RULE: South Polar Skua

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

IF
What SIZE was the TAIL = {Short} OR {Medium} OR {Long} OR {Unknown} AND
<What SHAPE was the TAIL> = {Rounded at the end} OR {Pointed or wedge-shaped} OR {Unknown} AND
Was the RUMP or LOWER BACK light = {No} 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 BELLY = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What colour was the BREAST = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What colour was the THROAT = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What colour was the BILL = {Blue} OR {Gray, or blue-gray} OR {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 LENGTH was the BILL> = {Short} OR {Medium} OR {Unknown} AND
What colour was the TOP of HEAD = {Brown, or chestnut (reddish-brown)} OR {Gray, or blue-gray} OR {Black, purple, or dark} 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 = {Crow-sized} OR {Goose-sized} AND
<What TYPE of bird was seen> = {Gull-like, or a Seabird}
THEN
South Polar Skua (Confidence: 1)