A sin to kill

Walking along the street we passed a bush full of sparrows (as blipped by GPZ before now) and noticed that the bird on the left was larger and fatter that the others. (Might be viewable here in blipfolio.) Looking at the image later I realized it wasn't a sparrow because it didn't have a brown head - then someone identified it as a mockingbird. It's the first time I've seen this bird, which has acquired iconic status by virtue of the title of Harper Lee's novel.
There's also the old lullaby Hush little baby don't say a word and daddy will buy you a mocking bird. Lots of people have sung it but I like this version with Bobby McFerrin and Yo-yo Ma.

What I didn't know is that it was the mockingbirds of the Galapagos that really provided Darwin's eureka moment when he noticed that birds from different islands varied in form, thus indicating that species were not stable but capable of change. (See here for more on this.)

Apparently they're called mockingbirds because they mimic other birds - you can hear their call here.