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in may 2009 the iupac / iupap joint working party reported on the discovery of copernicium and acknowledged the discovery of the isotope 283cn this implied the de facto discovery of the livermorium @@ 291 isotope from the acknowledgment of the data relating to its granddaughter 283cn although the livermorium data was not absolutely critical for the demonstration of copernicium 's discovery also in 2009 confirmation from berkeley and the gesellschaft für schwerionenforschung ( gsi ) in germany came for the flerovium isotopes 286 to 289 immediate daughters of the four known livermorium isotopes in 2011 iupac evaluated the dubna team experiments of 2000 2006 whereas they found the earliest data ( not involving 291lv and 283cn ) inconclusive the results of 2004 2006 were accepted as identification of livermorium and the element was officially recognized as having been discovered
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in recent years the synthesis of livermorium has been separately confirmed in two other laboratories
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= = = naming = = =
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using mendeleev 's nomenclature for unnamed and undiscovered elements livermorium is sometimes called eka @@ polonium in 1979 iupac recommended that the placeholder systematic element name <unk> ( with the corresponding symbol of <unk> ) be used until the discovery of the element was confirmed and a name was decided although widely used in the chemical community on all levels from chemistry classrooms to advanced textbooks the recommendations were mostly ignored among scientists in the field who called it element 116 with the symbol of ( 116 ) or even simply 116
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according to iupac recommendations the discoverer or discoverers of a new element have the right to suggest a name the discovery of livermorium was recognized by the joint working party ( jwp ) of iupac on 1 june 2011 along with that of flerovium according to the vice @@ director of jinr the dubna team originally wanted to name element 116 moscovium after the moscow oblast in which dubna is located the name livermorium and the symbol lv were adopted on may 23 2012 after an approval process by the iupac the name recognises the lawrence livermore national laboratory within the city of livermore california usa which collaborated with jinr on the discovery the city in turn is named after the american rancher robert livermore a naturalized mexican citizen of english birth
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= = predicted properties = =
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= = = nuclear stability and isotopes = = =
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livermorium is expected to be near an island of stability centered on copernicium ( element 112 ) and flerovium ( element 114 ) the reasons for the presence of this island are still not well understood due to the expected high fission barriers any nucleus within this island of stability exclusively decays by alpha decay and perhaps some electron capture and beta decay while the known isotopes of livermorium do not actually have enough neutrons to be on the island of stability they can be seen to approach the island as in general the heavier isotopes are the longer @@ lived ones
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superheavy elements are produced by nuclear fusion these fusion reactions can be divided into hot and cold fusion depending on the excitation energy of the compound nucleus produced in hot fusion reactions very light high @@ energy projectiles are accelerated toward very heavy targets ( actinides ) giving rise to compound nuclei at high excitation energy ( ~ 40 50 mev ) that may either fission or evaporate several ( 3 to 5 ) neutrons in cold fusion reactions ( which use heavier projectiles typically from the fourth period and lighter targets usually lead and bismuth ) the produced fused nuclei have a relatively low excitation energy ( ~ 10 20 mev ) which decreases the probability that these products will undergo fission reactions as the fused nuclei cool to the ground state they require emission of only one or two neutrons hot fusion reactions tend to produce more neutron @@ rich products because the actinides have the highest neutron @@ to @@ proton ratios of any elements that can presently be made in macroscopic quantities
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important information could be gained regarding the properties of superheavy nuclei by the synthesis of more livermorium isotopes specifically those with a few neutrons more or less than the known ones <unk> <unk> <unk> <unk> <unk> and 295lv this is possible because there are many reasonably long @@ lived isotopes of curium that can be used to make a target the light isotopes can be made by fusing curium @@ 243 with calcium @@ 48 they would undergo a chain of alpha decays ending at transactinide isotopes that are too light to achieve by hot fusion and too heavy to be produced by cold fusion
