Psarocolius montezuma

Psarocolius montezuma (Information about this image)

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Cladus: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Cladus: Telluraves
Cladus: Australaves
Ordo: Passeriformes
Subordo: Passeri
Infraordo: Passerida
Superfamilia: Passeroidea

Familia: Icteridae
Genus: Psarocolius
Species: P. montezuma
Name

Psarocolius montezuma (Lesson, 1830)

Type locality: Mexico.

Synonyms

Cacicus montezuma (protonym)
Gymnostinops montezuma

References
Primary references

Lesson, R.P. 1831. Centurie zoologique, ou, Choix d'animaux rares, nouveaux ou imparfaitement connus: enrichi de planches inédites, dessinées d'après nature par M. Prêtre, gravées et coloriées avec le plus grand soin. F.G. Levrault. Paris & Strasbourg. pp. i-x + 1-244, pls. 80. DOI: 10.5962/bhl.title.41400 BHL Reference page. p. 33 BHL, pl. 7 BHL

Additional references

Price, J.J. & Lanyon, S.M. 2002. A robust phylogeny of the oropendolas: polyphyly revealed by mitochondrial sequence data. Auk 119: 335–348 pdf DOI: 10.1093/auk/119.2.335 Open access Reference page.

Vernacular names
čeština: vlhovec aztécký
dansk: Montezuma Oropendola
Deutsch: Montezumastirnvogel
English: Montezuma Oropendola
español: Cacique de Moctezuma
suomi: kastanjakultapyrstö
français: Cassique de Montezuma
magyar: Montezuma-zacskósmadár
italiano: Oropendola di Montezuma
日本語: オオツリスドリ, ootsurisudori
Nederlands: Montezumaoropendola
norsk: Montezumaoropendola
polski: kacykowiec aztecki
русский: Оропендола-монтезума
slovenčina: trupiál aztécky
svenska: Montezumaoropendola
中文: 褐拟棕鸟

Psarocolius montezuma

The Montezuma oropendola (Psarocolius montezuma) is a New World tropical icterid bird. It is a resident breeder in the Caribbean coastal lowlands from southeastern Mexico to central Panama, but is absent from El Salvador and southern Guatemala. It also occurs on the Pacific slope of Nicaragua and Honduras and northwestern and southwestern Costa Rica. It is among the oropendola species sometimes separated in the genus Gymnostinops. The English and scientific names of this species commemorate the Aztec emperor Moctezuma II.
Description

Adult males are mainly chestnut with a blackish head and rump, and a tail which is bright yellow apart from two dark central feathers. There is a bare blue cheek patch and a pink wattle, the iris is brown, and the long bill is black at the base with a red tip. Females are similar, but smaller than males with a smaller wattle. Young birds are duller than adults and have a paler and less demarcated bill. No subspecies are currently recognized.

The sexes are very different in size; the male is 50 cm (20 in) long and weighs 520 g (18 oz); the smaller female is 38 cm (15 in) long and weighs 230 g (8.1 oz). In total body mass, the males are 100% bigger than the females, which is a 2:1 body-to-mass ratio and makes the Montezuma oropendola one of the most sexually-dimorphic birds in the world. Webster et al. says that the size difference in males and females is probably directly related to differences in foraging habits. The females often forage on thin branches, eating insects out of curled up leaves, while the males often perch on thick branches and forage in epiphytes and bromeliads.[2]

Webster et al. also found that sexual dimorphism was more obvious in length of the wing and body mass. Male size and body mass is associated with sexual fitness and dominance. Webster et al. observed that males defend sexually-receptive females, suggesting that Montezuma oropendolas have a female-defence mating system. While the females nest, the males fight and fend off one another, and the males were ranked depending on the outcome of each fight. The alpha male eventually pushes out all other males until he is the only one left. When the alpha males leave the others come back and defend females until he returns. This type of mating system is similar to that of polygynous mammals, not birds.[3]

The "unforgettable"[4] song of the male Montezuma oropendola is given during the bowing display, and consists of a conversational bubbling followed by loud gurgles, tic-tic-glik-glak-GLUUuuuuu. Both sexes have loud cack and crrrk calls. In a recent study by on male Montezuma oropendolas, researchers found that, when at breeding sites, males often changed the lowest peak frequency. When males were singing and their song overlapped, the largest male could out-compete the other males at the colony by changing how loud and how deep his lowest peak frequency was.[5]
Range and habitat
Hanging nests in farmland near Quesada, Costa Rica
British Honduras stamp featuring a Montezuma oropendola

The Montezuma oropendola is a quite common bird in parts of its range. They are omnivorous and are often seen in small or larger flocks foraging in trees for small vertebrates, large insects, nectar, and fruit, including bananas, Cecropia spikes, gumbo-limbo (Bursera simaruba) and Trophis racemosa (Moraceae).[6] Outside the breeding season, this species is quite mobile, with some seasonal movements.

