I've heard this before and I'm still confused as to an explanation behind something fundamental to localization (how do we know what direction a sound is coming

I've heard this before and I'm still confused as to an explanation behind something fundamental to localization (how do we know what direction a sound is coming from?) Humans are quite bad at localizing sound, and it gets worse with lower frequency. But the mechanism is pretty well understood - at a high level, we can only perceive the direction of sound based on the differences measured between our two ears and our brains interpolate direction based on those differences (there's a long discussion of what those differences are and how the geometry of the head and ears affect it, but it doesn't matter). And it makes sense why it's harder for humans to perceive direction at lower frequencies. If the wavelength is much greater than the distance between our ears then the variation in frequency/phase will be as well. Additionally, the shape of our ears will reflect sound waves differently based on their angle of incidence, but lower frequency sound doesn't reflect off the pinnae - it bends around the head. And at very low frequencies that bending is imperceptible due to the same reason. So the thing that comes to mind with birds is: how can they localize infrasound with tiny heads? The best explanation I've heard is that as they fly they can sense the change in the infrasound over the area they travel, but that seems really hard to verify experimentally. What's interesting is that we know human localization isn't time invariant (it's not just based on the sound as it hits your head, but also your head movements in context which can improve localization compared to just keeping still). So it's not implausible that birds do something similar, but it seems to be on much longer time scales. The other thing to reckon with is we know in humans that sound localization isn't an isolated sense - our brains interpolate direction using all of our senses, including sight (you can localize a sound better by looking at what makes it, or remembering that there was something nearby that could make a sound). Birds can see much better than humans, they can sense EMF, so if they can hear infrasound then we can reason that their brains are interpolating direction based on more than just the sound wave and using it as another input to the system. It's altogether fascinating. And don't even get people started on acoustic conservation, because we barely consider how the noise we make affects the environment around us.