What is suggested if an eagle has large white patches on the underside of its wings?

The presence of large white patches on the underside of an eagle's wings is an identifiable characteristic of an immature golden eagle. Immature golden eagles display these distinctive white patches as a part of their plumage. Adult golden eagles, by contrast, have a more uniform dark brown coloration without these prominent white spots, which helps differentiate them from their younger counterparts.

When assessing the other options, while adult bald eagles have distinct white heads and tails, their wing patterns are different and do not include large white patches under the wings. Harriers, which are a different type of bird altogether, exhibit a different body shape and plumage features that do not correlate with the characteristics seen in golden eagles. Therefore, recognizing these features is crucial in accurately identifying the age and species of the eagle in question.