white powder puff, then a slate-plumed juvenile?
Over 3 months it will become a downy, white powder puff, then a slate-plumed juvenile.
The sentence is referring to gannets' life.
I don't understand the meaning of white powder "puff" and "a slate-plumed"
Maybe the author tried to be too descriptive?
Anyway, I'll wait for your answer. Thanks!