thelcticopis severa is a species of huntsman spider found in china , laos , korea , and japan .

it is the type species for the thelcticopis genus , and was first described by charles athanase walckenaer in 1875 .

thelcticopis severa

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citation : world spider catalog ( 2018 ) . world spider catalog . version 19 . 0 . natural history museum bern , online at http : / / wsc . nmbe . ch , accessed on { date of access } . doi : 10 . 24436 / 2
2018 - 07 - 05 new taxonomic reference entry - ref sinodraconarius yui zhao & s . q . li , 2018
2018 - 07 - 05 new species inserted - ref sinodraconarius yui zhao & s . q . li , 2018
2018 - 07 - 05 new taxonomic reference entry - ref sinodraconarius muruoensis zhao & s . q . li , 2018
2018 - 07 - 05 new species inserted - ref sinodraconarius muruoensis zhao & s . q . li , 2018
2018 - 07 - 05 new taxonomic reference entry - ref sinodraconarius cawarongensis zhao & s . q . li , 2018
2018 - 07 - 05 new species inserted - ref sinodraconarius cawarongensis zhao & s . q . li , 2018
2018 - 07 - 05 li et al . , 2018b - - show included taxa
2018 - 07 - 04 isaia et al . , 2018 - - show included taxa
2018 - 07 - 03 cala - riquelme et al . , 2018 - - show included taxa
2018 - 06 - 27 caleb et al . , 2018 - - show included taxa
2018 - 06 - 27 hedin et al . , 2018b - - show included taxa
2018 - 06 - 23 lissner et al . , 2018 - - show included taxa
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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 .
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platnick , norman i . 2011 . the world spider catalog , v . 11 . 0 . american museum of natural history . database built by robert j . raven from the files underlying the website at urltoken doi : 10 . 5531 / db . iz . 0001
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scripps 's murrelet ( synthliboramphus scrippsi ) is a small seabird found in the california current system in the pacific ocean .

this auk breeds on islands off california and mexico .

it is threatened by predators introduced to its breeding colonies and by oil spills .

this species and the guadalupe murrelet were considered conspecific and were known collectively as xantus 's murrelet until 2012 .

the two species are now considered distinct based on a lack of evidence of interbreeding at a shared nesting colony on the san benito islands , differences in facial pattern and bill shape , and differences in vocalizatons and genetics .

scripps ' s murrelet

scripps ' s murrelet - channel islands national park ( u . s . national park service )
( note : as of august 2012 , xantus ' s murrelet has been split into scripps ' s murrelet and guadalupe murrelet . the scripps ' s murrelet breeds within the park , while the guadalupe murrelet visits after breeding season . however , there are unconfirmed accounts of breeding on santa barbara island )
scripps ' s murrelet come ashore only to breed , remaining at sea the rest of the year .
scripps’s murrelet : gives high pitched twitters , usually in a quick series and muted during nesting season .
scripps ' s murrelet : craveri ' s murrelet has dark wing linings , black extending onto sides of breast , black chin , and longer , thinner bill .
the scripps ' s murrelet spends all its time out to sea , coming into shore only to breed .
santa barbara island has the largest scripps ' s murrelet colony in the united states , and possibly the world .
the park has 80 % of the u . s . breeding population of scripps ' s murrelets .
the scripps ' s murrelet was listed as a threatened species by the state of california on december 22 , 2004 .
) . the specimens xantus collected from southern baja california remain among a relatively few records of scripps ' s / xantus ' s murrelet from that far south .
range : the scripps’s murrelet breeds on s californian channel islands , and on islands off the w coast of baja california . it winters offshore n along the pacific coasts to n california and s british colombia , and s to extreme s of baja california .
here’s something to celebrate : after biologists restored their nesting islands , scripps’s and guadalupe murrelets don ' t need federal protection .
the endangered marbled murrelet , craveri’s murrelet , and xantus’s murrelet are all threatened by habitat loss and pollution . the most endangered alcid , though , is the kittlitz’s murrelet ; a critically endangered species of the bering sea and alaskan coast with a small declining population threatened by oil spills and habitat loss .
the xantus ' s murrelet is the most southerly living of all the auk species .
scripps ' s murrelets nest primarily in natural rock crevices along steep edges around the periphery of islands .
scripps’s murrelet : feeds almost exclusively on northern anchovies and rockfish ; forages by diving and pursuing prey underwater . breeding success may depend on availability of prey .
invasive black rats on anacapa island decimated native seabird populations , particularly the threatened scripps’s murrelet ( formerly xantus’s murrelet ) , by eating eggs and young chicks . rats also directly preyed on the endemic anacapa deer mice , a species not found anywhere else .
introduction : the scripps’s murrelet was formerly a subspecies of the xantus’s murrelet , alongside the guadalupe murrelet . both are now considered full species . they occur along the coasts of california , one in north and the second in south . these species differ by facial pattern and bill shape , vocalizations and genetics . the scripps’s murrelet is threatened by introduced mammals at breeding colonies , and the global climate change could have a negative impact on food availability . the species is currently listed as vulnerable .
