Hokko chickens

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Hokko chickens
Portrait of a caruncle hokko (Crax globulosa)

Portrait of a caruncle hokko ( Crax globulosa )

Systematics
Superclass : Jaw mouths (Gnathostomata)
Row : Land vertebrates (Tetrapoda)
Class : Birds (aves)
Order : Chicken birds (Galliformes)
Family : Hokko chickens
Scientific name
Cracidae
Vigors , 1825

The Hokkohühner (Cracidae), also called Hokkos , are a family of birds from the order of the hen birds . They are distributed with 50 species in the tropics and subtropics of South and Central America . Despite their hidden way of life, they are well known to the locals for their very loud calls.

Names

Within the Hokkohühner there are three different groups, whose German names are not always clear:

  • The big or real Hokkos are often just called "Hokkos"; To avoid misunderstandings, the term "real" Hokkos is used in this article when referring to them. In English these birds are called curassows , which is derived from the name of the island of Curaçao .
  • In this article, the genera Penelope , Pipile , Aburria , Chamaepetes , Penelopina and Oreophasis are referred to as chickens . In English these birds are called guans .
  • The species of the genus Ortalis are referred to here as Chakalakas (corresponding to English chachalacas ); Grzimek's animal life calls the birds of this genus “real Guans”, a name that in other languages belongs to a completely different genus ( Penelope ).

Both the shako chickens and the chakalakas are called guans in German. In other languages ​​(English, Spanish, French) there is a division here, and the chakalakas are not called guans there. To avoid misunderstandings, the name “Guans” is avoided to a large extent in this article.

In South America, the Spanish-speaking population often refers to Hokkohenner as pavones (turkeys) or faisanes (pheasants), which is taxonomically incorrect.

features

The Brown-winged Guan ( Ortalis vetula ) belongs to the Chakalakas

All Hokko chickens show a typical chicken shape. They have a plump body, long neck, small head, and strong feet. The body length ranges from that of a black grouse to that of a turkey : it varies between 42 cm (yellow-browed guan) and 95 cm (hornhokko). The weight is between 385 g and 4.8 kg. The "real" Hokkos are proportionally heavier than chakalakas and shaku chickens because of their enlarged pelvis .

The plumage is mostly inconspicuous; Gray, brown and black are the predominant colors that serve as camouflage in the branches and on the ground. Some species also have shiny or pure white plumage, but these are usually hidden and are only presented during courtship . Many species have unfeathered, bare skin on the face and throat; sometimes this is extended to wattles or bulging helmets. These parts are colored red, yellow or blue.

A clearly visible sexual dimorphism exists in the "real" Hokkos, whereas it is difficult to distinguish between the two sexes in shako chickens and chakalakas. One of the differences that can hardly be used in field ornithological terms is that males are usually 5 to 10% larger than females, their bare skin is a little lighter than that of the females and the eye colors are often different. The Canyon Guan is an exception to the above rules; in this case, male and female birds are clearly colored differently, and the females are also larger.

The youth dress already resembles the appearance of adult birds and is often only a little darker. Only in the Gorges Guan do juvenile birds always resemble the female in color.

A common phenomenon in this family is polymorphism , which means that members of the same species can look completely different. An example of this is the Helmhokko. Most females are black with a white underside. However, there is also a dark brown morph with light brown stripes in the females of this species .

The wings are quite short and rounded. The "real" Hokkos rarely fly and only fly short distances; On the other hand, jack chickens and chakalakas use the ability to fly a little more frequently. As a rule, many powerful wing beats are followed by a gliding phase. A peculiarity of the shaku chickens is the "drumming" with the wings, which is heard especially during courtship (see reproduction ).

The legs have an anatomical peculiarity: the rear toe is at the same height as the front toe. This is a commonality with the large foot fowl that distinguishes both groups from other chicken birds. This feature has been the main reason why large-footed and crooked chickens were considered related (see systematics ).

