The ferruginous duck ferruginous pochard, common white-eye or white-eyed pochard is a medium-sized diving duck from Eurasia. The scientific name is derived from Greek aithuia an unidentified seabird mentioned by authors including Hesychius and Aristotle, nyrok, the Russian name for a duck; the breeding male is a rich, dark chestnut on the head and flanks with contrasting pure white undertail coverts. In flight the white belly and underwing patch are visible; the females are browner than the males. The male has a yellow eye and the females have a dark eye; the ferruginous duck prefers quite shallow fresh waterbodies with rich submerged and floating vegetation with dense stands of emergent vegetation on the margins. In some areas it will use saline or brackish wetlands. On passage and wintering will frequent coastal waters, inland seas and large, open lagoons; the breeding range of the ferruginous duck is from Iberia and the Maghreb east to western Mongolia, south to Arabia, although in the west is now scarce and localised and locally extirpated in some countries.
The duck winters throughout the Mediterranean Basin and the Black Sea, smaller number migrate into sub-Saharan Africa via the Nile Valley. Eastern birds winter in south and south-east Asia; these are gregarious birds, but less social than other Aythya species but where common it can form large flocks in winter mixed with other diving ducks, such as tufted ducks and common pochards. Forms pairs from January onwards and during courtship the male curls his tail so that it dips into the water forming a triangular white patch of the undertail coverts. In areas where it is common it will form colonies at protected sites such as islands in association with gulls. Where scarce it nests singly, in dispersed and concealed sites. Eggs are laid from the end of April or early May in a nest, sited on the ground close to water, or sometimes a floating nest is built among emergent vegetation; the eggs are incubated for 25–27 days and the fledging period is 55–60 days. These birds feed by diving or dabbling, they eat aquatic plants with aquatic insects and small fish.
They feed at night, will upend for food as well as the more characteristic diving. The species is threatened by the degradation and destruction of its favoured habitats by anthropogenic causes which are wide and varied including impoundment, drainage and mismanagement; the introduction of non-native species has caused habitat degradation, e.g. the stocking of lakes with and accidental introduction of grass carp Ctenopharyngodon idella has caused reductions in plant and animal biomass available for the ducks to feed on. In addition, the increased threat of drought due to climate change may pose a threat to the species in the drier parts of its range. Increased disturbance by fishing boats and anglers among marginal vegetation could cause abandonment of the breeding sites or disrupt the timing of breeding in populated areas, e.g. western Europe. Ferruginous ducks are threatened by hunting and large numbers are shot on passage in the autumn and in the wintering areas. Although protected in most European countries illegal and accidental hunting persists.
It is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies. Among recent local initiatives it should be mentioned inclusion of the breeding habitats of the species in Armenia into network of Emerald Sites protected by the Bern Convention Showler, D. A.. "Observations of Jerdon's Babbler Chrysomma altirostre and Rufous-vented Prinia Prinia burnesii in Punjab and North-West Frontier Provinces, Pakistan". Forktail. 15: 66–76. Singh, A. P.. "New and significant records from Dehra Dun valley, lower Garhwal Himalayas, India". Forktail. 18: 151–153. Vinicombe, K. E.. "Identification of Ferruginous Duck and its status in Britain and Ireland". British Birds. 93: 4–21. Vinicombe, K. E.. "ID in depth – Ferruginous Duck". Birdwatch. 176: 24–26. BirdLife species factsheet for Aythya nyroca "Aythya nyroca". Avibase. "Ferruginous duck media". Internet Bird Collection. Ferruginous pochard photo gallery at VIREO Interactive range map of Aythya nyroca at IUCN Red List maps Audio recordings of Ferruginous duck on Xeno-canto
Aristotle was a philosopher during the Classical period in Ancient Greece, the founder of the Lyceum and the Peripatetic school of philosophy and Aristotelian tradition. Along with his teacher Plato, he is considered the "Father of Western Philosophy", his writings cover many subjects – including physics, zoology, logic, aesthetics, theatre, rhetoric, linguistics, economics and government. Aristotle provided a complex synthesis of the various philosophies existing prior to him, it was above all from his teachings that the West inherited its intellectual lexicon, as well as problems and methods of inquiry; as a result, his philosophy has exerted a unique influence on every form of knowledge in the West and it continues to be a subject of contemporary philosophical discussion. Little is known about his life. Aristotle was born in the city of Stagira in Northern Greece, his father, died when Aristotle was a child, he was brought up by a guardian. At seventeen or eighteen years of age, he joined Plato's Academy in Athens and remained there until the age of thirty-seven.
Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon, tutored Alexander the Great beginning in 343 BC. He established a library in the Lyceum which helped him to produce many of his hundreds of books on papyrus scrolls. Though Aristotle wrote many elegant treatises and dialogues for publication, only around a third of his original output has survived, none of it intended for publication; the fact that Aristotle was a pupil of Plato contributed to his former views of Platonism, following Plato's death, Aristotle developed an increased interest in natural sciences and adopted the position of immanent realism. Aristotle's views on physical science profoundly shaped medieval scholarship, their influence extended from Late Antiquity and the Early Middle Ages into the Renaissance, were not replaced systematically until the Enlightenment and theories such as classical mechanics. Some of Aristotle's zoological observations found in his biology, such as on the hectocotyl arm of the octopus, were disbelieved until the 19th century.
His works contain the earliest known formal study of logic, studied by medieval scholars such as Peter Abelard and John Buridan. Aristotle's influence on logic continued well into the 19th century He influenced Islamic thought during the Middle Ages, as well as Christian theology the Neoplatonism of the Early Church and the scholastic tradition of the Catholic Church. Aristotle was revered among medieval Muslim scholars as "The First Teacher" and among medieval Christians like Thomas Aquinas as "The Philosopher", his ethics, though always influential, gained renewed interest with the modern advent of virtue ethics, such as in the thinking of Alasdair MacIntyre and Philippa Foot. In general, the details of Aristotle's life are not well-established; the biographies written in ancient times are speculative and historians only agree on a few salient points. Aristotle, whose name means "the best purpose" in Ancient Greek, was born in 384 BC in Stagira, about 55 km east of modern-day Thessaloniki.
His father Nicomachus was the personal physician to King Amyntas of Macedon. Both of Aristotle's parents died when he was about thirteen, Proxenus of Atarneus became his guardian. Although little information about Aristotle's childhood has survived, he spent some time within the Macedonian palace, making his first connections with the Macedonian monarchy. At the age of seventeen or eighteen, Aristotle moved to Athens to continue his education at Plato's Academy, he remained there for nearly twenty years before leaving Athens in 348/47 BC. The traditional story about his departure records that he was disappointed with the Academy's direction after control passed to Plato's nephew Speusippus, although it is possible that he feared the anti-Macedonian sentiments in Athens at that time and left before Plato died. Aristotle accompanied Xenocrates to the court of his friend Hermias of Atarneus in Asia Minor. After the death of Hermias, Aristotle travelled with his pupil Theophrastus to the island of Lesbos, where together they researched the botany and zoology of the island and its sheltered lagoon.
While in Lesbos, Aristotle married Hermias's adoptive daughter or niece. She bore him a daughter, whom they named Pythias. In 343 BC, Aristotle was invited by Philip II of Macedon to become the tutor to his son Alexander. Aristotle was appointed as the head of the royal academy of Macedon. During Aristotle's time in the Macedonian court, he gave lessons not only to Alexander, but to two other future kings: Ptolemy and Cassander. Aristotle encouraged Alexander toward eastern conquest and Aristotle's own attitude towards Persia was unabashedly ethnocentric. In one famous example, he counsels Alexander to be "a leader to the Greeks and a despot to the barbarians, to look after the former as after friends and relatives, to deal with the latter as with beasts or plants". By 335 BC, Aristotle had returned to Athens. Aristotle conducted courses at the school for the next twelve years. While in Athens, his wife Pythias died and Aristotle became involved with Herpyllis of Stagira, who bore him a son whom he named after his father, Nicomachus.
