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1.
Catsadorakis  G. 《Hydrobiologia》1997,351(1-3):157-174
The breeding avifauna of Prespa National Park is ofnational and international importance both due to itshigh richness and the internationally importantpopulations of rare species. The latter include theDalmatian (Pelecanus crispus) and Great White(Pelecanus onocrotalus) pelicans and the PygmyCormorant (Phalacrocorax pygmaeus). Populationsof national interest include Cormorant (Phalacrocorax carbo), Greylag Goose (Anseranser), Goosander (Mergus merganser), GreatWhite Egret (Egretta alba) and six otherspecies of ardeids. Among the 261 bird speciesobserved in the area of ca 250 km2 since thelate 60s, 164 breed and 41 are very rarely observed.Passage migrants and winter visitors include 91species. Twelve breeding species became extinct in theNational Park during the last 25 years and others areendangered. Raptors and aquatic birds suffered moredue to habitat and land use alterations brought aboutby the construction of an irrigation scheme.Eighty-one species observed in the area are listed asin need of special protection in Annex I of the 79/409EEC Directive and 32 of them breed. Lake Mikri Prespais of virtually no importance for wintering waterfowlsince it is frozen every winter, but the Greek part ofLake Megali Prespa, which never freezes, concentratesamong other species the 20% and 35% respectively ofthe Great Crested Grebes and Tufted Ducks wintering inGreece.  相似文献   

2.
Metacercariae of Bolbophorus species are serious pathogens of farmed fish. Molecular diagnostic tools, capable of identifying and differentiating these parasites, may assist in the development of rationale control strategies. The rDNA 18S (small sub-unit: SSU) genes of adult B. confusus and B. levantinus obtained from a pelican, Pelecanus onocrotalus, and a night heron, Nycticorax nycticorax, respectively, were amplified, sequenced, and aligned. Based on this alignment, we developed a genetic differentiation assay between B. confusus and B. levantinus. These 2 species were compared genetically with the North American species B. damnificus and Bolbophorus sp. ('Type 2'). The relationship between species is outlined and discussed. In addition to the molecular study, specimens of B. confusus and B. levantinus were compared morphologically, using scanning electron microscopy. Morphologic analysis revealed interspecific differences in details of the holdfast organ and the position of the acetabulum.  相似文献   

3.
In January 2004, Lake St Lucia, a major part of the Greater St Lucia Wetland Park, was reduced to a fraction of its normal capacity as a result of a severe drought in this region of KwaZulu-Natal, South Africa. After rains in the area, the lake level rose and then fluctuated considerably over the next 42 months. During the first 38 months the mouth of the estuary into the sea was closed. The area entered a second severe period of prolonged drought from mid 2005 through to the spring of 2006. Great white pelican ( Pelecanus onocrotalus Linnaeus, 1758 ) numbers and lake levels were monitored during these 42 months. Pelican numbers were highly variable ranging from 0 to 6000. When lake levels were very low or too high, no pelicans were present. Pelican numbers appeared more indicative of food availability. Implications of these trends to the management of the lake and the conservation of the avifauna are discussed. It is suggested that the great white pelican could be used as an indicator species for the fish dynamics of the lake at medium to low lake levels.  相似文献   

4.
We report a new fossil specimen of a pelican from the Tatrot Formation of the Siwalik Hills, India. It likely represents Pelecanus sivalensis Davies, 1880, the smaller of the two previously published species from the Siwalik Group stratigraphic sequence. This complete tarsometatarsus is the first fossil bone of a pelican collected in India for over 100 years. It is from the latest Pliocene (∼2.6 Ma), and is the youngest pelican fossil from the region. The new specimen exhibits a derived distoplantar ‘slant’ to the plantar margin of the medial crest of the hypotarsus, and a combination of features related to the morphology of the hypotarsus, the distal foramen, trochleae, and overall size that allow further differentiation from known tarsometatarsi of fossil and extant pelicans, including the three species of extant pelicans that occur in India (Pelecanus crispus, P. onocrotalus, and P. philippensis). It is of appropriate size for Pelecanus sivalensis, which to date has been known only by fragments of other skeletal elements of the wing, leg, and shoulder girdle. Thus, the observation that this tarsometatarsus is morphologically distinct from those of known pelicans provides further support for the distinctiveness of at least one extinct species of pelican from the Siwalik Group sediments. While the morphology of the tarsometatarsus allows for separation from other taxa known from tarsometatarsi, we found no clear shared derived states to place this taxon with any confidence in a phylogenetic context relative to any other pelican species, or even determine if it is part of the crown group of Pelecanidae. However, published molecular data are consistent with an origin of the crown clade prior to the Pleistocene, suggesting (along with one morphological character) the possibility that this species belongs to the Old World clade of pelican species.  相似文献   

