Sinaloa Martin

The Sinaloa martin is 17 to 18.5 cm (6.7 to 7.3 in) long; three individuals weighed between 42 and 43.7 g (1.5 and 1.5 oz). The sexes are dimorphic; both have a slightly forked tail. Adult males are mostly glossy steel-blue. Their wings and tail are black with a bluish gloss. Their lower breast and belly are white and their undertail coverts white with dark spots. Females have duller blue upperparts than males and sometimes have gray-brown mottling there. Their face, throat, upper breast, and flanks are dusky brown though the middle of the throat is paler than the breast. Their lower breast, belly, and undertail coverts are white. The two breast colors have a sharp demarcation. Both sexes are very similar to those of the Caribbean martin and less so to those of the purple martin.

The known range of the Sinaloa martin is on the western slope of Mexico's Sierra Madre Occidental from northeastern Sonora south to Jalisco and Michoacán. It is present there only between February and September. Its range during the rest of the year is unknown but is suspected to be northern South America. A March record in Guatemala and sight records of birds flying south over Belize in late August suggest that it makes this migration. However, the South American Classification Committee has no records from the continent. In Mexico the Sinaloa martin primarily inhabits pine and pine-oak forest in the subtropical and lower tropical zones. In elevation it ranges between 1,100 and 2,800 m (3,600 and 9,200 ft).

Almost nothing is known about the Sinaloa martin's diet or feeding behavior. It is assumed to feed on insects captured in mid-air like other members of genus Progne. It has been observed foraging over "pine-oak woodlands, pastures, orchards, and the barranca edge".