AlasY~ Dzpart~cnt of Fish and Ga~e
I'
' . .
· ~ f\nch'orag~. Alaska . ..
BRISTOL BAY ~·::'CRRE MORTALITY
At least 86,000 comrnon murres died in Bristol Bay, Alaska during a .I
brief per~od in late April of this year. Although the cause of death m~y
never be completely resolved to eveD•on~'s satisfaction, the evidence
suggests that it was a CGtastrophe of n?ture. The murres, apparently
still o;.;eakened after wintering in·the Bering Sea, probably died fro;n a I
combir.ation of starvation and exhaustion which \.;as aggravated by. a seve~e ~
storm that prevented the~ from feecing during a critical few days.
Post-mortem· examina::ions of c.ur;:es by p31thologists from the Bureau·
of Sport Fisheries and Wildlife research c~nters in North Dakota and
Maryland, the Arctic Health Research Center in Fairbanks, the National
.... ' Disease Laboratory in Iowa, and the_ California Department of Fish and Game .. . in Sacramento found no evidence that pathogenic bacteria or viruses con-
• tributed to the mass mortality. Foods were not found in the digestive .
tracts of these birds. Tests for presence of toxins in the smail quantitie~
of fluid
sp eci;~ens w'ere .emaciated and
inconclusive.
had no appreciable deposits in sub-
. ·:·--cutaneous,- ·abdoninal and cardiac fat tissue. Thirteen of the dead birds . I ..
!
were not available for this sau.e tine of the year, the 6~~-gram average
weight of these-birds was considerably less than the 972-gram average-
weight for male common ourres and 1022-gram average weight for female . I;:
co~on ~urres from Cap~ Tho~pson in northwestern Alas~~ in late June. The
weight loss, lack of bcidy fat and sorn~ hemorrhaging of the-intestines •
l
. ..
_,·
could contribute to starvation --:::: ... , ~u..-} n~ver be completelY. resolved.
Severe winds and turbulent sea~ ?roba.bly prec:Lpitated the die-off. that
was first reported on'April 24 by Ken Xanthey of theAl'aska Department
of Fish ar:d Game. During the t>;o ?receding days, 'Winds. reached peak vela-.
c~ties of 104'mph at Adak and 84 :-.:?hat Cold Bay,-and wind? gusted at l:ciwer
velocitie;" during this time at other reporting statfons within the Aleutian
IslanC.s. ar.d along the Alaska Pe1:::.nsula. · Three murres found on April 24 . . in the to-..;n of Cold Bay by res::.C.ents vere taken to the headquarters of the
. • I Izembek National Wildlife Range, but the inc~dent seemed insignificant at
• the tiGe because severe stor~s often blow pelagic birds inland.
11"\-t'recks of seabirds," occurre:-.ces v;here seabirds are driven far inland
and are often found dead and dying along the.beaches as a result of severe
stott.s, have been reported freque:l.tly. Leslie H. Tuck, Canadian Wildlife
· ~ervice biologist, sununa~ized wa~.Y. observations of "wrecks of murres" in ~-..
.· ~ .
- .. ~ -.
.... :-···· ~
): The oost significant •
of Beals .~m4 record of 11wrecks of murues" is that
for Unimak Island in 1941; they •,.;rote:
Longworth as reported
"Between Apr.il '2 and 4 nu:::erous dead and sick murres were along all the beaches. 'l-.7 e counted 37 dead birds along 3 miles of beach. · Tne co:l.dition was general along the strait, we ·vrere told. Oldtimers· on •Unimak told us that
' . this happens every ·sp:ri:l.g and, that some years the beach is black with dead birds. Sw'imming in close to the waterline many of the~ appeared to be sick or very weak hardly able to dive in shallow water. Altogether we­
.saw 38 dead birds and 40 or ~ore very weak ones along 3 miles of beach. For three days before this~ heavy winds and sno•,.;r ble>l fro~ the southeast."
and-.
i. I '•
Apparently "wrecks of murres" are not uncommon in this region, but seldom
-2- ';,
•
~
-~
; ~: ...