a scripps ' s murrelet chick will leave the nest for the open ocean at two days old tumbling down steep slopes and cliffs to reunite with parents in the water .
appearance the scripps ' s murrelet is a small bird . at under 10 inches in length , it is slightly smaller than an american robin . adults have a 15 - inch wingspan and weigh only six ounces . black above and white on the chin , throat , and belly , scripps ' s murrelet is very similar in appearance to craveri ' s murrelet , a species that shares a similar range . the two are most easily separated in flight by the distinct white underwing of the scripp ' s .
xantus ' s murrelet ( synthliboramphus hypoleucus ) is a small seabird found in the california current system in the pacific ocean .
s . scrippsi ( del hoyo and collar 2014 ) were previously lumped as s . hypoleucu s following sibley and monroe ( 1990 , 1993 ) .
scripps’s murrelet : one or two blue or green eggs with brown spots are laid among boulders or in a crevice near an island beach . incubation ranges from 27 to 44 days and is carried out by both parents .
and underwing coverts . bill is dark and thin . eyes are brown with broken white eye - rings . legs and feet are black . feeds on small crustaceans and fish . swift direct low flight with rapid wing beats . xantus ' s murrelet was split in 2007 by the aou into the guadalupe murrelet and scripp ' s murrelet .
incorporates endomychura , which has occasionally been used for a few of the murrelet species .
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behaviour in the wild : the diet of the scripps’s murrelet is poorly known , but it probably feeds on small prey such as larval fish , small crustaceans and marine invertebrates . the prey include sandheels , anchovies , rockfish and euphausiids , mainly taken during the breeding season . outside this period , it feeds in warmer waters often associated with large pelagic predatory fish like tuna . the scripps’s murrelet forages by diving and swimming underwater , propelled by the wings . it may forage in pairs or in family groups , depending on the season .
unlike other alcids , scripps ' s murrelet and other synthliboramphus murrelets—craveri ' s murrelet , ancient murrelet ( s . antiquus ) , and japanese murrelet ( s . wumizusume ) —have a highly precocial posthatching development pattern . two eggs are laid in rock caves or crevices or under dense shrubs . each egg weighs approximately 22 percent of an adult bird , which is among the largest relative to adult size laid by any bird . after hatching , the young spend only one or two days in the nest before leaving the island under cover of darkness , often scrambling or tumbling 100 meters or more down steep sea slopes and cliffs to follow their parents to sea . the young are then fed and raised to independence well out of sight of land .
protection / threats / status : the scripps’s murrelet is threatened by invasive , introduced mammals which are responsible for colony extinctions . experimental control of deer mice has been attempted since the early 2000s . the californian breeding colonies are now in protected areas , but at sea , oil - spills and fishing nets could cause disturbance and mortality . changes in sea temperature and global climate change could reduce the food resources in the future . the global population is estimated at 15 , 000 / 30 , 000 individuals and is still declining . the scripps’s murrelet is currently listed as vulnerable .
range this species is fond of warm , southerly climates . during the breeding season , the entire scripps ' s murrelet population is concentrated within a fairly small region off the coasts of southern california and mexico . however , birds disperse after breeding , sometimes as far north as british columbia . over eighty percent of the u . s . breeding population of scripps ' s murrelets ( 33 . 5 % of the world ' s population and the only breeding ground north of mexico ) occurs on the channel islands , while the mexican population nests primarily on the baja california islands of san benito , coronado , and san jeronimo .
this video was taken from a hidden camera in a scripp ' s murrelet nest on santa barbara island . near the end of the video the chicks depart the nest .
in april or may , xantus’s murrelet will move north and west , away from the breeding islands , travelling rather slowly to their wintering areas where they will remain until late november or early december ( 2 ) . xantus’s murrelet feeds mainly on larval fish , as well as other small prey such as sandeels and crustaceans ( 2 ) . diving down to maximum depths of 21 metres and remaining underwater for up to 28 seconds , xantus’s murrelet uses its wings to propel itself through the water to pursue and capture its prey ( 7 ) . during the breeding season , northern anchovies ( engraulis mordax ) comprise a significant part of this murrelet’s diet , and thus breeding effort has been noted to be lower when anchovy abundance is low ( 2 ) .
scripps’s murrelet : breeds off the coast of southern california , baja california , and mexico . occasionally wanders north to vancouver island . habitats include steep cliffs above the sea , as well as on slopes and canyons select areas , where there is a sparse cover of shrubs and herbs . during winter , they can be found offshore .
introduction this unique small bird of coastal pacific waters is among the world ' s rarest seabirds . the park is the nesting location for about a third of the world ' s population . it is also among the most threatened , nesting in as few as 10 locations . rarely seen from the coast , scripps ' s murrelets prefer the deep , warm offshore waters of the pacific .
