I remember there was a guy on this board claiming tjat the FRrench word "merle" could also mean "falcon". This is what he wrote:
"Lumping up the multiple sources, a 'merlin' is defined as: A small falcon of northern European & American regions. It has predominantly dark plumage and a black-striped tail.
The scientific names are 'falco columbarius' (pigeon hawk), 'falco lithofalco' (stone hawk?) and 'falco salon/aesalon' (salt/copper/hall/room halk? [purely guesswork]).
The lumped derivations are as follows: Middle English 'merlin' > Old English 'merlion' > Anglo-Norman 'merilun' > French '[é]merillon' > Old French 'esmerillon' > Old French 'esmeril' > Old High German 'smirl' / German 'schmerl' > Latin 'merula' meaning 'blackbird.' "