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ссылка на сообщение  Отправлено: 06.06.22 17:17. Заголовок: Fauna of Pacific Islands


I'm making this new topic to discuss the animals living in the Pacific islands. Since there is so many islands in the world, I believe that discussing about them in only one topic would be confusing. So, for the sake of organization, I'll leave the other topic that I did to discuss only the fauna of Atlantic islands.
To start this topic, I want to talk about the Easter Island. I believe that it would have an interesting fauna, with a combination of species introduced by the humans here and those from the close Eonesia. For example, the Chilean tinamou (Nothoprocta perdicaria) that was introduced here could have a flightless descendant in the Neocene of the island.

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ссылка на сообщение  Отправлено: 06.06.22 18:25. Заголовок: JOrnitho Great! The..


JOrnitho
Great! The Easter Island could have interesting fauna due to its isolation from continents.
A flightless large ratite-like bird is a good idea!

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ссылка на сообщение  Отправлено: 07.06.22 16:25. Заголовок: I made the descripti..


I made the description of this bird. For the predator of Easter Island, I was thinking that it could be a large bird of prey, similar to the haast eagle, that came from South America. What do you think?

False-nandu (Paranandu pumilus)
During the Holocene, the man introduced many species to other continents. Those that were able to survive left descendants in the Neocene. The false-nandu is one of them. This species is a large and flightless descendant of the Chilean tinamou (Nothoprocta perdicaria) which were introduced by the humans in Easter Island. This species inhabits all areas of the Island, being the largest herbivorous animal living on it.
As its name says, the false-nandu is similar to the extinct South American rhea. This species stands at 60 to 90 cm and has a length of 110 to 135 cm. The false-nandu is sexually dysmorphic. The males are brown above, barred with blackish colouration, and white below, with a long grey neck and head. Their breast and lower neck sides are chestnut and there is a pale brown wash to the back. They also have a black crest that is long, thin, and straight. The breast and neck of the female are buff, with brown and pale colouration over the rest of the plumage, also lacking the crests. Immature birds resemble females.
Differently from many flightless birds, the false-nandu maintained its wings. However, they are small and can't be used to fly. Their wing feathers were also modified, with the males having fluffy pure white primaries and secondaries, while in the females they are pale grey. Such fluffy feathers aren’t useful to fly, being used by the males for courtship.
The tail is very short. They have a gray and curved bill. The legs are pinkish red and strong, allowing them to run. The feet have long claws, which are used both to excavate the ground and to defend against a possible predator, or to be used in territorial fights.
The false-nandu eats seeds, berries, leaves, fruits and small animals. Mostly of the elements in their diet are collected in low branches or in the ground. The fruits and seeds are usually those that fell from the trees.
These birds are solitary during most of the year, but in the summer, when the mating season starts, they form pairs. The male will construct a rough nest in a semi-sheltered hollow on the ground in the center of his territory, using bark, grass, sticks and leaves to line it. Then, he will start to vocalize, as an invitation for the females. They will enter the male’s territory and follow his calls until reaching the place of the nest. Once he sees her, the male will flap his wings and sit on the nest with wings open, allowing the female to see his white feathers here. She will proceed to circle him and the nest, pulling her neck back while puffing out the feathers and flapping her wings. If she approves the male, the female will emit a low call to invite him to join her. Then, he will move closer, stretching his neck and erecting his feathers and will start to circle the nest with her. If another female appears, the incumbent female will try to repel them, usually by chasing and kicking.
The pair mate every day or two, and every second or third day the female lays one of a clutch of 6 to 15 very large, thick-shelled, green eggs. The eggs are incubated only by the male. During this period he does not eat, drink, or defecate, and stands only to turn the eggs, which he does about ten times a day. The incubation period lasts 50 days, during this period the female stays and defends the nest. When the chicks start hatching, she returns to her territory. Newly hatched chicks are active and can leave the nest within a few days of hatching; they will stay with the father until 6 months, when they will disperse to find their own territory. The lifespan of the false-nandu is 28 years.

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ссылка на сообщение  Отправлено: 07.06.22 16:58. Заголовок: JOrnitho Another fa..


JOrnitho
Another "false" creature, ha-ha But a good one!

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ссылка на сообщение  Отправлено: 07.06.22 19:29. Заголовок: Биолог пишет: Anoth..


