The Long Black Veil; Uncovering the Secret World of Tengmalm's Owl

In this episode, the first sound magazine concerns a selection of recordings if diurnal calls at Hällögern, Sweden. Join me as I share audio recordings of some wonderful species in the far north of Sweden. This audio appetizer serves as a starter, in order to warm your ears for the main course...

The main feature describes my journey uncovering the hidden migration of a rather special species along the Baltic coastline of Northern Sweden. Tengmalm's Owl is a species I dreamed about as a young birder. Over the course of the last few years, sound recording at night, along the coast of Västerbotten in Sweden, has allowed me a precious glimpse into the wonderful world of one of Northern Europe's most iconic species. The journey I have enjoyed with regard to this particular species has been a wonderful personal experience for me. Join me as I talk you through a voyage of birding discovery, from the first spark of personal joy, when a single call rang out through the darkness, to the resulting unravelling of the hidden world of a very special species...

Transcript

  You're all very welcome to wild bird acoustics. I'm your host, Alan Dalton, and I'll be taking you on a journey into sound. 

 Now welcome everybody to another episode here at Wild Bird Acoustics. It's episode 10 of season two, the halfway stage of the second season. We have a wonderful episode for you. We're going to start off up north in Hallegern. In fact, the whole episode is going to be based around Hallegern in Västerbotten in northern Sweden, an absolutely incredible location to record bird sounds.

It's wonderfully quiet. I spent a lot of time there as you'll all know by now, and I have some fantastic Audio to share with you today. 

 Now very quickly, folks, a quick call to action. If you haven't already done so, please take a little bit of time to just rate the podcast at your podcast provider. Just click in a little four or five three star review, whatever you think is appropriate. Also be fantastic if one or two of you dropped a little review on these same providers, it would really help.  And as always folks, if you can just spread the word verbally, if you know somebody who might enjoy the podcast, just let them know about it.  The podcast has been building quite nicely. And I've started to notice that a lot of the first season episodes are getting a bit of listening as well during the season two run.

And that's very, very nice. 

 Now, abrasive sound magazines coming up for you. I'm bringing you up to Vassarbottom in northern Sweden to Hallegern, where I spent an awful lot of time in 2024. Had a wonderful time there a couple of weeks in the summer and another couple of weeks in the autumn and I got some wonderful audio. Now, as many of you'll know, I have a listening station on the island, and I'm now finished actually going through the early morning diurnal audio, the VisMig audio on the island, and I got some lovely files.

Also, during the summer, a few recordings which I've stuck into this first sound magazine. Some lovely audio here, and lots to discuss. Without going into too much detail, I'm going to play that for you now. This is the VisMig files from Hallegern in Northern Sweden.

  Now, welcome everybody to the VisMig Files. We're going to be running through some miscellaneous audio here from October 2023. I got some lovely audio early in the morning and I'm going to run through a few recordings with you now. Now, the first recording I have for you concerns Parrot Crossbill and Fieldfare.

So in this recording, you're going to hear some lovely audio of a large flock of Parrot Crossbill going over the recorder. There's some feel fair checking away some very nice audio of the species very prevalent in the autumn Also here are some hooded crow cawing away in the background. And also some wing beats of golden eye.

So I'll play that for you now. This is part of Crossbill and Field Fair at Hallegern in northern Sweden. 

Now next up is a species that's very, very regular on the islands. Quite often close to the microphones. But I got some particularly nice recordings of the species in October 2023. The species I'm talking about is golden eye. I presume these are female birds very close to the microphone. And in the background here you will hear some missile thrush and some waxwing also moving around.

Now the main call here is quite loud. It's the kind of difficult to describe actually the calls of GoldenEye. They're very, very close to the recorder. We'll have a listen to that now folks. This is GoldenEye at Hallagern. 

Next up we have a very short recording. It's a very nice recording though. Very clear. It's a Chiff Chaff. Just moving through close to the recorder. The typical call of the species in Northern Sweden. And this is a call,  the kind of swio call of chiffchaff here. It's typical of birds actually moving through Northern Sweden.