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the synthesis of <unk> and 295lv could be accomplished by fusing the heavy curium isotope curium @@ 250 with calcium @@ 48 the cross section of this nuclear reaction would be about 1 <unk> after a few alpha decays these livermorium isotopes would reach nuclides at the line of beta stability additionally electron capture may also become an important decay mode in this region allowing affected nuclei to reach the middle of the island for example 295lv would alpha decay to 291fl which would undergo successive electron capture to <unk> and then 291cn which is expected to be in the middle of the island of stability and have a half @@ life of about 1200 years affording the most likely hope of reaching the middle of the island using current technology a drawback is that the decay properties of superheavy nuclei this close to the line of beta stability are largely unexplored
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other possibilities to synthesize nuclei on the island of stability include quasifission ( partial fusion followed by fission ) of a massive nucleus such nuclei tend to fission expelling doubly magic or nearly doubly magic fragments such as calcium @@ 40 tin @@ 132 lead @@ 208 or bismuth @@ 209 recently it has been shown that the multi @@ nucleon transfer reactions in collisions of actinide nuclei ( such as uranium and curium ) might be used to synthesize the neutron @@ rich superheavy nuclei located at the island of stability although formation of the lighter elements nobelium or seaborgium is more favored one last possibility to synthesize isotopes near the island is to use controlled nuclear explosions to create a neutron flux high enough to bypass the gaps of instability at 258 260fm and at mass number 275 ( atomic numbers 104 to 108 ) mimicking the r @@ process in which the actinides were first produced in nature and the gap of instability around radon bypassed some such isotopes ( especially 291cn and 293cn ) may even have been synthesized in nature but would have decayed away far too quickly ( with half @@ lives of only thousands of years ) and be produced in far too small quantities ( about 10 − 12 the abundance of lead ) to be detectable as primordial nuclides today outside cosmic rays
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= = = physical and atomic = = =
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in the periodic table livermorium is a member of group 16 the chalcogens in the periodic table below oxygen sulfur selenium tellurium and polonium every previous chalcogen has six electrons in its valence shell forming a valence electron configuration of <unk> in livermorium 's case the trend should be continued and the valence electron configuration is predicted to be <unk> therefore livermorium will have some similarities to its lighter congeners differences are likely to arise a large contributing effect is the spin orbit ( so ) interaction the mutual interaction between the electrons ' motion and spin it is especially strong for the superheavy elements because their electrons move much faster than in lighter atoms at velocities comparable to the speed of light in relation to livermorium atoms it lowers the 7s and the 7p electron energy levels ( stabilizing the corresponding electrons ) but two of the 7p electron energy levels are stabilized more than the other four the stabilization of the 7s electrons is called the inert pair effect and the effect tearing the 7p subshell into the more stabilized and the less stabilized parts is called subshell splitting computation chemists see the split as a change of the second ( azimuthal ) quantum number l from 1 to 1 ⁄ 2 and 3 ⁄ 2 for the more stabilized and less stabilized parts of the 7p subshell respectively the 7p1 / 2 subshell acts as a second inert pair though not as inert as the 7s electrons while the 7p3 / 2 subshell can easily participate in chemistry for many theoretical purposes the valence electron configuration may be represented to reflect the 7p subshell split as 7s27p2
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1 / <unk>
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3 / 2
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the inert pair effects in livermorium should be even stronger than for polonium and hence the + 2 oxidation state becomes more stable than the + 4 state which would be stabilized only by the most electronegative ligands this is reflected in the expected ionization energies of livermorium where there are large gaps between the second and third ionization energies ( corresponding to the breaching of the unreactive 7p1 / 2 shell ) and fourth and fifth ionization energies indeed the 7s electrons are expected to be so inert that the + 6 state will not be possible to attain the melting and boiling points of livermorium are expected to continue the trends down the chalcogens thus livermorium should melt at a higher temperature than polonium but boil at a lower temperature it should also be denser than polonium ( lv 12 @@ 9 g / cm3 α @@ po 9 @@ 2 g / cm3 ) the electron of the hydrogen @@ like livermorium atom ( oxidized so that it only has one electron <unk> + ) is expected to move so fast that it has a mass 1 @@ 86 times that of a stationary electron due to relativistic effects for comparison the figures for hydrogen @@ like polonium and tellurium are expected to be 1 @@ 26 and 1 @@ 080 respectively
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= = = chemical = = =
