the rook ( corvus frugilegus ) is a member of the family corvidae in the passerine order of birds .

it was given its binomial name by carl linnaeus in 1758 , the binomial is from latin ; corvus is for " raven " , and frugilegus is latin for " food-gathering " , from frux , frugis , " fruit " , and legere , " to pick " .

the english name is ultimately derived from the bird 's harsh call .

rook ( bird )

a nocturnal bird that can be seen hawking for food at dusk and dawn .
this bird species has different identifying features depending on sex / age / season .
despite widely beliefs that rooks and magpies are extensive raiders of other bird species nests it far more likely that domestic cats do far more damage to irish song bird populations .
that research is something for the members of the corvid bird family to ‘crow about’ .
telegraph view : a rook with a hook is something to be reckoned with .
the rook ' s diet , like most crows , is diverse and includes insects , worms , carrion and seeds . they will visit bird tables for scraps and fruit .
the rook ' s bill is longer and more pointed than that of the carrion crow .
the clever bird then uses the jar edge to bend the wire into a hook shape . . .
rook pair on a fence , waiting for humans to drop food at an adjacent picnic area . note shaggy belly feathers blowing to the right on the bird at the back . image by heinrich mallison .
this photo - one of a long sequence - shows a mating rook pair on the ground ( in this case , the mating was probably consensual ) . part - way through , a third bird intervened and a fight errupted . eventually , the third bird flew off . photo by naughty voyeur heinrich mallison .
the aptly named dr . chris bird discovers the remarkable problem - solving abilities of birds like crows and rooks
the rook is about the same size as the carrion crow but is more untidy in its appearance .
the rook is a member of the corvid or crow family , which is famed for its intelligence .
rooks do particularly well within the pastoral landscapes of ireland , as this map from bird atlas 2007 - 11 shows . relative abundance of rook during the breeding season , 2007 - 11 . ( click to enlarge )
mr bird told bbc news :
it was a big surprise to find out that rooks could use tools .
both rooks and new caledonian crows belong to the corvids , a bird group that is renowned for intelligent behaviour .
rook . adult semi - domesticated . akatarawa forest , february 2011 . image © duncan watson by duncan watson
lockie , j . 1956 . the food and feeding behaviour of the jackdaw , rook and carrion crow .
peter theobald considers our feathered friend the rook ; from tasty pies to their remarkable problem - solving skills .
krivolutsky , d . , n . lebedeva . 2004 . oribatid mites ( oribatei ) in bird feathers : passeriformes .
( baughman , 2003 ; bird and emery , 2008 ; feare , et al . , 1974 ; harrison , 1978 )
the british trust for ornithology ( bto ) is asking the public to take part in a national survey of bird intelligence .
the range of the rook extends throughout europe and asia ; in britain it is very widespread ( 6 ) .
buddle , g . a . 1947 . note on birds of mokohinau . new zealand bird notes 2 : 69 - 70 .
turbott , e . g . 1947 . birds of little barrier island . new zealand bird notes 2 : 93 - 108 .
the only member of the crow family found in new zealand in modern times , rooks were introduced by acclimatisation societies in 1862 - 74 . liberations in the nelson and auckland areas and failed , but after a slow start , populations in hawke’s bay and canterbury flourished and spread . the rook’s diet is a mixture of invertebrates and vegetable and the rook is often vilified by farmers for its crop destruction . others have accepted this intelligent bird as a welcome addition to our sparse large bird fauna .
software v . 5 . 0 , noldus information technology , wageningen , the netherlands ) without information on which stimulus was being viewed by which bird . we recorded how often the bird looked through the hole at the stimuli , and for how long . the bird ' s first look was noted in real time , but the duration of this look and all subsequent looks were coded from video .
a year ago , helen motteram from cheltenham found an injured rook by the side of a road and took him home .
the average lifespan for a rook is six years however a single individual has been recorded at 22 years and 11 months .
→ distribution map ( finnish breeding bird atlas , finnish museum of natural history , university of helsinki . licence : cc 3 . 0 )
the rook occupies agricultural land below 300 metres , and seems to prefer farms with both pasture and arable areas ( 6 ) .
the garden rook survey looked at six categories of behaviour : feeding , caching , tolerance , object play , social and vocalization .
in 2009 , they used this test to prove that rooks tend to be smarter than other bird species and than many non - human primates .
the rook is a bird embedded within our rural landscape and its presence can be seen in the literature and oral traditions of generations of rural inhabitants . the colonial , tree - top nests , so active at the very start of spring , stand testament to a species that has adapted to changing times . while not necessarily an easy bedfellow , the rook quite rightly acts as a totem for our agricultural heritage .
rook observed trying to fish something out of the water ( photo taken at marwell wildlife , uk ) . photo by darren naish .
spotting the worms in the bucket , but realising they are out of reach , the rook finds a piece of straight wire . . .
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coombs , c . j . f . 1959 . observations of the rook corvus frugilegus in southwest cornwall . ibis 102 : 394 - 419 .
check out the naked , gnarly face and very slender upper jaw tip in this rook ( the unworn bill tip shows that this bird indulges in relatively little - or no - probing behaviour ) . this individual had a damaged leg and was unable to walk or perch properly . photo by darren naish .
coleman , j . d . 1972 . the breeding biology of the rook corvus frugilegus in canterbury new zealand . notornis 19 : 118 - 139 .
species , the rook is expected to live 15 to 20 years in the wild . according to the euring european longevity records , the oldest rook found in the wild lived to be 22 years old . as is the trend , rooks in captivity may live for much longer . in a similar species ,
, commonly known as the oriental rook , extends from eastern asia west into northern mongolia . the two subspecies are generally geographically separated by the altai mountains .
the following habitats are found across the rook distribution range . find out more about these environments , what it takes to live there and what else inhabits them .
just a fable ? apparently not . footage shows a rook - a relation of the crow - performing the feat to reach a worm floating on the water’s surface .
mr bird said :
tool use is probably very important for these crows because of their ecology - they may get a large proportion of the protein they need from these grubs .
mullarney , k . , svensson , l . , zetterstrom , d . , & grant , p . j . ( 1999 ) collins bird guide . harpercollins publishers ltd , london .
no specific conservation action is targeted at the rook , but it should benefit from work for farmland birds in general , such as agri - environment schemes ( 8 ) .
auditory communication is vital to the rook . they have a sense of hearing which helps them distinguish amongst other populations and species . the rook is able to recognize the call of a mate or its young . in addition to vocalizations , rooks also rely on visual communication , which becomes increasingly more important once young are able to open their eyes . pecking is another form of communication , when an intruder rook comes too close to a territory ; pecking attacks can occur usually resulting in the retreat of the intruder .
few birds divide opinion like the rook . on the one hand we have farmers , who often endure massive damage to crops at certain times of the year , and on the other , the people who love to hear the most quintessentially english bird going about its business . certainly , no episode of midsomer murders would be complete without the background cawing of rooks .
porter , r . e . r . 2013 [ updated 2017 ] . rook . in miskelly , c . m . ( ed . ) new zealand birds online . urltoken
) lay two to seven ( average four ) blue - green eggs that are covered with brown and grey mottling . rook eggs are very similar in appearance to those of ravens (
rooks are highly social , living and interacting in large groups , although mating tends to monogamous . this bird species is largely arboreal and actively defends its territory . rooks are active primarily during the day .