5.
The Great White Pelican Pelecanus onocrotalus is an endangered migratory bird, threatened by diminishing natural feeding sites and by persecution by fishermen. The majority of the migrating White Pelican (71000) stop-over in Israel during their autumn migration to Africa. As part of a larger study, aimed to assess the necessity of feeding during the stop-over in Israel, we examined the blood chemistry of captive and migrating White Pelicans. Blood was sampled from captive birds maintained on a fish diet, after food deprivation for 48 h and from wild birds brought from the field during migration. Food deprivation resulted in increased plasma levels of triglycerides and in lower levels of urea, potassium and calcium. In migrating birds, increased plasma levels of urea and CPK and lower levels of creatinine were revealed. In general, the coefficient of variation in the blood chemistry of migrating pelicans was higher than in the captive birds, that is to say, that these birds were in a variable physiological condition. The blood profile of migrating and wintering pelicans did not indicate a state of dehydration but did indicate energy deficiency. The less extreme changes in blood chemistry of the 48 h food-deprived compared to migrating pelicans suggest that the former did not reach a state of starvation. We conclude that for White Pelicans the stop-over in Israel is a must in order to rest and replenish their fuel reserves for completion of their autumn migration to Africa.  相似文献   

6.
<正>2016年9月27日在江苏盐城湿地珍禽国家级自然保护区核心区北侧发现两只鹈鹕并拍摄照片(见封面),经鉴定为白鹈鹕(Pelecanus onocrotalus)。两只个体体色主要为白色,初级飞羽及次级飞羽黑褐色,头后具有短羽冠,胸部具有黄色羽簇,眼周裸区明显大于相似种卷羽鹈鹕(P.crispus)。两只个体的眼周裸区颜色、嘴峰长有区别,是否为雌雄差异,尚待确认。根据鹈鹕体羽形态的完整性及对观察人员靠近时的行为反应等,可确定两只鹈鹕非养殖逃逸个体。  相似文献   

7.
We examined the mitochondrial genetic structure of American white pelicans (Pelecanus erythrorhynchos) to: 1) verify or refute whether American white pelicans are panmictic and 2) understand if any lack of genetic structure is the result of contemporary processes or historical phenomena. Sequence analysis of mitochondrial DNA control region haplotypes of 367 individuals from 19 colonies located across their North American range revealed a lack of population genetic or phylogeographic structure. This lack of structure was unexpected because: 1) Major geographic barriers such as the North American Continental Divide are thought to limit dispersal; 2) Differences in migratory behavior are expected to promote population differentiation; and 3) Many widespread North American migratory bird species show historic patterns of differentiation resulting from having inhabited multiple glacial refugia. Further, high haplotype diversity and many rare haplotypes are maintained across the species' distribution, despite frequent local extinctions and recolonizations that are expected to decrease diversity. Our findings suggest that American white pelicans have a high effective population size and low natal philopatry. We suggest that the rangewide panmixia we observed in American white pelicans is due to high historical and contemporary gene flow, enabled by high mobility and a lack of effective physical or behavioral barriers.  相似文献   

8.
We recorded the choice of victims by a population of adult and first-winter laughing gulls (Larus atricilla) making attempts to steal food from adult and juvenile brown pelicans (Pelecanus occidentalis). Adult gulls made food theft attempts on juvenile pelicans with a disproportionately great frequency; first-winter gulls appeared to select pelican victims at random. Adult pelicans were more frequently successful in their foraging attempts than juvenile pelicans, suggesting that adults may be more reliable as potential food sources for gulls making theft attempts. However, juvenile pelicans attempted to evade kleptoparasitizing gulls less frequently than did adult pelicans, suggesting that the fish prey of juveniles may be more easily stolen. These patterns are discussed in relation to optimal victim choice by gulls, and to deferred maturity in both species.  相似文献   