It's a call I used to hear in Ireland on passage. And chiffchaffs can be quite confusing. They have quite a range of calls. And I suspect in places like the UK and Ireland it's because you get birds from Scandinavia and perhaps further east as well. So. Next up, this is Chiffchaff, very close to the recorder, October 8th, 2023. 

Next up is Missal Thrush, very typical species in October, they move through in good numbers. And in the background here, it's just a very nice autumnal scene, there's a waxwing, redwings and field fairs, just autumn thrush just moving through along the mainland, there's meadow paper going over. Some siskin, hooded crow is always cawing in the background.

And a ticking robin, on the ground, close to the recorder. But listen out for the rattling calls here of Missle's Rush. One of my favorite species in the autumn. Absolutely love this call. We'll give that a listen now. 

Now the next recording is a short recording. The species I'm actually focused on here is half inch. Quite scarce actually in northern Sweden along the coastline. But the majority of birds do go through in October. Now, in the background here, you're going to hear part of crossbill always in the area in October.

They move over in very large numbers. Also here, you will hear an alarming common blackbird. But listen carefully and see if you can pick out the calls of a species we've covered already in the podcast this season. And that is hawfinch, mainly the sea calls of the species, going overhead on the island in mid October 2023.

Have a listen folks. 

Now next up, quite a remarkable recording of what I think I'm pretty sure is a great spot at Woodpecker. Now this board actually got on to my box mount where my microphone was placed and proceeded to kind of give it a good pecking. It's, it's an amazing little recording. You can hear the board approach and it gets on to the box mount.

I keep my SM Mini inside a wooden box with a windshield over it, a 40 windshield. And the bird was obviously very curious and just pecking around the area, just checking the recorder out and it makes for quite a wonderful recording.  So this is a great spot of the woodpecker actually on my microphone or the box mount of my microphone.

Just checking everything out and it's extremely nice to hear these little chuckles and quiet calls as well as the kick call a couple of times in this recording.  I'll give you a listen now to this remarkable close range recording. 

Now fantastic stuff there, I think you'll agree. And wonderful to get such a kind of up close and personal recording. Now the next recording I have for you is a rarity. It's a little bunting. The bird went over on the 9th of October, not long after dawn, and gave a ticking call as it went by. It took me a little while to sort this one out, I was pretty sure what it was when I heard it by ear.

I just went through the motions, checked out the sonogram, and it worked out quite well. It's quite a clear recording. And it represents my first definite little bunting on the island, recorded early in the morning at about 7. 02.  So this is quite a nice recording. It's always nice to get a rarity, especially on the island.

And although I have had a few words on passage whilst I've actually been there, I've never actually nailed a species with 100 percent certainty before. So it was nice to finally get it onto the island list. This is Little Bunting on Halligan. 

Now another short recording for you now, and amongst the autumnal stuff here, like Pardot Crossbill, the call of Lesser Spotted Woodpecker. Now Lesser Spotted Woodpecker is actually very, very scarce on the island. I've recorded a few in the autumn. I suspect if I stayed through October, I would record quite a few more.

Now the species does move through on passage from Finland at that time of the year. It's very nice to get a nice recording of these species calling on the island. This is Lesser Spotted Woodpecker on the 21st of October, 2023. 

Now one of the most regular species in October is Parrot Crossbill and I particularly like the species. I love the autumn calls and it's a species I have absolutely tons of audio of. It's a species I really want to actually build up a nice reference library, if you like, of audio. So I'm going to play a few little excerpts now.

It's quite short recordings in general. Here's a nice one for you, and in the background you're going to hear a goldcrest just moving through the island. Some of the calls, the two calls of reed bunting. Some blue tit in the background. And also if you listen carefully towards the end, there's a waxwing.

But the main subject here is parrot crossbill.  Very, very common, as I say, on Halligarn in October. 

In this recording, there's some part of Crossbill going very, very close to the recorder. It's a lovely bit of audio. There's a little bit of background noise, but it doesn't really annoy me too much. And then it gets a little bit more difficult. There's a few calls that almost remind me of Two Barred Crossbill.

