Scaly-breasted Munia are tiny South-east Asian songbirds that were released locally or possibly escaped the exotic pet trade just thirty years ago and have now become widespread across Southern California. The highly social, seed-eating birds are now especially common in Orange County brushy riparian habitats, grasslands, and parks where they are seen in noisy, twittering flocks, spending their time clambering up tall grass stalks to forage or hopping on the ground eagerly scavenging for seeds.

Very prolific breeders, they have unwittingly become the primary host species to another introduced caged-bird trade species, the Pin-tailed Whydah of Sub-Saharan Africa. The female Pin-tailed Whydah does something quite extraordinary. She is a “brood parasite” meaning that she entirely foregoes building a nest of her own and just secretly lays her eggs in an unattended nest of a Scaly-breasted Munia. The oblivious Munia parents incubate the added eggs and then dutifully feed the hatchlings and fledglings alongside their own. The foster nestlings reportedly learn the song and calls of the host species while under their care, subsequently using the learned vocalizations in future mate selection!

This unusual cross-species relationship has proven quite successful for both non-native species as evidenced by the steady growth and expansion of both species throughout coastal Southern California in a remarkably short period of time.

Scaly-breasted Munia adults look alike with chocolate-brown upper parts, a large dark head, and pale underparts covered in distinct scale-like brown patterns. These finch-like seed-eaters have stout, black, conical beaks. Juveniles are much plainer, lacking the distinctive scaly pattern and dark head, appearing mostly buff-brown all over. The newly fledged Pin-tailed Whydahs being fed alongside them appear slightly smaller, paler, yet strikingly similar in their drab juvenile plumage. This remarkable pair of introduced species with their highly irregular breeding strategy is being keenly watched by the birding community.

Photos by James Kendall      Text compiled by Betty Kanne

Bird of the month flyer