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livermorium is projected to be the fourth member of the 7p series of chemical elements and the heaviest member of group 16 ( via ) in the periodic table below polonium while it is the least theoretically studied of the 7p elements its chemistry is expected to be quite similar to that of polonium the group oxidation state of + 6 is known for all the chalcogens apart from oxygen which lacks available d @@ orbitals for expansion of its octet and is itself one of the strongest oxidizing agents among the chemical elements oxygen is thus limited to a maximum + 2 state exhibited in the fluoride <unk> the + 4 state is known for sulfur selenium tellurium and polonium undergoing a shift in stability from reducing for sulfur ( iv ) and selenium ( iv ) through being the most stable state for tellurium ( iv ) to being oxidizing in polonium ( iv ) this suggests a decreasing stability for the higher oxidation states as the group is descended due to the increasing importance of relativistic effects especially the inert pair effect the most stable oxidation state of livermorium should thus be + 2 with a rather unstable + 4 state the + 2 state should be about as easy to form as it is for beryllium and magnesium and the + 4 state should only be achieved with strongly electronegative ligands such as in livermorium ( iv ) fluoride ( <unk> ) the + 6 state should not exist at all due to the very strong stabilization of the 7s electrons making the valence core of livermorium only four electrons the lighter chalcogens are also known to form a − 2 state as oxide sulfide selenide telluride and <unk> due to the destabilization of livermorium 's 7p3 / 2 subshell the − 2 state should be very unstable for livermorium whose chemistry should be essentially cationic though the larger subshell and spinor energy <unk> of livermorium as compared to polonium should stabilize <unk> − slightly
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<unk> ( lvh2 ) would be the heaviest chalcogen hydride and the heaviest homolog of water ( the lighter ones being h2s h2se <unk> and poh2 ) <unk> ( polonium hydride ) is a more covalent compound than most metal hydrides because polonium straddles the border between metals and metalloids and has some nonmetallic properties it is intermediate between a hydrogen halide like hydrogen chloride ( hcl ) and a metal hydride like <unk> ( <unk> ) <unk> should continue this trend it should be a hydride rather than a <unk> but would still be a covalent molecular compound spin @@ orbit interactions are expected to make the lv h bond longer than expected simply from periodic trends alone and make the h lv h bond angle larger than expected this is theorized to be because the unoccupied 8s orbitals are relatively low in energy and can hybridize with the valence 7p orbitals of livermorium this is the first molecule to be studied in detail to display this phenomenon dubbed <unk> hybridization although it was earlier predicted that the same phenomenon would occur with elements 156 164 which would use 7d 9s <unk> / 2 hybridizations despite only the 7d ( and occasionally 9s ) orbitals being partially filled the heavier livermorium dihalides are predicted to be linear but the lighter ones are predicted to be bent
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= = experimental chemistry = =
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unambiguous determination of the chemical characteristics of livermorium has not yet been established in 2011 experiments were conducted to create ununtrium flerovium and ununpentium isotopes in the reactions between calcium @@ 48 projectiles and targets of americium @@ 243 and plutonium @@ 244 the targets included lead and bismuth impurities and hence some isotopes of bismuth and polonium were generated in nucleon transfer reactions this while an unforeseen complication could give information that would help in the future chemical investigation of the heavier homologs of bismuth and polonium which are respectively ununpentium and livermorium the produced nuclides bismuth @@ 213 and polonium @@ <unk> were transported as the hydrides <unk> and <unk> at 850 ° c through a quartz wool filter unit held with tantalum showing that these hydrides were surprisingly thermally stable although their heavier congeners uuph3 and lvh2 would be expected to be less thermally stable from simple extrapolation of periodic trends in the p @@ block further calculations on the stability and electronic structure of <unk> uuph3 poh2 and lvh2 are needed before chemical investigations take place ununpentium and livermorium are expected to be volatile enough as pure elements for them to be chemically investigated in the near future a property livermorium would then share with its lighter congener polonium the chief barrier to their chemical investigation at present is the lack of known isotopes of these elements which are long @@ lived enough
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= american white ibis =
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the american white ibis ( eudocimus albus ) is a species of bird in the ibis family <unk> it is found from north carolina via the gulf coast of the united states south through most of the coastal new world tropics this particular ibis is a medium @@ sized bird with an overall white plumage bright red @@ orange down @@ curved bill and long legs and black wing tips that are usually only visible in flight males are larger and have longer bills than females the breeding range runs along the gulf and atlantic coast and the coasts of mexico and central america outside the breeding period the range extends further inland in north america and also includes the caribbean it is also found along the northwestern south american coastline in colombia and venezuela populations in central venezuela overlap and interbreed with the scarlet ibis the two have been classified by some authorities as a single species
