Macaroni penguin female are similar in appearance; males tend to be slightly larger. Males also bear relatively larger bills, which average around compared to in females; this feature has been used to tell the sexes apart. Immature birds are distinguished by their smaller size, smaller, duller-brown bill, dark grey chin and throat, and absent or underdeveloped head plumes, often just a scattering of yellow feathers. The crest is fully developed in birds aged three to four years, a year or two before breeding age. Macaroni penguins moult once a year, a process in which they replace all of their old feathers. They
The Bird with the Crystal Plumage but finds only another dead end. As he makes his way back to his apartment, Julia is attacked by the same black-gloved figure, but Sam arrives home just in time to save her and the assailant escapes. Sam starts to receive menacing phone calls from the killer, from which the police manage to isolate an odd cricketing noise in the background, which is later revealed to be the call of a rare breed of bird from Siberia, called "The Bird with Crystal Plumage" due to the diaphanous glint of its feathers. This proves important since the only one of its