According to the Suda, he had an erômenos, Palaephatus of Abydus. This period in Athens, between 335 and 323 BC, is when Aristotle is believed to have composed many of his works, he wrote many dialogues. Those works that have survived are in treatise form and were not
An estuary is a enclosed coastal body of brackish water with one or more rivers or streams flowing into it, with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments, they are subject both to marine influences—such as tides and the influx of saline water—and to riverine influences—such as flows of fresh water and sediment. The mixing of sea water and fresh water provide high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are classified according to their geomorphological features or to water-circulation patterns, they can have many different names, such as bays, lagoons, inlets, or sounds, although some of these water bodies do not meet the above definition of an estuary and may be saline.
The banks of many estuaries are amongst the most populated areas of the world, with about 60% of the world's population living along estuaries and the coast. As a result, many estuaries suffer degradation from a variety of factors including: sedimentation from soil erosion from deforestation and other poor farming practices; the word "estuary" is derived from the Latin word aestuarium meaning tidal inlet of the sea, which in itself is derived from the term aestus, meaning tide. There have been many definitions proposed to describe an estuary; the most accepted definition is: "a semi-enclosed coastal body of water, which has a free connection with the open sea, within which sea water is measurably diluted with freshwater derived from land drainage". However, this definition excludes a number of coastal water bodies such as coastal lagoons and brackish seas. A more comprehensive definition of an estuary is "a semi-enclosed body of water connected to the sea as far as the tidal limit or the salt intrusion limit and receiving freshwater runoff.
This broad definition includes fjords, river mouths, tidal creeks. An estuary is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides; the sea water entering the estuary streams. The pattern of dilution varies between different estuaries and depends on the volume of fresh water, the tidal range, the extent of evaporation of the water in the estuary. Drowned river valleys are known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley; this is the most common type of estuary in temperate climates. Well-studied estuaries include the Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border; the width-to-depth ratio of these estuaries is large, appearing wedge-shaped in the inner part and broadening and deepening seaward. Water depths exceed 30 m.
Examples of this type of estuary in the U. S. are the Hudson River, Chesapeake Bay, Delaware Bay along the Mid-Atlantic coast, Galveston Bay and Tampa Bay along the Gulf Coast. Bar-built estuaries are found in place where the deposition of sediment has kept pace with rising sea level so that the estuaries are shallow and separated from the sea by sand spits or barrier islands, they are common in tropical and subtropical locations. These estuaries are semi-isolated from ocean waters by barrier beaches. Formation of barrier beaches encloses the estuary, with only narrow inlets allowing contact with the ocean waters. Bar-built estuaries develop on sloping plains located along tectonically stable edges of continents and marginal sea coasts, they are extensive along the Atlantic and Gulf coasts of the U. S. in areas with active coastal deposition of sediments and where tidal ranges are less than 4 m. The barrier beaches that enclose bar-built estuaries have been developed in several ways: building up of offshore bars by wave action, in which sand from the sea floor is deposited in elongated bars parallel to the shoreline, reworking of sediment discharge from rivers by wave and wind action into beaches, overwash flats, dunes, engulfment of mainland beach ridges due to sea level rise and resulting in the breaching of the ridges and flooding of the coastal lowlands, forming shallow lagoons, elongation of barrier spits from the erosion of headlands due to the action of longshore currents, with the spits growing in the direction of the littoral drift.