·~
-.
.. have the observers had the mobility of those this year whdwere able to
assess the magnitude of l~ss.
Unresolved reports of oil ~hecns seen near the cbast and a·U. S.
Coast G'l,lard report of t\vO Jap.:>nese tra>ders that sank with 36 men aboa-rd
100 miles v:est of Unimak Island durir.g the severe storm gave rise to early
speculation that the birds were succumbir.g to diesel fuel or gasoline • l
escapji1g from the sunken vessels. ~one of the murres ex.:u'Tiined along_ the
beach were oil-stained. Only one obviously oil-killed bird, a fulmar, was
collected by the crevlS that co;r.bed portions of the beach. Organic extracts.
from samples of feathers taken from the dead murres and of beach sands were
analyzed by chemists of the Federal ~ater Quality Administration's Portland ~ .
laboratory. Gas chromatograph and infra-red scan testings revealed no
evidence of petroleuo products in any of the samples.
Tissues fro~ these murres were .tested ~or pesticides. Both DDE (a
metabol.ite of DDT) and hexychlorobenzine were found. in such small quanti~~_e:;:;,
each less than 1 part pe:- million, that they were not regarded as suspect y~ .. -. causes of death.
Because al~ost all affected birds were murres, pollutants seemed to
be an improbabl9 cause of death. Observations of pelagic birds in the •
eastern Bering Sea and B~istol Bay indicate that in winter the murr~s are
the most abundant birds, followed by glaucous-winged gulls and fulmars; . I
and from spring through su~er there are increasingly larger numbers of
kittivmkes, shearwa ters, and puffins. The few dead birds of other species
}
Perhaps one of the most unexpected findings from the pathological
examinations of these murres was the presence of arsenic, 2.77 parts per
t
million, in liver tissue. Tne significance of arsenic at this level is not •·
-.3- ~
..
>
:
-~'"'~
. .. ..... :····
knovm. However, some of the narine o.rga.nisms upon which murres feed are
reputedly concentrators o£ this ele:7-:ent, and arsenic levels of this .. . ... . . magnitude may be norr:<al in he.:;lthy 6urres. .
Hurres (the "urre" of the word wurre is pronounced like the "ur" in
the word fur) are found throughout the northern h~~misphere. Two species, . ·"'
the corr:raon murre and thick-billed murre,-are found in the Bering Sea and -- Bristol Bay area. There is considerable overlap in the distribution of
' . these §pecies, but the thick-'t>illed tlUrre teri.ds to have a more northerly
distribution than the co~on illurre. Studies of summer distribution of . . pelagic birds in Bristol Bay show tha·t commoh murres are most abundant, but
winter populations there may contain p~oportionately more 'thick-bill~d
murres. Nesting colonies of murres in Alaska are found along rocky portions
of the coast from Cape Lisburne, along the Aleutian Islands, to and in-
eluding the Ale:-ander Ar~hipelago in southeastern Alaska. Some of the
~\el\laska "bird cities," or nesting colonies, may contain tens of ~housands
of murres. Following the nesting season, when the pair attempts to raise
a single young on a precipitous cliff, the birds return to the sea until
next year. }1urres feed chiefly on small fish, such· as capclin, sculpins
~ and codfish; but invertE:•rates, such as shrimp,. mollusks and sea worms
furnish a part of their diet .
Leslie H. Tuck ("The Hurres," Canadian 1-lildlif e Service, Ottawa; 1960)
summari·zes the life his tory of the murres as ~ollO'.vS: ... I
"Murres are re=.ative ly large ·sea-birds, weighing on the average two pounds, with sharply defined hi-coloured plumage. The~ are highly specialized for catching small fish under wacer. Specialized developwent for this pur­ P9Se includes reduction ·of the length and area of the wing and so g=eat r:~odification of the bones and muscles of the legs that those birds walk very little and very awkvardly. They nest in large, compact colonies on steep
-4-
cliffs facing the sea.
