Record — capture the call without breaking the scene.

The minimum viable rig

A directional shotgun microphone, a portable recorder, and a phone running a timestamped behavior log. Anything beyond that is optimization. Anything less and you start losing data you can't recover.

• Mic: Sennheiser ME66/MKE600-class shotgun or a Røde NTG-2. Foam + furry windscreen. Off-axis rejection matters more than absolute sensitivity.
• Recorder: Zoom H1n or H5 at 48 kHz / 24-bit, mono, lossless WAV. Phone-only is acceptable but a real recorder gives you preamp headroom and accurate clock.
• Behavior log: phone app that timestamps events. Keep it boring: who, where, what behavior, who-with.
• Sync: at session start, clap once near the mic with the phone visible. You'll align audio and log at stage 6 by that clap.

Sample rate, bit depth, channels

48 kHz / 24-bit, mono. Crow energy lives 200 Hz – 8 kHz; 48 kHz captures everything with comfortable headroom for any downstream filter. 24-bit preserves quiet calls without quantization noise eating the spectral grain. Mono is the right choice — stereo doubles your file size for no per-clip benefit, and most models embed mono anyway.

The behavior log schema

Keep it append-only and structured. CSV or JSONL. Each row is a timestamped observation:

time         crow_id   behavior          partner   notes
13:42:01.4   AC-04     territorial-caw   --        from cottonwood, faces east
13:42:08.2   AC-04     mobbing-attempt   AC-04+    pair joined, target redtail
13:42:36.7   AC-07     food-discovery    --        new bird, lower branch
13:43:02.0   AC-04     companion-call    AC-04     contact w/ mate
13:43:18.9   --        rain-onset        --        recording cut short

Use stable crow IDs (banded if possible, descriptor like "left-eye-mark" otherwise). Resist the urge to interpret in the log — "long-caw, head-low, tail-flicked" is data; "agitated" is interpretation that belongs in analysis.

Synchronization in practice

The classic clap-sync works because it puts an audible transient on the audio track and a timestamped event in the log at the same instant. At stage 6 you'll subtract the clap time from the recorder timestamp to compute the offset; everything before the clap is unusable, everything after is aligned to ±50 ms.

For longer sessions, clap every 20 minutes. Recorder clocks drift; logs drift too. Multiple clap-sync points let you correct for both.