オナガカエデチョウ Estrilda astrild

Tiny finch with short wings, a red bill, and a long tail. The body is largely gray with subtle dark bars, a prominent red mask and a dark vent. Bill is dark in juveniles. Normally encountered in noisy flocks in grassy and reedy areas; listen for distinctive descending wheezy calls. Often found in urban areas outside of its natural African range; introduced widely across the world, including the Iberian Peninsula, Taiwan, Puerto Rico, Brazil, and various Indian and Pacific Ocean islands.