Murres are essentially ~arine species and approach .. land only during the breeding season. They obtain most of their.food by flying under water. They are the only sea-1: irds in t..~e ~orthern Hemispher.e which habitually lay their eggs in exposed situat~ons on bare ledges and rocks. They brood but a sinzle egg and yet they "-re probably the most abundant sea-birds in. the. !\orthe:rn Hemisphere.
A murre-colony (loo~ery or bazaar) is an orderly aggrega­ tion of birds. It is basical~y composed of a core of experienced adults, surrounded· on the submarginal fr~nge sites by less experienced birds or· those breeding for the first time. Early in the breeding season, cature ~urres ·take part in co~unal displays in the sea at the base of the cliffs. It is believed that those co~munal displays
-5-
-·-····-·..L-
i'
• I
l
, ..... :. ~ .... .... :· ____ : ___ _
not only stDnulate the birds to breed but enable them to "synchronize''' their breeding cycles so that the maximum number of young ar-e raised in a comparatively short period.
I . I
I .
The eggs and chicks are sut,jec.ted to many dangers, not the least of which is the likelihood of b~ing knocked off the narrow ledges. The surviving chicks are led to sea, and to com?<lrative safety, by single adults, not necessarily their parents~ ·In other ways also, murres show con4"Junal interest in t:he welfare of
- -the eggs and chicks of the colony."
--
:-:.;·c·.:~· =:.-."' - &::\-.:, ";'/.:/)3
April 1970
Alas}~ D~part~~nt of Fish and Ga~e
I'
. ,. BR:::STOL B .. W ~~.:?.:-zE MORTALITY
At least 86,000 common murres c:.cd in Bristol Bay, Alaska during a
brief per~od in late April of this year. .:J.
Although the cause of death may
never be co;:;1pletely resoLred to eve:-;o~~' s satisfaction, the evidence
suggests that it was a catastrophe o~ n~ture. The murres, apparently
still weakened after wintering in· the Bering Sea, probably died from a , combination of starvation and exhaustion v.rhich \-las aggravated by a seve-!e
~ storm that prevented them from feed:.~g during a critical few days.
Post-morte~·examinations of mu~~es by p~thologists from the Bureau·
of Sport Fisheries and Wildlife research centers in North Dakota and . Maryland, the Arctic Health Research Center in Fairbanks, the National .,.. '
Disease Labor a tory in Io..-a, and the California Departr-.ent of Fish and Game .. in Sacramento found no evidence that pathogenic bacteria or vir~ses con-
• tributed to the !nass mortality. Foods were not found in the digestive .
tracts of these birds. Tests for presence of toxins in the smail quantitie~
of fluid found in the in~estines were inconclusive. t . All specL~ens were a~aciated a~d had no appreciable deposits in sub-
· ··:·--cutaneous,- ·abdominal and cardiac fat tissue. ·J . .
Thirteen of the dead birds
varied in weight from .5J0 to 786 gra::s. Altho'ugh COi:iparable weight data
were not available for this sa~e ti::e of the year, the 6~~-gram average
- - w~ight of these-birds was co~sidera~ly less than the 972-gram average-
weight for male co~on m~rres a~d 1022-gram average weight for female . I,
I .
common murres from Cap~ Thompso~ in northwestern Alasl~ in late June. The ,
weight loss, lack of body fat and sci..e hemorrhaging of the. intesti-nes I#
l
.
'-it suggest that the birds died from stw.:-·,rc..ti_on, althou~;h all factors that
could contribute to starvation may ~_ever be completelY.. resolved.
