orthoptera) from Mexico, together with Paolo Fontana. We are trying to understand which body parts are involved in sound emission since some spp are without stridulatory file.
Relevant answer
Answer
I agree with Charles Henry about anatomical validation. In our lab we have modified a GoPro action camera (which records at 240 frames per second and fantastic resolution) with macro lenses and have been getting incredible "high speed" video of echolocating bats for a fraction of typical high speed camera costs. Contact me directly if you'd like more information on this setup--all the components are available commercially from various companies.
  • asked a question related to Bioacoustics
Question
10 answers
Biomedical use of ultrasonic acoustic waves usually use frequencies in the MHz or sometimes in the kHz ranges. I am working on a project that requires much lower frequencies, and would like to know the experiences of anybody using instruments currently available to produce these low frequencies.
Relevant answer
Answer
Dear Mr. Schlindwein
1. It was about generation not propagation.
2. Why these subhertz mechanical waves would not propagate in gas or liquids? The initial amplitude is low enough not to generate nonlinear dissipation mechanisms and the speed of sound is the same in a medium, independent of wavelength. It is well known that elephants (and wales, eg: sperm wales) generate (using large resonating cavities) low freg. vibrations that succeed to propagate incredibly far.
Looking at the mechanical waves' propagation eq (source, Wikipedia):
Feynman[2] derives the wave equation that describes the behavior of sound in matter in one dimension (position x) as:
{ \partial^2 p \over \partial x ^2 } - {1 \over c^2} { \partial^2 p \over \partial t ^2 } = 0 ,
there is no apparent reason for these waves not to propagate in fluid media.
  • asked a question related to Bioacoustics
Question
15 answers
I am trying to categorize burst-pulse sounds of dolphins within a data set, and am having trouble figuring out how to determine the pulse repetition rate of a sound. Raven (Cornell software) does not seem to have any instructions on how to do it in their software, but is this something another software can do? Can you count the number of pulses visually? Do I need a code, for example in Matlab? Any help would be greatly appreciated!
Relevant answer
Answer
Hi Christina, I have been working with bottlenose dolphin burst pulsed sounds during the last years and I understand your need to find to define the differences between sounds. The existing literature is vague because burst pulses have been traditionally discussed in terms of their sonic properties and is difficult to measure when calls are classified solely by ear or acoustic features. Terms such as “screeches,” “gulps”, “brays”, "barks", “quacks”, “yelps”, and more… commonly used to describe and distinguish burst pulsed sounds can result in misleading conclusions, as they primarily describe the subjective impressions experienced by human listeners. Additionally, the way the vocalizations are analyzed, and the authors tendency to split or lump, also affects the interpretation of repertoire size. For example, a bray is formed by two different types of burst pulsed sounds however a bark is only one... In one of my studies I have classified the burst pulses based on the duration of the sound (in the oscillogram), in other studies I also measured the Interclick interval or interpulse interval manually (for this I have used a software called soundruler).
As a start, I suggest you to form classes of burst pulsed sounds on the basis of structural characteristics (for example I used the duration), this would lead to more meaningful comparisons between categories.
Good luck!
  • asked a question related to Bioacoustics
Question
6 answers
I m interested on the effects of noise on animals, in particular in studies made in Italy
Relevant answer
Answer
Are you also interested in the studies on the effects of noise on animals, especially frogs in China? May exchange our results with your study.
  • asked a question related to Bioacoustics
Question
2 answers
Humans aren’t the only ones who lose their hearing as they grow older. Scientists report that wild Indo-Pacific humpback dolphins (Sousa chinensis), which can live 40-plus years, also have trouble picking up sounds as they age.
Relevant answer
Answer
As far as bottlenose dolphins go:
The following paper may help answer your question.