Should sonogram IDed bats count?

I realize this may be an unpopular opinion in mammal watching, but I feel like it should be discussed.  What it comes down to for me is you are not experiencing the bat with your senses in any meaningful way.  What you are doing is looking at an output on a screen.  If you’re lucky you might see a shadow fly by.  To me this is not an experience I care about.  If you can hear the call and know it or ID a bat visually in flight, I would count that.

Qualitative ID takes years of experience to be skilled enough to get accurate results on a number of species.  Location and conditions of recording can highly influence call shape making some species appear very different in various situations.  One or two classes is nowhere near enough to be able to trust your results in North America at least.

Acoustics are a great way to study bats, encourage interest in bats, and have an idea what’s around but are an unfulfilling way to pad your life or trip list with species you didn’t actually experience.

That said it’s your life list and  you can set your own rules.  If you love looking at sonograms and IDing bats that’s great.  Enjoy it.  I just think it’s a different thing than actually seeing or hearing a bat.

I look forward to other opinions.

Post author

Curtis Hart


  • CarlosBocos

    Hi Curtis, IMHO, no. I would not say that I have seen a bat because I have seen something on a screen. I like looking for bats very much and I always enjoy the challenge of finding them perched and photographing them and for me, thats all about. I have 380 documented bat sightings in Inaturalist, of 196 species and growing! Cheers

  • MarbledPolecat

    Hi Curtis. I regularly use sonograms (bat detector) to ID bats. I put them down as ‘heard’ on my list if somehow the ID is confirmed – like on my bird life list. But this means I do not count them on my life list. Neither birds or mammals, a ‘heard-only’ is not counted. I can undertsand however if the ID is confirmed (in Europe or US where relativly speaking few species possible) and the bat was spotlighted and confirmed that must be the one heard people would count them. As with the birding world the personal list is personal. So everybody accept species and count them according to his own rules. Of course the debate always comes that lists cannot be compared with each other if they are not based on the same criteria. But that is a totally different matter, when listing gets competitive. For most of us listing is a tool to keep track of sightings and a personal game but rarely a real competition. Cheers J

  • Jon Hall

    Good question Curtis! I agree with Carlos and Janos …. there is a real art to bat detecting and I think it is a fabulous tool and skill set. But I don’t get much satisfaction from simply seeing a bat in flight and IDing using a detector so I would not count a bat like this on my life list. At the very least I need to see something distinctive about the bat to be sure of it ID which is generally impossible in flight for most species. But when it comes to a big mammal day – which is competitive and quite different to a life list – I think there is a place to them.

  • craig9563

    I am a novice mammal watcher (who thoroughly enjoys this website, by the way, and especially the podcast). In my opinion, also a NO. I would also discount a nocturnal camera trap. Neither of those involve direct perception of the critter with one’s senses. I guess the mammal must be “seen” with ones own eyes. If I saw the bat and the sonograph identified it, then I would count it.

  • Charles Foley

    I wouldn’t count a bat I’d only recorded on a sonogram either. If I’d seen the bat well and the sonogram confirmed what it was, then yes. To that point I don’t count any animals that I’ve only heard. I once heard an Owl-faced monkey calling in Rwanda, and all it served to do was frustrate me that I couldn’t actually clap eyes on it. I wonder whether most birders would count a bird if they’d only heard it.

  • JanEbr

    I don’t know where the obsession with eyes as the sole acceptable sense comes from. Yes I know many birders who don’t count “heard only” birds and I always laugh at them, because it doesn’t make any sense. The best supporter of this view in the BirdForum community is one great birder who is almost blind – he even says that he wouldn’t count a “seen only” bird because that’s not the entire sensory experience! I have also no problems with “looking at a screen” – the distinction between “analog and digital”, that is between looking through an optical scope and a digital device is completely arbitrary. I watch most of my animals by taking a photo and looking at the screen afterwards.
    That having said, I think bat ID from sonograms is quite tricky and we do not count sonogram bats in our life list… yet! But I am trying to find the time to study some books and sort through my recordings – and I also have some recordings IDed from Niels, which is as good of an ID technique as there is 🙂 and some pips that are pretty foolproof, so we will probably include that soon.

  • BWKeelan

    Although I disagree with Curtis’ thesis, I do agree with most of the points he and other commenters have raised, particularly regarding the nature of the “experience” of detecting and identifying a bat. I do count bats on my life list that are identified based on sonograms, but I take pains to make the event as cohesive an experience as possible.

    First, I use a detector (Pettersson D240-X) with a built-in heterodyne detector as well as time-expansion. I wear headphones, and when a bat vocalizes, I hear in one ear a real-time frequency-shifted audio (having selected the shift factor myself, beforehand), which I use to manually trigger the time-expansion recording to capture the best segment of the series of calls. Then I hear a frequency-scaled (divided by 10) version of that recording in my other ear, which, by the end of a recording session, I can sometimes identify to species by sound.

    I then immediately (unless delayed by making another recording) examine the audiospectrogram and add my personal ID or at least a temporary classification to the filename. So, typically, I have heard the bat in real time, triggered a recording, listened to the recording, assessed the sonogram, and at least started the identification process in a period of one to two minutes — which I consider a perfectly satisfying mammalian encounter.

    Having spent hundreds of nights recording and countless hours studying echolocation call of bats in the U.S. and Canada — obtaining audiospectrograms of all but 3 species in the region — I believe that I can reliably assess whether a sonagram is diagnostic and if so, correctly identify the species. After the fact, I often double-check my IDs against the best algorithms (which I think are more discerning with pristine recordings in certain species groups), but the identification must be mine to count on my list.

  • Daan Drukker

    Ah I love these discussions. The policy for my list is: heard-onlies count and can be just as amazing as a visual sighting. This is universal for all species I’m interested in: grasshoppers, hyraxes, birds and bats. HOWEVER: I have to actually have heard them with my naked ears. I count a European free-tailed bat that I heard only (and recorded with my bat detector) which I instantly recognised by the low sound it made.

    I also count a bat that I see, but only identify by its ultrasonic recording. This does not have to be a perfect sighting. I put the line at no sighting at all. A bit arbitrary, but this feels right for me.

    So: I do not count ultrosonic-sound-recordings-onlies

  • JimBo

    I very often use Bat detectors for my work but currently identification by these devices is more or less unreliable for several groups of species, Myotis for example. But that will probably change soon, thanks to AI !
    But even if the identification is certain (perfect for a sensus), is it satisfying to twitch a shadow in the darkness ? Not for me.
    The same question can arise with a cetacean identified by acoustics (Sperm Whale, Humpback Whale…) and of which we have only seen a vague silhouette between two waves. Can we twitch ?…..

  • JanEbr

    One thing to consider when setting “rules” like this is that you can be influencing possibly a lot of people – in particular when it comes to mammalwatching, which is still pretty new and we are here basically making it. And the looser you set the rules for what “counts”, the better for the animals themselves. If people aren’t motivated to go to great lengths to “see” the animal, then they will be less disturbance. I have been trying to explain this to birders for years, but there the opinions are already heavily entrenched, but I think for mammalwatchers, there is still chance.

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