mr bird and colleagues from queen mary , university of london , conducted the study with five - year - old rooks cook , connelly , fry and monroe , which were hand - reared from fledglings .
footage of the experiments shows the rook first assessing the water level by peering at the tube from above and from the side , before picking up and dropping the stones into the water .
for those whose acquaintance with the rook is merely a passing one , there is a tendency to lump the species in with carrion crow and raven ; all are large and black and lack obvious features by which the casual eye can secure an identification . while there is something in the country saying , which infers that a single black bird will be a carrion crow , and a group of black birds will be rooks , identification is less challenging than it might at first appear . the steep forehead and peaked crown of a rook , together with the blue , purple and green iridescence to the body and wings feathers , provide useful pointers , as su gough explains on the bto bird id video on crows . that country saying does , however , hint at the more colonial nature of rook society , the birds typically nesting , feeding and roosting together . crows are territorial during the breeding season and so are far less likely to be seen in large gatherings at that time of the year .
porter , r . e . r . 1979 . food of the rook ( corvus frugilegus ) in hawke’s bay , new zealand . new zealand journal of zoology 6 : 329 - 337 .
lead author christopher bird , from cambridge university , said :
we have found that they can select the appropriate tools out of a choice of tools and they show flexibility in the types of tools they use .
like all corvids , rooks are renowned for their intelligence , quite able to use tools to solve problems . in one experiment , a rook was placed next to a test tube half full of water . on the water floated an earthworm , but the water level was too low for the bird to reach it . some pebbles were made available , and it did not take very long for the rook to work out that if it dropped the pebbles into the test tube , thus raising the water level , the worm would float to the top . i know some humans who wouldn’t be able to solve that problem !
the rook can be found in a number of locations including : asia , china , europe , mediterranean , russia , united kingdom , wales . find out more about these places and what else lives there .
to knock this myth on the head , the british trust for ornithology has called on the british public to take part in a national survey on bird intelligence ; people’s task is to observe and video rooks engaged in intelligent behaviour .
a black crow flies over - but is it a crow , a rook or even a raven ? let this video help you to separate these confusing species , along with their smaller cousins : jackdaw and chough .
the rook seems to be doing well with the population increasing slightly year - on - year and so seems to have adapted to the various changes in agricultural practices that many other species have been adversely affected by .
the finding is remarkable because rooks do not appear to use tools in the wild , yet they rival habitual tools users such as chimpanzees and new caledonian crows ,
said chris bird , a cambridge zoologist who led the study .
rooks , compared to other corvids , are tolerant of other species feeding with them , especially jackdaws . however , rooks are large birds that can dominate smaller birds and sometimes displace ( take the place ) other birds at a bird table .
ornithologists dislike the use of ‘birdbrain’ as shorthand for stupid , because our feathered friends are very intelligent , says rita de brun . the british trust for ornithology has called on the british public to take part in a national survey on bird intelligence
expectancy violation has not been used as a paradigm with birds , partly owing to the difficulty in identifying where a bird is looking ( martin 2007 ) , and their capability to switch from lateral to frontal vision depending on their distance from the observed object ( dawkins 2002 ) . we therefore used the natural tendency of rooks to look through small holes ( bird & emery 2008 ) to record the frequency and duration of their looking behaviour when viewing static images of possible and impossible support relations .
the first trial in which the rook connelly is required to raise the water level by a varying amount . in this trial , seven stones are needed to raise the water level and worm to the reachable height . connelly flies to the testing platform and investigates the apparatus before the stones are added . connelly adds seven stones before successfully acquiring the worm . he then leaves the testing platform . see the paper by bird and emery in current biology 19 ( 16 ) : urltoken
corvids are among the most social of bird species , and it is thought their intelligence helps them to recognise each other . the birds do not appear to have evolved tool skills , but are simply intelligent enough to work out how they can help .
and although rooks are farmland birds , and tend to keep away from the middle of big towns and cities , they are increasingly being tempted into our gardens by bird feeders , so researchers hope this will provide the ideal setting to study their natural behaviour .
here is a rook i have been feeding for the last two years on a daily basis . he arrived this particular day and often does this . he sits on the railing as seen and chats away , here in youghal ireland .
pleasing rook illustration , photographed at horn tavern , lyme regis ( while i and colleagues were there for the duration of a conference ) . apologies for not knowing the name of the artist : they didn ' t sign the piece !
a rook ' s plumage is completely black with slightly purplish gloss . around the base of the beak is bare skin . the bill and legs are black . juvenile rooks do not have the bare skin around the base of the bill .
timing was crucial ; a few days too soon , and the birds would still be in the nest , a few days too late , and the whole lot would disappear after the first shot . may 12th was the chosen day , and the meat from the slain was to be made into traditional rook pie , enjoyed by the entire village . i’m not sure if this tradition continues in any part of the country , still less , if many people fancy eating young rook .
the aptly - named christopher bird , a phd student and lead author of the study , said it has long been known that rooks are intelligent but it had not been proven as they have no need to make tools in the wild , unlike their new caledonian cousins .
tend to be the primary predators of rooks . raptorial bird species prey on fledglings from nests more often than attacking adults . humans may also pose as a threat to some species due to increasing tolerance of human presence . humans are a threat due to shootings and habitat destruction of rooks .
the rook is a black crow ( that is , a member of the genus corvus ) , so unusual compared to the other corvus species that goodwin ( 1986 ) wrote that “its relationships within the genus cannot be deduced on present evidence” ( p . 71 ) : his phylogram depicts the rook as the sister - taxon to the remainder of corvus . however , genetic data indicates that the species is deeply nested within corvus , closely related to the eurasian raven c . corax and its kin ( ericson et al . 2005 ) .
the rook is classified as least concern ( lc ) on the iucn red list ( 1 ) . receives general protection under the wildlife and countryside act 1981 ( 3 ) . included in the birds of conservation concern green list ( low conservation concern ) ( 4 ) .
explanations for the variation in the number of nests at bird colonies have focused on competitive or habitat effects without considering potential interactions between the two . for the rook , a colonial corvid which breeds seasonally but forages around the colony throughout the year , both the amount of foraging habitat and its interaction with the number of competitors from surrounding colonies are important predictors of colony size . the distance over which these effects are strongest indicates that , for rooks , colony size may be limited outside of the breeding season when colony foraging ranges are larger and overlap to a greater extent .
in the most impressive display of avian intelligence , the rooks were faced with a juicy worm in a tiny bucket at the bottom of a glass tube . each bird looked at the worm and then bent a length of wire left nearby into a hook and used it to haul the bucket up .
the rook is a crow and is one of ireland ' s top 20 most widespread garden birds . rooks are very sociable birds , and you ' re not likely to see one on its own . they feed and roost in flocks in winter , often together with jackdaws .
mr bird said :
rooks don ' t have the same pressures [ as new caledonian crows ] . in the wild they don ' t need tools - they have lots of access to other sources of food , like carrion , human rubbish , and seeds from agriculture , things like that .
