RULE: Black-vented Shearwater

<Question>
Match
{Variable}
Direct Choice
{Variable}
Infered Choice

IF
What color was the UNDERSURFACE of the wing as seen in flight = {Light} OR {Unknown} AND
What Color were the UNDERTAIL COVERTS = {Black, dark gray or dark} OR {Unknown} AND
What colour was the BACK = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What colour was the BREAST = {White, or pale (grayish-white)} OR {Unknown} AND
What colour was the THROAT = {White, or pale (grayish-white)} OR {Unknown} AND
What colour was the BILL = {Black, purple, or dark} OR {Unknown} AND
<What SHAPE was the BILL> = {Straight and slender} OR {Straight and thick} OR {Hooked} OR {Unknown} AND
What was the predominant colour of the HEAD = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
How BIG was the bird = {Robin-sized} OR {Pigeon-sized} OR {Crow-sized} AND
<What TYPE of bird was seen> = {Gull-like, or a Seabird} AND
What type of ENVIRONMENT was the bird seen in = {Flat saltwater shore; beach} OR {Rocky saltwater shore; cliff} OR {Open ocean; beyond sight of land} OR {In flight over saltwater} AND
WHERE was the bird seen = {Southwestern United States}
THEN
Black-vented Shearwater (Confidence: 3)