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their diet consists primarily of small aquatic prey such as insects and small fishes crayfish are its preferred food in most regions but it can adjust its diet according to the habitat and prey abundance its main foraging behavior is probing with its beak at the bottom of shallow water to feel for and capture its prey it does not see the prey
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during the breeding season the american white ibis gathers in huge colonies near water pairs are predominantly monogamous and both parents care for the young although males tend to engage in extra @@ pair copulation with other females to increase their reproductive success males have also been found to pirate food from unmated females and juveniles during the breeding season
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human pollution has affected the behavior of the american white ibis via an increase in the concentrations of methylmercury which is released into the environment from untreated waste exposure to methylmercury alters the hormone levels of american white ibis affecting their mating and nesting behavior and leading to lower reproduction rates
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= = taxonomy = =
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the american white ibis was one of the many bird species originally described by carl linnaeus in the 1758 10th edition of his systema naturae where it was given the binomial name of <unk> albus the species name is the latin adjective albus white alternative common names that have been used include spanish curlew and white curlew english naturalist mark catesby mistook immature birds for a separate species which he called the brown curlew local creole names in louisiana include bec <unk> and petit <unk>
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johann georg wagler gave the species its current binomial name in 1832 when he erected the new genus eudocimus whose only other species is the scarlet ibis ( e ruber ) there has long been debate on whether the two should be considered subspecies or closely related species and the american ornithologists ' union considers the two to be a superspecies as they are parapatric the lack of observed hybrids was a large factor in the view that the species were separate
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however in a field study published in 1987 researchers cristina ramo and benjamin busto found evidence of interbreeding in a population where the ranges of the scarlet and white ibises overlap along the coast and in the llanos region of colombia and venezuela they observed individuals of the two species mating and pairing as well as hybrid ibises with pale orange plumage or white plumage with occasional orange feathers their proposal that these birds be classified as a single species has been followed by least one field guide hybrid ibises have also been recorded in florida where the scarlet ibis has been introduced into wild populations of american white ibis birds of intermediate to red plumage have persisted for generations
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ornithologists james hancock and jim <unk> also consider the two to be a single species with the differences in plumage size skin coloration and degree of bill darkening during breeding season forming the diagnostic characters they have proposed the populations <unk> in northwestern south america after a period of separation and that the color difference is likely due to the presence of an enzyme that allows uptake of pigment in the diet they have questioned whether white @@ plumaged birds of south america are in fact part of the ruber rather than the albus taxon and acknowledge that more investigation is needed to determine this
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= = description = =
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the white plumage and pink facial skin of adult american white ibises are distinctive adults have black wingtips that are usually only visible in flight in non @@ breeding condition the long downcurved bill and long legs are bright red @@ orange during the first ten days of the breeding season the skin darkens to a deep pink on the bill and an almost purple @@ tinted red on the legs it then fades to a paler pink and the tip of the bill becomes blackish it is difficult to determine the sex of an adult american white ibis from its external appearance since the sexes have similar plumage however there is sexual dimorphism in size and proportion as males are significantly larger and heavier than females and have longer and stouter bills a study of the american white ibis in southern florida yielded weight ranges of 872 @@ 9 to 1 @@ 261 g ( 1 @@ 924 to 2 @@ 780 lb ) for males and 592 @@ 7 to 861 @@ 3 g ( 1 @@ 307 to 1 @@ 899 lb ) for females with average weights of 1 @@ 036 @@ 4 g ( 2 @@ 285 lb ) for males and 764 @@ 5 g ( 1 @@ 685 lb ) for females the length of adult female and male birds ranges from 53 to 70 cm ( 21 to 28 in ) with a 90 to 105 cm ( 35 to 41 in ) wingspan among standard measurements american white ibis measure 20 @@ 5 31 cm ( 8 @@ 1 12 @@ 2 in ) along each wing have a tail measurement of 9 @@ 3 12 @@ 2 cm ( 3 @@ 7 4 @@ 8 in ) a tarsus of 6 @@ 75 11 @@ 3 cm ( 2 @@ 66 4 @@ 45 in ) and a culmen of 11 16 @@ 9 cm ( 4 @@ 3 6 @@ 7 in )
