Western diving goose (Brantamergus occidentalis) During the Holocene, humans interfered with nature through several ways. While some local species suffered and had their populations reduced, others were introduced to many other continents. Sometimes, the local and introduced species were close enough to each other, being part of the same Genus. In these cases, they could reproduce with each other, giving origin to hybrids that would share the genes of both species. The western diving goose is an example of species that originated under these conditions. These birds originated from Western Europe and are the result of the long time hybridization between the barnacle goose (Branta leucopsis) and the Canadian goose (Branta canadensis), which was introduced in European lands by the humans. This species spends the summer in the coastal and estuarine areas of Scandinavia and in islands of the Barents Sea and Kara Sea. During the winter, these birds migrate in large flocks to the Bay of Biscaya. They are small and compact birds, with a short neck. Both male and female have 54 cm of length and a wingspan of 87 cm. They have a black neck with a white "chinstrap", while their head has a black strip crossing their eyes and joining the black of the neck. The top of the head is white. They also have grayish brown backs and wings, silver-gray rump, black tail feathers. Its belly is white, while the chest is pale gray. Adults also have a white neck ring at the base of the neck. The beak, legs and feet are dark gray. The main characteristic of this species are their large webbed feet, which they use to swim underwater. Due to that, these birds are slow and clumsy when moving on land. The western diving goose feeds on algae, crustaceans, molluscs and sometimes small fish that it catches by diving underwater. While doing it, these birds only use their large feet for propulsion. This adaptation allows these birds to avoid competition with the larger species of goose that feed on land, such as Hemiswans and the Gainsboro geese. During the second year of their lives, western diving geese find a mate. They are monogamous, and most couples stay together all of their lives. If one dies, the other may find a new mate. The female lays from two to nine eggs, and both parents protect the nest while the eggs incubate, but the female spends more time at the nest than the male. The nest is frequently built high on mountain cliffs close to the sea and away from predators. Like all geese, the goslings are not fed by the adults. Instead of bringing food to the newly hatched goslings, the parents show them the way to jump from the cliff and the goslings follow them by instinct and take the plunge. Unable to fly, the goslings jump off the cliff and fall. However, their small size, feathery down, and very light weight helps to protect some of them from serious injury when they hit the rocks below, but many die from the impact. While some families still need to do a clumsy walk toward the water, others are lucky enough to have nests so close to the sea that the goslings fall directly on the water. The goslings enter the fledgling stage with 8 weeks of age. They do not leave their parents until after the spring migration, when they return to their birthplace. The sexual maturity of this species is reached when they have two years and the lifespan is of 27 years. The western diving goose has a subspecies called American diving goose (B. o. americana), which nests in Greenland and in areas close to the Baffin and Labrador Sea. During winter, they migrate to the Gulf of Mexico. The plumage between the two is similar, but the American one is smaller. The eastern diving goose (Brantamergus leucocephalus) is another representative of the Genus Brantamergus. With 50 cm of length and 83 cm of wingspan, this species is the smallest of the Genus. Their plumage is similar to that of its western counterpart, with the exception of the head that is totally white. This species nests on the islands in the seas of Okhotsk and Bering, with their largest colony being located in the cliffs of the Kuril Islands. During winter, they migrate to the coastal areas of the East China Sea.
