Clayton Ferrell TN NWR Duck River Unit Humphreys County 06/20 - 21/11 The three sandhill cranes were observed again yesterday in Pool 4. Today five Caspian terns were observed resting on mudflats in Pool 2. The Duck River Bottoms are mostly open to vehicle traffic. There are a few areas closed to vehicle and even foot traffic due to a large construction project. This closure does not include those areas listed above.