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§ B · Bladerdak
Acoustics · north/south

Bladerdak listens to
what happens up high.

The microphones sit in the attic, pointing out from under the gutters towards the north and the south. From here we hear the treetops, the cranes passing over, the woodpeckers tapping out their territory. Since January we also know from which direction each bird is singing.

About the confidence score

An algorithm is no ornithologist

Every detection comes with a confidence score. 92% chance it's a blackbird, 23% chance it's a noctule. The number looks scientific, but it remains a model's guess. Often very good. Sometimes completely off.

A few from this garden. A bicycle bell once became a bullfinch. A bouncing ball down the street, an eider. One pipistrelle sounds almost identical to another, as far as BatDetect2 is concerned. The algorithm misfires there regularly, even at 95%. Rare species are extra suspect. The model has seen fewer of them, so a detection like that stands on shaky ground.

I check the less common and rare species myself. For each detection I play the recording back and see if it holds up. But that leaves me running behind sometimes. I might only get to it days later, and until then a doubtful case just sits on the site.

So those numbers are a hint, not an identification. An algorithm that listens day and night hears more than I ever could on my own, and that's already something.

Latest detection
Eurasian coot heading south? 89%
★ Hoogtepunthelderste opname die hier is geregistreerd

Staartmees

26 nov · 10:50 · 100%

↗ permalink
§ B-02 · Live on the roof From the microphones in the attic, aimed at the treetops

Just in.

Every detection from BirdNET-Pi Bladerdak appears here right away. A pause in the stream means no activity, not that the pipeline has stopped.

connecting
  1. Listening.

    No detections since you opened this page. A quiet stretch means nothing was heard, not that the pipeline is down.

§ B-03 · Today in view What we have heard so far

The day so far

grouped by species
  1. Eurasian coot 26× until 00:30 · south?
  2. Common moorhen 1× · centre
§ B-04 · What are we actually hearing Vocalisation types, top 10

Birds do not just sing. They call, they alarm and they keep in contact.

Our own CNN models decide, per detection, whether it is song, call, alarm or something else. Tally of the last seven days, for the top 10 most-heard species.

Species song call alarm other
Common swift 8,603 5,440 8 2,687
Common blackbird 3,358 1,572 662 2,262
Common wood pigeon 492 1,062 124 297
Western jackdaw 560 491 76 264
Eurasian blue tit 62 944 68 277
Great tit 781 238 47 174
Eurasian magpie 269 113 342 98
Common chaffinch 285 139 149 150
European robin 162 58 121 93
Eurasian collared dove 8 323 4 44

Song = territorial (song/subsong/display song). Call = communication (call/begging/flight call/nocturnal migration call). Alarm = predator spotted. Other = raw drumming, or not classified by the model.

§ B-05 · Listening Top 3 per species, top 9 on confidence

Highlights, automatically selected.

Every night a script makes a fresh selection: the three clearest recordings per species from the past year. No quality curation, only statistics. Confidence above 85 per cent.

  • Staartmees

    Aegithalos caudatus
    • 01 26 nov 25 · 10:50 100%
      vluchtroep ↗ link
    • 02 26 nov 25 · 10:50 100%
      vluchtroep ↗ link
    • 03 11 jan 26 · 13:20 100%
      zang ↗ link
  • Kolgans

    Anser albifrons
    • 01 20 jan 26 · 22:17 100%
      vluchtroep ↗ link
    • 02 19 jan 26 · 11:10 100%
      nachttrekroep ↗ link
    • 03 22 jan 26 · 23:10 100%
      nachttrekroep ↗ link
  • Pimpelmees

    Cyanistes caeruleus
    • 01 11 apr 26 · 08:28 100%
      bedelroep ↗ link
    • 02 1 apr 26 · 08:11 100%
      bedelroep ↗ link
    • 03 2 apr 26 · 08:14 100%
      alarm ↗ link
  • Ekster

    Pica pica
    • 01 20 jan 26 · 11:40 100%
      alarm ↗ link
    • 02 4 jan 26 · 09:59 100%
      vluchtroep ↗ link
    • 03 5 jan 26 · 08:53 100%
      alarm ↗ link
  • Groenling

    Chloris chloris
    • 01 15 mei 26 · 10:13 100%
      vluchtroep ↗ link
    • 02 22 jan 26 · 11:02 100%
      alarm ↗ link
    • 03 22 jan 26 · 11:02 100%
      alarm ↗ link
  • Waterhoen

    Gallinula chloropus
    • 01 1 mrt 26 · 06:21 100%
      bedelroep ↗ link
    • 02 1 mrt 26 · 06:21 100%
      vluchtroep ↗ link
    • 03 20 apr 26 · 03:27 100%
      nachttrekroep ↗ link
  • Roodborst

    Erithacus rubecula
    • 01 17 jan 26 · 09:09 100%
      zang ↗ link
    • 02 22 mrt 26 · 20:02 100%
      alarm ↗ link
    • 03 21 dec 25 · 11:18 100%
      alarm ↗ link
  • Houtduif

    Columba palumbus
    • 01 15 jan 26 · 11:25 100%
      subzang ↗ link
    • 02 18 jan 26 · 15:37 100%
      roep ↗ link
    • 03 18 jan 26 · 15:46 100%
      subzang ↗ link
  • Kauw

    Corvus monedula
    • 01 23 jan 26 · 08:03 100%
      zang ↗ link
    • 02 16 jan 26 · 09:41 100%
      bedelroep ↗ link
    • 03 2 mei 26 · 10:16 99%
      zang ↗ link

9 soorten · 27 fragmenten getoond · nog 95 soorten in het archief. Selectie gemaakt op 1 jun 26.

Alle soorten bekijken →
§ B-06 · Highlights · all time Hand-picked, with personal context

The classics.

Rarities, one-off passers-by, and moments I do not want to forget. Each one fished out of the archive by hand.

  • testkeep

    Brambling

    test

    vluchtroep 87% ↗ link
  • Common blackbird

    Blaffende hond en Merelzang

    alarm 75% ↗ link
§ B-07 · Today versus normal What stands out?
  • Today 2 different species, with a total of 27 detections.
  • Peak today around 00:00 (27 detections). The average over the last thirty days peaks around 08:00.
  • Today fewer detections than the average over the last thirty days (-99%).
Detections per hour 0–23 h
today 30-day average
§ B-08 · Under the hood How Bladerdak is built

Bladerdak runs on a Raspberry Pi 5 in the attic. Two microphones hang under the gutters, plugged into a Steinberg UR22mkII audio interface. One points north, one points south. BirdNET-Pi analyses the audio every three seconds. A second layer (197 of our own CNN models) decides whether it is song, call or alarm. From the difference in loudness between the two channels we know whether the bird is north or south of the house.