Биолог пишет:

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Another "false" creature, ha-ha But a good one!


Yes! Hahahaha
I was going to name it as giant tinamou, but there is already a bird with this name, so I went to the second name that made sense.

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ссылка на сообщение  Отправлено: 08.06.22 11:31. Заголовок: JOrnitho It's O..


JOrnitho
It's OK, don't worry

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ссылка на сообщение  Отправлено: 08.06.22 14:24. Заголовок: I was thinking that ..


I was thinking that the largest predator of the island could be a bird of prey, like the extinct haast eagle of New Zealand. Its ancestor could be a descendant of the cinereous harrier (Circus cinereus) that moved from South American to here. Finding a habitat lacking even owls, these birds could have originated two species: the large diurnal predator and one that was owl-like that hunts during the night.

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ссылка на сообщение  Отправлено: 08.06.22 16:39. Заголовок: JOrnitho Good ideas..


JOrnitho
Good ideas! But two different descendants of the same ancestor on an island (a limited habitat) seem unlikely: it can hardly develop a population so rich that it can split in two on the same island.

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ссылка на сообщение  Отправлено: 08.06.22 17:33. Заголовок: Биолог пишет: But t..


Биолог пишет:

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But two different descendants of the same ancestor on an island (a limited habitat) seem unlikely


In this case, I think that the large predator could be a descendant of the buzzar-eagle that reached the island coming from South America. With the presence of such large predator, the harrier would be forced to adapt to other niche. In this case that of an owl, feeding during the night by hunting the descendants of Polynesian rats.
Would bats be capable to reach the islands? If not, maybe a nocturnal species of passerine could have settled here, with the ancestor coming from South America or from Eonesia.

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ссылка на сообщение  Отправлено: 08.06.22 17:58. Заголовок: JOrnitho a descenda..


JOrnitho

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a descendant of the buzzar-eagle


Looks good, but note that the Haast's eagle had large prey - the moa. Your eagle has two ways: first is to become conspicuously smaller, while the second is to provide it with large prey. The second one needs a much larger island (near the size of New Zealand or at least New Caledonia). The size of the island (determining the limits of habitat and resources) is crucial here.

 цитата:
Would bats be capable to reach the islands?


Why not? They are present on New Zealand, which is not so far. But the new island for them must prodvide a diet, either vegetarian or predatory, sufficient for a constant population.

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ссылка на сообщение  Отправлено: 08.06.22 20:01. Заголовок: Биолог пишет: but n..


Биолог пишет:

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but note that the Haast's eagle had large prey - the moa.


Their main prey would be the false-nandu, which is a large bird. Of course, this eagle would not have same size of a haast-eagle, but would be strong enough to kill the false-nandu.

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ссылка на сообщение  Отправлено: 08.06.22 20:06. Заголовок: Биолог пишет: But t..


Биолог пишет:

 цитата:
But the new island for them must prodvide a diet, either vegetarian or predatory, sufficient for a constant population.


I think that after the extinction of the humans, Easter Island would be able to recover some forests and there would insects and fruits to feed the bats. I also think that passerines that appear on this island would be close related to Eonesia.

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ссылка на сообщение  Отправлено: 09.06.22 11:41. Заголовок: JOrnitho Their main..


JOrnitho

 цитата:
Their main prey would be the false-nandu, which is a large bird. Of course, this eagle would not have same size of a haast-eagle, but would be strong enough to kill the false-nandu.


OK.

 цитата:
after the extinction of the humans, Easter Island would be able to recover some forests


Insectivorous or small predatory bats seem the most likely.

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ссылка на сообщение  Отправлено: 09.06.22 15:30. Заголовок: Биолог пишет: Insec..


Биолог пишет:

 цитата:
Insectivorous or small predatory bats seem the most likely.


I agree. I think that they would be close related to those of South America rather than of Asia.
The fruits and nectar in the island would be consumed by birds. Would be interesting if one of these birds is a descendant of a South American tanager (Thraupidae)? This ancestor could generate a frugivorous and nectarivorous genera.

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ссылка на сообщение  Отправлено: 09.06.22 18:39. Заголовок: JOrnitho they would..


JOrnitho

 цитата:
they would be close related to those of South America rather than of Asia


OK.

