The title doesn't match the paper though. People had already decoded the bird calls. What the paper was giving evidence to was that the birds themselves are cognitively decoding the calls.

I’m glad we’re doing this research. It makes me wonder how much time and potential we’ve wasted over the years actively assuming non-human animals were just rote automatons.

It seems like a meaningful amount of science has been spent on systematically dismantling pre-existing prejudice over the last hundreds of years (and thousands in some cases and cultures).

  All humans are human.
  Babies can feel pain.
  Plants feel.
  Animals think.

I get that some cultures already thought some of these things, but many of these were sadly not prevailing.