Severe winds and turbulent seas ?~ob~bly precipitated the die-of~ t~t _.,.
was first re?orted on· Ap-;:-il 24 by ;(..:::-. ~~anthey of the Al"aska Department
of Fish and Game. During the tHO ?receding days' wir.ds. reached peak velo-
cities o.f 104 · wph at Adak and 84 r.:?~ at Cold Bay, and winds gus ted at J:ciwer
velocitie;" d:.~ring this time at othe:- :reporting stat:tons within the Aleut;lan
Islands. and along the Al.o_ska Peni-:-.s·...:.:a. · Three I::turres found on April 24 . . in the to-wn of Cold Bay by residents vere taken to the headquarters of the
• • Izembek National Wildlife Ranze, but the inc~dent se~ed insignificant at
• the time because severe storms ofte~ blow pelagic birds inland.
"Wrecks of seabirds, 11 occurre:-.ces v7here seabirds are driven far inland
and are often found dead and dying a:o~g the.beaches as a result of severe
storms, have been reported freque~:ly. Leslie H. Tuck, Canadian Wildlife
Se.rvice biologist, swr.ma=ized many. o'c:::;ervations of "wrecks of murres 11 in ~-..
his monograph on their l:::.fe history. Y..ass mortalities of thick-billed .. · murres during ston!ly wea:her have bee~ recorded over Anadyr in Siberia and
.· r .
..... :···· c;
at.the Pribilof Islands, both in the 3ering Sea. The ~ost significant
- ~ h . d rec.ord of "wrecks of mur::;es" is that or Beals ~n~ Longwort as reporte ~
fo.r Unimak Island in 1941; they w=ote:
"Between Apr.il '2 and 4 nu::.;;:-ous dead and sick murres were along all the beaches. he counted 37 dead birds along 3 miles of be3ch.· rne co~dition was general along the strait, we -vre::e told. Ole timers· on ·Uni!:-.ak told us that
' . this happens every·spri~; a~d that some years the beach is black with dend bircs. sw'inll!ling in close to the . waterline man; of the~ C..??eared to be sick or very weak hardly able t:> dive in s:-.c..llow water. Altogether we-
_saw 38 dead birds and 40 or more very weak ones along 3 n:.iles of beac:.. For th:-ee days before this~ heavy winds and sno•,.;r ble>~ fro-;n the so-..: theas t. 11
and..
. I:, ,
Apparently "wrecks of murres" are r.c: unco-c:::lon in this region, but seldom
-2-
r
~
·- __ ,,. "" ·------------------------
.. have the observers had the mobility of those this year whO' were able to
~~ assess the magnitude of loss.
Unresolv8d reports o~ oil ~hecns seen near the cbast and a·U. S. '\
Coast G\,lnrd report of t\·70 Japanese t:-a•~lers that sank with 36 men aboa-rd
·~
speculation that the birds were succuwbing to diesel fuel or gasoline • I
escapj_ilg from the sur.ken vessels. ~one of the murres exainined along the
beach were oil-stained. Only one obviously oil-killed bird, a fulmar, was
collected by the cre>:s tl·.at con:bed portions of the beach. Organic extracts.
from samples of feathers taken from the dead murres and of beach sands were •
analyzed by chemists of the Federal r,.;'ater Qu9.lity Administration's Portland ~ .
labor a tory. Gas chro:na tc·3raph and infra-red scan testings revealed no
evidence of petroleu~ products in any o~ the samples.
Tissues froill these curres were .tested ~or pesticides. Both DDE (a
metabolite of DDT) and hexychlorobenzine were found. in such small quantii~_e9,
each less than 1 part per million, that they were not regarded as suspect ., .. -.. causes of death.
I
Because aln:ost all affected birds were murres, pollutants seemed to
be an improbabl9 cause of death. Observations of pelagic birds in the •
eastern Bering Sea and Biistol Bay indicate that in winter the murr~s are
the most abundant birds, follo~ed by glaucous-winged gulls and fulmars;
• I and from spring through su~er there are increasingly larger numbers of
!