9.
The Great white pelican Pelecanus onocrotalus is a major predator of some freshwater fish stocks in much of Africa. Detailed population time-activity budgets allowed us to estimate that the south-western Cape Province population consumed 184 tonnes offish annually. Of this, 69% was required for adult existence, 17% for chicks and 14% for flight. Per capita consumption averaged 840 g per day, or 8–8% of body weight; very much less than the figure of 17–6% used in some energy budget calculations. Our integrative bioenergetics approach lends some support for the use of 10% of body weight as the amount of food consumed per day by large piscivorous birds for initial estimates of their impact on stocks.
Predation by Great white pelicans may account for some 10–25% offish production, a shortage of reliable data on fish production in African freshwater ecosystems makes a more precise estimate impossible. Food supplies and shoreline length may both be important factors for pelican populations.  相似文献   

10.
Two species of Clinostomum previously described from Australia, C. hornum from Botaurus poiciloptilus (Australian bittern) and Nycticorax caledonicus (Nankeen night heron) and C. australiense from Pelecanus conspicillatus (Australian pelican), which have previously been synonymised with C. complanatum, are redescribed and recognised as valid species. In addition, C. complanatum is recorded from Egretta alba (large egret), E. garzetta (little egret), E. intermedia (plumed egret), N. caledonicus and Ardea novaehollandiae (white-faced heron). C. wilsoni n. sp. is described from E. intermedia from Queensland. C. wilsoni differs from the other three species in size and shape of the body and in the oral collar, oral sucker, intestinal caeca, caecal diverticula and position of testes. Taxonomic problems within the genus Clinostomum are discussed.  相似文献   

11.
Ido Izhaki 《Ostrich》2013,84(2):213-217
Izhaki, I. 1994. Preliminary data on the importance of Israel for the conservation of the White Pelican Pelecanus onocrotalus L. Ostrich 65:213-217.

The majority of the western Palaearctic populations of the Great White Pelican Pelecanus onocrotalus stop over in Israel during their autumn migration. The annual average number of pelicans observed over Israel in autumn was 71,421±5,027. Although most of these birds were transient over Israel, increasing numbers of individuals (1130±303, between 1990 and 1993) stay and winter in the northern part of Israel. The natural feeding sites for pelicans were diminished during recent decades due to human activities such as the drainage of the Hula swamp in northern Israel 40 years ago. However, intensive fishery and aqua-culture sites became their favourite feeding laces either during migration or in winter. The fish industry complained that the birds seriously affect fish yield. The pelicans not only cause direct damage to the fix industry by predation, but they also transfer nematodes to fish (Oreochromis sp.). As et. there is no solution to the problem of these parasitic nematodes. This preliminary study revealed that the average daily fish consumption per individual was 0,52kg and the small sample size did not indicate any selection for certain fish species or size. Flight range estimation indicated that the pelicans, especially the weak individuals, nee xo feed during their stopover in Israel or in the relatively rare appropriate feeding sites along their southward migratory route over the desert in order to reach their wintering areas in eastern central Africa.  相似文献   

12.
A stocking program with rainbow trout (Salmo gairdneri) at High Rock Lake, Manitoba failed due to infections with large numbers of Contracaecum spp. larvae. Nematode larvae in the intestinal tract, body cavity and musculature made the fish unmarketable. A combination of experimental infections of rainbow trout and pelicans (Pelecanus erythrorhynchos), observations on the behavior of fish-eating birds, and numbers of larval Contracaecum spp. in minnow species led to the following conclusions. The introduction of rainbow trout attracted large numbers of fish-eating birds, particularly pelicans. Concurrent predation by rainbow trout on fathead minnows (Pimephales promelas), five-spined sticklebacks (Culaea inconstans), and nine-spined sticklebacks (Pungitius pungitius), concentrated the parasites. The combined increase in densities of the introduced fish host and fish-eating birds, and the short life cycle of the parasite, increased the numbers of parasites in rainbow trout over a season and in the indigenous minnow species between years. Numbers of larvae in the indigenous minnow species declined when stocking of rainbow trout was stopped and use of the lake by fish-eating birds, particularly pelicans, returned to normal levels.  相似文献   