habitat : the scripps’s murrelet nests on rocky slopes and steep cliffs on islands , usually under bushes , shrubby and herbaceous plants . outside the breeding season , it occurs offshore from the breeding colonies in the warm pelagic waters of the california current . it usually avoids the colder coastal waters . it may go well offshore , beyond the continental shelf .
carter , h . r . , sealy , s . g . , burkett , e . e . and piatt , j . f . ( 2005 ) biology and conservation of xantus’s murrelet : discovery , taxonomy and distribution . marine ornithology , 33 : 81 - 87 .
scripps ' s ( formerly xantus ' s ) murrelet , along with the closely related craveri ' s murrelet ( synthliboramphus craveri ) , is one of the southernmost species in the alcidae , a family that is predominantly northern in distribution . this small black and white seabird has a relatively limited breeding distribution on offshore islands from southern california to central baja california , mexico . postbreeding dispersal is largely to the north , as far as is known ; large numbers of birds spend the late summer and fall over the outer continental shelf off central california , and small numbers occasionally occur in similar habitats north to washington and southern british columbia .
franklin ' s gull : very rare , several records in april and may .
housands of birds use anacapa island as a nesting area due to its natural lack of predators . but invasive , non - native black rats were inadvertently brought to anacapa in the 1940’s aboard ships traveling to the islands . island conservation and other conservation groups began studying the impact of black rats on native seabird populations in the mid - 1990s . biologists discovered high rates of predation on murrelet eggs and found bird bands outside rat nests , evidence that rats were eating young birds . more than 96 % of scripps’s murrelet nests on anacapa were being predated by invasive rats .
despite some species nesting in obvious , dense colonies , the nests of the marbled and kittlitz’s murrelets are among the most difficult of bird nests to find . a north american nest of the marbled murrelet wasn’t discovered in old growth rain forests of the pacific northwest until 1974 , while the kittlitz’ murrelet nests on talus slopes of inaccessible mountains .
a small black - and - white seabird , the scripps’s murrelet breeds only on a handful of islands off the coast of southern california and baja california , mexico . with the loss of its safe breeding habitat on the rise and a global population of less than 10 , 000 , this rare seabird is listed as threatened by the state of california and as vulnerable by the international union for conservation of nature ( iucn ) . the murrelet was spared an “endangered” listing due to island conservation’s efforts to remove invasive species on many of the islands where the seabirds breed , including anacapa .
this small black and white alcid was formerly named
xantus ' s murrelet when it treated as conspecific with the nearly identical guadalupe murrelet . it is black above and white below with thin , pointed bill and bright white wing linings when seen in flight . the eye is completely surrounded by black , whereas guadalupe has white lores and white wrapping up in front and over the top of the eye . craveri ' s murrelet , which is also very similar , has more black extending below the eye and the wing linings are dark gray rather than white .
a small seabird , the cassin’s auklet depends on burrows for nesting . despite having a wide range from baja california up to alaska’s aleutian islands , cassin’s auklets were unable to breed on anacapa island in the face of rat predation . since the removal of rats , cassin’s auklets have returned to anacapa and started breeding on one of its islets .
keitt , b . s . ( 2005 ) status of xantus’s murrlet and its nesting habitat in baja california , mexico . marine ornithology , 33 : 105 - 114 .
sabine ' s gull : rare and irregular but sometimes seen in small numbers in may .
range : historically restricted to warm seas off southern california and baja california . more recently , this species has proven to be somewhat regular in deep waters north to british columbia during late summer and early fall , particularly in strong
el nino
( enso ) years . due to conspecific treatment , the extent of this new species ' range north of california is poorly known because subspecies was often left undetermined when
xantus ' s murrelets
reached the waters of oregon , washington and british columbia . it is generally believed that scripps ' s murrelet is more expected than guadalupe murrelet north of california , but this is speculative .
ancient murrelet : erratic ; usually uncommon winter visitor ( november - february ) , often fairly close to shore . not present each year .
conservation status according to the international union for conservation of nature - 2010 red list of threatened species , this species is considered to have a vulnerable status because of its limited range and small , declining population . several colonies have gone extinct , and introduced predators are causing declines in some of the remaining nine colonies . channel islands national park has implemented several restoration projects to reverse these declines . on santa barbara island , after feral cats were removed in 1978 , numbers of scripps ' s murrelets increased to approximately 1 , 500 in 1992 . additional work on santa barbara island includes restoring seabird nesting habitat by removing non - native plants and planting native vegetation . on anacapa island , the national park service eradicated the introduced black rat population that had decimated the population of nesting scripps ' s murrelets . notably in 2009 the number of scripps ' s murrelet clutches on anacapa increased 61 % over the previous year . visit seabirds for more information about restoration activities in the park .
