A field aid that helps identify the American Kestrel is...

The identification of the American Kestrel can indeed involve various behaviors or field aids that make them distinct when observed in the wild. Each characteristic mentioned contributes to recognizing this small falcon species.

Hovering is a notable behavior of the American Kestrel; they are known for their unique hunting style that often includes hovering in place while searching for prey. This can be quite distinctive among raptors.

Bobbing of the head is another behavior observed in American Kestrels. They frequently exhibit this action, which not only aids in their balance but also helps them gather visual information from different angles. This behavior becomes a subtle but recognizable trait for watching them in action.

Pumping the tail up and down upon landing is another behavior associated with kestrels. This tail movement can be an indication of their excitement or a signal during their hunting antics, adding to their overall flight behavior.

By combining these behaviors, it is easier to identify an American Kestrel in its natural habitat. Therefore, recognizing that all the mentioned behaviors contribute to identification makes the option indicating "All of the above" the most comprehensive and correct answer.