essorant

from The Century Dictionary.

• In heraldry, about to soar: said of a bird, especially an eagle, standing with the wings lifted up as if about to rise on the wing.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Her.) Standing, but with the wings spread, as if about to fly; -- said of a bird borne as a charge on an escutcheon.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective heraldry, of a bird Standing, with wings spread, as if about to take flight.
• adjective Soaring.