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the scripps’s murrelet performs post - breeding dispersal , largely offshore to w and to n . they can be seen in small family groups , usually pairs accompanied by their flightless chicks swimming on water . they arrive off californian coast in july / august to spend the winter , and remain until late november / early december . some of them winter n to british colombia . they return to the breeding grounds between november and january .
nesting success among scripps’s murrelets increased by 91 % the year after rats were removed . within seven years , nesting adults increased by more than 93 % . cassin’s auklets , previously absent from anacapa , are now breeding on the island , and the anacapa deer mice are thriving . in 2013 , for the first time ever , endangered ashy storm - petrels were recorded breeding on the island .
habitat during the breeding season , southern california ' s scripps ' s murrelets , who are crevice and burrow nesters , lay their eggs on the steep slopes and cliffs of anacapa , santa barbara . and san clemente islands . they prefer areas with sufficient vegetation for cover . away from the breeding season , the birds move far out to sea , preferring the deep waters beyond the continental shelf .
nelson , s . kim . 1997 . marbled murrelet ( brachyramphus marmoratus ) , version 2 . 0 . in the birds of north america ( p . g . rodewald , editor ) . cornell lab of ornithology , ithaca , new york , usa .
fws digital media library - - the u . s . fish and wildlife service ' s national digital library is a searchable collection of selected images , historical artifacts , audio clips , publications , and video .
most members of the auk family favor cold northern waters , but this one is found mostly off baja and southern california . it nests on offshore islands , and is almost never seen from the mainland . generally uncommon , it occurs at sea in pairs or family groups , not in flocks . young scripps’s murrelets get an early start on their sea - going life , leaving their nest only one or two days after hatching , often having to jump more than 200 feet down from cliffs into the surf before swimming away with their parents . formerly known as xantus’s murrelet .
tell congress and the department of the interior to uphold the country ' s most important bird protection law .
this species ' former common name honored the hungarian john xantus , a prodigious and colorful collector and student of natural history during the mid - to late 1800s . while employed by the u . s . coast survey at cabo san lucas , baja california , xantus collected specimens of 130 bird species . three of these , including xantus ' s murrelet , were new to science (
del hoyo , j . , collar , n . & kirwan , g . m . ( 2018 ) . scripps ' s murrelet ( synthliboramphus scrippsi ) . in : del hoyo , j . , elliott , a . , sargatal , j . , christie , d . a . & de juana , e . ( eds . ) . handbook of the birds of the world alive . lynx edicions , barcelona . ( retrieved from urltoken on 9 july 2018 ) .
reproduction of this species : the scripps’s murrelet usually arrives three weeks before the laying , at mid - february . the laying takes place from late february to mid - june , with peak in late march / mid - april . it breeds at low densities in small colonies established in cliffs on islands . it nests in caves , rock crevices or abandoned burrows and shrubs . it may lay on the ground under dense vegetation on maritime sandy slopes . there is no nest built .
whitworth , d . l . , carter , h . r . , young , r . j . , koepke , j . s . , gress , f . and fangman , s . ( 2005 ) initial recovery of xantus’s murrelets following rat eradication on anacapa island , california . marine ornithology , 33 : 131 - 137 .
xantus ' s murrelet feeds far out at sea , often in association with large pelagic predatory fish like tuna , on larval fish like anchovies , sardines and sebastes rockfish . like all auks it is a wing - propelled diver , chasing down prey under the water with powerful wingbeats .
the alcidae are maritime birds found off both coasts of north america . on the atlantic coast , they breed in maine and northeastern canada , wintering south to new jersey , while on the west coast , alcid species are found from the islands of the bering sea to southern california . although alcids are birds of salt water habitats , species such as the long - billed murrelet and the ancient murrelet occasionally show up as rare vagrants on freshwater lakes , and the marbled murrelet nests away from the shore in old growth forests .
bonaparte ' s gull : common spring migrant ( march - may ) , sometimes several hundred passing north in one day .
heermann ' s gull : common summer and fall visitor ( june - november ) , uncommon to rare at other seasons .
calls and songs : sounds by xeno - canto the scripps’s murrelet gives a loud , rapid call of 6 - 8 regularly spaced “seep” notes on the same pitch , fairly similar to the piping whistle of pigeon guillemot . it calls often at night at breeding colonies . it also utters “chip” notes and whistles . the sounds produced inside the nesting cavity or crevice are softer , and also given while feeding . calling starts at dusk and continue into the morning , 2 - 3 hours after sunrise , with nocturnal chorus in the middle of the night .
breeding on steep cliffs above the sea , as well as on slopes and canyons ( 2 ) , xantus’s murrelet selects areas where there is a sparse cover of shrubs and herbs ( 4 ) . during winter , this bird can be found offshore , in the warm waters of the california current ( 2 ) .
s californian channel is ( san miguel , santa cruz , anacapa , santa barbara , san clemente , and , formerly , santa catalina ) and islands off w coast of baja california ( coronado , todos santos , san jerónimo and san benito is ) # r . breeding on san martín i and cedros i , baja california , uncertain # r . winters offshore from area of breeding colonies n along pacific coast to ( rarely ) n california and s british columbia and s to s tip of baja california .
