Philippines eagle
| Philippines eagle | ||||||||||
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Philippines eagle ( Pithecophaga jefferyi ) |
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| Systematics | ||||||||||
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| Scientific name of the genus | ||||||||||
| Pithecophaga | ||||||||||
| Ogilvie-Grant , 1896 | ||||||||||
| Scientific name of the species | ||||||||||
| Pithecophaga jefferyi | ||||||||||
| Ogilvie-Grant, 1896 |
The Philippine eagle or monkey eagle ( Pithecophaga jefferyi ) is a very large and powerful bird from the hawk family (Accipitridae). The genus Pithecophaga is monotypical with the Philippine eagle as the only species. The Philippine eagle is endemic to the Philippines and inhabits primary rainforests, secondary forests and gallery forests there .
The main food of the Philippine eagle is tree-dwelling mammals, other mammals as well as larger birds and reptiles are also eaten. Due to continuous and rapid habitat destruction and hunting of the Philippine Eagle is loud IUCN threatened with extinction ( critically endangered ). If there are great uncertainties, the total number is estimated to be around 90 to 250 pairs, with a maximum of 340 pairs.
description
Philippine eagles are powerful birds of prey with a strikingly high but very narrow beak, an erect, long and loosely shaggy feather bonnet and relatively short but very broad wings. The tail is quite long and almost straight at the end, the legs are comparatively short but, like the toes, extremely strong. The tarsometatarsi are largely feathered. The species is similar in habit to the hawks and sparrows ( Accipiter ). The body length is 90-100 cm, the wingspan 184-202 cm and the weight 4.7-8.0 kg. The sexes do not differ in terms of coloration, but females are larger and heavier than males. More precise information on the extent of this sexual dimorphism is not yet available.
Adult birds are almost monochrome brown over the entire top. Back plumage and upper wing coverts are bordered in variable thickness beige or cream-colored. The wings are darker and more black-brown towards the tip. The upper side also brown control springs have a clearly separated white shaft and show three to four indistinct dark napkins, a wide and a narrow white Subterminalbinde tip. The skull, cap and neck are beige with long black dashes. The rein region is dark ash-colored, from the area around the eyes down to the upper throat the plumage shows fine black shaft lines on a beige background. The rest of the head, like almost the entire underside, is monochrome, creamy white. The leg fletching shows strong, the small under wing coverts weak reddish brown lines on this basis. The wings and control feathers are more silvery on the underside, the arm wings and the control feathers have wide, indistinct dark subterminal bands, the hand wings have faint dark bands and darker tips.
The iris is blue-gray to pale blue, the wax skin is dark green-gray to greenish black, the beak is black-gray. Legs and toes are yellow, the claws are black.
The juvenile plumage differs only slightly from that of the adult birds. The light-colored fringes of the upper side plumage are usually wider and more white than in adult birds, the arm wings are almost monochrome, and the subterminal band of the tail feathers is narrower and less noticeable. The iris is brown and the legs are lighter and more whitish yellow. It is not yet known at what age the young birds develop the adult dress.
Vocalizations
The calls are described differently, for example as strange-sounding whining or as long, soft or high- pitched whistles such as “whiiiiiiuh” , which usually rise in pitch, but occasionally also fall. Males are quite happy to call during courtship. Begging young birds utter conspicuous and far-reaching series of high and pointed calls.
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Phylogenetic system of the subfamily Circaetinae
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Name and system
The first specimen of the Philippine eagle was collected by John Whitehead on Samar in 1896 . The generic name Pithecophaga is derived from the Greek words πίθηκος, old Gr. pronounced píthēkos ("monkey") and φᾰγεῖν , pronounced phagein ("eat") put together, literally means "the monkey eater". This name was chosen by the first descriptor William Robert Ogilvie-Grant because the species should feed mainly on monkeys according to the stories of the natives on Samar. With the specific epithet jefferyi , Ogilvie-Grant honored Jeffery Whitehead, the father of John Whitehead.
For a long time, the Philippine eagle was placed in a subfamily Harpiinae of New Guinea together with the two neotropical species harpy eagle ( Harpia harpyja ) and strangler eagle ( Morphnus guianensis ) as well as the Papua eagle ( Harpyopsis novaeguineae ) . Common features of these species are the considerable size and the largely feathered tarsometatarsus, and there are similarities in behavior.