there seems to be some sort of relationship between rooks and falcons , with common kestrels falco tinnunculus and lesser kestrels f . naumanni both being well - known for their habit of sometimes nesting right within a rookery . even better , breeding in red - footed falcons f . vespertinus and amur falcons f . amurensis is ( sometimes ) seemingly dependent on the presence of rookeries and these species – which are colonial nesters themselves – don’t start their nesting activities until the rook nesting season is underway . they then move in and either take over disused rook nests , or else evict rook adults , nestlings and eggs from their nests before claiming them as their own ( madge & burn 1994 ) . long - eared owls asio otus and ospreys pandion haliaetus have also nested within active rookeries on occasion , and rookeries are sometimes mixed with active nests belonging to herons , cormorants and ibises .
adult ( at top ) and juvenile rook of the nominate form . illustration by peter hayman , from 1976 book the illustrated book of nature : a seasonal guide to the habitats of the british isles . adults of c . f . pastinator resemble the juvenile condition typical of c . f . frugilegus .
similar species : there are no other crow species confirmed to occur in new zealand , although a possible australian raven was reported from mokohinau and little barrier islands in october 1945 , and other australian crow species could occur as vagrants . the australian raven is larger than a rook , has a feathered face and long pointed ‘hackle’ feathers under the chin . all five australian crow species are larger than the rook , have feathered faces , white eyes , and lack the ‘baggy - trouser’ look , and are mainly distinguished from each other by their calls . single , silent , vagrant birds would be very difficult to identify to species .
this is one of the most common agricultural birds , yet , like many of its relatives , the rook has suffered persecution at the hands of farmers , gamekeepers and landowners for many hundreds of years , as it is perceived as a pest . organochloride chemicals are also known to affect this species ( 5 ) .
it is obvious that the present picture is confusing , and a complete census of the occupied nests at the county’s rookeries is required . ‘the relative conspicuousness of rook nests makes this one of the simplest breeding bird species to census . however , the extremely clumped , colonial distribution and the turnover in colony location from year to year make it especially important that , to be representative and adequately precise , censuses should cover large geographical areas and be either complete or drawn from a carefully constructed sample’ ( marchant & gregory 1999 ) . unfortunately , the coverage in cheshire and wirral for the last national sample survey in 1996 was so patchy that no useful figures can be obtained .
porter , r . e . r . ; clapperton , b . k . ; coleman , j . d . 2008 . distribution abundance and control of the rook ( corvus frugilegus ) in hawke’s bay , new zealand , 1969 - 2006 . journal of the royal society of new zealand 38 : 25 - 36 .
like many members of the crow family , the rook figures heavily in folklore . the sudden desertion of a rookery was said to be a bad omen for the landowner . rooks are believed to indicate rain by certain behaviour ( 7 ) , and are also believed to be able to smell approaching death ( 5 ) .
there is no doubt that rooks , like many other members of the crow family , are bright birds , quick to recognise opportunities and to take advantage of them . the bto’s garden ecology team are attempting to find out how clever rooks are by asking the public to take part in the garden rook survey . this resourceful nature can see rooks exploit feeding opportunities within gardens that may not be available to other birds . rooks have even been observed to hauling up bird feeders hanging from a branch on a bit of string . by pulling with its bill on the string to lift the feeder a few inches and then standing on it , a rook may gain access to food that was otherwise out of reach . rooks are not always welcome at garden feeding stations because they can arrive in numbers and make short work of food put out for other species . they can also damage crops and this brings them into conflict with landowners , who may use a range of measures to scare or control the birds .
rooks like to play with different objects , including sticks and stones . they will often play tug - of - war with another rook . although they don’t use sticks as tools , they do play with them , as well as use them to build nests . we asked if rooks were using objects , especially in unusual ways .
v . 10 , using a generalized linear mixed model ( glmm ) assessing the effect of stimulus type ( possible / impossible ) and trial number ( and the interaction between the two ) on looking behaviour . the experimental design meant that there were two levels of block structure : subject and sub - bird ( a subdivision of subject indicating trials nested within subject ) .
cook selectively drops stones into the tube containing water rather than the tube containing sawdust . cook flies to the testing platform and investigates both tubes before the stones are added . cook adds four large stones to the water before successfully acquiring the worm . he then leaves the testing platform . see the paper by bird and emery , current biology 19 ( 16 ) : urltoken
rooks exhibit a number of different display and signalling behaviours , no doubt because they live in close proximity to one another . many are used to communicate the status of an individual or to advertise ownership of a particular nest . bowing and tail fanning , typically accompanied with much calling , are a feature of the breeding season , when quarrels become more commonplace . display is an important behaviour because it helps to resolve conflict and support social status without the need for conflict which could prove physically damaging . other behaviours are used to reinforce the ‘pair bond’ that exists between a female and her mate , a bond that can last for many years – bird ringing has revealed that a rook may live for 20 years or more .
as an encore , these clever birds fashioned straight pieces of wire into hooks , with which to winkle food from a tube . this , say the experts , indicates a level of intelligence not normally associated with birds , but more akin to that of primates . in other words , a rook with a hook is something to be reckoned with .
during trials , each stimulus was presented consecutively in a pseudo - randomized order , remaining on - screen for 60 s ( following the bird ' s first look ) , separated by 30 s of black screen . subjects received four trials per experiment , such that each stimulus appeared in one of the four positions only once , so avoiding pseudo - replication and controlling for any effects of stimulus position .
rooks have numerous roles in the ecosystem . they serve as hosts for numerous protozoan organisms such as trypanosomes and leucocytozoans . such organisms are generally not pathogenic and merely occupy rooks as vectors . while rook hosting of these organisms does not directly cause it any harm , it makes infection of other species possible . in this way , rooks sustain the lifecycle of these organisms .
we thank n . clayton and t . dickinson for useful discussion . we also thank c . donovan for bird care and b . mccabe for statistical advice . the work was funded by the biotechnology and biological sciences research council , the royal society and the university of cambridge . n . j . e . was supported by a royal society university research fellowship . there are no conflicts of interest to report .
they are also steeped in folklore , many people believing rook even bring good luck . it is said that if rooks abandon their communal nest site , a death is imminent . also , if they build their nests high in the trees , you can look forward to a fine summer , but built low in the branches and you can expect a summer of wind and rain .
any adventures about the more rural parts of the uk typically involve ( for me , anyway ) a lot of looking at the rook corvus frugilegus , a remarkable old world corvid that occurs from the far western shores of the uk and france all the way east to japan ( it’s generally absent from the cold northern parts of eurasia , only visits the iberian peninsula and most of southern europe during the winter , and is absent from much of tropical asia ) . the east asian birds represent the distinctive subspecies c . f . pastinator ( sadly , not the more awesome sounding dastinator * , as it says in one particularly famous book on crows ) . i’ve been loosely ‘collecting’ rook images over the years and thought it high time to put a bunch of them together .
even farmers have a grudging respect for the rook when it is doing them no harm , and one gets the feeling that while rooks will certainly take eggs and young birds , they do not actively look for them , unlike other members of the corvid family , such as crows and magpies . few countrymen have any regard for the latter , while secretly admiring the antics of the former .
