Not sure what device your are referring to - the IPod Touch seems to be no longer updated, with the last model brought out in 2019… and to be honest 4G does not sound like the latest….
Basically most phones can record OK, and devices like the Birdmic create a neat way to use a phone with a small parabolic dish. Importantly, the interface allows for simultaneous headphone monitoring and recording, which you cannot do with a lot of smaller phone mics.
The problem with most mics, is performance - the small directional mics that plug into the USB-C socket are generally poor - perhaps a bit of reduction in off-axis sound, but no or very little improvement in sensitivity compared to the in-built mics, so not great for faint or distant sounds. And most products of this type don’t even say what the spec is, so you need to purchase on faith or others advice.
Bulkier vlogging mics can be OK, but you need a way to carry the mic and phone. I have an MKE400 which works well, but I use it with a tiny 32 bit record, with the mic and recorder attached to a pistol grip. Some vlogging kits include a clamp (for the phone) and mini-tripod that doubles as a pistol grip, which kind of achieves the same thing.
Unfortunately I don’t think any phones do 32bit float recording, which is much simpler to use and you can get away without monitoring the recording or levels. This would be nice as it would make the kits more ‘point and record’, but I doubt this will come anytime soon to phones, as I understand it requires a complete change in the architecture of the recording system - and for phones sound recording is not the prime feature, particularly as 32bit float can be a drain on battery life.
… but depending on what it is, you may get a passable recording just using a phone. Particularly is you can place the phone relatively close to the bird and leave it recording.
