Whimbrel
Detailed Description
In general, Whimbrels (like the one in this photo) are brown and grey in appearance in contrast to the brown and cinnamon tones of curlews. In addition, these two species can always be distinguished by their vocalizations. The curlew has a very distinct whistle, "chiu-eet", which sounds like the whistle humans make when they are trying to get someone's attention.
Sources/Usage
Public Domain.