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the newly hatched american white ibis is covered with purple down feathers deepening to dark brown or black on the head and wings the chest is often bare and there can be a white tuft on the head the irises are brown the exposed skin is pinkish initially apart from the tip of the bill which is dark gray but turns gray within a few days of hatching the bill is short and straight at birth and has an egg tooth which falls off between days five and nine and develops three black rings from around day six before turning gray by around six weeks of age the gray to sandy gray brown juvenile plumage appears between weeks two and six and face and bill become pink a few weeks later while the legs remain gray the irises have turned slate @@ gray by this stage once fledged the juvenile american white ibis has largely brown plumage and only the rump underwing and underparts are white the legs become light orange as it matures white feathers begin appearing on the back and it undergoes a gradual molt to obtain the white adult plumage this is mostly complete by the end of the second year although some brown feathers persist on the head and neck until the end of the third year juvenile birds take around two years to reach adult size and weight
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like other species of ibis the american white ibis flies with neck and legs outstretched often in long loose lines or v formations a 1986 field study in north carolina noted over 80 of adult ibis doing so while juveniles rapidly took up the practice over the course of the summer the resulting improvement in aerodynamics may lower energy expenditure these lines fly in an undulating pattern as they alternately flap and glide soaring in a circular pattern is also seen heights of 500 to 1 @@ 000 m ( 1 @@ 600 to 3 @@ 300 ft ) may be reached as birds glide over flights of 20 km ( 12 mi ) or more more commonly birds fly between 60 and 100 m ( 200 and 330 ft ) above the ground gliding or flapping at a rate of around 3 @@ 3 wingbeats a second
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the main call of the american white ibis is a honking sound transcribed as <unk> <unk> or hunk hunk the call is used in flight courtship or when disturbed birds also utter a muted huu @@ huu @@ huu call while foraging and make a squealing call in courtship young in the nest give a high @@ pitched <unk> as a begging call
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= = = similar species = = =
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immature american white and scarlet ibises are very difficult to tell apart although scarlet ibises tend to have darker legs and bare skin around the face an immature american white ibis could be mistaken for an immature glossy ibis but the latter is wholly dark brown and lacks the white belly and rump the adult is distinguishable from the wood stork which is much larger and its wings have more black on them
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= = distribution and habitat = =
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the american white ibis is most common in florida where over 30 @@ 000 have been counted in a single breeding colony it also occurs throughout the caribbean on both coasts of mexico ( from baja california southwards ) and central america and as far south as columbia and venezuela the non @@ breeding range extends further inland reaching north to virginia and west to eastern texas
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the species is known to wander and has been sighted sometimes in small flocks in states far out of its usual range
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in north america breeding takes place along the atlantic coast from the carolinas south to florida and thence west along the gulf coast laguna cuyutlán is an isolated and regionally important wetland in the state of colima on méxico 's west coast where a breeding colony has been recorded american white ibises are not faithful to the sites where they breed and large breeding colonies composed of ten thousand birds or more can congregate and disband in one or two breeding seasons breeding populations across its range have fluctuated greatly with wholesale movement between states until the 1940s the species only bred in large numbers in florida mostly within the everglades drought conditions elsewhere in the united states led to over 400 @@ 000 american white ibis breeding there in the 1930s in the 1950s and 1960s large colonies appeared in alabama louisiana and then north and south carolina and the gulf coast of florida and finally texas in the 1970s then between the 1970s and early 1990s breeding colonies declined and disappeared in south carolina and florida and greatly increased in louisiana and north carolina colonies last between one and seventeen years their longevity related to size and quality of nearby wetlands the longest @@ lasting are associated with wetlands over 800 km2 ( 310 sq mi ) in size degradation of wetland or breeding sites are reasons for abandonment the population of american white ibises in a colony at pumpkinseed island in georgetown county south carolina dropped from 10 @@ 000 to zero between 1989 and 1990 as hurricane hugo had inundated nearby freshwater foraging areas with salt water
