Barn Swallow (Hirundo rustica subsp. erythrogaster) The USA subspecies is sexually dimorphic. In this subspecies males have an orangish belly, females with a whitish-beige belly. Photographed clinging to the side of the pavilion at the entrance to Anahuac National Wildlife Refuge, Chambers County, Texas, USA. Gulf prairies and marshes at ca. 2 m (6.6 ft) elevation.