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Fork-tailed flycatcher (Tyrannus savana) Maybe there are only few birds that know South America better than the fork-tailed flycatcher. This bird lives in the South (in Argentina, Paraguay and the southern part of Mexico. After summer, fork-tailed flycatcher migrate, by thousands, to the Amazonian region, where they stay until winter is over. At the beginning of spring, they come back to their original region, where they are going to reproduce, grow up their offspring and migrate in the following year again. Thus, fork-tailed flycatcher are very abundant in the regions where they inhabit, however, only in some periods of the year. In other periods, they completely disappear. In Brazil, they look for open areas, such as savannahs (what explains the savanna in its scientific name), grazing lands and agricultural areas, where they rest on posts of fences, posts, wires and isolated trees. They can be found also in woods, or even in towns. When they are at a specific region (end of August in Brasília, for example), the fork-tailed flycatcher do not catch very much people's attention, since they are not attractive in color (it is white at the low part, and its head, wings and tail are black), besides having no strong singing. There is a faint sexual dimorphism (difference between males and females): males have a large prolongation at their tail, specially in the two more external feathers. Females and young ones have a less accentuated prolongation. Despite not being noticed in most of the situations, it is impossible to leave male fork-tailed flycatchers unnoticed when they are exhibiting themselves to the females. During small flights, they pirouette and spin, effusively showing their almost 30-centimetre long tails, from where their name is originated. RICARDO BOMFIN MACHADO Biologist Department of Ecology - University of Brasília |
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