so how do you tell the difference between a rook and a crow ? an old country saying sums it up nicely , “if you see a rook on its own , it is a crow , but if you see a flock of crows , they are rooks . ” this certainly applies at distance , but in the hand , they are easy to tell apart , rooks have a distinctive area of skin round the base of the beak , and crows do not . however , young rooks do not get the area of skin round their beaks until they are around six months old , leading to some confusion , fooling some shooters into believing they are killing crows , when in fact , they are immature rooks . in any case , rooks have a blue sheen to their feathers , quite unlike the black colouring of crows .
for testing , subjects were individually isolated in testing areas separate from the main aviary . these areas each consisted of an indoor testing room connected to an outdoor “run . ” subjects were free to move between the room and the run . when in the run , subjects could see the rest of the group , whilst when in the room they were visually isolated . experiments followed the same general procedure . the apparatus was baited with a waxworm ( wax moth larvae , achroia grisella ) and placed into the testing room ; the bird performed the behavior or was timed out after 5 min if not successful , and the apparatus was removed . in experiments where subjects were given a choice of tools , the tools were placed next to the apparatus and the position of the tools was pseudorandomized so that no one tool was consistently closest to the apparatus . each test consisted of between 10–60 trials per bird ( see methods ) .
we thank n . clayton and j . hinde for critical discussion and useful ideas . we also thank i . miller for making the apparatus , c . donovan for bird care , b . mccabe for statistical advice , c . margerison for interobserver reliability coding . the work was funded by the biotechnology and biological sciences research council , royal society , and the university of cambridge . n . j . e . was supported by a royal society university research fellowship .
a rookery survey should also obtain information about the species of tree used – only beech and pine being mentioned in data submitted for this atlas – and a habitat assessment of the surrounding habitat . the atlas habitat codes for rook show 46 % of records in farmland and 46 % in woodland , with 7 % in human sites . these figures are probably of little value because many fieldworkers recorded the nest site rather than the feeding habitat .
rooks are one of the most social crows , forming very large flocks . but rooks also form life - long partnerships , called pairbonds . rook pairs spend a lot of time close together , feeding one another , displaying and vocalising together and preening . they also act at the same time , one copying the other’s movements . we wanted to know if rooks were interacting in pairs and groups , and whether they were aggressive to each other .
rook feeding habits often vary due to the location of their nest . unlike those occurring in natural areas as above , those that live near urban sites also act as scavengers and take advantage of trashcans as well as abandoned food . most rooks spend much of their time foraging at dawn and dusk . primarily searching at dawn , rooks will pick through garbage bags to obtain food . however , they have been seen foraging during the day . like all
however , the breeding bird survey is not a good way to census rooks or any colonial species , and a coordinated count of nests is required . the last census in cheshire and wirral , in 1975 , found 346 rookeries containing 8 , 824 nests within the present recording boundaries , a substantial reduction from the previous count in 1944 - 45 which recorded 439 rookeries with a total of 15 , 866 nests . if the figure from the bbs were taken at face value , which is not advisable , the present total of around 5 , 000 pairs would represent a further major decline . some observers count nests annually , with figures included in the county bird reports , and figures from the largest rookeries appear to be relatively stable for the last decade . currently the county’s largest known colonies , with regular three - figure counts , are at alderley park ( sj87m ) , inner marsh farm ( sj37b ) , kelsall ( sj56p ) , foden’s flash ( sj75j ) and the crewe / alsager area .
rooks are almost entirely black with a purplish gloss . the face is bare light grey skin , the beak is long , pointed and black , and the eye is dark brown . when walking on the ground they have the appearance of baggy - trouser like feathers on the upper leg . juvenile rooks have feathered faces . with steady wing beat in the air , the rook creates a short - necked silhouette , like a black cloth being towed through the sky .
numerous anecdotes describe unusual bits of behaviour in this species , most of which can be interpreted as sensible ( and plausible ) responses to stimuli . burton ( 1978 ) described an instance in which a flying rook dove at a sparrowhawk , forcing the hawk to release a live starling it had captured , and another in which a breeding pair seemingly enlisted helpers to quickly re - build a nest a few hours after the original one had been destroyed by a person .
subjects were seven adult rooks ( corvus frugilegus ) , 4 years of age at the time of testing ( one male and six females ) . these were part of a hand - raised group colony of 12 rooks , kept in large outdoor aviaries ( 20 × 8 × 3 m ) at the university of cambridge ' s subdepartment of animal behaviour at madingley , uk . all subjects had previous experience with image presentation on an lcd screen ( bird & emery 2008 ) and all took part in four consecutive experiments .
rooks used to feed in gregarious flocks . they would roost in large winter roosts containing birds from a number of breeding colonies . they would visit the breeding rookery first thing in the morning and again in the evening before returning to the roost site . nowadays they are seen roosting only in small numbers . they usually travel up to 10 km from their night - time roost to feeding sites , while in the breeding season they forage within a few kilometres of the rookery . they are an extremely wary bird now and little is known of their habits .
a noisy customer is the rook , as anyone living close by a rookery will testify . but this particular corvid is also , it seems , extremely smart . a study reveals that it is blessed with a high degree of innate intelligence , not just a well - honed ability to adapt to its environment . researchers found that rooks raised in captivity – and therefore unschooled in the skills of survival – were still able to choose the right size of stone to pop into tubes of varying diameters to release a nutritious reward .
a colony of rooks recorded at culver , near exeter in devon . rooks are highly sociable birds that form rookeries among tree tops surrounding open fields and suburban areas . from nesting to feeding , almost everything is done together , which makes a lone rook a very unusual sight . with their black plumage , heavy grey - white beak and ‘kaah’ calls , rooks could share the same dark reputation as crows and ravens . however , their friendly disposition seems to have shone through and rooks are considered one of the ‘nicest’ members of the crow family .
) . it resembles the carrion crow in size ( 45 cm [ 18 inches ] ) and in black coloration , but the adult rook usually has shaggy thigh feathers and has bare white skin at the base of its sharp bill . the species ranges discontinuously from england to iran and manchuria and is migratory . rooks nest in large colonies ( rookeries ) in tall trees , sometimes within towns . their nests are solidly constructed of twigs and soil and are used year after year . the birds lay three to five light greenish , heavily speckled eggs , and the young are able to fly about a month after birth . rooks dig for
the apparatus was initially placed on a platform inside the main aviary ( fig . s1 , configuration 1 ) . connelly , cook , and monroe initially solved the task by nudging the stone into the tube . after 5 trials of nudging the stone , it was placed at the base of the apparatus and all 3 birds immediately picked up the stone , dropping it into the tube . fry picked up the stone from the base of the tube and dropped it in without the nudging phase . once each bird had solved the task 15 times ( 5 × nudging , 5 × stone at apparatus base , 5 × stone on aviary floor ) , they were moved into the testing compartment to allow the rest of the group access to the apparatus .