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the scripps ' s murrelet has a very small range off the coast of california in the united states and extending only so far as the baja peninsula in mexico . though this bird can be found in canada , mexico and the united states the california colonies are the only self - sustaining . the global population of this bird is estimated to be only a few thousand breeding pairs . this equates to roughly 39 , 700 total individuals . this species is a marine bird and can be found in coastal waters and along sea cliffs . currently , it is believed that the population trends for this bird will continue to
the largest nesting colony of scripps ' s murrelet in the united states is on santa barbara island in the california channel islands . important colonies off the coast of baja california are on islas los coronados , islas san benito , and isla guadalupe . the species has been extirpated on some of the baja california islands by introduced cats and other predators , and it is threatened on other islands . although the colony at santa barbara island has maintained numbers in the low thousands since the mid - 1970s , it is very localized and subject to several threats , including oil spills and other pollution as well as avian and mammalian predation .
the scripps’s murrelet is a small seabird slightly smaller than an american robin . the adult has black upperparts with blue - grey wash in fresh plumage , but mostly dull brown in worn plumage . some dark feathers may sometimes form a partial collar on neck sides . the underparts are white including chin , throat , underwing - coverts and undertail coverts . the flanks are sometimes mottled grey and white . on the black head , we can see more or less distinct white eye - crescents above and below the eye . the short bill is blackish . the eyes are dark brown . legs and webbed feet are bluish - grey .
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in 2001 and 2002 , island conservation and our partners removed invasive rats from anacapa island , and subsequent monitoring confirmed the rats were gone . in the absence of these invasive predators , scripps’s murrelets rebounded almost immediately . we continue to see strong evidence of murrelet population growth through the expansion of breeding area , increased nest occupancy , and a higher number of eggs laid at one time . today , hatching success among the murrelets is greater than 90 % , compared to less than 20 % when rats occupied the island . cassin’s auklets have also re - colonized the island . in 2011 , endangered ashy storm - petrels established nesting sites on the island for the first time ever . with the island free of invasive rats , we continue to see the island return back to what it once might have been .
gaston , a . j . ( 1994 ) ancient murrelet ( synthliboramphus antiquus ) . in : poole , a . ( ed ) the birds of north america online . cornell lab of ornithology , ithaca . available at : urltoken
in addition to the threats of invasive species , xantus’s murrelet could be affected by oil spills , drowning in fishing gear , pollution , and disturbance of nesting sites ( 4 ) . in the future , changes in sea temperature caused by global climate change may also have a detrimental impact on this species if it alters the availability of prey , such as the northern anchovy ( 4 ) .
feeding scripps ' s murrelets feed by diving and swimming underwater in pursuit of small fish and crustaceans . interestingly , they are nearly always observed feeding in pairs rather than in flocks . adults are active at the colony only at night . this curious feeding strategy takes place year - round , including during the breeding season . since one member of each breeding pair is at the nest throughout the breeding season , unrelated birds may pair up to feed cooperatively .
marbled murrelet : fairly common to uncommon resident . a pair or two are usually present throughout the year , often fairly close to shore . large numbers occur in spring and fall when over a hundred have passed pigeon point in a day .
xantus’s murrelet breeds off the coast of southern california , usa , and baja california , mexico ( 4 ) . the two subspecies have different breeding ranges , overlapping only on the san benito islands off baja california . s . h . scrippsi breeds on the southern california channel islands and on islands off the west coast of baja california , while s . h . hypoleucus breeds only off baja california , on the three san benito islands and on two rocks offshore of guadalupe island . previously , more breeding colonies may have existed on other islands , before they were destroyed by invasive animals ( 4 ) . outside of the breeding season , this small seabird ranges from the southern tip of baja california , north to british columbia , canada ( 2 ) .
the third location for sea - watching may seem counterintuitive at first , but yields your best chance at seeing a marbled murrelet . in the southeast portion of the state park , there is a trail to another viewing deck . this deck , completed in recent years , appears to have been established as a photo - opportunity : if you stand in the viewing circle , the lighthouse forms a backdrop for your souvenir shot . but from a birder ' s point - of - view , the waters between the shore and the point often hold the diminutive marbled murrelet . pigeon point is one of the most reliable locations , especially during spring and summer , for observing marbled murrelet . a few pairs are resident in the area and may often be found feeding just beyond the surf when the sea is not too rough . this also provides a good angle on año nuevo island : as you search for murrelets , look for rhinoceros auklets as well .
one of the most significant threats to this vulnerable bird is the impact of invasive mammals , including feral cats , black rats and house mice , which prey on the eggs , young , and occasionally adults of xantus’s murrelet ( 4 ) ( 8 ) ( 9 ) . the extinction of some breeding colonies in the past as a result of invasive mammals demonstrates the devastating affect that they can have on this species ( 4 ) .