 цитата:
The fruits and nectar in the island would be consumed by birds. Would be interesting if one of these birds is a descendant of a South American tanager (Thraupidae)


Quite plausible, why not? Tanagers are beautiful!

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ссылка на сообщение  Отправлено: 10.06.22 01:11. Заголовок: Биолог пишет: Tanag..


Биолог пишет:

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Tanagers are beautiful!


Yes! They are my favourite group of Neotropical birds. I hope to be able to work with them when I do my Master degree some day.

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ссылка на сообщение  Отправлено: 10.06.22 12:56. Заголовок: JOrnitho when I do ..


JOrnitho
Скрытый текст


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ссылка на сообщение  Отправлено: 12.06.22 17:01. Заголовок: I finished the descr..


I finished the description for the largest predator of Easter Island, with some alterations from the original idea.

Rapa Nui caracara (Sociophalco insularis)
The human actions during the Holocene caused the collapse of many ecosystems. Easter Island was one of these cases. This place was completely deforested and many of its endemic species perished. However, with the arrival of the Neocene it was able to recover, developing a new endemic fauna. One of the species living here is the Rapa Nui caracara, a descendant of the chimango caracara (Mivalgo chimango) that arrived in the island coming from South America and evolved here to this new species.
The Rapa Nui caracara is larger than their ancestor, having a total length of 65 cm and a wingspan of 132 cm. The female is larger than the male. This species has a mantle and back with cinnamon brown feathers. Neck, chest, abdomen and belly are dark brown, while the head is pale. The tail is light brown with a white terminal band. The legs are orange in the male and light yellow in the female and hatchlings. Their claws are long and sharp, being capable of inflicting deep wounds. The wings are quite broad, an adaptation that increases maneuverability in forested areas of their habitat. Their shoulders are chestnut and dark grey primaries and secondaries, with white tips.
This species is the largest predator of Easter Island, hunting even the false-nandu. While most raptors are solitary, only coming together for breeding and migration, the Rapa Nui caracara will hunt in cooperative groups of two to six. When hunting, all the caracaras spread around the prey and one bird starts chasing it out. To bring the false-nandu down, these birds will take turns to attack the prey, causing several wounds until the false-nandu bleeds to death. These birds will often chase prey on foot, and are quite fast on the ground and their long legs are adapted for this.
These birds are monogamous, forming pairs that remain together for the rest of their lives. They nest in the top of trees. It’s made of sticks, plant roots, and stems, and are often lined with leaves, moss, bark and plant roots. They are built mainly by the female. There are usually two white to blueish white eggs sometimes with a speckling of pale brown or gray. The nestlings start out light buff, but in five to six days turn a rich brown. The incubation lasts for 36 days. The young begin to explore outside the nest at 38 days, and fledge at 45 to 50 days. The female sometimes breeds two or three times in a year. Young stay with their parents for up to three years, helping to raise later broods. They reach sexual maturity with 5 years and have a lifespan of 27 years.

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ссылка на сообщение  Отправлено: 12.06.22 17:42. Заголовок: JOrnitho Good one!..


JOrnitho
Good one!

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ссылка на сообщение  Отправлено: 12.06.22 18:25. Заголовок: JOrnitho, we've ..


JOrnitho, we've made a record of your idea about the Easter Island for a future potential chapter. It can be seen in our Collection of Potential Chapter Ideas topic, #53 in the starting post of the topic.

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ссылка на сообщение  Отправлено: 12.06.22 18:59. Заголовок: Good one, but I see ..


Good one, but I see a bit of controversy in that its claws are sharp yet it runs pretty much on the ground. Won´t the claws become blunt from running?

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ссылка на сообщение  Отправлено: 12.06.22 19:15. Заголовок: медведь пишет: Won&..


медведь пишет:

 цитата:
Won´t the claws become blunt from running?


Good point. I was thinking that this bird could move like the Harris' hawk when hunting. They have sharp talons, but still can move well on land. I think that the caracara would land, chase after the prey, fly again and land. Repeating this process during the hunt.

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ссылка на сообщение  Отправлено: 12.06.22 19:36. Заголовок: By the way, I finish..


By the way, I finished another description.