The Red Paul like call. I'm really not sure about this one. And then you hear some really odd calls. And you hear things like this in part of Crossbill quite often. And here it's almost a cricket like or grasshopper like call as a bird just gives some quiet calls from a nearby spruce, I presume, which are quite close to the recorder.

We'll have a listen to the recording now. There's definitely plenty of Parrot Crossbills in here and like I say, I can never be sure sometimes of some of the calls I hear and they remain mysteries, perhaps for a little while before being solved sometimes. Well, I'll play the recording for you now. Have a listen to this. 

One last recording now of Parrot Crossbill.  Not the best recording in the world if I'm quite honest, a little bit more distant this time. But this recording is made by Reed Buntings and the Nasal Calls of the Species. Quite a nice recording. There's some distant raven in here too. And I love these recordings, they just take you back to the autumn so quickly.

And I'll just simply play that for you now. This is a few part of Crossbell passing by, but listen for the nasal calls also of Reed Bunting and the distant calls of Raven. 

Now I'm going to leave you with a species that appears from mid October onwards and that is a waxwing and I absolutely love this call. It's the doorbell call of a waxwing. In this recording you will hear part of Crossbell as always, a few calls of reed bunting, some hooded crow. But listen carefully and it builds quite nicely as the recording goes on.

You will hear the doorbell recordings of a waxwing passing by the recorder. 

So there you go folks, that's a little selection of sounds for you from Vasabotten in northern Sweden in October 2023. I hope you've enjoyed this short sound magazine here at Wild Bird Acoustics. Thanks for listening folks.   

 So there we go, that's a lovely range of recordings from the islands through the summer and the autumn and it's been wonderful to go through that audio. I love going through this kind of passive audio that is actually recorded when I'm not there and you just never know what you're going to get and it's wonderful to come across these little audio scenes  and yeah, sometimes it's difficult to go through it and realise what you've missed if you had of been there only during the autumn, all the way through some of the lovely birds I would have seen and heard. But that's life. And it's been absolutely wonderful all the same to actually have a listening station on the island.

It's been very, very educational. And that brings me on to the main sound magazine of this, the tenth episode of the second season. 

 Now, this main sound magazine from Halligan is something I've had in mind.  I've been collecting audio on the island now for about 10 years. And I've learned an awful lot in the process.

But I think one of the biggest discoveries I made was an incredible passage of Tengmam's Owl. Or Boreal Owl as they're sometimes known in the States.  It's a very iconic species. It's a species I, when I grew up, I was just pouring through the bird books all the time. And Tengmamsel, in fact, all of the Northern Elves were just species that just kind of had a kind of a magical allure.

 You know, when you're a teenager, you just dream of seeing these things. And actually, to grow up to Halligarn on those first couple of autumns and realize that these birds were passing overhead on autumn migration was absolutely absolutely incredible to me. And since then, I've been collecting a lot of audio at the listening station there, and I'm starting to build up a pretty good picture of what is actually going on.

Now, once again, all will be explained in the sound magazine, and I will probably just get straight into it. This is a sound magazine about Tengmam's Owl along the coast of Västerbotten in northern Sweden. The migration patterns and the audio that I've recorded, all will be explained during the sound magazine.

I really hope you enjoyed this as much as I enjoyed actually making and listening to the recordings. It's been quite incredible for me personally. Enjoy this. 

  Now, you're all very welcome to another sound magazine here at Wild Bird Acoustics. And this is a section I've had in mind for quite a long time. And what we're going to be talking about is the occurrence of Tangman's Owl at Hallegern in Västerbotten in Sweden.  Now, growing up as a birder in Ireland, Tangman's Owl was very much a mythical species.

And it was one of those species I pored over in field guides when I was a kid. And I just hoped someday, maybe I might come across the species and that has come to fruition over the last few years, but not in the way perhaps that I would have expected.  Now I have to take you back in time a little bit to explain how all of this came around and it basically involves my first trips to Halligarn.

And initially I started to first visit the island about 12 years ago. And generally speaking, in the beginning, I went up during the summer. 

My first several trips to Halgaran, I was actively birding. I wasn't actively sound recording. But it was quite obvious in the beginning that this was going to be an incredible place to bird watch. And I really enjoyed my first few years on the islands. And I really did hope at some point that I would come across maybe one of the Northern Owls.