) , in neotropical birds online ( t . s . schulenberg , editor ) . cornell lab of ornithology , ithaca , ny , usa . retrieved from neotropical birds online :
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lutmerding , j . a . and a . s . love . longevity records of north american birds . version 2015 . 2 . patuxent wildlife research center , bird banding laboratory 2015 .
cassin ' s auklet : quite uncommon , occurring further offshore than the other alcids . most likely here in winter . however , most reports are of mis - identified marbled murrelets which appear all dark
vulnerable . overall population placed in the range 10 , 000–20 , 000 mature individuals . breeds on islands off s california , usa , and w baja california , mexico ; on large islands . . .
sometimes placed in brachyramphus or in endomychura . sympatric ( as is s . hypoleucus ) with closely related s . craveri at san benito is ( baja california ) , where further study required to determine degree of mixing and gene exchange ; may be conspecific with s . craveri . often treated as conspecific with s . hypoleucus , but now generally considered a separate species , most recently # r on the grounds of “lack of evidence of interbreeding where the two are sympatric on the san benito islands , and on differences in morphology ( especially facial pattern and bill shape ) , vocalizations , and genetics” # r ; more specifically , black vs white lores , preocular supercilium and ear - coverts ( 3 ) ; shorter , stubbier bill ( allow 2 ) ; call a piping whistle vs cricket - like rattle ( at least 2 ) . monotypic .
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hamilton , c . d . , golightly , r . t . and takekawa , j . y . ( 2005 ) characteristics of diving in radio - marked xantus’s murrelets . marine ornithology , 33 : 155 - 159 .
. the 80 % decline in zooplankton off southern california from 1951 to 1993 may be detrimental to the species . changes in sea temperature associated with global climate change could have an impact on food availability in future ( s . wolf
or all dark , exceptions being the guillemots ( with white wing patches ) , and the mottled brown breeding plumages of the marbled and kittlitz’s murrelets . some species have bright colors such as orange , yellow , and red on head
kushlan , j . a . , m . j . steinkamp , k . c . parsons , j . capp , m . a . cruz , m . coulter , i . davidson , l . dickson , n . edelson , r . elliott , r . m . erwin , s . hatch , s . kress , r . milko , s . miller , k . mills , r . paul , r . phillips , j . e . saliva , w . sydeman , j . trapp , j . wheeler and k . wohl ( 2002 ) . waterbird conservation for the americas : the north american waterbird conservation plan , version 1 . washington , dc , usa .
in 2001and 2002 , island conservation , the channel islands national park , california department of fish and game , the u . s . fish and wildlife service , and the national oceanic and atmospheric administration removed invasive rats from anacapa island .
there is little information on marbled murrelet population trends , but they appear to be a species in decline . the north american waterbird conservation plan estimates a continental breeding population of 300 , 000 - 800 , 000 birds , rates the species a 15 out of 20 on the continental concern score , and lists it as a species of high concern . populations of marbled murrelet in washington , oregon , and california , are on the 2014 state of the birds watch list , which lists bird species that are at risk of becoming threatened or endangered without conservation action . the species is listed as endangered on the iucn red list , and as threatened under the endangered species act by the u . s . fish and wildlife service . logging and development of forested nesting habitat are considered the greatest threats to this species . significant portions of nesting areas have already been lost . oil spills and entanglement in gill - nets are also major risks . back to top
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a number of colonies have been extirpated by introduced predators and alien invasive species continue to threaten some colonies . a number of other threatening processes are on - going , the combined effects of which are suspected to be causing a moderate decline in this species ' s global population .
xantus’s murrelet is thought to be a monogamous bird which arrives at its island breeding colony around mid - february , about three weeks before it lays its eggs . the female lays two eggs , eight days apart , into a crevice in a cliff , at the back of a small cave , under a boulder , or occasionally , on bare ground beneath thick vegetation ( 2 ) . following the laying of the second egg , the male and female will take it in turns to incubate the eggs for the next 34 days . during this time , the eggs are highly vulnerable to predation by deer mice ( peromyscus maniculatus ) ( 2 ) . the chicks are very well - developed on hatching , with limbs that are already 98 percent of the size of adults’ ( 5 ) , and are taken to sea , just one to two days later , by their parents ( 2 ) . here , unique to synthliboramphus , the remainder of the chick’s development takes place ( 6 ) .
it nests in small crevices , caves and under dense bushes on arid islands in loose scattered colonies . it returns to the colony only at night , laying two eggs which are incubated for about a month . like other synthliboramphine murrelets ( e . g . the ancient murrelet ) the chicks are highly precocial , leaving the nest within two days of hatching and running actively towards the sea , where the parents call to them . once at sea the family swims to offshore waters .
