The paper is in Norwegian, and we've been given the word "svarttrost" which loosely translates into "blackbird". So far I've argued that because "black" is not inflected (in Norwegian, adjectives are inflected for indefinite/definite, masculine/neuter and singular/plural), it is indeed one word. If it was two, "black" would be inflected to match the instance of "bird".
Other than that, I'm not quite sure what other reasons I can give. Any thoughts on the matter would be greatly appreciated :)