Steppe goose (Geochen migratorius) During the Holocene, humans introduced many species to other continents. With their extinction, some of these creatures continued to thrive, giving rise to new genera. The steppe goose of the Genus Geochen is a representative of this situation. This bird is a descendant of the Egyptian goose (Alopochen aegyptiaca) who had been introduced by humans to Western Europe. This species evolved to live in forested steppes and grassland of Europe, with the easternmost part of its range being North of the Fourseas. During winter, this species migrates to the savannas of Africa and Zinj Land. This species only forms flocks when they are in their wintering areas. While breeding, the pairs will not tolerate the presence of others of the same species. The steppe goose has 64 cm of length and 110 cm of wingspan. This species is highly dysmorphic, with the males being slightly larger than the females. The plumage between the two is also different. The males have a black neck and head, with a bright auburn circle around their eyes. Their chest is chestnut and their body is white. The wing coverts are black, the primary are dark grey, and the secondaries green and chestnut. The females have a pale gray neck and head, with a brownish-red circle around their eyes. Like the males, they also have a chestnut chest and white body, but their wing coverts are pale gray, with the primary and secondaries being brown. Both male and female of this species have a serrated beak, which allows them to crush their food and catch small animals. Both the beak, legs and feet are red. Their legs are longer than that of their ancestors, which allows them to run swiftly through the grassland. During its evolution, the web present on the feet of the steppe goose became greatly reduced. This was an adaptation for the terrestrial lifestyle that this species adopted. Even then, they will occasionally appear in shallow freshwater reservoirs to eat molluscs, plants and crustaceans. However, they swim poorly, only staying in places where the water doesn't cover their legs. With the exception of the occasional aquatic food that they eat, most of the steppe goose's diet comes from things that they can find in the grasslands and steppes. They eat seeds, leaves, grasses and plant stems. However, they have preference for locusts, worms, or other invertebrates, which increases during the nesting season. This species is monogamous, with pairs staying together even during the migration. Usually, their nests are built on hollowed trees, rock crevices and empty nests of other birds that are high enough from the ground. It forces the goslings to jump down from there. However, some will also build nests in the ground, hidden among the vegetation. During the breeding season, these birds are very aggressive, not tolerating individuals of the same species to make nests near them. Predators that approach the nest are attacked mercilessly, including birds of prey. In these cases, the female will distract them by flying while the male targets their wings, seeking to make them fall off the sky. Even peaceful herbivores that decide to graze near the nest will be attacked. Individuals that make nests in the ground are more agressive. The female lays eight eggs in a nest made of reeds, leaves and grass and both parents take turns incubating them. The incubation period lasts for 33 days with only the female looking after the nest, the male remains near the nest, protecting it against predators. The goslings leave the nest immediately after hatch The fledging period for the downy young lasts on average eight weeks. The young remain with the parents during the migration, but once arriving on their wintering grounds they leave them.
Пост N: 2236
Откуда: Крысиный Мир, нора номер ###
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Отправлено: 12.01.24 21:39. Заголовок: JOrnitho I think it..
JOrnitho I think it's good idea - barbary macaques already live in Europe, but they're endangered, so their convergent analogue can appear in Neocen. However, it shouldn't be European endemic species - in Neocene, Iberian peninsula is connected to Atlas Mountains.
Отправлено: 13.01.24 00:10. Заголовок: лягушка пишет: I th..
лягушка пишет:
цитата:
I think it's good idea - barbary macaques already live in Europe, but they're endangered, so their convergent analogue can appear in Neocen. However, it shouldn't be European endemic species - in Neocene, Iberian peninsula is connected to Atlas Mountains.
Yes, I thought that it would be another species that arrived here when the Iberian Peninsula connected with Africa. Maybe the same ancestor of the black-handed guenon.
Отправлено: 16.01.24 23:59. Заголовок: I finished the descr..
