The birds will tell you. Watch. Take this one, for example. This strident singer, pausing mid-trill to make the expression that translates loosely to never mind. This upon finding herself in the company of another kind of bird than she expected. The place to which instinct had led her had changed. The other bird is frightened by these strange notes. They belong in an elsewhere that used to be here. Now it may be nowhere. She makes sounds that translate loosely to it’s okay. Once calmed, the frightened bird returns to singing the familiar notes of the region. The now silent stranger waits, nodding, then flies again, wings sighing. It had been so long between landings. The next will be longer.
Now she remembers. There is a way to stay in flight while sleeping. Hold the wings. Let the currents do the work, move only to pivot and slice between them when you must. Decide there is no other place but this flight. Forget wanting to land. Here is the song. She pulls it to her, full and close.