Many Hokko chickens make extremely loud noises. A greatly enlarged windpipe ensures that calls can sometimes be heard over a distance of 1 km. The chakalakas utter loud screams in chorus. Shaku chickens can make a variety of cackling, screaming and croaking sounds. The typical sound of the males of the "real" Hokkos, on the other hand, is a dull roar that sounds like blowing into an empty bottle. This call lasts for 5 to 7 seconds, followed by a pause of 12 seconds before the next call. Female "real" Hokkos do not master these sounds and instead emit a deep whistle.

distribution and habitat

Bronze Guan ( Penelope obscura )

Hokko chickens live in the forests of South and Central America. The dense tropical rainforest is the typical habitat, but there are differences:

  • Chakalakas are the least closely tied to specific habitats and inhabit not only real rainforests but also dry bare forests, gallery forests , forest edges, mangrove forests and tree savannas . They also settle in secondary forests . In all habitats, however, the presence of trees is a prerequisite.
  • Shako chickens live mainly in rainforests and cloud forests .
  • The "real" Hokkos live exclusively in tropical rainforests and can be found here along river banks or swamps.

Most of the Hokkohenner are birds of the lowlands, but there are also distinct high mountain dwellers; The Andenguan, which occurs in Peru up to 3900 m, holds the altitude record .

Hokkohenner are distributed among the regions of the Neotropic as follows:

Way of life

activity

Hokkohenner are predominantly diurnal birds. They show the greatest activity in the very early morning before sunrise. They rest in the hottest hours of the day. Sometimes they call out even on moonlit nights. The Rothokko was long considered an exception, which is also shown by its English name Nocturnal Curassow (= "Nocturnal Hokko"), as its calls can always be heard at night. But we now know that he also goes foraging for food during the day.

As sociable birds, Hokkohenner often gather in groups of 10 to 50 individuals in fodder trees. However, these groups are loose associations that always dissolve.

The resting places of the Hokkohenner are always in trees. They often take dust baths. These serve primarily to ward off parasites , but can also be part of the courtship ceremony.

nutrition

White-fronted Guan ( Penelope superciliaris )

The food of the Hokkohenner is almost exclusively vegetable. Fruits, leaves, flowers, seeds, buds and twigs are eaten. There are small differences here: Chakalakas and jack-chickens prefer soft food. They mainly eat leaves and berries and also peck at fruits such as mangoes and guavas . The "real" Hokkos are able to digest harder foods such as nuts, seeds and twigs due to their particularly powerful gizzard . Another difference is in the location of the foraging: Chakalakas and shaku chickens mainly eat in the branches, "real" Hokkos look for fallen fruits and nuts on the ground.

Hokkohenner are generalists, that is, they do not depend on specific food crops. For example, a study of smooth-billed hokkos found that they use 80 different types of plants as food sources.

In addition to plants, beetles, grasshoppers, caterpillars, spiders and millipedes are rarely consumed as complementary foods. In addition, like many herbivorous birds, hokko chickens also swallow stones ( gastroliths ) that help digest food.

Reproduction

As a rule, boiled chickens are monogamous . In older literature there are reports of basic polygyny among the Chakalakas, but this is not the case based on current knowledge. It is true that some cases of polygyny have been found in “real” Hokkos and also in the Zapfenguan, but these are also rare exceptions.

The courtship is quite easy with the Chakalakas. This includes mutual cleaning and hunting. The shako chickens drum their wings. Their outer hand wings are modified in such a way that they produce a very loud, drumming noise when the wings are flapped quickly. Shaku chickens make this sound all year round, but especially often during courtship. They fly from one tree to another and suddenly beat their wings twice as fast as usual, which creates the drum sound. The "real" Hokkos perform elaborate courtship dances on the floor. Light-colored plumage is presented, wings, tails and bonnets are set up, the booming sounds described are uttered and pebbles are thrown.

