Rollulus rouloul (Scopoli, 1786)

森に輝く赤い冠羽のシャコ
A Crested Fireback with a Brilliant Red Crest

東南アジアの低地熱帯林に生息するキジ科の鳥で、分布はインドネシア（スマトラ島・ボルネオ島）、マレー半島、タイ南部に及びます。主に湿潤な原生林や二次林の林床に生息し、茂みの多い環境を好みます。体長は24～28cmで、体は丸みを帯びています。体色には雌雄差があり、オスは光沢のある暗い青褐色で赤茶色の長く大きな冠羽を持ち、メスは緑褐色で全体的に地味な色合いをしています。羽毛は光沢を帯び、薄暗い林内でも目を引く美しさを持ちます。

「シャコ（鷓鴣）」とは尾の短いキジ類を指し、本種もその名の通り地上性の生活を送ります。熱帯雨林の林床で落ち葉をかき分けながら、昆虫やミミズ、木の実や種子などを探して歩き回ります。イノシシが食べた果実の残骸を利用することがあり、イノシシが砕いた果実の残りを食べることで、自分では取り出しにくい中身を得ています。

繁殖期には地上の目立たない場所にドーム状の巣を作り、数個の卵を産んで抱卵・育雛を行います。普段は歩いて行動することが多いのですが、飛翔力もあり、危険を感じると短く飛び立ち、夜は木の上で休みます。森林伐採や農地開発による生息地の減少が進んでおり、地域によっては個体数の減少も報告されています。森林環境に依存する種として、その保全が重要視されています。

The crested fireback is a member of the pheasant family that inhabits the lowland tropical forests of Southeast Asia, occurring in Indonesia (Sumatra and Borneo), the Malay Peninsula, and southern Thailand. It primarily lives on the forest floor of humid primary and secondary forests, favoring dense undergrowth. Measuring 24–28 cm in length, it has a compact, rounded body. The sexes differ markedly in appearance: the male has glossy dark bluish-brown plumage and a long, prominent rufous crest, while the female is overall greenish-brown and more subdued in coloration. Its iridescent plumage appears especially striking in the dim light of the forest.

The term “shako” refers to short-tailed pheasants, and as the name suggests, this species is largely terrestrial. It walks along the forest floor, scratching through leaf litter in search of insects, worms, fruits, and seeds. It is sometimes seen taking advantage of fruit remains left by wild boars, feeding on pieces broken open by them and thus accessing food that would otherwise be difficult to obtain.

During the breeding season, it builds a dome-shaped nest in a concealed location on the ground, where it lays several eggs and raises its young. Although it usually moves about on foot, it is capable of flight; when threatened, it makes short bursts of flight, and at night it roosts in trees. Habitat loss due to logging and agricultural expansion is a growing concern, and population declines have been reported in some areas. As a species dependent on forest ecosystems, its conservation is considered important.

参考文献

“Crested Wood Partridge” Happy Hollow Park & Zoo. 2026年4月29日閲覧

BirdLife International. 2021. Rollulus rouloul. The IUCN Red List of Threatened Species 2021: e.T22679106A196436384.  2024年9月14日閲覧

Crested Partridge. oiseaux-birds.com. 2024年9月14日閲覧