MARCH 8th 2008 - LYNX !

I recently visited one of my regular sites in the Jura about 3 km NW of Arzier. I had last been there on 17th Feb and recorded a Pygmy Owl (Glaucidium passerinum) which I was hoping to get a better recording of. On that same day I had also recorded a pair of foxes and a Roe deer alarm call. I call this place "Les Frasses Valley" after a nearby farm.

On March 8th between 0630h and 0900h I walked slowly to the head of the valley recording various sounds, I then sat quietly for a while, no other people were around. With no sound of my owl I decided to give up, as I was descending the valley back to Arzier I suddenly heard a loud "scream" which came from within the forest to the east of me. I was walking along the edge of the forest, about 10m clear of the trees in the pasture, the call came from within the forest and my guess is that it was about 200m away from me. I was able to get about 58 secs of sound before it stopped calling:

[NOTE: This recording has been edited and frequencies below 600Kz suppressed slightly to reduce the interference from a nearby aircraft. The frequency of the call and the rhythm of calling are as recorded in the field.]

A sonogram of 4 calls is shown below:


FIGURE 1: Sonogram of 4 calls of European Lynx (Lynx lynx), horizontal axis time in secs, vertical axis Khz. The call starts at about 900Hz rising to a peak of about 1.6 Khz before tailing off back down to about 800 Hz. The dark "trails" after each call are the echo within the forest. Each calls lasts for about 0.5 sec and is repeated at about 2 sec intervals.

The call did not match any of the sounds I am familiar with. It was powerful, not a gentle call, as can be judged from the echo. The timbre made me think it was mammalian rather than avian, if it were the latter only a large owl would be likely.

However earlier in the morning I had seen fresh tracks in the snow about 1 km south of the recording site which I felt at the time may certainly have been a Lynx. The tracks were rounded like a cat, four toes and a pad clearly visible, longish stride (close to a metre ?), at least 3 times the size of nearby fox tracks. The tracks approached a bank where the animal had clearly sat back and leapt about 2m forwards and 1.5 m vertically before landing and walking into the forest. No human tracks nearby so I ruled out a dog-walker.

It was only after returning home and listening carefully to the recording and searching the for reference material that I linked together the tracks and the call and wondered if I had indeed been able to record a Lynx.

Subsequent to this story, with the assistance of Prof Urs Breitenmoser, a lynx expert of more than 30 years standing at the University of Bern, I have now been able to confirm that this is indeed the call of a Lynx.

[NOTE: Recordings were made with a Telinga Pro 5 microphone in a hand held parabola, recorded on a Fostex FR2LE digital recorder].


There was about 30cm of old frozen snow in the woods above Arzier, air temperature was about -2 deg C with a clear blue sky and glorious sunshine. Spring was in the air, very invigorating weather and with a firm footing good to be out.

I had been following a small flock of Crossbills (Loxia curvirostra) steadily uphill for about 20mins when I emerged into the small valley through which runs the path to Les Frasses. The valley is about 100 m wide and 1 km long, and at 1100m above sea level more or less at the limit of decidouous trees. The valley bottom is used for summer grazing so deviod of woody vegetation but with the largely coniferous forest rising on either side quite steeply.

Standing quietly at the edge of the woods I could hear activity on the frozen snow further up the valley. Scanning carefully, about 200m away were two foxes playing around. One ran towards me with raised tail and arched back, being chased by the other - clearly some early spring randy behaviour going on here. I watched them in silence for a while and they disappeared into the woods on the eastern side of the valley. As I turned back to my Crossbills which were still calling further up and to my right, I heard one of the foxes begin to bark about 100m away and was able to get a short recording:

It was a busy morning at Geneva airport (about 35km away) with lots of aircraft rumble so unfortunately I had to suppress frequencies below 500Hz quite heavily in post-editing. But nonetheless I was very happy with my first recording of this animal which actually is reasonably common in my neighbourhood.

However back to the Crossbills, and I climbed up through the woods on the north and eastern side of the valley towards where I could hear their "excitement" calls coming from the tree-tops. After about 10 mins hiking through the trees I stopped to listen and realised that the foxes, probably aware of my presence had done the opposite, and were working their way up the western side of the valley, and were now at about the same elevation as myself and maybe 300m away across the divide. With one of them yapping away at intervals, I tried to get a secure footing in the icey underbrush and began recording, as I did, I became aware of a "pooping" noise away to the north (my right) which I later leasrned came from a Pygmy Owl (Glaucidium passerinum). I had never heard one before and presumed it had been disturbed by the noise of the foxes (later learning they do call in the day time). So after getting a few fox calls I turned the parabola towards the owl realising it was some way off deeper in the forest. Meanwhile the Crossbills were still chattering above my head somewhere.

Turning back to the foxes I then discovered that a Roe Deer (Capreolus capreolus) had now wandered between us and began to bark an alarm at me in irritation, before running off south through the forest. This new interloper had the effect of silencing the Pygmy Owl, but the Foxes and Crossbills each continued with their business.

I was lucky in being able to capture this whole event, and four sequences from the longer recording follow, each related to the above story. As before I suppressed frequencies below 500Hz to reduce the aircraft rumble, with the exception of the third sequence when the Roe Deer was barking where I felt filtering took too much out of the sound of the deer

There are small handling noises occasionally in this piece, caused by my discomfort on a steep, icey and rather unstable surface. But for a February morning I felt priviliged to have had such encounters.

