EXIF metadata

Every photograph your phone takes carries a block of metadata alongside the pixels. For bird identification the useful fields are the timestamp and the location, because together they rule out a great many species before the model has looked at a single feather.

Keep it where you can. Screenshotting a photo, sending it through some messaging apps, or exporting with location stripped will throw the metadata away, and the identification gets harder as a result. If you share photographs publicly and would rather not publish your home coordinates, strip location on the copy you share rather than on the original.