But it wasn't until I actually started sound recording that actually I realised exactly what was going on at this very special site.  And it was only in 2019 really, I went up in September for the first time ever, late September. And that autumn was the first I did any kind of knock mig recording on the island.

So what I did was I left my Tlingit prabal out overnight, hoping for things like red wing.  And I really had no idea what to expect. It was quite exciting. I knew this location was extremely far north, and I thought maybe it would throw up a few surprises. And, the very first night I left my Prabhla out, I collected the audio the next morning, and I was just going through it, and there was plenty of redwing and other species going over.

I was quite happy with the results. And halfway through the night, I just got this extraordinary sonogram, and when I played it back, my heart skipped a beat, I was pretty sure it was a Tengmam's Owl. Now, this was a magical moment for me, it was the first time I'd ever recorded this species, and I was thrilled with the recording.

Now, I'll play that recording for you now. As I mentioned, this is the first time I'd ever recorded this species, so I was just thrilled with that. And it was a very distinctive call, and I made a note in my journal at the time about the recording, and the note read,  Possibly migrating over the island. 

The call itself, I'd never quite heard anything like it, and it really fired my imagination. And I still remember the buzz of actually coming across this recording. It's etched in my mind to this very, very day. So I'll play the recording now. This is my first ever recording of Teng Mam's El at Hallegurn in Vastamontan.

Have a listen. 

Now, as I sit here actually recording this section, I'm just over a period where I had some streptococcal throat, and my voice is a little bit husky still. I didn't get rid of it until a few days ago. But it's actually not unlike the call of Tengmam's Owl in some ways. It's quite a husky kind of call. And it was something I'd just never heard before.

And I was quite surprised by it. I'd actually been listening to Tengmam's Owl song recordings. And this, of course, was nothing like that. And this is the call that the birds give when they are on migration or moving around in the autumn. So I was blown away by this and incredibly I got a second recording on the very same night.

And to my great surprise, there was multiple birds in this one. At least two birds. So we'll have a listen to that recording now. So I was over the moon at this stage. I mean, this is my second recording of the species on the very same night. And at the time, I was just blown away by this. So we'll have a quick listen to that.

Now, this is another recording of Tangman's Owl at Hallegern in Sweden in late September 2019. 

So there you go. That was the first night I recorded Tangman's Owl at Hallegern in Västerbotten. And for those of you listening from the United States, Tangman's Owl is also known as Boreal Owl.  And the species is, it's quite a scarce breeder here in Sweden. It's actually probably more plentiful than people actually realize.

And certainly north of Uppsala, say, here in Sweden, the species is pretty common. And if you get out at night in March and April, you will hear singing birds. But nevertheless, for me, this was a new species to record. And I was absolutely delighted.  I wasn't completely surprised by the occurrence of the species in Vastabotten, so far north, it stood to reason that the birds were moving around in autumn at night.

But still, I had this question, are these migrating birds, or are they just local birds? But I had actually spent a lot of time sitting out in the summer, in July and early August, and I had heard nothing to suggest that the birds were breeding on the island, or even normal on the island. Like I said, this is the first time I had recorded them or had any kind of hint of their presence.

So, as time had gone over the next few days, it was a little bit windy, had some fantastic boarding. But over the next couple of nights, there were no more records of Tengmam's El. That is, until the 2nd of October, when I recorded the following. 

Now, over the course of that week, and that was beginning the 26th of September into early October, I recorded at least five Tangman's Owl on the island at night, and for me, this is just an incredible result and I was made up. So the week came to an end and I had to go back to Stockholm, but I had great plans for the next year.

As a result, I wanted maybe to get the sling back out again overnight and see if there was any more birds passing. I also wanted to know if the birds were migrating or if the birds were actually regular and just hanging out on the island in autumn. 

Now that week in late autumn 2019 was the first time I'd spent any kind of a length of time on the island in late autumn. And overall it was an incredible week. There were so many birds overflying day. And I just had an absolutely incredible time birding. I had lots of nice birds like grey headed woodpecker, three toed woodpecker,  some nice migrants and  All the signs were that this location was somewhere I really needed to focus on.

