RULE: Black-backed Wagtail

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

IF
Was the bird seen in ALASKA = {Yes} AND
What SIZE was the TAIL = {Medium} OR {Long} OR {Very Long} OR {Unknown} AND
What colour TAIL PATTERN was there if any = {Light outer edge or corners} OR {None} OR {Unknown} AND
What colour was the BACK = {Black, purple, or dark} OR {Unknown} AND
What colour was the BELLY = {White, or pale (grayish-white)} OR {Unknown} AND
What colour PATTERN if any was shown on the BREAST = {Uniform color} OR {Unknown} AND
What colour was the BREAST = {Black, purple, or dark} OR {Unknown} AND
What colour was the THROAT = {White, or pale (grayish-white)} OR {Black, purple, or dark} OR {Unknown} AND
What SHAPE was the BILL = {Straight and slender} OR {Straight and thick} OR {Unknown} AND
What LENGTH was the BILL = {Very short} OR {Short} OR {Medium} OR {Unknown} AND
What FACIAL or HEAD features were noted if any = {Light area near or around the eye} OR {Dark area near the eye} OR {NONE or a PLAIN unmarked FACE} OR {Unknown} AND
What colour was the TOP of HEAD = {White, or pale (grayish-white)} OR {Black, purple, or dark} OR {Unknown} AND
What was the predominant colour of the HEAD = {White, or pale (grayish-white)} OR {Black, purple, or dark} OR {Unknown} AND
How BIG was the bird = {Sparrow-sized} OR {Robin-sized} AND
<What TYPE of bird was seen> = {Warbler-like} OR {Songbird} AND
WHEN was the bird seen = {Spring} OR {Summer} OR {Fall} AND
WHERE was the bird seen = {Northwestern Canada or United States}
THEN
Black-backed Wagtail (Confidence: 1)