Perhaps one of the most unexpected findings from the pathological
examinations of these murres was the presence of arsenic, 2.77 parts per
t
.
million, in liver tissue. The sign~ficance of arsenic at this level is not •.
-.3- rll -·
•
~
_,·
:
-.. --.....
.·.
. ~
~ ..... •'."'
...
known. However, some of the marine orga~iSQS upon which murres feed are
reputedly conce1:trators of this ele:7-.ent, and arsenic levels of this .,. ·,
magnitude rr.a.y be normal :.n he.sl:.hy ~-:..lrres.
Hurres (the "urre" of the ·,.:ord :::.urre is pronounced. like the "ur" in
the word fur) are found :hrougbout t:te northern h_~misphcre. Two species, . ·"'
-the con:::aon murre and thick-billed <.:.L-"rre, ·are found in the Bering Sea and -- Bristol Bay area. There is cor..siderable overlap in the distribution of
I • .
these ~pecies, b~t the thick-billed ~urre tends to have a more northerly
distribution than the co:rnon murre. Studies o~ summer distribution of· ; I
pelagic birds in Bristol Bay sho~ t~at commdh murres· are most abundant, but
·winter populations there may contain p~oportionately more 'thick-bill~d
murres. Nesting colonies of m~rres in Alaska are found along rocky portions
of the coast from Cape Lisburne, along the Aleutian Islands, to and in-
eluding the Alexander Ar~hipelago in southeastern Alaska. Some of the
.',J.,laska "bird cities," or nestir.3 co:.onies, !:lay contain tens of ~housands
of murres. Following the nest:.ng season, when the pair attempts to raise
a single young on a precipitous cli:f, the birds return to the sea until
next year. Hurres feed chiefly on sinall fish, such· as capclin, sculpins
and codfish; but invertE~rates, such as shrimp,_ mollusks and sea worms
furnish a part of their diet.
Leslie H. Tuck ("The Hurres ," Canadian \Hldlif e Service, Ottawa; 1960)
summari-zes the life his tory of the :::urres as follo~o~s:
I
"Hurres are relatively la::-ge-'sea-birds, weighing on the average two ~ounds, ~ith sharply defined bi~coloured plumage. They are highly specialized for catching £mall _ fish under water. Specialized developinent for this pur­ p<,:>se include£ reduction of the length and area of the wing and so great ~odification of the bones and muscles of the legs that th~se birds walk vety little and very aw1~ardly. They nest in large, compact colonies on steep
-4- ;.
cliffs facing the sea.
Murres are essentially ~arine species and approach ~land only during the breeding season. They obtain most of their.food by flying under water. Th~y are the only sea-t irds in t."1e ~orthern Hemispher.e which habitually lay their eggs in exposed situa t.ions on bare ledges and rocks. They brood but a sinzle egg and yet they are prob~bly the most abundant sea-birds in. the !\orthern He:-uisphere.
There are two species; the co~~on murre (Uria aalge), with some tolerance for warmish water, and th·e thick­ billed murre .'Uria lomvia), largely restricted to arctic waters. They occupy in the Northern Hemisphere an ecological niche similar to that 'occupied in the Southern Hemisphere by pe~~uins, which they res~mble superficially in coloration and postures.
' The habit of nesting in large colbnies (some colonies contain· more :han one million individuals) has made the species of substantial ec.onOmic importance in some parts of the N.orthe-:--n.Hemisphere. Thei'r .eggs, and to a lesser extent the birds themselves, have been traditionally used in. the Old World for food, 'and were so used for a brief apd over-enthusiastic period in the New World. Reeent investigations indicate that there is more nourish­ ment in a murre's egg than in the equivalent ·volume of a dom~stic fowl 1 s. The utilization of murres, with some minor excepti::ms, has been outlmved in the ~-e-..1 World· for more than half a century. Elsewhere utili.zation has de-
. creased in some places (e.g., Great Britain), remained the same (e.g., the Faeroes), or increased (e.g., Russia).
