How I'd do it:
Paper piece the curved flying geese piece.
and then applique it to the border -you can remove the excess border fabric underneath after.
The applique can be done many different ways -
hand stitch it applique it down
machine stitch it down with a small zigzag - after you've turned the seam under.
??? -
is the sky of the geese the same color as the border background fabric?
If it's the same, depending on the width of the border and FG, I might do it a bit differently.
I just don't really like all those seams on the border pieces.