The Common Kestrel can be found near wetlands as well as grassland and farmland areas throughout Japan in autumn and winter, and it nests in cliffs and on bridge beams on the island of Honshu in spring and summer. Females and juveniles are brown in color from head to tail, whereas adult males show blue-grey coloring on the head and tail. The moustachial pattern on the face is a shared feature of the Falconidae family. Their wings and tail are longer than those of pigeons, which are roughly the same size, and they give a sharp song “Ki-, ki-, ki-” during the mating season.
Play birds singing
Since raptors are most often noticed when in flight, it would be good to take notice of flying crows and pigeons in order to detect and distinguish the Common Kestrel.
Like pigeons, the tips of the wings on falcons look narrow, whereas hawks, like crows, spread their feathers like fingers. In the Falconidae family, if the bird is roughly the size of a crow then it is a Peregrine Falcon; the others are all about the size of a pigeon, and if the wings and tail look longer than a dove then it is a Common Kestrel. The Merlin is a rare winter bird, and males are smaller than a pigeon, roughly the size of a Brown-eared Bulbul. In northern Japan, the summer resident Eurasian Hobby flies quickly with longer and narrower wings than the Common Kestrel, hunting mostly small birds in mid-flight.
The Common Kestrel frequently hovers in the air and then suddenly dives toward its prey on the ground, pinning it down. It is reported that the Japanese grass vole is its primary food source, but it eats a variety of other creatures, including small birds and large insects, depending on the location, habitat and time of year.
In the 1970s, the Common Kestrel was building nests on buildings constructed on reclaimed land in Tokyo to the extent that “raptor adopting to the urban” became a topic. Nowadays, these birds also build nests in the crevices of bridge beams or behind billboards on buildings, and there are reports of them nesting at train stations and department stores in suburban areas of Tokyo.
It is thought that this is a result of abundant food sources, such as mice in the reclaimed lands, and small birds in suburban areas, which is near the Tama River with rich nature. The Common Kestrel originally nested in high cliffs, however it could be that it turned its attention away from declining and unstable cliff habitat to the ledges and crevices of sturdy buildings and bridges.
The number of Common Kestrel nesting at some specific site, which has been designated as a national natural treasure of Japan, has decreased sharply. It is thought that this is due to a declining number of voles and attacks by Peregrine Falcons.
It appears that Peregrine Falcons, which are now more commonly seen in urban areas, hunt their smaller cousins, the Common Kestrel.
The blue-grey coloring the male develops on its head and tail feathers when it reaches maturity is beautiful, but it is smaller in size than the female. (A smaller male compared to female is common among raptor species.)
Hovering in the air like a helicopter, it searches for prey and sets aim on its target.
Canon sites where this bird is seen