What large bird, the tallest native to North America, became an icon of conservation efforts in the 20th century?

What large bird, the tallest native to North America, became an icon of conservation efforts in the 20th century?

A Turkey vulture
B Blue heron
C Whooping crane

The whooping crane population reached an estimated low of 28 in the 1930s. Decades of legislation, land protection, and breeding programs have helped to increase their population to more than 800.

The correct answer is Whooping crane.