And also, it was kind of a local patch kind of vibe. I really enjoyed my time. There was nobody in the area. Nobody had done any warden there before. And so for me, it was a no brainer to make plans to go back the same week the next year. So in 2020, I made my plans and I couldn't wait to get up there, folks.

And eventually I'll go back up more or less for the same baits the next year. Now, what happened next was quite incredible.  So the next year I eventually arrived, I think it was on the 27th of September. I was alone again for the entire week. And this time I was really well prepared. I got the Talinga out every single night.

And I had some incredible birding once again. And I really enjoyed myself. And being alone, of course, I could just concentrate on birding. And sound recording and over the course of this particular week, it became quite apparent to me that at least some of these birds were in fact migrating straight over the island in the southerly direction. 

So that recording was a single bird and that came on the 28th of September, 2020.  And it was my first night in up making on the island that week. And immediately there were results, and I was absolutely thrilled with this. So I picked up a couple of birds that night and the next night I decided to leave my Tlingit prabal out.

And also on this occasion, I decided to sit out and listen to see exactly what was going on and what I was trying to discern was whether the birds were actually moving purposely south or whether birds were actually sitting on the island.  And what I actually discovered was that birds were moving south over the island and I had a wonderful experience that night as I sat out and just listened to birds just overflowing the water calling as they moved south and it was quite an incredible experience.

I had a small head torch with me and the highlight for me was just picking up a bird in the beam of the torch and it was just flying southeast over the island calling as it went and it was an incredible experience.  Now I actually have a recording of a bird that went over the island that night whilst that was sitting there watching it, and I'll play that for you now.

So once again, this is Tang Mazel moving southeast over the island in the middle of the night, on the 29th of September, 2020. Have a listen to this folks. 

Now, the final results in 2020 were quite fantastic. In the week I was there, I actually recorded 17 birds on passage. In addition to that, I'd actually sat out on three nights. And all of the birds that I heard on those occasions were certainly moving. They were flying low over the island and moving in a south eastly direction.

Pretty much following the coast and they were calling constantly. And on one occasion, I was actually sitting out and I heard a bird calling from the mainland. And as soon as it began to call, almost instantly, a bird that was passing southwards started to reply. And to me this begged the question, what are these birds actually doing?

And I still wasn't completely clear as to whether these birds were actually actively migrating, or whether they were moving around in some sort of capacity along the coast in the autumn.  2020 was quite a difficult year. It was the year of the COVID pandemic and the springtime was very, very tough. And that year I wasn't actually sure whether I would actually get up to the island or not.

And the fact that I actually did so was quite nice. It gave me some time for some peace and quiet and a little bit of reflection.  I have always found that it's one of the great healing properties of being out in the field, having time to think, having time to be yourself and just be at one with nature.

It allows you just to clear your head and get things in order.  And that's why I always think it's a great thing to actually have in your locker, just to be able to be comfortable in your own skin, get out into nature and enjoy the world around you. It really does give you a great power. It's a great tool to deal with the tougher times in life.

And I think this is something that a lot of birders will understand, you know, that kind of escapism that just getting away from stressful life, a busy job, just the general humdrum of life and getting out into the field can just help you straighten out your mind. And in 2021, I made plans to get up to the island once again in the autumn. 

Now that autumn, I decided to go up to the island a little bit earlier, and I just wanted to check place out on slightly different dates to those I had been there. Before. This time my wife came with me and she hadn't been up to the island in autumn in many, many years. And, to be honest, to be up there at that time of the year is quite incredible.

I'd been filling her in on how beautiful the place looked in the fall when all the leaves turned gold. And she joined me for the week and we had the most wonderful time. Boarding was absolutely fantastic and it remains one of the best weeks I've had on the island. The passage migration was absolutely incredible. 

Once again, Tangman's Owl was very much on the menu, and I recorded 13 birds during the course of that week on passage. And once again, I sat out a couple of nights and had birds purposely flying southeast at night.  The birds were also calling from the mainland, and it's a feature I've noticed over the years, that these birds are very, very vocal.