After molecular genetic studies of the Philippine Eagle is however not closely related with these three species, but to the subfamily Circaetinae to provide to inter alia, the short-toed eagle ( Circaetus ), the snake ordinations ( Spilornis ) and the jugglers ( Terathopius ecaudatus ) belong. The sister group of the Philippines eagle within the Circaetinae According to these studies, a group of species which the juggler, the snake Adler and snake Bussard ( Dryotriorchis spectabilis ) comprises. The latter was previously listed as a monotypical genre, but Lerner & Mindell could not confirm this special position. According to their results, the snake buzzard is to be placed with the short-toed eagles ( Circaetus ).
A systematic affiliation of the Philippine eagle to the Circaetinae was not previously suspected, Lerner & Mindell have therefore checked this finding several times and with the DNA of three different individuals, always with the same result. The similarities with the other three species of the subfamily Harpiinae confirmed as Monophylum are therefore based on convergence .
distribution and habitat
The Philippine eagle is endemic to the Philippines and occurs there in the east of Luzon , on Samar , Leyte and Mindanao . The size of the total distribution area is estimated at around 146,000 km². It is unclear whether it used to appear in the entire Philippines or has always been missing in the drier west of the archipelago. Philippine eagles inhabit primary rainforests dominated by wing fruit plants (Dipterocarpaceae), especially in mountainous terrain, as well as secondary forests and gallery forests . The species occurs at altitudes from 0 to 1800 m.
In Mindanao, in the 1990s, relatively uniform distances of 8.3–17.5 km were found between 14 neighboring districts, with an average of 12.7 km. The authors assume that a circle with a radius of half this distance should encompass the action area of a couple, which accordingly has an average size of 133 km². In this calculated action area there was an average of 73 km² of forest, the rest consisted of open land with different uses. Of 13 nests found, nine were less than 100 m from the edge of the forest. The other four were further away from the edge of the forest, but the associated action areas still contained a significant proportion of open land. It is uncertain whether these findings indicate a preference for forest edge areas. It is also possible that the nests are just easier to find there or that this distribution is enforced by the strong fragmentation of the remaining forest areas.
Way of hunting and food
Philippine eagles are opportunistic hunters and prey on a wide range of vertebrates, primarily tree-dwelling animals. The main food is mammals, on Mindanao mainly Philippines gliders ( Cynocephalus volans ) and Fleckenmusangs ( Paradoxurus hermaphroditus ). In addition, other mammals such as macaques , flying squirrels , fine squirrels and other rodents, bats, flying foxes , larger birds such as hornbills , owls and birds of prey as well as reptiles such as snakes and monitor lizards are eaten. There are hardly any representative studies on the diet of individual couples. Out of 17 prey animals of a breeding pair in central Mindanao that were detected by observation at the nest, seven each were Philippines gliders or spotted musangs, and two rats ( Rattus spp.) And one samar cobra ( Naja samarensis ) were brought to the nest. Studies on the diet of the Philippine eagle on other islands are not yet available. The food spectrum there is likely to differ significantly from that on Mindanao, so there are neither Philippines gliders nor gliding squirrels on Luzon.
Detailed observations on hunting behavior are not yet available, after individual observations the eagles hunt from the hide, but also in direct pursuit flight. In one case, the first seat control room was high up on the slope of a hill, after every 5 to 10 minutes the waiting room was changed by gliding down the slope until the valley floor was finally reached after about an hour. Then the eagle circled upwards in a thermal column until it had reached its starting height again. Philippine eagles hunt both individually and in pairs. According to reports from locals, the eagles cooperate primarily in hunting monkeys, with one eagle distracting a monkey and the other grabbing the monkey from behind.
Reproduction
Philippine eagles live in monogamous pairs and are strictly territorial. The courtship consists of common circles above the nest, with the male mostly circling above the female, as well as pursuit flights with playful attacks by the male, where the female occasionally throws herself on her back and in turn presents her claws to the male, and joint gliding flights through it District. The male also calls very intensely on the nest during courtship and gives prey to the female there.
