[ahazred8ta]

TLDR - the pigeon problem coincided with high-decibel infrasound from sonic booms from the Concorde SST. That suggests they were temporarily deafened in that frequency band. (At 11 octaves below middle C, they're sensitive to anything over 0.1 Hertz.)

[Dylan16807]

Is it actually possible to be specifically deafened at such a low frequency? There's no resonance down there, and it would be so much lower energy. I would expect all other hearing to be severely and possibly permanently impacted before infrasound could be deafened.