And the Crossbills ? They chattered away in the tree tops quite unconcerned by the activity below, more focussed on getting their own breeding activities underway:

So I felt this was quite a satisfactory time for a cold Sunday in February.

Tech Notes: all recordings with a Telinga Pro5 and hand-held parabola into a Fostex FR2LE. Editing done with Adobe Audition. Photos thanks to Wikipedia.


A new machine to hit the market in recent months has been the Sony PCM M10 this has attracted a huge amount of attention as it is a smaller, cheaper, lighter version of its big brother the Sony D50 but with similar performance at a price most of us prefer. Along with the Olympus LS10 (and now LS11) these three seem to be the best of the small pocket-sized recorders which allow linear PCM recording up to 96 kHz/ 24 bit levels from both built-in or external PIP-powered mics.

I was lucky enough to be travelling in Asia and found the Sony M10 in Singapore at a price much lower than it can be found in Europe. There are many reviews that have been made elsewhere by those with much more technical expertise than I, so I will not attempt go through everything here - this is more for posting some field trials with the built-in mic.

I have found the machine extremely easy to use, can be held like a mobile phone and has a great very clear menu. With 4 GB of built-in memory, and the 16 GB card I bought it will give about 16 hours of recording time at 44.1kHz/24bit which is my normal level, at this the two AA batteries are supposed to last 41 hours which is quite extraordinary.

The built-in mics are reputed to be amongst the best of these small recorders and so the whole thing presents a small autonomous unit which can be left running in a target location. My purpose was exactly that and so have been experimenting with unattended and in some cases overnight recordings:

Palm Swifts (Cypsiurus balasiensis)

Impatient to try it out on my travels I discovered a small colony of Asian Palm Swifts nesting in a Chinese Fan Palm in the garden of my hotel. These are great little birds that fascinate me and which I once studied, they build their nests out of wind-dispersed seeds ("fluff") which are glued in the fold of the palm frond with their saliva, here they incubate the eggs by perching vertically on the nest. The birds were flying around the garden and coming in to their nest calling to each other. I set up the recorder below the tree just after dawn - propped up in my running shoe with the two mics pointed up to the leaf, then retired a good distance to drink tea and watch that no-one pinched the machine !

The first sample is of three cuts with action sequences, no filtering has been applied just a conversion to mp3 format. There is lots of man-made noise as this was close to the hotel and the sea - so air conditioners and boat engines all rumble away:

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The birds are tiny - they weigh only about 9g and so their call is not that strong and of high frequency - with a fundamental between 3-4 kHz and harmonics beyond 14kHz (where my ears no longer work !!) - the sonogram is taken from this recording and in my view the M10 did a great job of picking up the sound.

This next sample is exactly as above but with equalisation applied below 1kHz to take out those horrible rumbles - you can better appreciate what the machine does at that frequency and what great little birds these are:

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Nocturnal Birds

Back at base I have been experimenting with the machine unattended in the forest to pick up nocturnal sounds. This is a bit worrisome as we have a pretty good choice of biting, chewing, stealing nocturnal carnivores that could have fun with my new toy. I bought a small cage-type mouse trap and put the recorder in there strapped to a tree - I assumed that if it kept things in then it would likewise keep 'em out ! I have not yet worked out how to protect it from the elements and still let sound in though....

With the above battery / memory life I can easily leave the machine in place at 2000h and recover it the next morning at 0700 before going to work. The machine has worked perfectly, having now done this for about 6 test nights. When a file reaches 2 GB it automatically closes and opens a new one with seemingly no interruption (or none that has bothered me anyway), this is just over 2 hours recording so I have about 5 very large files to examine the next day (a problem in itself actually). All sorts of weird nocturnal events happen, some of which I can only guess at !

The site where these samples come from is at about 1300m altitude in the Jura mountains. It is 5km in a straight line from the nearest rural public road and 10km from the highway in the valley, aircraft rumble is a perpetual problem. In the full flow of a dawn chorus the machine sounds really great (to my ears anyway) - in the following the cow bells are about 1km away and you can also hear a milking machine generator from a mountain farm about 2kms distant, no filtering was applied, about 0600h:

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However in the quietest of moments the self-noise of the internal mics is clear, here is a sequence (no filtering) on a calm night which is just the forest background at about 0400h:

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Once some action happens then the noise is less evident, here is another unfiltered sequence just as darkness falls, the last day singers are running out of steam and a Woodcock (Scolopax rusticola) flies over making his "roding" display calls:

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Louder action of course is even better. Here is one of my target species - Tengmalm's Owl (= Boreal Owl) (Aegolius funereus) which performed quite nicely close by, this piece does have some low frequency equalisation applied as of course "sod's law" dictated that just as it called well an aircraft was passing !

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So that is where I have got to. I am delighted with the machine - a great take-with-you-anywhere device (that incidentally also has a 5 sec buffer in it as well). But for the quietest of locations would need some better external mics. It does supply PIP and can drive those kind of mics, if I got some I could then put the machine in a water-tight case and run cables out of it.....but how to keep the mics weather and animal-proof for a night in the forest ? Next challenge I suppose.......

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