The birds on the Pacific Flyway have re-established their original migration pattern, but the swans east of the Rockies no longer fly south for the winter;
(The birds on the Pacific Flyway; have re-established; their original migration pattern) (the swans east of the Rockies; no longer fly south; T:for the winter)
The birds on the Pacific Flyway the swans east of the Rockies
have re-established no longer fly south
their original migration pattern
T:for the winter