"Corsons Inlet"

In "Corsons Inlet" on line 93 you can find the word "field" marked with quotations.  Ammons shares his interest in nature throughout the poem and in this particular section of the poem he is describing tree swallows as they begin to take flight for migration.  He writes:

"the news to my left over the dunes and reeds and bayberry clumps was fall: thousands of tree swallows gathering for flight: an order held in constant change: a congregation rich with entropy: nevertheless, separable, noticeable as one event, flight from winter, cheet, cheet, cheet, cheet, wings rifling the green clumps, beaks at the bay berries a perception full of wind, flight, curve, sound: the possibility of rule as the sum of rulelessness: the "field" in action with moving, incalculable center. 

My idea for the reasoning for why Ammons quoted the word field is because I think Ammons in his vision while writing this he seen a great majority of the tree swallows gathering in the field preparing for the flight of migration and noticed the birds as they move around the fields as if the field its self was moving about.  I have noticed myself when birds in large groups seek a near by field for a gathering area they go about creating almost a sea  like effect, from a distance its almost wave like.  Its only times like these that the field has such action. Most of the time they are empty and still waiting to come to life in the fall when the birds have returned.  For Ammons to quote the word field it could be a pun or just emphasis on expressing how the field came into action with the help of the birds.