Face:
Matt is right, in the Pacific Flyway, you will rarely see any 'red' on the bird. Just so you know, the 'red' is actually iron that is in a reduced state. Without a lot of detail, soils saturated for long or very long periods of time will usually exhibit reducing conditions (hope you remember your chemistry). Under these conditions, ions of iron are transformed from a ferric valence state to a ferrous valence state. Or in simplistic terms, the 'red' color comes from the iron in the soil that is under anaerobic (no oxygen) conditions.
The sandhill crane is a classic example of this coloring. The bird is actually all grey (except for the eye patch), and during the breeding season, they cover their feathers in mud. As a result, the reduced iron from the soil 'stains' their feathers and produces the 'red' color. Hope this helps :beer: