This research took place at the University of Florida, where Professor Doug Levey, a zoologist, is reported as saying:

Mockingbirds can quickly learn to recognise individuals

“We don’t know whether it’s unique to mockingbirds, but it does suggest these birds are a heck of a lot more intelligent than people have ever given them credit for. People have known for a long time that crows and parrots for example have a lot of intelligence. But these birds are fairly small. … It’ll change the way people view the intelligence of birds like this.”
The mockingbirds live in what is considered to be a natural environment, and researchers say their scientific paper will be the first published research to show that “wild animals living in their natural settings recognize individuals of other species.”

These clever birds show us yet again that we need to respect animals’ abilities when human actions affect their lives.