The Rustic Bunting is distributed across northern parts of the Eurasian Continent, migrating to Japan in winter to mountain forests, croplands, or riverbeds. As spring approaches, the head of the male turns black as its summer plumage. Its call is a short “Chi, Chi,” but its long, melodious song, like that of the Eurasian Skylark, can also be heard in the early spring before it leaves Japan.
Play birds singing
The IUCN (International Union for Conservation of Nature) recently designated the Rustic Bunting as Vulnerable. This was the result of recent surveys that shows a global decline in its numbers. In Japan, it is not such a rare species in residential areas; however, these days opportunities to observe the bird in familiar environments, such as gardens and parks, have become fewer. Since bird populations and their increase and decrease vary according to region, season or year, their true status is not easy to grasp. And, for endangered species, the criteria for determining status vary among organizations, such as the IUCN, Japan's Ministry of the Environment, and prefectural governments, and also change over time.
For example, since the Rock Ptarmigan, which Japan's Ministry of the Environment has designated as Endangered, is distributed widely across the Northern Hemisphere, it is not designated as such by the IUCN. Incidentally, in the Tokyo Metropolis, endangered species are designated independently by each of the 23 wards and other municipalities in the region, such as Tama area. A case in point is the Meadow Bunting; it is designated as Endangered in the 23 wards but not in the Tama area.
Usually, the main diet of small birds is insects; however, the family Emberizidae, which includes the Rustic Bunting, the family Passeridae, and the family Fringillidae are the exceptions. They are seed-eaters, except for during the breeding season when catching insects is necessary for them to raise their chicks. For that reason, their bill is rather thick. However, the bills of most species of Emberizidae are smaller than those of Passeridae and Fringillidae due to the fact that they prefer to eat the small seeds of gramineous plants.
There is a theory that both the family Emberizidae and gramineous plants have their origin in the American Continents. It is thought that they spread to the Eurasian Continent via Alaska. This theory accounts for the abundance of birds from the family Emberizidae in the Americas. Not only the Rustic Bunting but also the calls of other species of the family Emberizidae are repeated single syllables “Chi, Chi.” Exceptions are the Meadow Bunting, which has a repetitive call of “Chichichi,” and the Common Reed Bunting, which has a prolonged call of “Chi-n.” These two are easily distinguished from other species by their calls.
When its crown feathers are not raised, it is easily misidentified as a Eurasian Tree Sparrow or a Meadow Bunting, so pay attention to the field markings on its breast and flank.
In many cases, the change to summer plumage is a noticeable replacement of feathers but the Rustic Bunting is an exception. The outer feathers of its plain winter plumage are worn away, revealing its black inner feathers.