Niigata has a healthy and abundant Eurasian Tree Sparrow (Passer montanus) population. Kemushi (Caetpillpars) love to cacoon in the cherry blossom trees. And they hatch late spring after the cherry blossoms flowers have fluttered away in the wind. These caterpillars cause a lot of skin problems such as rashes, itchiness, redness, and pain. You do not need to become in direct contact with them, the kemushi hairs fly in the wind and attach to human skin, eyes like a micro sliver, but if you do come into direct contact with these insects, a much more serious reaction will occur. And this is why in the Tokyo Kanto region of Japan and other urban centers, insecticides are sprayed to control their population. Unfortunately, the sparrow, other birds and large insects, small mammals, and reptiles feed on these Caetpillpars. Where I live in Niigata by the sea of Japan, we have a healthy population of sparrows, and our cherry blossom trees do not need to be sprayed, as the sparrow takes care of the caterpillars feasting on them. And in my yard, I have a 100-year-old cherry blossom tree that has never been touched by insecticides, and throughout the year, we have flocks of dozens of Eurasian tree sparrows feeding in my cherry blossom tree.
On a side note, Japan is latitudinally long at over 3000 kilometers, located in the Northwest Pacific Ocean; climates range from the sub-arctic condition in the north to subtropical in the south. There are two distinct ecological lines dividing Japan’s natural indigenous plant and animal life. “The Blakiston’s Line” and the “Watase’s Line.” Due to this uniquely rare ecological condition, Japan is abundantly avifauna rich, making it the perfect location for wildlife and birding photographers. Over 600 bird species have been recorded to date, such as the Steller's sea eagle, Blakiston fish owl, Shima Enaga, white-tailed eagle, and many others. Case in point, if you join me on a Japan photo birding workshop or specifically a Niigata photo expedition, you will be able to photograph the tree sparrow in sublime settings as they can be found from Hokkaido all the way down to Okinawa, but they tend to be more plentiful in open rural areas, farmlands, and forests.
At home in Nigata, I always have set up my Nikon Z7 MarkII with my Nikon 800mm f5.6 fixed Nikon lens ready for visiting birds. Throughout the year, we get dozens of bird species visiting, such as The Tree Sparrow, which is a small bird, between 12 and 14 cm in length, a dapper bird with a rich brown-colored head with a hint of chestnut or rust. Tree sparrows also have black coloration on their cheeks and two white bars gracing their brown wings. As if Mother Nature felt the need to add more distinction to the tree sparrow, the face is a melange of black from the chin, throat, and ear coverts. Males and females are approximately the same size. Their bills vary depending on the season; during the summer months, their bills are a grayish blue, but in the wintertime, an unfathomable black. Their legs are a pale brown, and their short tail almost always stands at attention. In my memories of spotting these rascals, I recall almost always seeing their tail cocked as if in search of food or ready to confabulate with a fellow flock member. Tree sparrows subsist on a diet of foraged seeds from the ground or directly from trees, and they also feed on invertebrates like caterpillars, especially during breeding season as the sparrows are feeding their young as well as eating for themselves.