Both partners participate in building the nest . It consists of branches, sometimes leaves are built in. The nest is flat and bowl-shaped and is built in a tree or shrub. Two ("real" Hokkos) or three to four (Chakalakas and shako chickens) eggs are laid, which are plain white or cream-colored. The dimensions of the eggs are 5.8 × 4.1 to 9.2 × 6.7 cm.

Only the female breeds. The male stays close to the nest and accompanies the female on excursions in search of food. These last about an hour, during which the nest is unguarded. It takes 24 to 34 days for the young to hatch. You are initially wrapped in a light brown and black patterned downy dress. As a fiduciary , they can walk around after just a few hours. In the "real" Hokkos and the Zapfenguan, the female alone is responsible for looking after the young, in other species both partners. The parent birds feed the young for a few months, with the shako chickens even predigested food is choked out, which is unique among hens.

In captivity, boiled chickens reached a maximum age of 24 years, and lifespans of more than twenty years are not uncommon. There is no reliable knowledge about life expectancy in nature.

Tribal history

The oldest Hokko chickens are known from the Oligocene . The genus Gallinuloides of the Eocene , formerly often referred to as the "oldest Hokkos", is no longer considered to be related to the Hokkos. Numerous fossil Oligocene and Miocene Hokko chickens have been found in North America, evidence that the family was once more widespread. Outside of the American double continent, however, no boiled chickens were found.

Systematics

External system

The most widespread, if not undisputed theory sees Hokkohühner as a sister group of the Australasian large foot fowl . Although the areas of distribution and, above all, the way of life are completely different, in addition to some anatomical similarities, biochemical studies of the eggs and DNA hybridization have further solidified this theory.

Internal system

Traditionally, Hokko chickens are divided into two subfamilies, the "real" Hokkos (Cracinae) and the shako chickens and Chakalakas (Penelopinae). The differences between these groups are clear: Cracinae are larger, have a more powerful beak and a proportionally larger pelvis . In addition, they are not as extreme tree-dwellers as the shako chickens and chakalakas.

On the basis of DNA analyzes, this classification could largely, but not completely, be confirmed. As a result, the "real" Hokkos are actually a monophyletic taxon . However, the genera Ortalis and Oreophasis are closer to these than the other Penelopinae. Based on these findings, the following classification results:

Bare-faced hokko ( Crax fasciolata )
Helmhokko ( Pauxi pauxi )
Rust-bellied Guan ( Penelope purpurascens )

Cladogram according to Pereira, Baker and Wajntal:




Ortalis


   

Oreophasis


   

Crax


   

Nothocrax


   

Pauxi


   

With U







   


Chamaepetes


   

Penelopina



   

Penelope


   

Aburria


   

Pipile






Humans and Hokko chickens

use

The people of South and Central America have always known the Hokkohenner. Although they mostly live in secret, they cannot be ignored because of their far-reaching vocalizations. The Maya Yucatans have their own name for each species. There are onomatopoeic paraphrases for the calls of some species. This is how one interprets the call of the female red-winged guan in Colombia as ¿Se cae la casa? (“Is the house falling over?”), And the male's reply as ¡No se cae, no se cae! (“No, it won't fall over!”). Accordingly, the call of the chacoguan is interpreted as Quero casar pelo natal ("I want to get married for Christmas").

Even the Maya used the feathers of the Hokkohenner for the fletching of their arrows and ate the meat. As a food, Hokkos still play an important regional role today. In the Peruvian part of the Amazon, the blue-throated guuan is the most hunted bird and is an important source of protein. Real domestication of the Hokkohenner has never occurred. In some villages they are kept semi-tame, but not bred. They cannot be kept together with domestic chickens , as both species are incompatible with each other.

Breeding in zoos has been successful for a number of species. Hokkos were first brought to Europe in the 17th century. Because they came from Curacao , they got their English name curassows . However, they were probably initially imported to Curacao, because according to today's knowledge, Hokkohenner were never native there. Breeding as a meat and egg supplier was attempted in Europe, but it was not worthwhile because the clutch is too small and the birds are too sensitive to cold.