rooks are famous for their bare , pale faces and bill - bases ( the east asian subspecies c . f . pastinator differs in having a feathered face and bill - base ) . the vernacular name bare - faced crow was apparently used for the species in the past ( coombs 1978 ) . claims that the bare face only occurs due to the soil - probing behaviour practised by this species are not correct : you can read more about this issue in the tet zoo ver 2 article linked to below . a tall forehead and shaggy , loose flank feathers that give the bird a so - called ‘baggy trousered’ look are also distinctive . males and females look the same ( though males are slightly larger ) and there are no seasonal changes in plumage .
for the 16 to 18 day incubation period the female rook covers the eggs unless she has to briefly leave the nest , in which case the male takes over this duty . after hatching , the female tends to the young exclusively while the male delivers food . this continues for approximately the first ten days until the young become more self - sufficient , at which point the female joins the male in food gathering . at around 32 to 33 days old the young rooks fledge and leave the nest , but roost in nearby trees to remain close to the parents . the young continue their relationship with the parents for several weeks until they become fully independent . even after reaching full maturity and independence , rooks generally remain members of their original rookery .
rooks are familiar birds and ubiquitous . they are a bird of farmland , mainly feeding on soil invertebrates , especially earthworms , but they will scavenge on urban scraps and flock to landfill sites . rooks nest colonially in the tops of trees , the largest rookeries holding more than one hundred pairs , and are a veritable cacophony of noise during the breeding season . as was said in our first atlas , there is probably no tetrad in the county where rooks do not appear at some stage during the breeding season , often miles away from a rookery . some of these are one - year - old birds , too young to breed ; family parties similarly can be found far away from breeding sites . therefore , we follow the same convention as in our first atlas and map only the categories of breeding status code referring to nesting sites : confirmed ( ny , ne , on and un ) and probable ( b ) . this atlas shows a significant reduction in the number of tetrads occupied , from 266 confirmed and 12 probable twenty years ago to 205 confirmed and 4 probable now .
this bird is very sociable , and nests communally in groups of trees known as ' rookeries ' ( 5 ) . communal roosts form in winter , consisting of birds from a number of breeding rookeries ( 6 ) . these roosts can be huge ; one in northwest scotland contained 65 , 000 rooks ( 6 ) . by february , the rooks return to their own rookery in order to start breeding ( 6 ) ; pairs defend a small area around their nests . during courtship , the male struts around , bowing , posturing and cawing ; he may then empty the contents of his food pouch into the female ' s mouth before mating takes place ( 5 ) . the nest is constructed of twigs , and three to five blue or grey - green eggs are laid towards the end of march . these are incubated by the female for up to 18 days ; whilst the female incubates the eggs and broods the chicks she is fed by the male ( 5 ) . after 40 days , the chicks are fully grown , but they remain dependent on their parents for food until they reach 60 days of age , and only become truly independent after around five months ( 5 ) .
in the final set of experiments , we tested our subjects on a different tool use task , similar to the type of tool use used by new caledonian crows ( 10 , 11 ) . the task required the rooks to use a hook tool to retrieve an out of reach bucket containing a waxworm , located in a vertical clear tube ( fig . s9 ) . in the initial task , we provided a hook tool next to the apparatus . this consisted of a 16 cm long stick with an arrow shaped hook on one end ( fig . s9 a ) . subjects were required to insert the tool the correct way round ( hook end down ) , hook the tool onto the bucket handle and pull up ( rather than push down as previous experiments had required ) . all 4 subjects successfully solved this task ( success rate was 90 . 8 ± 4 . 4 % of trials ) , with 3 of the 4 birds solving the task on trial 1 and the fourth bird solving the task from trial 2 ( movie s8 and fig . s10 a ) . all subjects inserted the hooked end into the tube significantly more often than the straight end ( glm ; tool end f 1 , 17 = 4 . 54 , p = 0 . 048 ; subject f 3 , 17 = 1 . 60 , p = 0 . 226 ) ; however , this required some learning ( block f 2 , 17 = 10 . 93 , p = 0 . 001 ) .
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as the 2000 - year - old story goes , the crow filled the bucket of water with stones until the level became high enough for him to quench his thirst .
the study , published by current biology , says that crows are innovative tool users , even though they are not known to use tools in the wild .
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i thought you might be interested in this item at urltoken title : biology letters publisher : london : royal soc . , 2003 - isbn / issn : 0962 - 8452 oclc : 265429584
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some corvids have demonstrated cognitive abilities that rival or exceed those of the great apes ; for example , tool use in new caledonian crows , and social cognition , episodic - like memory and future planning in western scrub - jays . rooks appear to be able to solve novel tasks through causal reasoning rather than simple trial - and - error learning . animals with certain expectations about how objects interact would be able to narrow the field of candidate causes substantially , because some causes are simply ‘impossible’ . here we present evidence that rooks hold such expectations and appear to possess perceptual understanding of support relations similar to that demonstrated by human babies , which is more comprehensive than that of chimpanzees .
the physical world is governed by unobservable forces such as gravity . these forces govern how objects interact and impose causal regularities . there is debate about whether any non - human animals appreciate unobservable forces ( povinelli 2000 ; emery & clayton 2009 ) ; however , there is evidence to suggest that some animals , including some species of corvid such as rooks and new caledonian crows , are able to appreciate causal regularities when solving technical problems ( seed et al . 2006 ; taylor et al . 2009 ) .
the causal structure of the world may be represented by formulating expectations about what is possible and what is not , and so may be used to build more general rules about physical concepts , such as support . certain conditions are required for support , such as contact between an object and its supporting platform . only certain types of contact are appropriate for support and there must be a sufficient amount of contact between the surfaces . solving support - related problems may involve an understanding of means–end relations or may be based on the specific perceptual features related to the spatial arrangement of object and support ( povinelli 2000 ) . the causal structure of the world cannot be perceived directly ( one cannot ‘see’ gravity ) and must be inferred from the spatio - temporal relationships between objects ( chappell 2006 ) .


isacia conceptionis , the cabinza grunt , is a species of grunt native to the pacific coast of south america and nicaragua .

it can be found at depths of 0 to 50 m ( 0 to 164 ft ) in areas with rocky or sandy substrates .

this species grows to 60 cm ( 24 in ) in tl , with a maximum known weight of 1.83 kg ( 4.0 lb ) .

it is important to local commercial fisheries .

i. conceptionis is the only known member of its genus .

isacia conceptionis

olfactory transduction in ciliated receptor neurons of the cabinza grunt , isacia conceptionis ( teleostei : haemulidae ) .
olfactory transduction in ciliated receptor neurons of the cabinza grunt , isacia conceptionis ( teleostei : haemulidae ) . - pubmed - ncbi
the cabinza grunt , isacia conceptionis , is found from peru to chile . it has also been reported from nicaragua ( sánchez 1997 ) .
there are no species - specific conservation measures in place for isacia conceptionis , however its distribution coincides with a number of marine protected areas . monitoring of the harvest levels of this species is needed .
moraga , f . a . and urriola - urriola , n . , 2015 . acetylcholine produces contraction mediated by cyclooxigenase pathway in arterial vessels in the marine fish ( . isacia conceptionis ) brazilian journal of biology = revista brasileira de biologia , vol . 75 , no . 2 , pp . 362 - 367 . urltoken . pmid : 26132019 . [ links ]
justification : the cabinza grunt , isacia conceptionis , has been assessed as least concern . despite this species been commercially fished , it apparently remains abundant throughout its range and there is no indication it is undergoing severe population declines at present . monitoring of the harvest levels of this species is needed to ensure harvesting and climatic events such as el nino do not cause future declines . .
ratio response in g . laevifrons ( black ) and i . conceptionis ( open ) from afferent branchial artery ( aba ) ; efferent branchial artery ( eba ) ; mesenteric artery ( ma ) and dorsal artery ( da ) . each symbol represents the mean ± s . e . m . * p < 0 . 05 g . laevifrons vs i . conceptionis .