White crested pigeon (Lophocolumba elegans)
During the Holocene, the man introduced many species to other continents. Those that were able to survive left descendants in the Neocene. The white crested pigeon is one of them. This species is a descendant of the rock pigeon (Columba livia) which was introduced by the humans in Easter Island. This species now inhabits all areas of the Island, being one of the members of its endemic fauna.
The white crested pigeon has 40 cm of length and 72 cm of wingspan. The head, back and rump are slate-gray. The tail is dark gray with white tips. Their main characteristic is the pure white crest coming from the cere to the forehead. Their neck, chest and belly are also white, while the wings are iridescent green. The beak is red, while the legs and feet are pale pink. The male has a bright blue cere, while it's pale in the females and subadults.
These birds are omnivorous, but prefer plant matter: chiefly fruits and grains. They forage both in open areas and in trees. Larger flocks of white crested pigeons can be seen feeding on fruits at trees.
The white crested pigeon is gregarious, forming flocks of 20 to 50 individuals. Such groups can become larger when there is too much food. They are socially monogamous, but extra-pair matings do occur, often initiated by males. This bird breeds at any time of the year, but peak times are spring and summer. Nesting sites are along coastal cliff faces, sometimes close to the colonies of seabirds. Due to their ability to produce crop milk, pigeons can breed at any time of year.
During courtship, the male will stay on the top of a tree cooing loudly. If a female is interested, she will land in a branch near to him. Then, he will start to puff up the feathers on his neck to appear larger, while flapping his iridescent wings. At first, the female invariably flies a short distance away and the male follows her until she stops. At this point, he repeats the same ritual in front of her. The male then proceeds to feed the female by regurgitating food, as they do when feeding the young. The male then mounts the female. The mating is very brief, with the male flapping his wings to maintain balance on top of the female.
The nest is a flimsy platform of straw and sticks, laid on the ledge of rocks, under cover, often on cliffs. Two white eggs are laid; incubation, shared by both parents, lasts 19 days. The newly hatched nestling has pale yellow down and a flesh-coloured bill with a dark band. For the first few days, the chicks are tended and fed exclusively on "crop milk". The pigeon milk is produced in the crops of both parents. The fledging period is about 30 days. They reach sexual maturity with 2 years and have a lifespan of 19 years, but many are killed early by predators.

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ссылка на сообщение  Отправлено: 13.06.22 11:46. Заголовок: JOrnitho Good pigeo..


JOrnitho
Good pigeon!

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ссылка на сообщение  Отправлено: 16.06.22 03:24. Заголовок: I was thinking if Eo..


I was thinking if Eonesia could have some species of passerines that have great sexual dismorphism, like the birds-of-paradise. They could also be descendants of South American Thraupidae. Or perhaps of the Pipridae (manakins).

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Из скромности умолчу.




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ссылка на сообщение  Отправлено: 16.06.22 05:48. Заголовок: In one article I had..


In one article I had seen an info on the opposite trend in the evolution of island-dwelling birds. Lesser species variety lowers the competition, so the features of sexual dimorphism are less expressed in island species compared to its mainland relative.

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ссылка на сообщение  Отправлено: 16.06.22 17:12. Заголовок: Автор пишет: Lesser..


Автор пишет:

 цитата:
Lesser species variety lowers the competition, so the features of sexual dimorphism are less expressed in island species compared to its mainland relative.


This is interesting. What if this descendant of the Thraupidae have both males and females with similar appearance and doing elaborated mating rituals together?

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Пост N: 5582
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ссылка на сообщение  Отправлено: 16.06.22 19:23. Заголовок: JOrnitho пишет: bot..


JOrnitho пишет:

 цитата:
both males and females with similar appearance


Yes, and they may look like female more probably
JOrnitho пишет:

 цитата:
doing elaborated mating rituals together?


here I have lots of serious doubts. If the coloration turns duller, the mating ritual seems to tend to simplification compared to mainland species. Mating ritual is an energy-demanding action, and in island conditions (= limited resources) it seems to be less profitable for survival, than in conditions of strict competition of mainland habitats.

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ссылка на сообщение  Отправлено: 17.06.22 00:37. Заголовок: Автор пишет: If the..


Автор пишет:

 цитата:
If the coloration turns duller, the mating ritual seems to tend to simplification compared to mainland species.


I understand. Would be possible for the males of these birds to have complex songs? They could still use it for attract females and to show that they are health.

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ссылка на сообщение  Отправлено: 17.06.22 11:34. Заголовок: JOrnitho Would be p..


