Northern hawk-cuckoo explained

The northern hawk-cuckoo, rufous hawk-cuckoo, or Horsfield's hawk-cuckoo (Hierococcyx hyperythrus) is a bird in the family Cuculidae formerly thought to be conspecific with Hodgson's hawk-cuckoo (Hierococcyx fugax) and placed in the genus Cuculus.

It is found in eastern China, North and South Korea, far eastern Russia,^[1] and Japan. Northern populations winter in Borneo.

Juvenile northern hawk-cuckoos have a yellow skin patch on the underside of each wing, which parents use to detect whether offspring are begging for food.^[2]

Notes and References

1. There is no evidence of this species on Sakhalin island according to Russian sources: (Гизенко А. И. Птицы Сахалинской области, М. Изд-во АН СССР, 1955. 324 с.; Судиловская А. М. 1951. Отряд Кукушки. // Птицы Советского Союза. Том 1, Под общ. ред. Г. П. Дементьева, Н. А. Гладкова. М.: Советская Наука. С. 46; Флинт В. Е., Бёме Р. Л., Костин Ю. В., Кузнецов А. А. Птицы СССР. М.: Мысль. 1968. С. 348-350.)
2. Rojas Ripari . Juan M. . Ursino . Cynthia A. . Reboreda . Juan C. . De Mársico . María C. . 2021-12-03 . Tricking Parents: A Review of Mechanisms and Signals of Host Manipulation by Brood-Parasitic Young . Frontiers in Ecology and Evolution . 9 . 10.3389/fevo.2021.725792 . 2296-701X. free .