Condensed version of old scots playground taunt “Has your budgie died?”. Used to tease people who have outgrown their trowsers or shrunk them in the wash, thus exposing their ankles. The trousers were like a flag at half mast (a sign of respect for the dead) hence the question. Popular in 1990s Glasgow schools.
Your trowsers are pure budgied.
Has yer budgie died?
Here, check the nick of his budgies by the way.
He's boostin about way budgies like Michael Jackson