JOrnitho

 цитата:
Would be possible for the males of these birds to have complex songs?


Why not? If they live in dense forests, song calls is a good idea.

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ссылка на сообщение  Отправлено: 21.06.22 17:48. Заголовок: I finished the descr..


I finished the description of some of the Eonesian tanagers.

Atarapan symphonic tanager (Paratangara atarapaensis)
With the passing of the Holocene to the Neocene, the movements of tectonic plates caused the changes in the disposition of the continents and the appearance of new islands. The islands of Eonesia are some of these that appeared during this new geological period. These new habitats gave opportunity for the animals that could reach them. There they found new resources and evolved into new species. The symphonic tanager of the Genus Paratangara, part of the Family Thraupidae, is endemic to the islands. Their ancestors reached Eonesia coming from Central America. The type species of the genus is the Atarapan symphonic tanager, an endemic species to the forests of the Atarapa islands.
The Atarapan symphonic tanagers have 15 cm of length and 27 cm of wingspan. These birds have a bright red plumage on the head, neck, back and rump. The chest and belly are bright green. The wings, ear-coverts and tail is black. While there wasn’t a great sexual dismorphism, the females' plumage is a bit duller. The beak and legs are dark gray.
These birds eat mainly fruits and small buds. The fruits are usually swallowed whole, with the seeds being regurgitated. Insects are also taken, mainly from the underside of branches. 
The Atarapan symphonic tanager is usually found in pairs, but sometimes small groups are formed. The males have elaborate songs that they use to attract the females. This species is monogamous, with pairs staying together for the rest of their lives. While they are mostly silent, the females will vocalize with the males. They form a "duet" that is used to strengthen the pair's bond. When they are in a flock, the birds will vocalize in such a way that reminds of a natural symphony. The parents work together to build the nest, but only the female incubates them. One to three, usually two, dark-marked whitish to gray-green eggs are laid in a deep cup nest in a high tree fork. Incubation lasts for 14 days with the chicks fledging after 17 days. They reach sexual maturity with 11 months and have a lifespan of 12 years.
The Genus Paratangara have other two species that also inhabits Eonesia:

Burotu symphonic tanager (Paratangara burotuensis)
This species inhabits the Burotu islands. They have 13 cm of length and 25 cm of wingspan. These birds have a bright orange plumage on the head, neck, back and rump. The chest and belly are bright green. The wings, ear-coverts and tail is black. Their song is also different of the Atarapan species.

Fisaga symphonic tanager (Paratangara fisagaensis)
This species inhabits the Fisaga islands. They have 16 cm of length and 31 cm of wingspan. These birds have a bright yellow plumage on the head, neck, back and rump. The chest and belly are bright bluish-green in the males, with the females being a duller green. The wings, ear-coverts and tail is black. Their song is also different from the other previous species.

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ссылка на сообщение  Отправлено: 21.06.22 17:49. Заголовок: JOrnitho Good ones,..


JOrnitho
Good ones, thank you!

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ссылка на сообщение  Отправлено: 21.06.22 18:37. Заголовок: JOrnitho пишет: Ata..


JOrnitho пишет:

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Atarapan symphonic tanager


Very good!
Suitable for the chapter of the Atarapa islands http://sivatherium.borda.ru/?1-6-1634149619956-00000280-000-10001-0#034.002.001.001

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ссылка на сообщение  Отправлено: 21.06.22 19:24. Заголовок: wovoka Um... The pr..


wovoka
Um... The problem is that the bestiary you refer to is already quite full and unlikely to have more birds in it.

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ссылка на сообщение  Отправлено: 21.06.22 20:01. Заголовок: Биолог пишет: Um.....


Биолог пишет:

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Um... The problem is that the bestiary you refer to is already quite full and unlikely to have more birds in it.


There are chapters with 17 species.

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ссылка на сообщение  Отправлено: 22.06.22 06:40. Заголовок: I finished the descr..


I finished the description of the owl-like harrier of Eastern Island.

