Montezuma's Cassique
Scientific name: Psarocolius montezuma
Family: Icteridae
Genus: Psarocolius
Geographic range: From Mexico to Panama
Who is it?
The Montezuma's jacobin (Psarocolius montezuma) or Montezuma's oropendola is a large bird of Central America. Contrary to what one might think, it does not take its name from the city of Montezuma in Costa Rica, but from the Aztec emperor Moctezuma II, who ruled the Aztec Empire in the early 16th century. This name was therefore given to it in tribute to this important historical figure in the culture of its range. The term "jacobin" comes from the words "kasike" or "kassiquan", meaning "chief" or "guardian of the house" in the language of the Taínos, an indigenous people of the Greater Antilles and the Bahamas. The species was first described in 1830 by a French naturalist (cocorico) named René Primevère Lesson.
Portrait of Moctezuma II - Source: Antonio Rodriguez (1636-1691)
Crested jacobin - Source: The Lila Breasted Roller
The Montezuma's oropendola is one of the two largest species, along with the crested jacobin, among the 24 species of jacobins known to date. Indeed, an adult male can measure about 50 cm for an estimated weight of around 500 g, while an adult female will reach about 38 cm. However, these data remain estimates due to the small amount of information available and the little research done on the species, especially compared to other species in the region that are much more studied.
This magnificent bird is quite recognizable, whether by its appearance or its singular song.
It is mainly dark brown except for the yellow feathers of its tail. Its beak is black on the first half and bright orange on the second, although for males this orange extends up to the forehead. This bird has a hard life, only about 0.5% of the chicks survive due to their many predators such as snakes, monkeys, other birds or even tropical fly larvae.
Montezuma's jacobin, Arenal Volcano, Costa Rica
Formidable builders
Colony of gourd-shaped nests, Alajuela, Costa Rica
These nests, made from banana tree fibers and twigs, are gourd-shaped just like those of other species in the region, except that they are solid and grouped by the dozens in the same tree: about 30 to 40 nests although this number can rise to about 150! This behavior is indeed rare among birds, which generally build nests isolated from each other.
These nests are most often built in Guanacastes, Costa Rica's national tree, by the females who emit constant calls while the males defend them as well as their territory.
Guanacaste (Costa Rica's national tree) — Source: Flicka
However, only a few males have the opportunity to mate, a size-based hierarchy being observed within this species. The females incubate about 2 eggs at a time during an incubation period lasting about fifteen days. However, it happens that cowbirds (sort of "parasite" birds) lay their eggs in the jacobins' nests. To prevent this, they maintain a mutualistic relationship with hornets whose nests keep cowbirds away. In return, the jacobins hunt the bees that harm the hornets.
As for food, the oropendolas are mostly frugivorous, although they occasionally eat insects, flowers or other organic matter.
The photographs in this article were taken near a national reserve, not far from the Arenal Volcano site, located in the Alajuela region of Costa Rica. The tree where the nests are located borders the road and is located at the edge of the forest, an environment to which jacobins adapt easily. These nests were identified with the help of Théo, a local guide.
