 Tertials arise in the brachial region and are not considered true remiges as they are not supported by attachment to the corresponding bone , in this case the humerus . These elongated " true " tertials act as a protective cover for all or part of the folded primaries and secondaries , and do not qualify as flight feathers as such . However , many authorities use the term tertials to refer to the shorter , more symmetrical innermost secondaries of passerines ( arising from the olecranon and performing the same function as true tertials ) in an effort to distinguish them from other secondaries . The term humeral is sometimes used for birds such as the albatrosses and pelicans that have a long humerus . 
