Nicholas Colangelo and Fred Christensen were recently fishing at a frozen lake in Pennsylvania. To their shock, the tug on their line wasn't from a fish, but a bird!
It was an adult male red-breasted merganser, which is a type of duck. National Geographic explains that although this was an unusual encounter, it makes sense. During the winter, red-breasted mergansers hunt for fish under the ice:
That's because mergansers are fish-eating ducks that often hunt under ice, where they can stay submerged for up to about five minutes. The ducks are common in the Northeast, although many of those that have been wintering on inland bodies of water have been struggling this year, with high ice cover restricting their movement and access to prey.
Many of the birds have been food deprived, making them more likely to go after the easy prey of fish on hooks.