How to record bird song

1. Get closer before you do anything else

This is the whole guide in one line. A phone microphone is small, omnidirectional, and designed for a face about a foot away. Every meter you close is worth more than any setting, app or accessory.

Move slowly, stop when the bird stops, and use cover. Halving the distance roughly quadruples the sound energy reaching the microphone — often the difference between a Low-confidence guess and a High-confidence answer. If you cannot get closer without flushing the bird, stay put and record anyway: a distant clip you actually have beats a close one you scared off.

2. Know where your microphone is, and point it in the right direction

Most phones have several microphones, and the one used for recording is usually at the bottom edge near the charging port. Find yours — record yourself tapping gently near each one and see which is loudest — then aim that edge at the bird rather than holding the phone flat like a camera.

• Keep fingers, cases and lanyards clear of the microphone port.
• Cupping your free hand behind the phone makes a crude reflector and genuinely helps.
• If you are filming for the audio, remember the camera and the microphone are not pointing the same way.

3. Wind is the number one killer

Air moving across a bare microphone produces a low-frequency roar that sits right on top of the frequencies you need. It is not background noise to be filtered out afterwards — it is loud enough to saturate the recording entirely.

• Put something solid between the wind and the phone: a hedge, a wall, a tree trunk, the lee side of a building.
• Turn your body into the windbreak. Stand with your back to the wind and record in the pocket of still air in front of you.
• A sock, a fleece cuff, or a scrap of soft fabric loosely over the microphone end is a serviceable improvised windshield. Loose and fluffy is the goal — pressed tight against the port it muffles the bird too.
• On a genuinely windy day, move to shelter and accept a more distant bird. Sheltered and far usually beats exposed and close.

BirdAmp does fight wind on your behalf, at both ends of the process. Before a clip is identified it goes through a 100Hz high-pass filter, which removes most of the rumble from wind and traffic while leaving bird song — almost all of it above 500Hz — untouched. Then, when you boost a detection, the separator resynthesises that one species and everything it did not recognise as that bird, wind included, is routed to the background channel. The background fader is what you turn down to push the wind back.

That is recovery, not immunity. Filtering removes rumble that sits underneath the bird; it cannot invent a bird that the wind has already buried. If the gust and the song arrive at the microphone together and the gust wins, there is nothing left in the file to separate.

4. Ten to thirty seconds beats three minutes

A short clip in which the bird sings clearly two or three times is far more useful than a long one where it sings once at the start and a dog barks for the rest. The model works in short windows and corroborates across them, so what it wants is several clean repetitions, not duration.

If the bird is singing steadily, twenty seconds is ample. If it calls only occasionally, keep recording through the gaps and trim afterwards — but do not submit five minutes of silence with one call buried in it.

5. Stop moving, and stop narrating

Handling noise is the mistake people are least aware of making. Fingers sliding on the case, a coat sleeve brushing the phone, footsteps on gravel — all of it is far closer to the microphone than the bird is, and all of it lands squarely in the recording.

• Get into position, then hold still. Brace your elbows against your body rather than holding the phone at arm’s length.
• Do not whisper the species name into the clip. Human speech is loud, broadband, and sits right where the model is listening. Note it down afterwards instead.
• Wait two or three seconds after pressing record before the bird sings, and leave a moment at the end. Trimming is easy; recovering a clipped first note is not.
• Rustling rain gear are worse than they sound. If you can, still your jacket with your free hand.

6. Traffic, aircraft and rain

Not all noise is equally damaging. Steady, low-frequency noise — distant traffic, a generator, a highway a mile off — is largely below the frequencies most songbirds use, and the model copes with it better than you would expect. It is worth recording through.

Broadband noise is the problem. An aircraft passing overhead, heavy rain, a river in flood or a strong wind through dry leaves spreads energy across the whole spectrum and buries the bird. With an aircraft, simply wait: thirty seconds of patience gets you a far better clip. With rain, find cover — recording from inside a porch or a car with the window down works well.

7. Go out at the right time

The first two hours after dawn are the best of the day, and not only because birds sing more. The air is usually still, traffic is thin, and sound carries further in the cool, stable air just after sunrise. The same species that is a Low-confidence smear at four in the afternoon is a High-confidence answer at six in the morning.

• Spring, through the breeding season, is when song is most frequent and most complete.
• Still, overcast mornings are better than bright windy ones.
• Late evening is a decent second best, particularly for owls, waders and roosting flocks.
• Outside the breeding season birds still call, even if they do not sing — short contact calls are harder, but perfectly identifiable from a close, clean recording.

8. Phone-specific notes

Recording live in BirdAmp handles the settings for you. If you are using another app and uploading the file afterwards, a few things are worth knowing.

• On iPhone, Voice Memos applies noise reduction intended for speech, which can chew up quiet high-frequency song. Turning off the enhancement option, where your version offers it, gives the model more to work with.
• On Android, recorder apps vary enormously. Prefer one that saves uncompressed audio or a high-bitrate format, and avoid anything advertising voice isolation or automatic noise suppression.
• Automatic gain control is a mixed blessing. It lifts a quiet bird, but it also lifts the noise floor between phrases. There is nothing to be done about it on most phones — just be aware that a hissy, pumping recording is the phone, not the bird.
• Video is a perfectly good source. The audio track from a clip you filmed can be uploaded and analyzed like any other recording.

9. What to upload

BirdAmp accepts the common audio formats a phone or recorder produces — WAV, MP3, M4A, AAC, FLAC, OGG — as well as the audio from a video file. Uncompressed WAV or FLAC preserves the most detail, but a good M4A from a phone is entirely serviceable.

• Do not re-encode a compressed file to a different compressed format. Each pass discards more of the quiet, high-frequency detail that identification depends on.
• Avoid messaging apps as a transfer route. Most heavily compress audio and some resample it down to speech quality. Use a file transfer, a cloud folder, or a cable.
• If you trim a long recording, keep a couple of seconds either side of the song rather than cutting tight to the first and last note.

The quick checklist

When there is a bird singing and no time to think:

• Get closer.
• Point the bottom edge of the phone at the bird.
• Put your back to the wind, or find shelter.
• Press record, then hold still and stay quiet.
• Give it twenty seconds and two or three clear repetitions.
• Play back a moment to check it is the bird you can hear, not rumble.

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