RULE: Sabine's Gull

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

IF
What colour were the LEGS or FEET = {Blue} OR {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What SHAPE was the TAIL = {Square or slightly notched at the end} OR {Forked} OR {Unknown} AND
What colour was the BACK = {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 = {Gray, or blue-gray} OR {Black, purple, or dark} OR {Unknown} AND
What colour was the BILL = {Yellow} OR {Black, purple, or dark} OR {Unknown} AND
<What SHAPE was the BILL> = {Straight and thick} OR {Hooked} OR {Unknown} AND
<What LENGTH was the BILL> = {Short} OR {Medium} OR {Unknown} AND
What colour were the EYES = {Red, orange or rusty} OR {Brown or blackish brown} OR {Black or dark gray} OR {Unknown} AND
What was the predominant colour of the HEAD = {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
WHEN was the bird seen = {Spring} OR {Summer} OR {Fall}
THEN
Sabine's Gull (Confidence: 1)