13.
Crèching behaviour is common in colonial seabirds; nevertheless, the factors inducing chicks to aggregate remain relatively poorly understood. It has been proposed that brood size, laying date and nest attendance are important factors in the formation of a crèche. Moreover, in most species of pelicans, chicks join crèches following the development of homoeothermy and coincident with the end of the brooding behaviour. We studied effects of feeding rate, nest attendance, brood size, laying date and homoeothermy on the age at which chicks entered the crèche at a colony of Dalmatian pelicans (Pelecanus crispus), in Srebarna, Bulgaria. Single chicks were fed more frequently than chicks from two-chick broods. Unlike American white pelicans (Pelecanus erythrorhynchos), Dalmatian pelicans maintained brooding behaviour a further 9 days after chicks had developed thermoregulation abilities. In contrast to nests with two chicks, nests with only one chick were never left unattended by the parents before the chick reached the crèching stage. Laying date, nest attendance and brood size did not affect the age that the chick entered the crèche. The age the chick entered the crèche was not correlated with the age of homoeothermy acquisition, but chicks significantly joined the crèche at younger ages when the mean number of feeds per chick per day during the rearing period in the nest was higher. This result suggests an implication of growth rate in the crèching age. Joining the crèche earlier can provide benefits that could have strong implications for the chicks’ future reproductive lives.  相似文献   

14.
The late Quaternary Kibish Formation of the Omo Valley, southwestern Ethiopia, preserves environments reflecting a history of fluctuations in the level of nearby Lake Turkana over the past 200,000 years. The Kibish Formation has yielded a diverse mammalian fauna (as well as birds and crocodiles), stone tools, and the oldest anatomically modern Homo sapiens. Fish, the most common vertebrate fossils in this unit, are reported in this study. Catfish (especially clariids and Synodontis) and Nile perch (Lates niloticus) predominate, but the gymnarchid Gymnarchus, a cyprinid (Barbus), tigerfish (Hydrocynus), pufferfish (Tetraodon), and other catfish are also present. In total, nine teleost genera are found in the Kibish Formation, representing a subset of the 37 genera that constitute the modern Omo-Turkana ichthyofauna. Several taxa present in the modern fauna, including Polypterus and members of the family Cichlidae, are not found in the Kibish deposits. Most specimens are preserved as disarticulated or broken skeletal elements, but some preservation of articulated elements (e.g., sets of vertebrae, crania with lower jaws or cleithra) also occurs. Many of the catfish and Nile perch specimens are larger than the largest reported from the modern river or lake. Faunas of Kibish Members I and III closely resemble one another; the fauna from Member IV contains only the three most common taxa (Clarias, Synodontis, Lates), though this may result from insufficient sampling. Barbed bone points have been collected from the upper part of the formation, indicating a long association between the human inhabitants and the fish fauna of the Omo Valley.  相似文献   

15.
本文描述了产自华南贵州下奥陶统红花园组(桐梓红花园标准剖面,沿河甘溪剖面和贵阳黄花冲剖面)的四个镰箭类牙形刺种:Drepanoistodus sp.cf.nowlani,Paltodus sp.cf.P.subaequalis,Paltodus sp.A和Paroisto-dus sp.。D.sp.cf.nowlani为红花园组常见种,但另三种则相对稀少。在红花园组标准剖面,Paltodus sp.cf.P.subaequalis最低出现于该组底部,证实此层位为晚特马豆克期。文中详细图示了产于瑞典下奥陶统的两个带化石种:Paltodus deltifer和Paroistodus proteus,以及瑞典镰箭刺属的三个常见种:Drepanoistodus forceps,D.basiovalis和D.sp.cf.D.suberectus。通过与瑞典材料的详细对比,我们认为华南以前关于P.proteus和P.deltifer两种的记述多有误,须重新厘定。  相似文献   

16.
The Kibish faunal remains are useful for reconstructing the habitat of the earliest documented Homo sapiens and for understanding the community within which early modern humans existed. A diverse assemblage of large mammals, including many species of bovids, suids, and equids, has been recovered from the Kibish Formation. There are no extinct large mammals represented in the fossil assemblage, and the overall taxonomic composition of the fossil fauna is similar to the modern-day wildlife community living near the Omo River. The fossil faunal assemblage shows a paucity of arboreal primates, and carnivore species are rare. However, the faunal sample includes possible Cephalophus (duiker) remains and Hylochoerus meinertzhageni (giant forest hog), taxa that are extremely rare in the African fossil record, and both indicate more closed habitats. Comparative analyses of the Kibish faunal remains using the ecological-diversity approach document close associations with edaphic grassland and woodland vegetation types. These vegetation forms are similar to current habitats surrounding the Omo River.  相似文献   