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the american white ibis is found in a variety of habitats although shallow coastal marshes wetlands and mangrove swamps are preferred it is also commonly found in muddy pools on mudflats and even wet lawns populations that are away from the coast and shoreline particularly in southern florida often reside in other forms of wetlands such as marshes ponds and flooded fields in summer these move to more coastal and estuarine habitats as inland waterways become flooded with summer rains and the ibis find the water levels too deep to forage effectively
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= = = fossil record = = =
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remains similar to the american white ibis have been found in middle pliocene deposits of the bone valley formation in central florida and lower pliocene deposits of the yorktown formation at lee creek in north carolina two species one living and one extinct have been recovered from the talara tar <unk> in northern coastal peru eudocimus peruvianus was described from a tarsometatarsus that differed slightly from e albus whose remains were also found there remains of neither species are common in the beds the tar seeps have been dated at 13 @@ 900 years old the american white ibis is still found in peru
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= = behavior = =
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a field study late in the florida nesting season revealed that on an average day adult american white ibis spent 10 @@ 25 hours looking for food 0 @@ 75 hours flying 13 hours resting roosting and attending to their nests much of the time roosting is spent preening biting and working their feathers with their long bills as well as rubbing the oil glands on the sides of their heads on back plumage american white ibis generally only preen themselves not engaging in allopreening unless part of courtship behavior bathing often takes place before preening ibis squat in water 5 20 cm ( 2 @@ 0 7 @@ 9 in ) deep and flick water over themselves with each wing in succession hundreds of birds may bathe together around the time of courtship
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the american white ibis is territorial defending the nesting and display sites against intruders agonistic or threat displays include lunging forward with the bill in a horizontal posture and standing upright and snapping the bill opposite another bird engaging in the same display birds also lunge and bite often holding onto an opponent 's head or wings
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= = = breeding and lifespan = = =
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the american white ibis pairs up in spring and breeds in huge colonies often with other waterbird species nesting begins as soon as suitable foraging and nesting habitat is available the female selects the site usually in the branches of a tree or shrub which is often over water and builds the nest and males assist by bringing nest material anywhere from one to five eggs are typically laid with two or three being the most common the eggs are matt pale blue @@ green in color with brown splotches and measure 5 @@ 8 cm × 3 @@ 9 cm ( 2 @@ 3 in × 1 @@ 5 in ) and weigh on average 50 @@ 8 g ( 1 @@ 79 oz ) clutch sizes are usually lower in coastal colonies as compared to inland colonies although there are no statistically significant differences in the fledging rate of both colonies throughout the mating and incubation period the male undergoes a period of starvation to stay close to the nest and aggressively defend his nest and mate from both predators and other ibises in preference to foraging for food in the 2006 breeding season a non @@ breeding adult female was observed to be tending to multiple nests that belonged to other american white ibises the first time the behavior has been documented for this species
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although the american white ibis is predominantly monogamous and both sexes provide parental care to their young the male often flies off to engage in extra pair copulation with other nesting females after mating with its primary female partner these extra @@ pair copulations are usually done after the within @@ pair copulations and make up about 45 of all total matings although only about 15 of all extra @@ pair copulations are successful by not restricting the number of females it copulates with the male is able to increase its reproductive success considerably although females are receptive towards extra @@ pair copulations male mate @@ guarding greatly reduces the rate of successful female involvement in attempted extra @@ pair copulations by other males
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the breeding success of the american white ibis is sensitive to the hydrological conditions of the ecosystem such as rainfall and water levels low and decreasing water levels predict good prey accessibility water level reversals where levels rise in the breeding season disperse prey and impact on foraging success nest numbers and average clutch sizes are smaller in periods of reduced prey availability the success rate of parents raising one or more young to 20 days of age ranges widely from 5 to 70 of nests and varies greatly between nearby colonies american white ibis parents have been known to supplement their chicks ' diet with items such as cockroaches and rotting food from human garbage in poorer years when fish and crayfish are more scarce studies have also shown that years with higher nesting numbers had significantly faster spring drying rates of water bodies than years with low nesting numbers this is because faster drying rates means that there are fewer fish and increased available area where crayfish can be hunted this highlights the fact that american white ibises do not use probability of nesting failure as a key factor in determining nesting sites but instead rely on other criteria such as prey availability and nest @@ site predation rates the draining of wetlands in south florida has also impacted on species that forage in shallow water such as the american white ibis and its increase in numbers is a key indicator of restoration of habitat within the everglades