The nests are mainly built on the largest tree in the area at a height of up to 45 m; the eyrie tree is often less than half the height of a slope in a very deeply cut valley. The nest is usually located in a main stem fork within the crown. Epiphytes often serve as a base . The nests are usually large structures made of branches with a diameter of about 1.5 m, the nest hollow is covered with green branches over and over again during the entire reproductive period.
The eggs are laid on Mindanao in the period from the end of September to the beginning of December, on Luzon after individual observations from mid-December to mid-January. The clutch usually consists of one, rarely two eggs. The breeding season is 58-60 days, it mainly breeds the female. In an intensely observed brood on Mindanao, the proportion of females was 74%, and the female almost always brooded at night. There are different statements about the duration of the nestling period, in one case 105 days were given, but in several other broods 134-164 days. Only one young bird will fledge. A young bird provided with a transmitter became independent 17 months after escaping, a complete successful breeding cycle therefore takes about 2 years. After a brood loss, however, new eggs can be laid very quickly. It is not yet known exactly when sexual maturity will be reached, but it will probably not be known until the age of 6 to 8 years.
Duration
The exact total is not known. A reasonably well-founded estimate is only available for the size of the population on Mindanao. The authors calculated a total population of 82–233 pairs for the 1990s from the estimated action area size of 133 km² on the basis of the 13 occupied territories and the remaining forest area. At the beginning of the 21st century, the population on Luzon was estimated at only "very few" pairs, that on Samar at 6 and the population on Leyte at perhaps 2. This results in a world population of around 90–250 pairs .
However, the numbers on the population on Luzon, Samar and Leyte are very uncertain. A more recent estimate, which assumes a density similar to that of Mindanao for the other three populated islands, comes to a total population of about 340 pairs. However, this number is also very questionable, as nothing is known about the population density on these three islands. It is undisputed that the majority of the world's population lives on Mindanao.
Danger
The long-term main cause of endangerment is the continuing destruction of forests in the entire distribution area. At the beginning of the 21st century the primeval forest area in the area of the Philippine Eagle was 9,220 km², and timber utilization licenses have already been issued for most of the remaining primeval forest areas in the lowlands. However, the main short-term threat is arguably human persecution. In particular, the little shy young birds can be easily shot or caught, as can adult birds whose nests are close to the edge of the forest. The IUCN classifies the Philippine eagle as critically endangered due to the very small total population, the assumed strong decline in the last 3 generations (56 years) and the continued existence of the main threats .
Starting in 1969, a number of initiatives to protect the species were started, including legal measures to protect against human persecution and the protection of nests, inventory surveys, campaigns to raise public awareness of the protection of the species, the establishment of a breeding group in captivity as well Projects with the local population to improve their incomes and relieve pressure on the species' habitats. A part of the breeding areas is under protection, e.g. B. in the Northern Sierra Madre Natural Park on Luzon, as well as in the Mount Kitanglad Range Natural Park and the Mount Apo Natural Park on Mindanao. In 1987 the Philippine Eagle Foundation (PEF) was founded, which operates the Philippine Eagle Center in Davao City , Mindanao. There, captive breeding, inventory surveys and protective measures are coordinated. In 2008 there were 32 Philippine eagles at the Philippine Eagle Center, 18 of which were born in captivity. The PEF is planning a stock support program by releasing offspring.
Despite the ongoing destruction of the forest, which the government has apparently played down to its extent, the prospects for conservation of the species are not consistently rated as bad. The reproduction of the remaining population is apparently good, at least in Mindanao, and the species has proven to be quite adaptable to habitat changes to some extent. The nests are not only found in primeval forests today, but also in old secondary forests and even in highly disturbed areas. In addition, when broadcasting breeding birds whose breeding grounds were located in widely isolated forest fragments, it was found that the birds sought out other forest areas to hunt and flew over vast, forest-free landscapes with grassland and arable land.
The current main threat from human persecution, as a problem of human behavior, as opposed to restoring forests, can at least in principle be solved in the relatively short term. This is one of the main focuses of the PEF's work.