I'm sure some birds are resting on the mainland, and as soon as one calls, quite often it is answered by another.  Now, by this stage, I had no doubt whatsoever that the birds were moving purposefully south. And one of the things I did that autumn was to set up two recorders. And one went on the far side of the island on the northeast side and one right in front of the cabin.

And what that allowed me to do was track individual birds over the island when they did pass. southeasterly direction, generally speaking. Following the coast, as I suspected, and like I say, I recorded 13 birds and got some lovely recordings. I'll play one of those for you now. So this is from the autumn of 2021.

Once again, Tangmamsel passing southeast over the island of Halleck.  Have a listen. 

Finally, in 2022, having recorded these birds over a number of autumns, I wanted to do a more accurate study of this species. I decided to set up a passive recorder, an SM4, on the island, and I wanted to record right through the autumn, just to see exactly how many of these birds were passing. By this stage, I'd been doing a lot of knockmeg, especially at Landsart, and I knew if I set up a recorder over a longer period of time, I would get a very accurate representation of how many birds were actually passing the island through the autumn. 

Again, a clearer picture of what's actually going on on Halligarn, and that's what I decided to do. So 2022 was a seminal year for the species, and it was quite incredible. In all, I recorded 157 birds on migration over the island, and this is an amazing result. Quite simply, in 2022, I went up to the island in late July, stayed until early August, and left a passive recorder running on the island.

I went back to the island in late September, spent the week there as usual, had a wonderful week of boarding, and when I left I replaced the batteries in the recorder, left it running, and it wasn't until the next summer in actual fact I got to actually analyse all of that audio from the previous October.

But the result was an entire autumn of nocturnal audio, and as I say, this led to an incredible total of 157 Teng Mam's Owl. 

Now, these results piqued my curiosity and I began to do a lot of digging around online. I rang a few Swedish boarders and reached out to some ringers about the species. I genuinely knew very little about the species and I needed to learn more and this led me to an amazing discovery of a study that took place in 1999  at a place called Stora Fjellreg.

And that is located about 60 miles away from Halligern. But I'll get to that shortly.  Now, naturally, because I recorded so many birds that autumn, I got some incredible audio, and some of the birds were very, very close to the recorder. I'm going to play one such recording for you now, and this is one of my favorite recordings of these species to date from the location.

Once again, this is Tengmam's Owl, migrating over Halligern in Vasterbotn. 

Now, over the course of that autumn, some of the birds were incredibly close to the SM4. And some of the calls actually got blown out as a result. It's quite difficult, of course, to control this when you're not present, but some of the recordings were quite amazing. I'm going to play another one now. Again, this is Teng Mam's Owl at Fastabotten in Sweden in late September 2022. 

Have a listen to this one. 

So that's a quite incredible bit of audio. A little bit longer than the usual recordings. And it was very nice to get these longer segments of birds being present on the island. And it had occurred to me when I initially thought about this section about migrating Tengmam's Owl, that it might be a little bit boring to actually play a lot of audio of the same species.

But I think when it comes to a species like Tengmam's Owl, it is nevertheless quite interesting. And it's good to document kind of the journey into understanding the migration of these birds over this site. Now, because it's such a rare species overall in Europe, it's quite enigmatic, and I really do hope you are actually enjoying these audio sections.

Once again, it just opens up that hidden world as to what's going on in certain places in the middle of the night. And especially at such a remote location in the far north of Sweden, where nobody's really recorded before.  For me, it was just very, very eye opening and it was something of a voyage of discovery.

And I hope you actually share a little bit of my fascination into this species. It's been really interesting for me just to discover this little passage of Tengmamsel along the coast of Västerbotten in autumn.  I got so much incredible audio that year, and I'm going to play you one more, some birds again, really close to the recorder.

Have a listen to this one. It's quite amazing. 

Now I mentioned previously my discovery of a study of birds that had been ringed at a ringing station called Stortfjellreg. And the location of this ringing station is Hallegirn as crow flies. It's about 60 kilometers. It's an active ringing station. I found this study from 1999 online, and I was quite amazed by the parallels to my own knock make study up until 2022, and I'm going to run through some of those parallels with you now.