The Montezuma oropendola inhabits forest canopy, edges and old plantations. It is a colonial breeder and only the females build hanging woven nest of fibres and vines, 60–180 cm (24–71 in) long, in a tree that is up to 30 meters high. Each colony has a dominant male, which mates with most of the females following an elaborate bowing display. The female lays two dark-spotted white or buff eggs, and she incubates them without the male until they hatch in 15 days; the young fledge in 30. While the young are still in their nests they are most often fed spiders and other arthropods, frogs, lizards, and fruits. There are typically about 30 nests in a colony, but up to 172 have been recorded.[7]
Intraspecific relationships

Although the chestnut-headed oropendola shares much of this species's range, it is smaller, mainly black with a chestnut head (instead of mainly chestnut with a blackish head), and lacks coloured facial patches, so the two oropendolas are unlikely to be confused.

Unlike some populations of its relative, the chestnut-headed oropendola, the Montezuma oropendola does not tolerate brood parasites near their nests. Although Montezuma oropendolas do not have many defenses against Cowbirds, when females see a Giant Cowbird near their own nest they actively defend their nest by attacking the Cowbirds and forcing them to leave their colony. Webster et al. found that the females did not drive the cowbirds away until they were approaching their own nests. This study also found that unlike chestnut-headed oropendolas, the Montezuma oropendolas did not nest near social Hymenoptera. Combined with the fact that Montezuma oropendolas do not allow Cowbirds near their nest, they have no defense against botflies. Nest success is fairly low for the Montezuma Oropendola. The females lay an average of two eggs per nest, but only one is fledged and only one third of the nests in the colonies are successful. Because of their relatively low nest success rate, brood parasites are too high a risk to have around the Montezuma oropendolas nest.[8]
References

BirdLife International (2020). "Psarocolius montezuma". IUCN Red List of Threatened Species. 2020: e.T22724004A138236998. doi:10.2305/IUCN.UK.2020-3.RLTS.T22724004A138236998.en. Retrieved 12 November 2021.
Webster, Michael S. (1997). "Extreme Sexual Size Dimorphism, Sexual Selection, and the Foraging Ecology of Montezuma Oropendolas". The Auk. 114 (4): 570–580. doi:10.2307/4089276. JSTOR 4089276.
Webster, Michael S. (1994-10-01). "Female-defence polygyny in a Neotropical bird, the Montezuma oropendola". Animal Behaviour. 48 (4): 779–794. doi:10.1006/anbe.1994.1302. ISSN 0003-3472. S2CID 53178647.
Howell, Steven N. G. & Webb, Sophie (1995): A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, Oxford & New York. ISBN 0-19-854012-4
Price, J. Jordan; Earnshaw, Sarah M.; Webster, Michael S. (2006-04-01). "Montezuma oropendolas modify a component of song constrained by body size during vocal contests". Animal Behaviour. 71 (4): 799–807. doi:10.1016/j.anbehav.2005.05.025. ISSN 0003-3472. S2CID 53179839.
* Foster, Mercedes S. (2007): The potential of fruiting trees to enhance converted habitats for migrating birds in southern Mexico. Bird Conservation International 17(1): 45-61. doi:10.1017/S0959270906000554 PDF fulltext
"Montezuma Oropendola - Diet and Foraging | Neotropical Birds Online". neotropical.birds.cornell.edu. Retrieved 2018-04-04.

Webster, Michael S. (1994). "Interspecific Brood Parasitism of Montezuma Oropendolas by Giant Cowbirds: Parasitism or Mutualism?". The Condor. 96 (3): 794–798. doi:10.2307/1369483. JSTOR 1369483.

Jaramillo, Alvaro & Burke, Peter (1999): New World Blackbirds. Christopher Helm, London. ISBN 0-7136-4333-1