( of pristipoma conceptionis cuvier , 1830 ) froese , r . & d . pauly ( editors ) . ( 2018 ) . fishbase . world wide web electronic publication . , available online at urltoken [ details ]
six juvenile girella laevifrons and six juvenile isacia conceptionis were extracted during low tide in the totoralillo bay ( 30º 17’ s , 71º 31’ w ) south of coquimbo , chile . all specimens were carried to our laboratory in the universidad católica del norte and maintained for 3 - 5 days in filtered recirculation containers of fresh marine water at 15 °c . prior to experimentation , g . laevifrons or i . conceptionis were anaesthetized with benzocaine ( 1 : 1000 ) and sacrificed by decapitation . afterward , corporal mass ( 115±12 and 140±8 g ) and longitude oral - tail ( 18±0 . 6 and 21±0 . 8 cm ) were measured for each specimen , respectively . all animal care , maintenance , procedures , and experimentation were reviewed and approved by the faculty of medicine ethics committee of the universidad católica del norte .
estudos anteriores , realizados no peixe intertidal ( girellalaevifrons ) no peixe marinho ( isacia conceptionis ) , mostram que a acetilcolina ( ach ) provoca contrações mediadas por ciclooxigenases que eram dependentes da área e potencia da contração em vários vasos arteriais . tendo em conta que o papel do óxido nítrico é mal compreendido em peixes , o objetivo do nosso estudo foi avaliar o papel do óxido nítrico em vasos arteriais de ambos os peixes girella laevifrons e isacia conceptionis . nós estudamos os vasos aferente , branquial ( aba ) , eferente branquial ( abe ) , dorsal ( da ) e mesentérica ( ma ) , que foram dissecadas de seis espécimes juvenis . estudos de tensão isométrica foram realizados utilizando as curvas de dose - resposta ( drc ) para ach ( 10 –13 a 10 –3 m ) e bloqueio com l - name ( 10 –5 m ) , e na drc para o nitroprussiato de sódio ( snp , doador do no ) . l - name produziu uma atenuação da resposta contrátil nas artérias dorsais , aferentes e eferentes branquial e uma potenciação da contração no ma . snp causaram 70 % da dilatação da artéria mesentérica e 40 % na artéria dorsal . nossos resultados sugerem que ach promove dilatação precária em ma mediada por no ; dados que é suportada pela utlilização de nitroprussiato de sódio . em contraste , nos vasos de da , aba e eba nossos resultados suportam que a via de ach - no - relaxamento está ausente em ambas as espécies .
previous studies performed in intertidal fish ( girella laevifrons ) , as well as marine fish ( isacia conceptionis ) , showed that acetylcholine ( ach ) produced contractions mediated by cyclooxygenases that were dependent on the area and potency of contraction in several arterial vessels . given that the role of nitric oxide is poorly understood in fish , the objective of our study was to evaluate the role of nitric oxide in branchial afferent ( aba ) , branchial efferent ( abe ) , dorsal ( da ) and mesenteric ( ma ) arterial vessels from both girella laevifrons and isacia conceptionis . we studied afferent and efferent branchial , dorsal and mesenteric arteries that were dissected from 6 juvenile specimens . isometric tension studies were done using dose response curves ( drc ) for ach ( 10 –13 to 10 –3 m ) and blockade with l - name ( 10 –5 m ) , and drc for sodium nitroprusside ( snp , a donor of no ) . l - name produced an attenuation of the contractile response in the dorsal , afferent and efferent branchial arteries and a potentiation of the contraction in the ma . snp caused 70 % dilation in the mesenteric artery and 40 % in the dorsal artery . our results suggest that ach promotes precarious dilatation in ma mediated by no ; data that is supported by the use of sodium nitroprusside . in contrast , in the vessels da , aba and eba our results support that the pathway ach - no - relaxation is absent in both species .
sodium nitroprusside concentration - response curves in : ( a ) g . laevifrons ( black ) and ( b ) i . conceptionis ( open ) of isolated rings of arteries from afferent branchial artery ( aba , squares ) ; efferent branchial artery ( eba , triangles ) ; mesenteric artery ( ma , rhombus ) and dorsal artery ( da , circles ) each symbol represents the mean ± s . e . m .
the ciliated receptor neurons of fish olfactory organs are thought to transduce amino acids through a camp - dependent transduction pathway , but direct physiological evidence for this hypothesis remains scarce and is confined to catfish and trout . we investigated olfactory transduction in a marine fish , the cabinza grunt isacia conceptionis ( perciformes , teleostei ) . the olfactory epithelium was characterized using light and electron microscopy , and isolated ciliated receptor neurons were recorded with the perforated patch - clamp technique . cells were stimulated with puffer pipettes containing amino acid odourants , ibmx plus forskolin or 8 bromo - camp . all three stimuli triggered transient inward currents at a holding potential of - 70 mv and responses with outward - rectifying current - voltage relationships . the characteristics of the transduction currents induced by each stimulus were similar across cells and indistinguishable within the same cell , supporting the hypothesis of a camp pathway mediating transduction of amino acids in ciliated olfactory receptor neurons .
in order to corroborate the role of no , we studied the effect of snp , a no donor , in all the vessels . we found that aba and abe in g . laevifrons were insensitive to stimulation with snp , and a poor response in the same vessel was observed in i . conceptionis . the lack or poor response to snp in these areas suggests a different mechanism of activation for vessel dilation , independent of no . this lack of dilation in the fish vessels studied was also described in the isolated ventral aorta of o . mykiss ( miller and vanhoutte , 1992 ) . in addition , an eel contraction response in the presence of snp was described by pellegrino et al . ( 2002 ) suggesting that no could be mediated via reaction with superoxide ions to produce the very reactive peroxynitrite that promotes vasoconstriction ( beckman and koppenol , 1996 ) by a reduction in the bioavailability of no and a stimulation of cox that promotes the production of vasoconstrictors . in contrast , our results show dilatators response of 70 % in girella laevifrons and 60 % were observed in isacia conceptionis , in ma , and dilation close to 40 % in da in both species . this evidence supports a coupled mechanism of dilation in these vessels mediated by the no - gmpc - relaxation pathway . furthermore , our results are in agreement with the presence of snp - mediated dilation described in arteries of the trout ( o . mykiss ) : coronary , celiacomesenteric and efferent branchial ( olson and villa , 1991 ; small et al . 1990 ; olson et al . , 1991 , olson et al . , 1997 ) .
our study compared vascular function of two fish with completely different habitats : g . laevifrons that lives and develops in an environment with extreme variation ( intertide ) , and i . conceptionis that lives in an environment with little variation ( open coast ) . previously , we demonstrated that both species possess a vasoconstrictor mechanism mediated by acetylcholine supporting the presence of two muscarinic receptors : one having high sensitivity and a second one of lower sensitivity coupled to different mechanisms of activation ( moraga and urriola - urriola , 2014 , 2015 ) .