So in 1999, from the 1st of September until the 17th of October, the ringing station there decided to tape lure Tangman's Owl in autumn, and the overall result was 143  birds caught and ringed. Now, of the 143 words that were caught in total, 136 were sexed and the results were quite incredible. Most of the birds were female.

So all of these birds were accurately aged and sexed. And I'm going to run through some of the figures with you now. Of the juveniles caught, that is, birds in their first calendar year, 65 percent were female. Of the second calendar year birds, 63 percent were females. And the birds that were aged as third calendar year or older were 57 percent female.

Now, of these birds, four birds were actually controlled. These birds had been ringed previously, and all of them had been ringed in Finland. Only one of them was an adult bird, and the rest were either second or third calendar birds. I thought that was quite illuminating.  Now, further details actually emerge after these birds were ringed in Stora Fjallraeg.

Three were released and controlled again. Two of them were actually controlled in Finland, having been caught in Sweden that autumn. And a further bird was caught further down the coast here in Sweden. So what does all of this mean? I'm actually going to share now with you some of the breeding biology of Tangman's Owl as a species, based on current knowledge.

And what they think actually goes on is as follows. Now it should be mentioned that this study took place in a year when rodent numbers were low. So, rodent numbers cycle over several years, and when this study took place, rodent numbers were very, very low at the location. So in a nutshell, what happens with this species is, males are pretty much sedentary and set up a permanent territory.

They will call in spring to attract females, and areas with high densities of rodents attract females.  So males who are present in areas of high rodent density in any given year will do very well. They will attract a lot of females. And it's thought that the females are actually nomadic, and it looks like these birds actually move over a very large area indeed, involving Finland, Norway, and Sweden.

The females are not particularly sight faithful, and they will choose areas based on prey density, which if you think about it makes a lot of sense. They will go to areas where there is a lot of food, they're going to go to places where they can raise as many young as possible. But males, on current knowledge, think unless prey is very, very low, will actually stay on their territory. 

Now, there's some doubt about the theory, and a number of adult males were actually caught and ringed at Stora Fjallraeg, including, interestingly, one bird that actually bred over 50km away from the site. And this was a 5th calendar male. So, there's a lot of specific information to read into there. And it seems quite likely that when prey is very, very low, even male birds will desert territories and move around looking for food.

But as I say, the general trend of thought is that male Tangman's owls, generally speaking, take up specific territories and they stay on them. Is the females, and later in the year, after breeding has ceased, the juveniles that disperse. And this probably leads to local migration along the coast at sites like Vasterbotten.

And it seems very, very likely that in years where the rodent cycle is at a low and birds are quite hungry, that is when the largest numbers will occur on passage.  So it's all very interesting, I think, and it paints a picture of a population of birds dispersing basically over a broad area. It's also quite incredible to think of some of these birds leaving Finland, being recorded, moving down the coast of Sweden, only to return to Finland at a later date.

And there's obviously a lot to learn about this species. Owls are a particularly difficult species group to study. They're nocturnal. They're quite secretive. And there's a lot to be learned about them. It makes a lot of sense that the numbers are very much controlled by the presence of numbers of rodents.

And when they cycle, and there's a lot of rodents around, perhaps things are better for the birds themselves, and they are more stationary. When food is scarce, obviously, they will move around a lot more, and in some years will move in very large numbers indeed. One thing that is absolutely obvious to me is the value of actually recording birds at night, and the power of audio recording.

It's very hard to actually discount the parallels between the two studies, really. And I think that's quite exciting going forward. And I plan to continue the study on Vasturbutton.  As I sit here and record this for you, I'm actually wondering now what's on my passive recorder from last autumn. And when I return to the island this summer, I will be collecting the results for October  2023.

But the simple answer, of course, is I'll just have to wait until the summer until I get up there and actually download the audio. We'll see what happens. But there's no doubt in the meantime that it's incredibly interesting to record in these places and just see what goes on at night. When I first visited the area and began to actually sound record, I had no idea that any of this was going to happen.

