Mockingbird combines English mock with English bird, which derives from Old English bridd from Proto-Germanic brūdiz, while mock comes from Middle Dutch mocken.
mockingbird (English): A long-tailed American songbird of the Mimidae...
Definitions
A long-tailed American songbird of the Mimidae...
Ancestry of “mockingbird”, step by step
mockingbird traces back through two separate lines of ancestry.