"A magpie cannot sing."
Translation:까치는 노래를 못 합니다.
I think its usage is similar to 안~. They can only be placed in front of pure Korean verbs or adjectives. For Sino-Korean verbs (~하다), 못 needs to be in front of 하다, instead of the noun.
It is probably the same for compound verbs like 꿈꿉니다. It should be 꿈을 못꿉니다, instead of 못 꿈꿉니다. Please correct me if I am wrong though.
A magpie is most often described as a type of crow/raven, or jaybird. It is likely to be black and white or green-blue and white, sometimes with an extra long tail. As a name "Magpie" is bad because it refers to them being non-stop loud, not because they are also known for being extremely intelligent.