Barrier beaches form in shallow water and are parallel to the shoreline, resulting in long, narrow estuaries. The average water depth is less than 5 m, exceeds 10 m. Examples of bar-built estuaries are Barnegat Bay, New Jersey. Fjords were formed where pleistocene glaciers deepened and widened existing river valleys so that they become U-shaped in cross s
New Zealand scaup
The New Zealand scaup known as a black teal, is a diving duck species of the genus Aythya. It is endemic to New Zealand. In Māori it is known as papango matapouri, raipo. Overall dark brown/black colors; the male has a dark colored head. The female is similar to the male, but without the yellow eye and has a white face patch during breeding season. A white wing bar can be seen in both sexes when in flight; the scaup is a diving duck which may submerge for twenty to thirty seconds and go down three metres to look for aquatic plants, small fish, water snails and insects. It is sometimes seen with the Australian coot, it is found throughout both the North and South Islands of New Zealand in deep freshwater lakes and ponds. Unlike other members of this genus, the scaup is not migratory, although it does move to open water from high country lakes if they become frozen in winter, they nest from October to March. They lay five to eight cream/white eggs in a nest close to water under banks or thick cover.
The nest is lined with grass and down. The eggs are incubated for four weeks by the female; the newly hatched ducklings begin diving for food on their first outing
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
A reservoir is, most an enlarged natural or artificial lake, pond or impoundment created using a dam or lock to store water. Reservoirs can be created in a number of ways, including controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, through excavation, or building any number of retaining walls or levees. Defined as a storage space for fluids, reservoirs may hold gasses, including hydrocarbons. Tank reservoirs elevated, or buried tanks. Tank reservoirs for water are called cisterns. Most underground reservoirs are used to store liquids, principally either water or petroleum, below ground. Reservoir is most an enlarged natural or artificial lake. A dam constructed in a valley relies on the natural topography to provide most of the basin of the reservoir. Dams are located at a narrow part of a valley downstream of a natural basin; the valley sides act as natural walls, with the dam located at the narrowest practical point to provide strength and the lowest cost of construction.
In many reservoir construction projects, people have to be moved and re-housed, historical artifacts moved or rare environments relocated. Examples include the temples of Abu Simbel, the relocation of the village of Capel Celyn during the construction of Llyn Celyn, the relocation of Borgo San Pietro of Petrella Salto during the construction of Lake Salto. Construction of a reservoir in a valley will need the river to be diverted during part of the build through a temporary tunnel or by-pass channel. In hilly regions, reservoirs are constructed by enlarging existing lakes. Sometimes in such reservoirs, the new top water level exceeds the watershed height on one or more of the feeder streams such as at Llyn Clywedog in Mid Wales. In such cases additional side dams are required to contain the reservoir. Where the topography is poorly suited to a single large reservoir, a number of smaller reservoirs may be constructed in a chain, as in the River Taff valley where the Llwyn-on, Cantref and Beacons Reservoirs form a chain up the valley.
Coastal reservoirs are fresh water storage reservoirs located on the sea coast near the river mouth to store the flood water of a river. As the land based reservoir construction is fraught with substantial land submergence, coastal reservoir is preferred economically and technically since it does not use scarce land area. Many coastal reservoirs were constructed in Europe. Saemanguem in South Korea, Marina Barrage in Singapore and Plover Cove in China, etc are few existing coastal reservoirs. Where water is pumped or siphoned from a river of variable quality or size, bank-side reservoirs may be built to store the water; such reservoirs are formed by excavation and by building a complete encircling bund or embankment, which may exceed 6 km in circumference. Both the floor of the reservoir and the bund must have an impermeable lining or core: these were made of puddled clay, but this has been superseded by the modern use of rolled clay; the water stored in such reservoirs may stay there for several months, during which time normal biological processes may reduce many contaminants and eliminate any turbidity.