·There is no evidence that murre populations are appreci- ·. ably less numerous today than they were in historical
· times. . . Q . li •
Nesting n1u~re.8 require scarcely one square foot of territory per individual. Such compact colonies are possible. because. the food of murres is al~ost unlimited in sumner. Murres provide a vital •link in the ecology
. '
in many respects the fertilizi~g factories of the north- · - ern seas.
A murre·color.y (loomery or bazaar) is an orderly aggrega­ tion of bird~. It fs bas ical~y composed of a core of experienced cdults, surrounded. on the submarginal fr~nge sites by less experienced birds or· those breeding for the first time. Early in the breeding season, cature rnurres .take part in co~unal displays in the sea at the base of the cliffs. It is believed that those co~~unal displays
-5-
-·-····-·.-.L-
,. ..... :- .... __ ;· ____ ; __ , ...
not only stDnulate the birds to breed but enable them to "synchronize" their breeding cycles so that the maximum number of young ar-e raised in a comparatively short period.
The eggs and chicks are subjected to many dangers, not the least of which is the likelihood of b~ing knocked off the narrow ledges. The surviving chicks are led to sea, and to com?arative safety, by single adults, not necessarily their parents~ ·In other ways also, murres show cor.1:-:1unal interest in the welfare of
- -the eggs and chicks of the colony."
'·
_,.
!- \ ::- ~~-
}
A Joint Effort by; U. S. Dcp~rt~ent of Interior
·a~
.. \ )
- BRISTOL BAY ~~~RRE MORTALITY
At least 86,000 common murres died in Bristol Bay, Alaska during a
brief per~od in late April of this year. .;J.
Although the cause of death m~y
never be completely resolved to eveD'On~'s satisfa~tion, the evidence
' suggests that it was a catastrophe of nfture. The murres, apparently
stilY weakened after wintering in· the Bering Sea, probably died from a , .. .
combination of starvation and exhaustion which was aggravated by. a seve~e ~
storm that prevented them from feeding during a critical few days.
Post-mortem· examinations of 'Glur::=es by p_athologists from the Bureau·
of Spo~t Fisheries and Wildlife research centers in North Dakota and . . l
Maryland, the Arctic Health Research Center in.Fairbanks, the National
.... . Disease Laboratory in IoKa, and the California Department of Fish and Ga:n.e .. in Sacramento found no evidence that pathogenic bacteria or vir~ses con-
- tributed to the mass mortality. Foods were not found in the digestive . . . , c..; tracts of these birds. Tests for presence of toxins in the smail quantitie?
. . of fluid found in the in~estines were inconclusive • . c . All speci;:1ens w"ere .emaciated and had no appreciable deposits in sub- .·
··:·--cutaneous~~bdominal and cardiac fat tissue. Thirteen of the dead birds ·J • .
}
were not available for this same tine of the year, the 6~~-gram average
- ·- weight of these-birds was considerably less than the 972-gram average-
weight for male cou:rnon m..1rres and 1022-gram average weight for female . I·'
• I .
""""' ,·· ...
_,'
•..: :..·
.. ::-···· 0
suggest that the birds died fro::: starvation, although all factors that
could contribute to starvation l.'.ay n_ever be completelY, resolved.
Severe winds and turbulent seas ?rob~bly precipitated the die-of~ t~t
was first reported on.Ap~il 24 by Ken Xanthey of the·Al'aska Department
of Fish and Game. During the t•:o preceding days, winds. reached peak velo-·
c_ities of 104 'mph at Adak and 84 :aph ·at Cold Bay, -.and winds gusted at l'ciwer
--velocities durir,g this tirr,~ at other reporting stat:tons within the Aleut;tan
Islands· and along the Alaska Pe1:insula. · Three tJ.urres found on April 24 . . in the town of Cold Bay by resicents vere taken to the headquarters of the
. . ' Izembek National Wildlife Ranze, but the inc~dent se~ed insignificant at . ~
the time because severe storms often blow pelagic birds inland.
