Next, the longest primary feather is identified, and the differences between the length of that primary and that of all remaining primaries and of the longest secondary are also measured, again in millimeters.
Seguidamente, identifícase a pluma primaria máis longa, e mídense tamén as diferenzas entre a lonxitude desa primaria e a de todas as restantes primarias e da secundaria máis longa, de novo en milimetros.