17.
The effect of selected anthelmintics (albendazole, fenbendazole, piperazine dihydrochloride and clorsulon) against three major helminths (Contracaecum multipapillatum, Mesostephanus appendiculatoides, and Phagicola longus) were studied in 29 brown pelicans (Pelecanus occidentalis). Albendazole and fenbendazole were highly effective against all three parasites. Clorsulon had moderate effect against M. appendiculatoides and poor effect against C. multipapillatum and P. longus. Piperazine dihydrochloride had no effect against these helminths.  相似文献   

18.
F. JIGUET  A. DOXA  & A. ROBERT 《Ibis》2008,150(3):606-618
We tested whether spatial and annual patterns of occurrence of out-of-range Great White Pelecanus onocrotalus , Dalmatian Pelecanus crispus and Pink-backed Pelicans Pelecanus rufescens recorded in Europe between 1980 and 2004 supported a natural vagrancy theory. Candidate variables tested were those likely to influence dispersal and escape probability (distance to the usual breeding/wintering range, national captive stock), and wild breeding population sizes and their movements (size of breeding colonies, climate conditions on wintering grounds or during dispersal). Spatial vagrancy patterns supported the hypothesis of wild birds dispersing from their normal range, with decreasing national totals with increasing distance to the usual range for the three species. Annual out-of-range numbers of Great White Pelican were predicted by breeding colony size and breeding success in Greece, with a further effect of Sahel rainfall during the previous year. Annual numbers of Dalmatian Pelican were related to the North Atlantic Oscillation index and to breeding success in Greece. Finally, annual numbers of Pink-backed Pelican were predicted by summer Sahel rainfall, which is known to drive dispersal of the species northwards into the sub-Sahelian steppes during wet summers there. Hence, annual vagrancy patterns in Europe were well predicted for all three species by population size indices, reproductive success and/or climatic components, which presumably influence survival and/or dispersal. We therefore consider that vagrancy patterns were driven by wild birds, whereas escapes – even if potentially numerous – do not create sufficient 'noise' to hide these patterns.  相似文献   

19.
This paper describes the excavation, stratigraphy, and lithic assemblages of Middle Stone Age sites from the Omo Kibish Formation (Lower Omo Valley, southwestern Ethiopia). Three sites were excavated, two in Kibish Member I (KHS and AHS) and one at the base of Member III (BNS). The assemblages are dominated by relatively high-quality raw materials procured as pebbles from local gravels. The principal modes of core preparation are radial/centripetal Levallois and discoidal. Retouched tools are rare. Foliate bifaces are present, as are larger tools, such as handaxes, picks, and lanceolates, but these are more common among surface finds than among excavated assemblages. Middle Stone Age assemblages shed light on the adaptations of the earliest-known Homo sapiens populations in Africa.  相似文献   

20.
Most seabirds are diurnal foragers, but some species may also feed at night. In Peruvian pelicans (Pelecanus thagus), the evidence for nocturnal foraging is sparse and anecdotal. We used GPS-dataloggers on five incubating Peruvian pelicans from Isla Lobos de Tierra, Perú, to examine their nocturnality, foraging movements and activities patterns at sea. All instrumented pelicans undertook nocturnal trips during a 5–7 day tracking period. Eighty-seven percent of these trips (n = 13) were strictly nocturnal, whereas the remaining occurred during the day and night. Most birds departed from the island after sunset and returned a few hours after sunrise. Birds traveled south of the island for single-day trips at a maximum range of 82.8 km. Overall, 22% of the tracking period was spent at sea, whereas the remaining time was spent on the island. In the intermediate section of the trip (between inbound and outbound commutes), birds spent 77% of the trip time in floating bouts interspersed by short flying bouts, the former being on average three times longer than the latter. Taken together, the high sinuosity of the bird''s tracks during floating bouts, the exclusively nocturnal trips of most individuals, and the fact that all birds returned to the island within a few hours after sunrise suggest that pelicans were actively feeding at night. The nocturnal foraging strategy of Peruvian pelicans may reduce food competition with the sympatric and strictly diurnal Guanay cormorants (Phalacrocorax bougainvillii), Peruvian boobies (Sula variegata) and Blue-footed boobies (S. nebouxii), which were present on the island in large numbers. Likewise, plankton bioluminescence might be used by pelicans as indirect cues to locate anchovies during their upward migration at night. The foraging success of pelicans at night may be enhanced by seizing prey close to the sea surface using a sit-and-wait strategy.  相似文献   

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