And it's quite incredible to think, actually, the journey I've been on since that very first recording of a nocturnal Teng Mam's Owl. I had no idea, as I say, where it was all going to lead, and here I am several years later. Still trying to uncover the mysteries of Tengmam's Owl on the island. And that's why I thought really I'd put this little section together.

It started at a very simple place when I just opened an audio file and was mesmerized by the sound of a calling Tengmam's Owl. And I was just in awe of the entire sound. And then of course the realization that the words were moving through in numbers in the autumn. And it was just something I wanted to know more about. 

Now, I've already learned a lot about the species on the island, but I'm also very aware there's a lot more to learn and it'll probably take several years of recording to get a clearer picture of exactly what's going on along this section of northern Swedish coast. But in the meantime, it's been wonderful just to share the journey so far.

I hope you have enjoyed just listening to that journey here and some of the audio that I put together for you.  Now before I go, I'll just leave you with one last recording of Tengmamsel. This one from Vasterbotten in 2023. It's one of my favorite recordings to date. It's quite a close recording and such an incredible call.

Have a listen. 

So there you go. That's the final recording on this Wild Bird Acoustics Sound magazine. I do hope you have enjoyed it and I want to thank you all once again for listening to the podcast.  Naturally, there's a lot more to learn here and perhaps we'll revisit this in future episodes. We'll see how things go.

As always, I can't wait to get back to the island this summer, collect the audio and just have a little listen and unravel the secrets of migrating Tengmamsel along the coast of Northern Sweden.  Thanks for listening folks.  

 So there you go. 📍  That's my journey with Teng Mam's Owl today at Hallegern in Vastobotn, Sweden. It's been quite incredible. Now, I think what this has actually opened up to me is the That sound recording has really, really allowed me to determine exactly what's going on at this location.

And I would say the sound recording is an incredible tool for the birder. You may think you know your local patch pretty, very well, but put a recorder out at night and it will open up a whole new world to you.  

 Now there's no doubt in my mind whatsoever. Have I not been using the tools of sound recording, I would not have half an iota of what's going on at this location. And it's extremely valuable as well from a citizen science point of view. I have some incredible statistics now on this species, Tangmanzo passing the coast of Aster Button  the data that I've actually collected so far is actually very, very valuable. And I aim to continue to continue to study and continue recording at night at this location. So we'll see what that brings in the future. And of course, it's not just Time Mammals that are passing the island at night there's a range of other incredible species and who knows what the future will bring.

 So as I say, sound recording is just another string to the birdie's bow. It's extremely useful. It gives you some wonderful insight into what's going on in areas that you think you might know well, but perhaps maybe you don't.  

 For me really birding has always been about a voyage of discovery and sound recording has just opened up more avenues of discovery  and I just love uncovering these kind of intricacies of bird life and what's going on under cover of darkness 

it's real insight, it gives you a lovely kind of picture of what's going on,  hidden world really that's just opened up to you and it's quite incredible 

 Sound recording really does open up new areas and one thing leads to another. It's quite wonderful really, one project leads to another. So, I highly recommend folks you start listening to birds very, very carefully and maybe using some sound recording techniques in your own birding.   Now that's off me, Alan Dalton, here at Wild Bird Acoustics. Hope you have enjoyed the episode. As always, we'll see you next time here at the podcast. 

 So that brings us to the end of another episode of Wild Bird Acoustics, and I hope you've enjoyed it. As always, you can find us on YouTube by simply searching for Wild Bird Acoustics. We do have a mailing list also, and if you want to be part of that, folks, you can drop us an email at wildbirdacoustics at gmail.

com.  Now, all feedback is gratefully received here at the podcast, and if you'd like the right review of the podcast, you can do so at the Buzzsprout header page. In addition, if you'd like to make a small financial donation to the podcast, you can do so using the buy me a coffee button, and you'll find that also on the Buzzsprout header page. 

We'll be back in a couple of weeks with more from Wild Bird Acoustics. Until then, take it easy folks. And as always, don't be afraid to get out into the field and relax and just listen to the wildlife out there. Maybe even do a little bit of field recording of your own.  We'll talk to you soon folks. Take it easy.

That's all from Wild Bird Acoustics.