The merlin (Falco columbarius) is a small species of falcon from the Northern Hemisphere, with numerous subspecies throughout North America and Eurasia. A bird of prey once known colloquially as a pigeon hawk in North America, the merlin breeds in the northern Holarctic; some migrate to subtropical and northern tropical regions in winter. Males typically have wingspans of 53–58 centimetres (21–23 in), with females being slightly larger. They are swift fliers and skilled hunters who specialize in preying on small birds in the size range of sparrows to quail.  

A merlin appeared in "Running" when it was compared to an emu.