Owl-harrier (Strigocircus solitarius)
The human actions during the Holocene caused the collapse of many ecosystems. Easter Island was one of these cases. This place was completely deforested and many of its endemic species perished. However, with the arrival of the Neocene it was able to recover, developing a new endemic fauna. One of the species that is now living here is the owl-harrier, a descendant of the cinereous harrier (Circus cinereus) that reached the island after the disappearance of humanity.
When their ancestors reached the island, they found that no species of owl lived here. This way the owl-harrier evolved to fill the niche of these birds. This bird is crepuscular, being more active during the dusk and early hours before dawn.
The female of the owl-harrier is larger than the male with an average size of 46 cm compared to the male's 40 cm. The wingspan is 90 to 115 cm. Both sexes have a 40 cm long tail. Morphologically, these birds are similar to an owl. They have large eyes that allow them to see during the night and a good hearing. Their plumage is dark grey above with black wingtips and a dark brown rump. The underparts are pale grey, with a rufous streaked belly. The face is chestnut brown with a black border. The beak and legs are dark grey.
This species eats mainly rodents and bats, but also birds that are sleeping in branches during the night. Insects are also eaten, but more occasionally.
While being monogamous and sharing a territory, the pair stays separated during most of the year, with only some occasional meetings happening. They come together durig their breeding season, which starts during the summer. During this period, males and females reforce their bond by engaging in nocturnal aerial courtship displays and chatter very loudly. This is the only period that they vocalize more frequently, being silently birds most of the time. The nest is built hidden in rock crevices. Nests are made of sticks and are lined inside with grass and leaves. Four to eight whitish eggs are laid by the female, who incubates them for 32 days. When incubating eggs, the female sits on the nest while the male hunts and brings food to her and the chicks. The male will help feed chicks after they hatch, but does not usually watch them for a greater period of time. The male usually passes off food to the female, which she then feeds to the young, although later the female will capture food and simply drop into the nest for her nestlings to eat. The chicks fledge at around 36 days old, though breeding maturity is not reached until 2 years in females and 3 years in males. Their lifespan is of 22 years.

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ссылка на сообщение  Отправлено: 22.06.22 10:59. Заголовок: JOrnitho Another go..


JOrnitho
Another good species, I've added it to the catalogue.

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ссылка на сообщение  Отправлено: 06.07.22 04:29. Заголовок: Beyond working in id..


Beyond working in ideas for plants of Easter Island, I also thought about some other animals that could fill some niches here: a hamster-like rat eating fallen fruits and tubercules (sweet potato and yam), a parakeet to eat fruits of palm trees, a wren or warble to eat insects, an aquatic rallid and a dwarf descendant of the chicken to eat in the forest floor. Is it too much for the island? With its size, the false-nandu would be capable to reach food in places that the dwarf chicken couldn't and the hamster-like rat would be the prey of the owl harrier.

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ссылка на сообщение  Отправлено: 06.07.22 11:31. Заголовок: JOrnitho Good ideas..


JOrnitho
Good ideas!

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ссылка на сообщение  Отправлено: 07.07.22 04:23. Заголовок: I finished the descr..


I finished the description of more animals for Easter Island.

Скрытый текст


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ссылка на сообщение  Отправлено: 07.07.22 11:42. Заголовок: JOrnitho Wow, five ..


JOrnitho
Wow, five in a row! Thanks!

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ссылка на сообщение  Отправлено: 07.07.22 15:05. Заголовок: Would a hummingbird ..


Would a hummingbird be capable of reaching the island? Or another bird could have evolved to feed on nectar and thus help with pollination?

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Из скромности умолчу.




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ссылка на сообщение  Отправлено: 07.07.22 19:01. Заголовок: JOrnitho пишет: Wou..


JOrnitho пишет:

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Would a hummingbird be capable of reaching the island?


Their flight abilities make it possible. So, it's not a main question here.
JOrnitho пишет:

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to feed on nectar and thus help with pollination


Here is the question. The flora of islands is usually rather poor. So, Stephen Buchmann and Gary Paul Nabhan in their book "The Forgotten Pollinators" noted the poor flora and pollinator diversity of the Galapagos Islands compared to the continent. Of course, Hawaii seem to ba an exception, but I think the fauna of pollinator birds at the remote islands of non-continental origin must be poor.

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ссылка на сообщение  Отправлено: 07.07.22 19:48. Заголовок: Автор пишет: but I ..


Автор пишет:

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but I think the fauna of pollinator birds at the remote islands of non-continental origin must be poor.


I see. Then I think that it would be more probably that insects are the ones doing pollination here.

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