Bird Families

Bluetail / Tarsiger cyanurus


Bluetail (Tarsiger cyanurus) feeds on stem fruits Balanophora yakushimensis.

Seeds of parasitic plants Balanophora yakushimensis spread by migratory birds. This is the conclusion reached by the Japanese botanist Kenji Suetsugu after careful observation of this species on the Japanese island of Yaku. Probably, it was the feathered migrants who ate the fruits B. yakushimensis, helped him to settle in the Ryukyu archipelago and get to Taiwan. Until now, the spread of plant seeds from the genus Balanophora remained a mystery. Research results published in the journal Ecology.

Many plants distribute seeds with the help of animals that eat their fruits. This strategy not only reduces competition between the parent organism and its offspring, but also provides the latter with an advantage at the very beginning of life: when passing through the digestive tract, the seeds increase germination, and the droppings serve as an excellent fertilizer.

In order to attract animals, many fruits become bright and large. However, in some species, they are so small that it is difficult to imagine that they might be of interest to anyone. For example, each seed of parasitic plants from the genus Balanophora contains from one hundred thousand to one million tiny dry fruits, some of the smallest in the world. Who exactly is distributing them remains unknown until now.

According to some observations, infertility Balanophora attract rodents, possibly due to their resemblance to fungi. However, in most species of the genus, they are odorless, which is not typical for plants whose seeds are spread by mammals.

Botanist Kenji Suetsugu from Kobe University decided to sort this out. He focused on the sight B. yakushimensisthat grows in the forests of the Japanese Ryukyu archipelago and Taiwan. In December 2019, a researcher installed photo and video traps near the fruit bearing plants from Yaku Island to capture any animals that approached them. In addition, he periodically conducted personal observations. The study continued until February 2020.

Fertility Balanophora yakushimensis

It turned out that the fruits B. yakushimensis blue tails often feed (Tarsiger cyanurus) (small passerine birds from the flycatcher family (Muscicapidae)) as well as pale thrushes (Turdus pallidus). During the observation period, representatives of the first species were recorded 45 times, and the second - ten. The birds were not interested in the fruits themselves, but in the red fleshy tissues of the fruit. When they ate them, they swallowed the seeds. At the same time, the rodents completely ignored this plant species.

Suetsugu managed to collect the droppings of several bluetail after feeding them on B. yakushimensis... Having studied it, the researcher found many plant seeds that retained their germination. However, birds could also carry seeds together with pieces of seed stuck to the beak.

Interestingly, both blue-tails and palethrushes do not nest in places where it grows B. yakushimensis, but only spend the winter here. Most likely, this species timed fruiting with the appearance of migratory birds, which are able to carry seeds between the islands. Suetsugu believes that this explains the widespread use of B. yakushimensis on the islands of the Ryukyu archipelago and in Taiwan.

Perhaps some closely related species, for example, B. japonica and B. nipponica also spread the seeds with the help of birds. This is indicated by the red color of their fruit. However, other species of the genus clearly rely on some other distributors, which are still unknown. For example, in the species B. tobiracola the stems are yellowish in color and smell like yeast, which is not very suitable for propagation by birds.

This is not the first time Kenji Suetsugu has devoted his research to bizarre plants. For example, a few years ago, he and a colleague proved that plants from the genus Aspidistra are pollinated by mushroom gnats, which are attracted by the similarity of these flowers to mushrooms.


  • Superclass Tetrapoda Class Birds Aves
  • Order Passeriformes - Passeriformes
  • Suborder Singing Passerines - Oscines group Passerida
  • Superfamily Flycatchers - Muscicapoidea
  • Family Flycatchers - Muscicapidae
  • Subfamily Mint - Saxicolinae
  • Genus Bluetail - Tarsiger (Currently assigned to the subfamily Chekana - Saxicolinae in the family Flycatcher - Muscicapidae)

Bluetail - Tarsiger cyanurus Pallas. A small bird. Often twitches its tail and jumps along the ground. Dexterously climbs trees, resembling a titmouse. Older males have a bright blue back (young and females have a brownish blue). A white stripe runs from the beak to the eye. The bottom is creamy white, the sides are reddish. Sings in a low voice and softly. Song: "chuu-iy" (pause), "chuli-chuli" (quickly). The female at the nest whistles like "to drink, to drink", and the male in another way: "vark-vark". At the end of the summer they echo with a sharp "fit". Cautious bird.

Sinechvostka inhabits the dark coniferous forests of the East Siberian taiga. The nest is built low on a tree (sometimes in a hollow), in the hollows of a cliff, between stones, in cracks in rocks. Clutch - 5-7 white or pinkish eggs with brownish spots. It feeds on insects in the lower layer of the forest.