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thank you for taking the time to provide feedback on the iucn red list of threatened species website , we are grateful for your input .
gland , switzerland , 5 july 2018 ( iucn ) – australia’s unique reptiles – including lizards and snakes – face severe threats from invasive species and climate change , with 7 % of th . . .
the value of medicinal and aromatic plant trade has increased three - fold in the past 20 years , but traditional harvesting practices are being replaced by less sustainable alternatives . . . .
a recently released iucn technical brief recommends increasing investments in sustainable land management practices , as well as better cooperation between agriculturalists and conservationists to conse . . .
marine ; benthopelagic ; depth range 0 - 50 m . subtropical ; 5°s - 55°s , 81°w - 70°w
southeast pacific : peru to chile . also reported in nicaragua ( ref . 13613 ) .
maturity : l m ? , range 17 - ? cm max length : 60 . 0 cm tl male / unsexed ; ( ref . ) ; max . published weight : 183 . 00 g ( ref . 53696 )
over rocky and sandy bottoms . maximum size assumed to be the same as for the family . feeds on small crustaceans such as isopods and amphipods but also on polychaetes and algae .
chirichigno , n . f . , 1974 . clave para identificar los peces marinos del peru . inf . inst . mar perú ( 44 ) : 1 - 387 . ( ref . 5530 )
) : 11 . 3 - 27 . 7 , mean 20 . 5 ( based on 12 cells ) .
phylogenetic diversity index ( ref . 82805 ) : pd 50 = 1 . 0000 [ uniqueness , from 0 . 5 = low to 2 . 0 = high ] .
bayesian length - weight : a = 0 . 01288 ( 0 . 00716 - 0 . 02316 ) , b = 2 . 99 ( 2 . 84 - 3 . 14 ) , in cm total length , based on lwr estimates for this species & ( sub ) family - body ( ref . 93245 ) .
trophic level ( ref . 69278 ) : 2 . 9 ±0 . 39 se ; based on food items .
resilience ( ref . 69278 ) : medium , minimum population doubling time 1 . 4 - 4 . 4 years ( assuming tm = 2 - 3 ) .
vulnerability ( ref . 59153 ) : moderate to high vulnerability ( 51 of 100 ) .
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de silva , r . , milligan , h . , lutz , m . , batchelor , a . , jopling , b . , kemp , k . , lewis , s . , lintott , p . , sears , j . , wilson , p . , smith , j . & livingston , f .
to be the most abundant fish species along the northern chilean coast . it is thought that , like other species in the region , it suffered population declines during el nino events ( sielfeld
the cabinza grunt occurs over rocky and sandy bottoms and has a depth range of 0 - 50 m . this species is dominant in shallow rocky subtidal areas ( angel and ojeda 2001 ) . its diet consists of small crustaceans , polychaetes and algae .
the cabinza grunt is harvested commercially as a food source . landings in the humboldt current have ranged from between 1 , 000 to near 7 , 000 tonnes over the last ten years : 1995 - 3 , 282 . 34 tonnes , 1996 - 2 , 362 . 11 tonnes , 1997 - 1 , 701 . 67 tonnes , 1998 - 2 , 545 . 16 tonnes , 1999 - 6 , 119 . 10 tonnes , 2000 - 3 , 361 . 92 tonnes , 2001 - 3 , 244 . 06 tonnes , 2002 - 3 , 842 . 05 tonnes , 2003 - 2 , 882 . 75 tonnes , 2004 - 3 , 158 . 12 tonnes . while there are annual fluctuations in the landings of this species , there is no obvious decline assuming the catch per unit effort has remained relatively constant . fluctuations in the landings of this species might be attributed to el nino events .
this errata assessment has been created because the map was accidentally left out of the version published previously .
( errata version published in 2017 ) . the iucn red list of threatened species 2010 : e . t155309a115299279 .
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froese , r . & d . pauly ( editors ) . ( 2018 ) . fishbase . world wide web electronic publication . , available online at urltoken [ details ]
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centro de neurociencias de valparaiso , facultad de ciencias , universidad de valparaiso , avda . gran bretania 1111 , playa ancha , valparaiso , chile . oliver @ urltoken
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disclaimer : itis taxonomy is based on the latest scientific consensus available , and is provided as a general reference source for interested parties . however , it is not a legal authority for statutory or regulatory purposes . while every effort has been made to provide the most reliable and up - to - date information available , ultimate legal requirements with respect to species are contained in provisions of treaties to which the united states is a party , wildlife statutes , regulations , and any applicable notices that have been published in the federal register . for further information on u . s . legal requirements with respect to protected taxa , please contact the u . s . fish and wildlife service .
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to cite this page : myers , p . , r . espinosa , c . s . parr , t . jones , g . s . hammond , and t . a . dewey . 2018 . the animal diversity web ( online ) . accessed at https : / / animaldiversity . org .
disclaimer : the animal diversity web is an educational resource written largely by and for college students . adw doesn ' t cover all species in the world , nor does it include all the latest scientific information about organisms we describe . though we edit our accounts for accuracy , we cannot guarantee all information in those accounts . while adw staff and contributors provide references to books and websites that we believe are reputable , we cannot necessarily endorse the contents of references beyond our control .
this material is based upon work supported by the national science foundation grants drl 0089283 , drl 0628151 , due 0633095 , drl 0918590 , and due 1122742 . additional support has come from the marisla foundation , um college of literature , science , and the arts , museum of zoology , and information and technology services .
a laboratorio de fisiología , hipoxia y función vascular , departamento de ciencias biomédicas , facultad de medicina , universidad católica del norte – ucn , larrondo 1281 , guayacán , p . o . box 117 , coquimbo , chile
after decapitation , arterial vessels were carefully dissected from the following areas : branchial afferent ( aba ) , branchial efferent ( abe ) , dorsal ( da ) and mesenteric ( ma ) and placed in cold ( 4 °c ) physiological saline solution ( pss ) . individual arterial ring segments having 2 mm length were mounted in a four channel small vessel wire myograph ( model 510m danish myotech , aarus , denmark ) . the vessels were threaded onto two tungsten wires of 40 μm in diameter and attached to a force transducer and a micrometer for isometric measurements . all signals were acquired by a system acquisition ( powerlab 8sp , adinstrument , australia ) and the data collected on a personal computer for further analysis . after mounting the rings , the arterial segments were incubated in pss at 15°c and gassed with air for 30 min . each vessel segment was stretched to its optimal diameter , i . e . the diameter at which it developed a contraction response to pss - k + , using a diameter–tension protocol as previously described for mammalian small arteries ( stassen et al . , 1997 ) . in this way , the myograph permitted direct measurement of vessel wall tension while the internal diameter was controlled .
