Great Frigatebird

Cf. Magnificent Frigatebird.  Magnificent and Great Frigatebirds occur together regularly in the Galápagos and Ecuadorian waters, around remote Mexican islands, and to a very limited extent in Brazilian waters.  They likely occur together somewhat more often in the eastern Pacific, but would be difficult to recognize due to their confusing similarities and the difficulty of tracking the various distinctions that apply to certain plumages.

Adult Males:  Effectively indistinguishable under most field conditions.  If the upperparts are visible, the presence of a distinct alar bar on the wings would suggest Great.  If the lighting is right to catch reflections, Great often shows a strong green or purple gloss on the back feathers, whereas Magnificent is usually duller and purplish or coppery.

Adult Females:  Distinctive.  Magnificent has a full blackish hood, whereas Great has a pale throat.  In the eastern Pacific populations, which are most likely to occur together, the females also differ in their eyerings: bluish on Magnificent, red on Great.  Bill color differs accordingly, but to a lesser extent.

Immatures:  Often distinctive, but complex and sometimes indistinguishable.  Juveniles and older immatures are often distinguishable, as most juvenile Greats have a tawny (or buffy or orange or reddish) hood, which they retain at least in part into the second year.  However, immature Greats are polymorphic and some portion of them have an all-white head like Magnificent—in which case there may be no reliable difference.  As they age, the differences become less pronounced, such that second-cycle immatures are mostly similar both within and between the two species.

Subadult Females:  Sometimes distinguishable, but complicated.  Female Magnificents begin to darken on the throat, whereas female Greats do not, so this may allow for positive identification of Magnificent in some cases.  Female Greats often have pinkish bills, while female Magnificent’s bill is generally pale grayish or horn-colored.