. in 2003 , fishing and other extractive uses were banned within important areas of the channel islands national marine sanctuary in an attempt to reduce light and noise pollution in important near - shore staging areas . however , the exclusion zone covers only a small buffer area around some colonies , and may be ineffective at minimising threats ( s . wolf
- - natureserve explorer is a source for authoritative conservation information on more than 50 , 000 plants , animals and ecological communtities of the u . s and canada . natureserve explorer provides in - depth information on rare and endangered species , but includes common plants and animals too . natureserve explorer is a product of natureserve in collaboration with the natural heritage network .
a good spotting scope and sturdy tripod are essential for good views . dress warmly and be patient . consult local weather forecast before your visit to get current conditions . there is no better academy for sea - watching from land than a few hours spent at pigeon point , whether honing your skills alone or learning from one of the county ' s accomplished experts .
by slowly and repeatedly scanning the sea from surf to horizon , a birder ' s patience is often rewarded . there are three principal spots from which to scan for ocean birds . if your time is limited , set up your scope anywhere along the rocky shore north of the lighthouse . the road here has a wide shoulder on the west side , and the rocks themselves produce good numbers of shorebirds , including wandering tattler .
located 50 miles south of san francisco , pigeon point has become famous among birders as one of the finest vantage points for observing seabirds anywhere on the california coast . its accessibility , geography ( located immediately to the north of bird - rich monterey bay ) and the presence of deep ocean waters very close to shore combine to produce excellent birding possibilities . success can be extremely variable , ranging from fair to excellent , depending on season , visibility , observer ' s skill , duration of visit , wind direction and wind velocity .
the introduction article is just the first of 11 articles in each species account that provide life history information for the species . the remaining articles provide detailed information regarding distribution , migration , habitat , diet , sounds , behavior , breeding , current population status and conservation . each species account also includes a multimedia section that displays the latest photos , audio selections and videos from macaulay library’s extensive galleries . written and continually updated by acknowledged experts on each species , birds of north america accounts include a comprehensive bibliography of published research on the species .
gregg has been working in the island conservation field for more than nineteen years , and since 1999 has focused on the restoration of island ecosystems internationally . gregg serves as island conservation’s director of global and external affairs , and his experience and expertise are utilized for many of ic’s projects worldwide . gregg has developed a diverse array of north american partnerships among federal government agencies , private industry , ngos , research scientists , and local communities . these partnerships have led to the direct implementation or consultation on more than forty island restoration projects and programs throughout north america—ranging from the aleutian islands , alaska , to tropical mexico and west to hawaii , the central pacific , and micronesia , as well as south america on the galápagos islands . gregg earned an ms in ecotoxicology from the university of british columbia , vancouver , and has assisted the us environmental protection agency , fish and wildlife service , and the department of agriculture , among others , with project planning and policy guidance . together this work established a precedent for the successful registration and authorized use of conservation rodenticide products for rodent removals on islands in north and south america .
in addition to seabirds , pigeon point can also be a good place to check for unusual land birds during periods of migration , especially fall ( september - november ) . check the wires , scrub , and weedy edges of the roadside and brussels sprout plantings for
field birds .
rarities such as tropical kingbird , bobolink , palm warbler , red - throated pipit , common ground - dove , and clay - colored sparrow have been spotted here . there are often a few band - tailed pigeons on the wires , especially in the morning . pigeon point , however , was not named for its pigeons but rather in memory of the u . s . s . pigeon , a ship that crashed into the rocks here early in the twentieth century ) . large flocks of tricolored blackbirds may be found throughout the year in freshly plowed fields and cow pastures in this vicinity . northern harriers often patrol these fields , replaced at night by a pair of resident barn owls , who can sometimes be seen along telephone wires prior to dawn ; great horned owls use the area , too . pigeon point is also an excellent vantage point from which to scan for migrating gray whales during their northbound migration from march through may . seals , sea lions , porpoises and sea otters are regularly spotted from pigeon point .
globally is considered a vulnerable species , because the populations are declining , and several breeding colonies , have become extinct . in mexico are endangered . the main threats are low population densities , restricted distribution , destruction and modification of nesting sites , reduction of their food by oil spills , introduced mammals such as rats and cats , increased predation by natural predators ( such as mice and owls ) . because the status of populations in mexico is little known , but much of the world ' s population lives in the country , it is important to conduct studies on their ecology , reproductive biology and food , perform monitoring of the species , propose conservation strategies , and continue those already underway . some conservation actions underway include the removal of introduced mammals , recolonization of former colonies , the regulation of tourism in the islands of baja california , the change in fishing techniques to reduce pollution from light and sound , and creating protected areas in nesting colonies .
crustaceans diverse group of arthropods ( a phylum of animals with jointed limbs and a hard chitinous exoskeleton ) characterised by the possession of two pairs of antennae , one pair of mandibles ( parts of the mouthparts used for handling and processing food ) and two pairs of maxillae ( appendages used in eating , which are located behind the mandibles ) . includes crabs , lobsters , shrimps , slaters , woodlice and barnacles . flanks the sides of the body between the ribs and the hips . larval of the stage in an animal’s lifecycle after it hatches from the egg . larvae are typically very different in appearance to adults ; they are able to feed and move around but usually are unable to reproduce . monogamous having only one mate during a breeding season , or throughout the breeding life of a pair . subspecies a population usually restricted to a geographical area that differs from other populations of the same species , but not to the extent of being classified as a separate species .
