It turns out that the article is talking about a species of bird, the Bengal finch, that appears to recognise some kind of grammar within its bird songs. Bengal finches make a lot of noise when they hear unfamiliar bird songs, most probably related to maintaining their territory in the face of strange birds. Scientists familiarised a group of finches with a new song, which they then ‘remixed’ by cutting it and putting it back together in four different ways.
The birds only reacted strongly to one of these four mixes, leading researchers to believe that this particular version had broken some cardinal rule of finch grammar. Birds raised in isolation didn’t react to this breach of grammar, but they did after spending two weeks with normal birds. There were also some brain lesion experiments conducted that suggested that the birds had a particular area dedicated to ‘speech’ recognition and production.
Full article: New Scientist.