following an equilibration period of at least 30 min , doses response curves ( drc ) were performed for kcl ( 5 . 6 - 125 mm ) and the cholinergic agonist acetylcholine ( ach ) at concentrations ranging from 10 –13 to 10 –3 mol / l . afterward , drc for ach were performed in vessels pre - incubated for 30 min with n g - nitro - l - arginine methyl ester ( l - name , 10 –5 m ) , a nitric oxide synthase inhibitor . furthermore , drc for sodium nitroprusside ( a donor of no ) were obtained at concentrations ranging from 10 –13 to 10 –3 mol / l in arteries previously contracted with potassium chloride at 60 mm ( maximum potassium contraction ) . the curve is expressed as dilation of maximum contraction to potassium and represents maximum dilation ( dmax ) . between experiments , the arterial preparations were allowed to recover for at least 30 - 60 min to return to resting basal tension .
the pss contained ( in g / l ) : nacl 7 . 37 , kcl 0 . 31 , kh 2 po 4 0 . 46 , na 2 hpo 4 2 . 02 , mgso 4 0 . 14 , cacl 2 0 . 1 , glucose 0 . 9 with ph adjusted to 7 . 8 ( olson and villa . 1991 ) . for the pss - k + solution ( 125 mm kcl ) , nacl was replaced by an equimolar amount of kcl . all chemicals were reagent grade and purchased from sigma chemical ( st louis , mo , usa ) . the following drugs used in the study : acetylcholine ( ach ) , n g - nitro - l - arginine methyl ester ( l - name ) , and sodium nitroprusside ( snp ) were purchased from sigma chemical ( st louis , mo , usa ) .
drc were analyzed in terms of maximal response ( rmax ) , sensitivity ( ec 50 or pec 50 ) and maximum dilation ( dmax ) to different contractile agents by fitting the individual data with a nonlinear sigmoid regression curve ( prism 4 . 0 , graphpad , san diego , ca , usa ) . rmax was expressed as ( n / m ) and dmax was expressed as ( % k + max ) . sensitivity was expressed as ec 50 ( the concentration of agonist at which 50 % of rmax was obtained ) or as pec 50 ( - logec 50 ) .
in order to evaluate the role of the ach - nos - no - relaxation pathway , data were expressed as ratio response ( rr ) of rmax ach plus lname divided by rmax of ach , the evaluation of the ratio response ( rr ) should give values of rr > 1 if there is an increase in wall tension due to decreased production of no mediated by ach , and values of rr = 1 ach - nos - no - relaxation is uncoupled and rr < 1 , ach promote dilation don’t mediated by no .
all results were expressed as mean ± sem . a two way anova for repeated measurements was used for statistical analysis of physiological variables . differences were considered significant when p < 0 . 05 ( primer of biostatistical v 3 . 0 , mc graw hill ) .
the calculated internal diameter for all arteries is given in table 1 . the data show that not differences were observed in the optimal diameter determined for each of the arterial segments from the different territories studied in both species .
table 2 provides a summary for rmax parameters obtained from analysis of the arterial response curves in both species . these data reveal that rmax was significantly greater in the aba and abe in i . conceptions as compared to g . laevifrons . no differences were observed between da and ma in both species . in addition , no differences were observed in the ec 50 in any of the arteries evaluated in both species .
†† eba vs da , aba and ma ( p < 0 . 05 ) .
in figure 1 we can observe an increase in the contractile response to ach , only in ma in comparison with da , aba and eba . on the other hand , in da was observed such as maintenance . however , a dilation response was observed in aba and eba to ach . on other hand , significant differences were observed between species in aba , eba and ma , but not in da . table 2 summarizes the rmax values obtained from analysis of the arterial curves . no differences were observed in the pec 50 in any of the arteries evaluated .
in order to evaluate the role of no , arteries were pre - contracted by ach , and drc for snp ( 10 –13 –10 –10 m ) were evaluated . figure 2 reveals that the mesenteric artery exhibited dilation close to 70 % , whereas the dorsal artery only had dilation close to 40 % . no effect in dilation was found in aba and abe in the presence of snp . table 2 summarizes the pec 50 and rmax values obtained from analysis of the arterial curves . no differences were observed in the pec 50 in any of the arteries evaluated .
our results show that all vessels studied ( aba , eba , ma and da ) exhibited a similar pattern of vasoconstriction mediated by ach as previously described by moraga and urriola - urriola ( 2014 , 2015 ) , in the same species . in addition , the same authors describe that this vasoconstriction was abolished by the use of atropine ( 10 –5 m ) . this evidence has been corroborated by other studies in trout , shark and eel ( nilsson and grove , 1974 ; pellegrino et al . , 2003 ; pellegrino et al . , 2002 ; small et al . , 1990 ) , supporting the presence of muscarinic receptors in fish vasculature .
in mammalian vascular endothelium , several extracellular signals can stimulate nos , increasing the production of no , including ach , shear stress , etc . ( furchgott and zawadzki , 1980 ) . the nitric oxide produced by endothelium rapidly diffuses into the smooth muscle cell where it activates a soluble guanylyl cyclase ( sgc ) , which generates cyclic guanosine monophosphate ( cgmp ) that mediates vasodilation ( mondaca et al . , 1991 ) . a traditional approach to evaluate coupled ach - dilation is by the use of blocking agents that inhibit nos , decreasing no production , such as l - name or others ( buxton et al . , 1993 ) . the expected effect of blocking no production would be an increase in the basal tension , or an increase in the ach - mediated tension . therefore , evaluation of the ratio response ( rr ) should give values of rr > 1 if there is an increase in wall tension due to decreased production of no mediated by ach , and values of rr = 1 or rr < 1 if ach - nos - no - relaxation is uncoupled . indeed , studies show that there is an absence of muscarinic receptors coupled to the nos - no dilation pathway in fish ( donald and broughton , 2005 ) . in contrast , our results revealed a different effect when blocking with l - name in the arterial vessel . for example , in aba and abe there was a reduction in the ach - mediated vasoconstriction suggesting activation of other mediators that promote vasodilation , such as prostacyclin , h 2 s or co ( olson and villa , 1991 ; miller and vanhoutte , 1986 ; evans and gunderson , 1998b ; feng et al . , 2007 ; dombkowski et al . , 2008 ; jennings and donald . , 2010 ) . on the other hand , da did not modify arterial tension in the presence or absence of l - name , supporting the lack of ach - nos - no - relaxation coupling . in ma , we described an increase in ach - mediated vasoconstriction indicating the presence of a coupled ach - nos - no dilation . this evidence suggests that there is ach - nos - no - relaxation coupling in ma in both species , such as that shown in danio rerio in the same vascular area ( fritsche et al . , 2000 ; holmberg et al . , 2006 ) .
in conclusion , our results suggest differences in the vascular function between i . conceptions and . g . laevifrons , could be explained by ontogenic , habitat and / or phylogenetic components furthermore , our results suggest that the ma expresses a vascular response when the ach - nos - no relaxation pathway is coupled , whereas the results in da , aba and eba suggest the presence of another mechanism . future studies are needed to further evaluate the vascular response in these species .
we are grateful for the technical assistance of mr . hervis galleguillos and medical students carolina norero , daniela gonzalez , natalia soto and marietta nuñez who collaborated in the experiments . this research was partially supported by project dgip 10301272 , universidad católica del norte .
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