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del hoyo , j . , collar , n . j . , christie , d . a . , elliott , a . and fishpool , l . d . c . 2014 . hbw and birdlife international illustrated checklist of the birds of the world . volume 1 : non - passerines . lynx edicions birdlife international , barcelona , spain and cambridge , uk .
24 cm . small , black - and - white alcid . black upperparts . white underparts . white underwing linings . black on head extends to bill . partial white eye - ring . shortish , stout bill . nominate subspecies has more extensive white on face and ear - coverts , forming crescent in front of and over eye .
has partial breast - band , black extending under bill and different underwing colour and bill shape .
this newly split species is listed as vulnerable because it occupies a small range when breeding , nesting on only a few islands and islets , and is inferred to be in on - going decline owing mainly to the impacts of invasive mammalian predators . if it is found to be breeding at more than 10 locations , the species may warrant downlisting to a lower threat category .
. 2012 ) . on large islands the species is confined largely or entirely to offshore rocks ( drost and lewis 1995 ) . breeding on san martín and cedros islands , baja california , is uncertain ( chesser
. 2012 ) . in the usa , an estimated 885 - 2 , 575 breeding pairs occur , the biggest colony on the island of santa barbara holds 500 - 1 , 250 pairs ( b . keitt and d . whitworth
. the santa barbara colony has been stable since the 1980s , but may have declined since the turn of the century ( b . keitt and d . whitworth
to be 39 , 700 , of which 17 , 900 are thought likely to be mature breeding individuals . birt
to include fewer than 5 , 000 breeding birds . on the basis of these data , the population of
is placed in the band for 10 , 000 - 19 , 999 mature individuals , assumed to equate to 15 , 000 - 30 , 000 individuals in total .
. adults enter and leave the nesting colonies at night when there is little or no moon , typically arriving on the channel islands in mid - february . nesting persists through mid - june with peak nesting from late march to late april ( jones
2005 ) . clutches consist of two eggs laid approximately eight days apart with replacement of lost clutches unusual . incubation takes c . 34 days ( jones
2016 showed 191 % more eggs were hatching and 94 % less nests were being predated . house mice were recently introduced to the coronados islands and deer mice
( native to nearby cedros island ) have also been introduced to the san benito islands . deer mice predate eggs on santa barbara ( murray
2006 ) . all breeding colonies in california are legally protected as national parks , private protected areas or military bases . pollution from offshore oil - wells or the los angeles oil - tanker lane could extirpate the species from the south california bight ( drost and lewis 1995 )
all potential breeding islands in the usa and mexico have been surveyed , with the exception of the offshore rocks of cedros island ( b . tershy
. over the past 10 years , most invasive mammals , including cats , rats , goats , sheep , rabbits , donkeys and dogs have been removed from almost all islands that are known current or suspected historical nesting sites in the us and mexico ( mcchesney and tershy 1998 , b . keitt and d . whitworth
, including the invasive house mice from coronados island and recently introduced deermice from the western san benito island ( b . tershy
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anacapa island , ca located 14 miles off the coast of ventura , california , anacapa island comprises three islands strung closely together : east , middle and west anacapa . the easternmost island in the channel islands archipelago , anacapa is part of the channel islands national park established in 1978 .
each channel island is home to a unique subspecies of deer mouse—the islands’ only endemic mammal . until 2002 , invasive rats competed with the anacapa deer mouse for food and directly preyed on them . during removal of invasive rats , anacapa deer mice were held in captivitiy to ensure their safety and survival . today the mouse population is thriving .
to restore habitat for native animals and plants on anacapa island by removing invasive rats .
total population probably low . vulnerable to predators , even small ones , on nesting islands ; in one study , almost half of all eggs were destroyed by deer mice . accidental introduction of rats could devastate colonies .
ocean , islands . generally in relatively warm waters and well offshore . may be close to nesting islands but almost never close to mainland ; may go far out beyond continental shelf . nests on islands with steep cliffs , rocky slopes , dense cover of bushes .
forages by diving and swimming underwater , propelled by wings . pairs or family groups may forage together .
2 , rarely 1 . large for size of bird , pale blue to dull green , with few or many brown spots , sometimes solid brown . incubation is by both sexes , 27 - 44 days .
parents do not feed young in nest . 1 - 2 nights after hatching , downy young are led from nest by parents , who then fly away ; young make way to water , often jumping from cliffs more than 200’ down to surf . parents and young reunite in water and swim away from island . young remain with parents and are fed by them for lengthy period . 1 brood per year , but may lay a 2nd clutch if first clutch is lost .
poorly known . probably eats mostly small crustaceans and other marine invertebrates . thought not to be much of a fish eater .
breeds on islands in small colonies . birds typically have same mate and same nest site each year . nest site is in rock crevice , under dense bush , under debris , or in abandoned burrow of other species ; no nest built
. a few are present off southern california all year , but common mainly march through june . numbers drop sharply in mid - summer , with many of these birds evidently going north ( at least to central california ) . whereabouts in winter poorly known . probably does much of migration by swimming , not flying .
audio © lang elliott , bob mcguire , kevin colver , martyn stewart and others .