I looked in my heart while the wild swans went over.
And what did I see I had not seen before?
Only a question less or a question more;
Nothing to match the flight of wild birds flying.
Tiresome heart, forever living and dying,
House without air, I leave you and lock your door.
Wild swans, come over the town, come over
The town again, trailing your legs and crying!
The poet, significantly, refers to a ‘house’ rather than a ‘home’. Usually, associated with safety and comfort, for the speaker the house is metaphorically ‘without air’, therefore mentally constricting.  Also, we lock doors for security and protection, but she is doing so to keep herself out, to liberate herself.
Wild Swans