The use of bank-side reservoirs allows water abstraction to be stopped for some time, when the river is unacceptably polluted or when flow conditions are low due to drought. The London water supply system is one example of the use of bank-side storage: the water is taken from the River Thames and River Lee. Service reservoirs store treated potable water close to the point of distribution. Many service reservoirs are constructed as water towers as elevated structures on concrete pillars where the landscape is flat. Other service reservoirs can be entirely underground in more hilly or mountainous country. In the United Kingdom, Thames Water has many underground reservoirs, sometimes called cisterns, built in the 1800s, most of which are lined with brick. A good example is the Honor Oak Reservoir in London, constructed between 1901 and 1909; when it was completed it was said to be the largest brick built underground reservoir in the world and it is still one of the largest in Europe. This reservoir now forms part of the southern extension of the Thames Water Ring Main.
The top of the reservoir is now used by the Aquarius Golf Club. Service reservoirs perform several functions, including ensuring sufficient head of water in the water distribution system and providing water capacity to out peak demand from consumers, enabling the treatment plant to run at optimum efficiency. Large service reservoirs can be managed to reduce the cost of pumping, by refilling the reservoir at times of day when energy costs are low. Circa 3 000 BC, the craters of extinct volcanoes in Arabia were used as reservoirs by farmers for their irrigation water. Dry climate and water scarcity in India led to early development of stepwells and water resource management techniques, including the building of a reservoir at Girnar in 3000 BC. Artificial lakes dating to the 5th century BC have been found in ancient Greece; the artificial Bhojsagar lake in present-day Madhya Pradesh state of India, constructed in the 11th century, covered 650 square kilometres. In Sri Lanka large reservoirs were created by ancient Sinhalese kings in order to save the water for irrigation.
The famous Sri Lankan king Pa
The ring-necked duck is a diving duck from North America found in freshwater ponds and lakes. The scientific name is derived from Greek aithuia an unidentified seabird mentioned by authors including Hesychius and Aristotle, Latin collaris, "of the neck" from collum, "neck". Ring-necked ducks are small to medium-sized diving ducks; the adult male is similar in color pattern to the Eurasian tufted duck, its relative. Males are a little bit bigger than the female, it has two white rings surrounding its gray bill, a shiny black angular head, black back, white line on the wings, a white breast and yellow eyes. The adult female has a grayish brown angular head and body with a dark brown back, a dark bill with a more subtle light band than the male, grayish-blue feet and brown eyes with white rings surrounding them. Females make a noise like trrr; the cinnamon neck ring is difficult to observe, why the bird is sometimes referred to as a "ringbill". Their breeding habitat is wooded ponds in the northern United States and Canada.
The main breeding area is Northwest boreal forest territories. Their breeding habits take place in the eastern boreal region of Canada but no where near the same amount in the northwestern region. Winter months they are found in southern North America in lakes, rivers or bays. Ring-necked duck pairs start during spring migration. Unpaired ducks showing up on breeding grounds will most end up being non-breeders; the pairs stay together only for reproduction, until they separate. The nest is bowl-shaped, built on water in dense emergent vegetation with sedges and woody plants; the female lays one egg per day. They are incubated 25–29 days and the female may remain with the young until they are able to fly; these birds are omnivores and feed by diving or dabbling at the surface. Ducklings are dependent on animal matter such as insects, leeches and snails; as they mature they tend change their diet to submerged plants such as pondweed and coontail, emergents such as annual wild rice and snails. This strong migrant is a regular vagrant to western Europe.
In Britain, occasional small flocks occur, including five at Loch Leven, Scotland in September 2003 and four at Standlake in Oxfordshire in April 2015. In Ireland one or two individuals can be seen at any time of year. Vagrant individuals occur each year in Central America as far south as Costa Rica between October/November and May/June. Ring-necked Duck Species Account – Cornell Lab of Ornithology Ring-necked Duck - Aythya collaris - USGS Patuxent Bird Identification InfoCenter Ring-necked Duck at eNature.com Ring-necked Duck at Mass Audubon Breeding Bird Atlas "Ring-necked Duck media". Internet Bird Collection. Ring-necked Duck photo gallery at VIREO