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the main cause of nest failure among the species is due to nest abandonment the leading cause of which is inundation from extremely high tides parents abandoned 61 of all nesting starts either during or immediately after extremely high tides the eggs float out of the flooded nests or get washed out into the sea by wave action <unk> parents usually abandon the nest when the water or tidal levels reaches 3 to 8 cm ( 1 @@ 2 to 3 @@ 1 in ) above the bottom of the nest cup nevertheless there have been instances where the parents have been observed to transport their eggs to another nest in an attempt to salvage some eggs however despite the fact that some nesting sites face high chance of tidal damage every breeding season american white ibises still continue to nest in these areas because of other favorable conditions such as abundant nearby food sources and low egg predation rates
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the eggs hatch after about three weeks and the young are attended by both parents males are present around the nest for most of the day and females most of the night the parents exchange nest duties in the morning and in the evening most of the feeding of the chicks occurs during the period where they swap nesting duties little feeding is done in the period of the day that is between the two duty swaps and no feeding is done between midnight and 6 am chick mortality is highest in the first twenty days post hatching with anywhere from 37 to 83 of hatchlings surviving to three weeks of age in the everglades during periods of food limitations and starvation events the american white ibis tends to exhibit sex @@ dependent pre @@ fledgling mortality for many bird species that have sexually dimorphic nestlings mortality rates are higher for larger @@ sized male nestlings as a result of the parents ' inability to meet its greater nutritional needs however in the case of the american white ibis the male nestlings actually have a lower mortality rate as compared to the females despite being on average 15 greater in mass as compared to its female counterparts although current research has yet to discover the underlying factors to why the males tend to have better survival rates under such conditions it is suspected that the parents tend to feed the larger male nestlings first because they are either perceived by the parents to have a higher chance of survival or being generally larger the male nestlings simply out @@ compete the small females for food
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bird predators may seize anywhere from 7 to 75 of the progeny in a breeding colony the fish crow ( corvus ossifragus ) is common raider of american white ibis nests accounting for up to 44 of egg loss in a field study at battery island north carolina other predators of eggs and young include the boat @@ tailed grackle ( <unk> major ) black @@ crowned night heron ( nycticorax nycticorax ) gulls and possibly vultures as well as the common opossum ( didelphis marsupialis ) raccoon ( procyon lotor ) and rat snakes ( <unk> species ) egg predation rates of the american white ibis decline with nest age owing to increased nest attentiveness by the parents especially during the last week of incubation high nest densities and reduced synchrony increase egg predation rates because of the increased opportunities afforded by the longer incubation times as well as the greater availability of nests available for predation
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the american white ibis begins breeding in its third summer although birds in captivity may breed as young as nine or ten months of age the oldest member of the species recorded in captivity was over 20 years of age and a wild bird has been picked up 16 years and 4 months after being banded
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= = = diet = = =
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the american white ibis prefers to eat crayfish and other crustaceans but also takes aquatic insects and small fish outside the nesting season the diet is highly variable as abundance and types of prey depend on the both region and habitat in los llanos located on the border of columbia and venezuela the most frequent prey are insects such as fly larvae and beetles generally in north america the main prey are crustaceans mostly crayfish in the everglades and cypress swamps the diet is primarily made up of crayfish while those that feed in willow ponds eat predominantly fish american white ibises that feed in mangrove swamps focus on crabs the tactile nature of the ibis 's probing for food in mud means that it catches prey that are too slow to evade the ibis once located by its bill in the everglades this means that crayfish make up a large part of the diet but a more diverse array of invertebrates are taken in coastal areas although crayfish are sought by foraging ibises