11Wrecks of seabirds, 11 occur:-ences -.;here seabirds are driven far inland
and are often found dead and dying along the.beaches as a result of severe
storms, have been reported frequently. Leslie H. Tuck, Canadian Wildlife
~ervice biologist, summarized oany. observations of "wrecks of murres" in ~-.. his monograph on their life history. Mass mortalities of thick-billed ..
· murres during sto~y weather have been recorded over Anadyr in Siberia and· I .
at· the Pribilof Islands, both in the Bering Sea. The most significant • . ~
record of "wrecks of murtes" is that of Beals {:lnd, Longworth as reported
for Unimak Island in 1941; they wrote:
"Between Apr.il ·2 and 4 nu:::erous dead and sick murres were along all the beaches. We counted 37 dead birds along 3 miles of beach. T'na co:1dition was general along the strait, we vrere told. Old timers· on ·Unimak told us that this happens 'every· spring a:1d, that some years the beach is black with dead birds. Swi~ing in close to the waterline many of the~ ap?eared to be sick or very weak hardly able to dive in shallow ~ater. Altogether we-
_saw 38 dead birds anci 40 or more very weak ones along 3 miles of beach. For three days before this, heavy ~inds and snow ble>J from the southeast. 11
and_
' I;, I .• '.
Apparently "~reeks of murres" are not uncorr:rnon in this region, but seldom
-2-
f·.
~··
~
'
. ~·
..... ~ .....
.... ..
have the observers had the mobility of those this year 'Who were able to
assess the magnitude of loss .
Unresolved reports of oil .sheens seen near the cbast and a·U. S. ~
Coast Gt,~ard report of two Jap.:lnese tra>o~lers that sank with 36 men aboa-rd
100 miles -;.:est of Unimak Island during the severe store gave rise to early
speculation that the birds were succumbing to diesel fuel or gasoline • l
escapiitg from the sunken vessels. None of the murres exa...-uined along. the
beach v.•ere oil-stained. Only one obviously oil-killed bird, a fulmar, was
collected by the crev.•s that combed portions of the beach. Organic extracts .
from samples of feathers taken from the dead murres and of beach sands were
~ .
laboratory. Gas chromatograph and infra-red scan testings revealed no
evidence of petroleum products in any of the samples.
Tissues frohl these murres were .tested ~or pesticides. Both DDE (a
metabol.ite of DDT) and he.xychlorobenzine were found. in such small quantii:t,.~9,
each less than 1 part per million, that they were not regarded as suspect ~ ... -- causes of death.
I
Because almost all affected birds were murres, pollutants seemed to
be an improbabl9 cause of death. Observations of pelagic birds in the •
eastern Bering Sea and Baistol Bay indicate that in winter the murr~s are
the most abundant birds, follo'Wed by-glaucous-winged gulls and fulmars;
• I and from spring through ~u~er there are increasingly latger numbers of
kittiv;akes, sh.ear..:aters, and puffins. The few dead birds of other species
}
Perhaps one of the most unexpected findings from the pathological
examinations of these murres 'Was the presence of arsenic, 2.77 parts per
l
million, in liver tissue. The significance of arsenic at this level is not • · ·.
-.3- ~ -·
•
·~
..
__ .......
..... :····
...
.
knovm. However, some of the rna ri:-.e orga.'nisms upon which murres feed are
reputedly concelltrators of this ele..=-.ent, and arsenic levels of this ..... ·,
magnitude may be normal in healthy ;::;.Jrres.
