"Imitation is the sincerest of flattery"

This quote comes from Charles Caleb Colton (1780 - 1832).

 

I have nesting mockingbirds in a young oak tree 25 feet or so from the house.  Incubation is on day 9 of 12-13 expected days.  This photo is from several days ago when mom and dad were busily building their "digs".  The dad is always close by keeping watch over the female who is the sole incubator.

 

This morning I sent the dogs outside as usual and when I called them in, I gave a two note whistle that they are familiar with.  From the tree closeby I heard myself as if an echo.  I whistled again, and once again I heard the echo.  Why, the mockingbird was imitating me, and with tonal precision!  Are they mocking me? or should I be flattered?