How the word "macarico" (halcyon) came into Portuguese vocabulary meaning: beginner, inexperience.

In it migration movements, halcyon come from North to South and vice versa, gathering, in large number, in the littoral of Guine. 
Before the beginning of the Portuguese colonial war, early years of 1960,  Portuguese soldiers sent to Portuguese colonies wore yellow uniform. After that they wore camouflaged one.
When the first soldiers, wearing camouflaged uniform, landed at Bissau, a Guinean said:
- These soldiers are like "macaricos" (Comparing the camouflaged uniform which the new soldiers wore with the "macarico" speckled plumage)
Soon this comparison spread among soldiers and all the new comers passed to be called "macaricos"

First, this way of address  between colleges was restricted to soldiers. Later,  with  demobilization, spread   through Portuguese civil society with the same meaning. Now, it's currently used.