Threat and protection

Especially due to the increasing deforestation , many Hokko chickens are endangered or even threatened with extinction. Only the Chakalakas also adopt secondary forests as habitat, while shaku chickens and "real" Hokkos are dependent on untouched primary forests . In 2008 the IUCN listed almost half of all species in a hazard category. Six species are listed as critically endangered , three as critically endangered and one as extinct in the wild .

The four most endangered boar chickens are:

  • White-winged Guan ; the species was described in 1877 but not seen again after that year until it was rediscovered in Lambayeque in 1977 . It is now known that there are fewer than 100 copies in Lambayeque and Piura . There is a captive breeding program to save the species.
  • Trinidad Guan ; this bird, endemic to Trinidad, used to be very common. Due to the deforestation of the island, only 70 to 200 individuals in the east of the Northern Range have survived.
  • The blue-ragged hokko is restricted to a tiny distribution area in the Serrania de San Lucas in northern Colombia. In 1994 the population was estimated at 1000 to 2500 birds. After that, however, there was a gold rush , as a result of which the population collapsed completely. The current population is estimated at 250–999 animals.
  • The Mituhokko (or Mitu) was described in the 17th century, but then not seen for so long that its existence was already considered a legend. A dead animal was found for the first time in 1951, and in 1978 - after 300 years - a living Mituhokko was seen again. The species was endemic to the Brazilian state of Alagoas . Since the rainforests of this region have now been completely destroyed, survival in nature is almost impossible. However, specimens caught in 1978 formed the basis of a population in the Rio de Janeiro Zoo , so the species still exists in human care.

Sources and further information

Sources cited

Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:

  1. ^ Bernhard Grzimek: Grzimeks Tierleben , Volume 7 ( Birds 1 ). Kindler 1970, ISBN 3-423-03205-7
  2. ↑ Gerald Mayr: The fossil record of galliform birds: comments on Crowe et al. (2006) . In: Cladistics 2008, No. 24, pp. 74-76
  3. ^ M. Laskowski, WM Fitch: Evolution of avian ovomucoids and of birds . In: B. Fernholm, K. Bremer, H. Jörnvall: The hierarchy of life: molecules and morphology in phylogenetic analysis . Excerpta Medica, Amsterdam 1989
  4. ↑ CG Sibley, JE Ahlquist, BL Monroe: A classification of the living birds of the world based on DNA-DNA hybridization studies. In: Auk 1985, No. 105, pp. 409-423
  5. ^ A b Sergio L. Pereira, Allan J. Baker, Anita Wajntal: Combined Nuclear and Mitochondrial DNA Sequences Resolve Generic Relationships within the Cracidae (Galliformes, Aves) . In: Systematic Biology 2002, No. 51 (6), pp. 946-958
  6. ↑ David W. Winkler, Shawn M. Billerman, Irby J. Lovette: Bird Families of the World: A Guide to the Spectacular Diversity of Birds. Lynx Edicions (2015), ISBN 978-8494189203 . Page 46 and 47.
  7. ↑ Alfredo J. Begazo, Richard E. Bodmer: Use and conservation of Cracidae (Aves: Galliformes) in the Peruvian Amazon . In: Oryx 1998, No. 32 ($), pp. 301-309
  8. ↑ Penelope albipennis in the endangered Red List species the IUCN 2011. Posted by: BirdLife International, 2010. Accessed November 13, 2011th
  9. ↑ Pipile pipile in the Red List of Threatened Species of the IUCN 2011. Posted by: BirdLife International, 2010. Accessed November 13, 2011th
  10. ↑ Crax alberti in the endangered Red List species the IUCN 2011. Posted by: BirdLife International, 2010. Accessed April 19, 2012th
  11. ↑ Mitu mitu in the endangered Red List species the IUCN 2011. Posted by: BirdLife International, 2010. Accessed November 13, 2011th

literature

Web links

Commons : Hokkohühner (Cracidae)  - Collection of images, videos and audio files