Hurres (the "urre'' of the ..._,ord ::-.urre is pronounced like the "ur" in
the w~rd fur) are found throughout the northern h_~misphere. Two species, .< I
the corr=aon mur:e and thick-billed :::urre,-are found in the Bering Sea and -- Bristol Bay area. There is consiC.e:-able overlap in the distribution of
' . these ~pecies, but the dlick-billed ~urre tends to have a more northerly
distribution than the ccrrnon murre. Studies of summer distribution of I
' pelagic birds i::: Bristol Bay shor.' t:-.at coromcln murres· are most abundant, but
·winter populations there ~ay contair: proportionately more 'thick-bill~d
murres. Nesti~g colonies of ruurres in Alaska are found along rocky portions
9f the coast from Cape Lisburne, along the Aleutian Islands, to and in-
eluding the Alexander Ar~hipelago in southeastern Alas~~. Some of the
·~J.laska "bird CitieS t II Or nesting COlOnieS t may COntain tenS Of ~hOUSandS
of murres. Following r.he nesting season, when the pair attempts to raise
a single young on a precipitous cliff, the birds return to the sea until
next year. }iurres feed chiefly on s~all fish, such· as capelin, sculpins
and codfish; but invertE~rates, such as shrimp,_ mollusks and sea worms
furnish a part of their diet .
Leslie H. Tuck ("Tbe Hurres," Canadian \-lildlife Service, Ottawa; 1960)
summari·zes the life his :ory of the ::::urres as (ollo~o~s: ' .
I
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cliffs facing the sea.
Murres are essentially ~arine species and B??roach ~land only dur::.ng the breeding season. They obtain most of their· food by flying under water. Tney are the only sea-birds in t.~e !\orthern Hemispher.e which habitually la:r their eggs in exposed situa t.ions on bare ledges a~d rocks. They brood but a sinzle egg and yet they are prob~bly the most abundant sea-birds in. the !\orthe:-n Hemisphere.
There are two species; the common murre (Uria aalge), with some tolerance for warmish wa'ter, and the thick­ billed murre (Uria lo:nvia), largely restricted to arctic waters. They occupy in the Northern Hemisphere an ecological niche similar to that 'occupied in the Southern Hemisphere by pe~~uins, which they res~mble superficially in coloration and Pfstures.
The.habit of ~esting in lar~e col~nies (so~2 colonies contain· more than one million individuals) has ~ade the species of substantial ec.onOmic importance in some parts of the ~orthern.Hemisphere. Their ~ggs, and to a lesser extent the birds themselves,. have been traditionally used in. the Old Horld for food, 'and were so used for a brief and over-enthusiastic period in the New World. Reeent investigations indicate that there is more nourish­ ment in a murre's egg than in the equivalent ·volume of a dom~stic fowl 1 s. The utilization of murres, with some minor exceptions, has been outlm11ed in the ~~er,y World· for more than hal£ a century. Elsewhere utili.zation has de-
. creased in some places (e.g., Great Britain), remained the same (e.g., the Faeroes), or. increased (e.g., Russia). There is no evidence that murre populations are appreci­ ably less numerous today than they were in historical
·times.
Nesting m~rr,e.~ require scarcely one square foot of territory per individual. Such compact colonies are possible. because' the food of murres is alcost unlimited in sur:uner. Hurres provice a vital •link in the ecology
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in many respects the fertilizi~g factories of the north- · ~ ern seas •
A murre·color:y (loo-.nery or bazaar) is an orderly aggrega­ tion of bird~. It is basicaLl-Y composed of a core of experienced adults, surrounded- on the sub~arginal fr~nge sites by less experienced birds or· those breeding for the first time. Early in the breeding season, ~ature ~urres .take part in con:munal displays in the sea at the base of the cliffs. It is believed that those co~~unal displays
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not only stirrulate the birGs to breed but enable them to "synchronize" their breeding cycles so that the maximum number of young a~e ralsed in a comparatively short period.
The eggs and chicks are s~bjected to many dangers, not the least of which is the likelihood of b~ing knocked off :he narrow ledges. The surviving chicks are led to sea, and to co~?arative safety, by single adults, not necessarily :heir parents~ ·In other ways also, murres show cor.:::n;-:-. .::1 interest in the welfare of
--the eggs and chicks of t:-:e colony."
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