prey switching to fish does occur if fish are found in great abundance it is unclear whether the fish are more easily caught if overcrowded or whether sheer numbers of fish mean that ibises are catching them instead of crayfish normally fish are more agile than crayfish and hence elude the ibis 's bill more easily fish are a more energy @@ rich source of food for the american white ibis in the breeding season american white ibises in a colony at pumpkinseed island travelled further to forage in freshwater wetlands and catch crayfish than nearby saltwater areas where fiddler crabs predominated indicating their benefit was worth the extra energy expended in fetching them for their young this travel results in the wholesale transport of nutrients across the landscape by the colony in a successful breeding year the colony at pumpkinseed island was estimated to have contributed a third as much phosphorus to the neighboring estuary as other environmental processes
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the american white ibis is found in mixed @@ species foraging flocks with the glossy ibis ( plegadis falcinellus ) in flooded fields and the two species select different food items with little overlap the former foraging for crabs and aquatic insects and the latter feeding mainly on grain the wood stork is also found in the same habitat in florida but hunts larger prey and a higher percentage of fish so there is little overlap in the llanos where american white ibis coexist with the scarlet ibis their diets differ the former consuming more bugs fish and crustaceans while the latter eat a much higher proportion of beetles the <unk> ( tringa <unk> ) has been observed trailing american white ibis and catching prey disturbed by them and even <unk> ( stealing ) from them in j n ding darling national wildlife refuge on sanibel island in florida an isolated event of intraspecific predation in juvenile american white ibis has been observed where a juvenile attacked and consumed a chick from another nest
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= = = foraging = = =
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during the summer the american white ibis roams along the coast of tidal flats and mangrove swamps as the inland marshes are usually flooded however as the water level recedes in the fall populations at the coast shift their foraging area inland to inland marshes and swamplands it has become more common in urban landscapes in florida since the late 1990s and is one of a number of wetland @@ dependent bird species which forages in man @@ made ponds on golf courses in the southwest of the state
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the american white ibis is a tactile <unk> forager which limits its ability to choose from a wide variety of prey for the most part the american white ibis forages for food by tactile probing it wades slowly through shallow water and sticks its long downcurved bill into the substrate of the water body with its bill held at around 1 to 2 cm ( 0 @@ 39 to 0 @@ 79 in ) agape at the tip and sweeps its long bill back and forth across the bottom to pick out suitable food items birds may also probe when standing still <unk> with a wide open bill is a technique used by ibis in deeper water when alone as is head swinging in which the ibis swings its wide open bill widely in open water others copy this type of foraging if they see one ibis doing it on land the american white ibis locates prey by sight and pecks and does not have to insert its bill into the substrate the american white ibis seeks small prey when other birds are around as it needs time to break up larger food items into smaller pieces to eat and other predators such as herons and egrets often take the opportunity to rob the ibis of its catch along with the scarlet ibis the species coexists with another five species of ibis in the llanos in venezuela american white ibis males are aggressive to and take prey items from smaller ibises but the smaller females are more often the victims of this behavior
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juveniles have lower foraging efficiency compared to adults and in most feeding flocks the juveniles are usually outnumbered by the adults they usually tend to stay close to one another and forage for food together at the peripheral region of the group during the breeding season adult male ibises have been recorded raiding other parent ibises who are feeding their young in the colony the raiders force their bill down the throat of the victim either the parent about to disgorge their food or recently fed young and extract the ball of food this behavior allows the otherwise starving adult males to obtain food without having to spend long periods of time away from the nest and prevent its female mate copulating with another male ibis which would reduce its own reproductive success females and juveniles almost never try to drive off the larger and more aggressive pirating males but instead try to avoid or move away from them this pirating behavior is less common between two male ibises as the males will actively fight off the pirate the explanation of the species ' sexual dimorphism of body size is unclear because no differences between the sexes in feeding success rates or the foraging behavior have been observed and as males are larger they need more food than females
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= = parasites and mortality = =
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