Unlike other shorebirds, phalaropes are not territorial. However, during the nesting season, mates may be vigorously defended. This behavior reinforces the bond between the mated birds. Home ranges vary from one to ten acres or more and overlap greatly. Predators on the nesting ground include foxes, weasels, jaegers, gulls, and owls.
Jaegers can capture and feed on phalaropes at sea.
Occasionally there is mass mortality of phalaropes at sea due to starvation. Some phalaropes probably live for ten or more years. Phalaropes are visual hunters. During the summer, their diet is principally freshwater insects and other invertebrates. When feeding in deeper water, phalaropes sometimes swim rapidly in a small circle and create a vortex.