I finished the description of the European monkey:
Basajaun, Iberian guenon (Eurosimia iberiana) Order: Primates Family:Cercopithecidae Habitat: Subtropical woodlands and scrubs of the Iberian region. In the Neocene, the Gibraltar Strait had closed, connecting Europe with Africa. It allowed an interchange of fauna and flora between the two continents. Among the newcomers were the guenons (Cercopithecidae), with their descendants evolving to new species such as the Black-handed guenon (Calypsopithecus melanopus). Another of their descendants is the basajaun, an inhabitant of subtropical woodlands and scrub of the Iberian region. They share their name with a mythological hominid from the Basque folklore. Basajaun is a large monkey. Males have a head-body length of 66 to 76 cm and typically weigh 16 to 30 kg. Females measure 53 to 62 cm in head-and-body length and weigh 7 to 15 kg. Their tail is 66 to 92 cm long. Males' canines are longer than those of the females. They have a long coat. The fur on the back is dark brown. The underfur is light-gray. In males, the rump and areas around the genitals are multi-colored, consisting of red, pink, blue and purple skin,blue and purple skin, with a red penis shaft and violet scrotum. The genital and anal areas of the female are red. The diet of the basajaun consists of a mixture of plants and insect prey. It consumes a large variety of gymnosperms and angiosperms. Almost every part of the plant is eaten, including flowers, fruits, seeds, seedlings, leaves, buds, bark, gum, stems, roots, bulbs, and corns. Common prey caught and consumed by them are snails, earthworms, scorpions, spiders, centipedes, millipedes, grasshoppers, termites, water striders, scale insects, beetles, butterflies, moths, ants, and tadpoles. They can also eat eggs, lizards, small mammals and birds. They use stones to break nuts. They search for food both on the trees and on the ground. They sleep during the night in trees. When resting in trees, they generally prefer the highest branches. The basajaun is gregarious, forming mixed groups of several females and males. Troops can have 20 to 100 individuals. At the core of social structures are males, which patrol the territory, protect group members, and search for food. Males remain in their natal communities, while females generally emigrate at adolescence. Males in a community are more likely to be related to one another than females are to each other. Among males, there is generally a dominance hierarchy, and males are dominant over females. Disputes for power between males inside a group are common, but in these cases displays of aggression are preferred over physical attacks. The males are much more aggressive in disputes with outsider males. Fights for territory and resources between groups can be brutal. Females enter in oestrus during late autumn, giving birth in early spring. They are promiscuous: during oestrus, females mate with several males in their community, while males have large testicles for sperm competition. During reproduction, females form coalitions to defend themselves against the advances of males. Males become attentive with them, trying to convince females to mate with them. A male and female can form a consortship and mate outside their community. In addition, females sometimes leave their community and mate with males from neighboring communities. Different of other primates, the males participate in rearing the young. Males may spend a considerable amount of time playing with and grooming infants. In this way, a strong social bond is formed between males and juveniles, both the male's own offspring and those of others in the troop. Dominant males are usually more attentive with the young than other males. This is a case of selectivity on the part of the females, whose coalitions will be more open to mate with males that help take care of the young. Given its promiscuous nature, newly established alpha males will not risk killing what could be their own offspring. Females usually have only one offspring per pregnancy, with case of twins being rare. Offspring reach maturity at seven to fourteen years of age, and may live for 40 years or more. A subespecies of the basajaun, the Pyrenean guenon (Eurosimia iberiana pyrenaica) inhabits the montane forests at the slopes of the Pyrenees. They are slightly large and have a denser fur. Their groups are also smaller, with 10 to 50 individuals. They climb down the mountains during the winter. Another subespecies, the Atlas guenon (Eurosimia iberiana africana), inhabits the woodlands and scrubs of North Africa, including the forests in the slopes of the Atlas Mountains. The members of this population are smaller, but form larger groups, with 25 to 150 individuals.
Good monkey, but why it lives only in former Iberian peninsula? Monkeys are quite adaptive, so I think that it may olso live in Atlas mountains.
My idea was originally for an European species. Do you think that the population living in the Atlas Mountains should be the same species or another one?
Пост N: 2241
Откуда: Крысиный Мир, нора номер ###
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Отправлено: 17.01.24 23:23. Заголовок: JOrnitho IMHO it sh..
JOrnitho IMHO it should be single species - it isn't much difference between conditions of Neocene Atlas and Iberia, they both are dry mountain upland regions with mediterranean climate, and monkeys are quite adaptive.
IMHO it should be single species - it isn't much difference between conditions of Neocene Atlas and Iberia, they both are dry mountain upland regions with mediterranean climate, and monkeys are quite adaptive.
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