The Philippines eagle was declared the national bird of the Philippines on July 4, 1995 by Presidential Proclamation No. 79. In order to raise public awareness for the protection of the species, there will be held in the Philippines from 4–10. July the "Philippine Eagle Week (PEW)" takes place.
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Individual evidence
- ^ A b J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London 2001, ISBN 0-7136-8026-1 : pp. 226 and 722
- ↑ a b c d e BirdLife International (2010) Species factsheet: Pithecophaga jefferyi . ( Online , accessed December 6, 2010)
- ↑ a b c d e Jayson C. Ibañez, Hector C. Miranda Jr., Gliceria Balaquit-Ibañez, Donald S. Afan, and Robert S. Kennedy: Notes on the Breeding Behavior of a Philippine Eagle Pair at Mount Sinaka, Central Mindanao . The Wilson Bulletin, 115 (3), 2003: pp. 333-336
- ↑ a b c d H. RL Lerner, DP Mindell: Phylogeny of eagles, Old World vultures and other Accipitridae based on nuclear and mitochondrial DNA . Molecular Phylogenetics and Evolution 37, 2005: pp. 327-346.
- ^ NJ Collar: The Philippine Eagle: one hundred years of solitude . Oriental Bird Club Bulletin 24, 1996 online
- ^ NJ Collar, AV Andreev, S. Chan, MJ Crosby, S. Subramanya and JA Tobias (Eds.): Philippine Eagle - Pithecophaga jefferyi. In: Threatened Birds of Asia: The BirdLife International Red Data Book. BirdLife International 2001, ISBN 0-9468-8844-2 : p. 633
- ↑ a b c Glen Lovell L. Bueser, Kharina G. Bueser, Donald S. Afan, Dennis I. Salvador, James W. Grier, Robert S. Kennedy, Hector C. Miranda Jr: Distribution and nesting density of the Philippine Eagle Pithecophaga jefferyi on Mindanao Island, Philippines: what do we know after 100 years? Ibis 145, Issue 1, 2003: pp. 130-135
- ^ J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London 2001, ISBN 0-7136-8026-1 : p. 722
- ↑ a b c N. J. Collar, AV Andreev, S. Chan, MJ Crosby, S. Subramanya and JA Tobias (Eds.): Philippine Eagle - Pithecophaga jefferyi. In: Threatened Birds of Asia: The BirdLife International Red Data Book. BirdLife International 2001, ISBN 0-9468-8844-2 : pp. 646-648
- ^ NJ Collar, AV Andreev, S. Chan, MJ Crosby, S. Subramanya and JA Tobias (Eds.): Philippine Eagle - Pithecophaga jefferyi. In: Threatened Birds of Asia: The BirdLife International Red Data Book. BirdLife International 2001, ISBN 0-9468-8844-2 : p. 649
- ^ A b DJI Salvador and JC Ibanez: Ecology and Conservation of Philippine Eagles. Ornithological Science, 5 (2), 2006: pp. 171-176
- ↑ Dieldre S. Harder, Rex Labao, Florence Ivy Santos: Saving the Philippine Eagle: How Much Would It Cost and are Filipinos Willing to Pay for It? , August 2006 ( Online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this note .; PDF; 570 kB)
- ^ Department of Environment and Natural Resources (DENR): List of Nationally and Internationally-significant Environmental Events / Celebrations. ( Online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice .; PDF; 68 kB)
literature
- NJ Collar, AV Andreev, S. Chan, MJ Crosby, S. Subramanya and JA Tobias (Eds.): Philippine Eagle - Pithecophaga jefferyi. In: Threatened Birds of Asia: The BirdLife International Red Data Book. BirdLife International 2001, ISBN 0-9468-8844-2 : pp. 633-677.
- J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London 2001, ISBN 0-7136-8026-1 : pp. 226-227 and 721-722.
Web links
- Pithecophaga jefferyi in the endangered Red List species the IUCN 2010. Posted by: BirdLife International, 2009. Retrieved on 3 December of 2010.
- Videos, photos and sound recordings for Pithecophaga jefferyi in the Internet Bird Collection
- Homepage of the Philippine Eagle Foundation
- Philippine eagle photos by animal photographer Klaus Nigge
