{"id":125,"date":"2015-11-03T21:27:30","date_gmt":"2015-11-03T21:27:30","guid":{"rendered":"http:\/\/studentblogs.viu.ca\/danagullison\/?p=7"},"modified":"2017-08-23T17:31:14","modified_gmt":"2017-08-23T17:31:14","slug":"increasing-occurrences-of-beak-deformities-emerging-in-northwestern-crows","status":"publish","type":"post","link":"https:\/\/wordpress.viu.ca\/biol325\/2015\/11\/03\/increasing-occurrences-of-beak-deformities-emerging-in-northwestern-crows\/","title":{"rendered":"INCREASING OCCURRENCES OF BEAK DEFORMITIES EMERGING IN NORTHWESTERN CROWS"},"content":{"rendered":"

\"Fig13_NOCR_maxilla<\/a><\/p>\n

As I mentioned in my previous post, Northwestern Crow populations have shown a strong overall increase over the past half century, despite a 4% \u00a0(BC Conservation Data Centre, 2015)<\/a>\u00a0decline in BC and Alaskan records over the past 2 decades . The crow populations appear superficially healthy, however there may be an emerging reason for concern. In Alaska, and further south, beak deformity has been recorded at rates significantly\u00a0(Van Hemert and Handel, 2010)<\/a>\u00a0higher than ever previously observed in a wild bird population\u00a0(Van Hemert and Handel, 2010)<\/a>.\u00a0<\/span>This suggests a possible epizootic, equivalent to an epidemic in humans\u00a0<\/span>This epizootic of beak deformities may be a warning that this seemingly robust bird may be more vulnerable in its environment than it\u2019s adaptive behaviour might suggest, or there has been a marked change in\u00a0the ecosystem<\/span>\u00a0(Handel et al., 2010)<\/a>.<\/span><\/span><\/p>\n

\"NOCR_flyer\"<\/a><\/p>\n

 <\/p>\n

In Alaska, government scientists have been studying native bird populations to learn more about the beak deformities. Normally bill deformities are not prevalent within populations\u00a0(Van Hemert and Handel, 2010)<\/a>.\u00a0 High incidents of beak deformity in wild bird populations can point to environmental problems\u00a0(Handel et al., 2010)<\/a>\u00a0\u00a0(Van Hemert and Handel, 2010)<\/a>.<\/span><\/span>\u00a0Through her research on Black-capped Chickadees, Alaskan scientist\u00a0Colleen Handel was alerted to a few birds with deformed bills showing up at bird feeders in the late 1990\u2019s. Handel requested public help in documenting occurrences of beak deformities in chickadees at bird feeders and received numerous accounts about other birds, including a considerable number of Northwestern Crows with beak deformities, many of them south of Alaska. \u00a0Beak elongation affected either the top and bottom beak or both beaks at the same time and frequently resulted in the bird having difficulty feeding\u00a0(Kay, 2014)<\/a>\u00a0The abnormalities of the two avian species was found to be a result of avian keratin disorder, a condition that occurs when the outer keratinized layer on the beak becomes grossly overgrown\u00a0(Van Hemert et al., 2012)<\/a>.\u00a0The parallel condition led to a study on the prevalence and morphological extent of beak deformities in crows and the geographic range of occurrences\u00a0(Van Hemert and Handel, 2010)<\/a>.<\/span><\/span><\/p>\n

\"NWCrow<\/a><\/p>\n

Handel and her research\u00a0partner Caroline Van Hemert\u00a0<\/span><\/span>\u00a0sampled crow populations at six coastal sites in Alaska for 1 year between 2007 and 2008. Each site was near a human settlement and provided a mixture of natural and human generated food available to the crows\u00a0(Van Hemert and Handel, 2010)<\/a>.\u00a0They\u00a0measured 186 crows and found 19 adults with beaks classified as deformed and no juveniles with the deformity. The overall level of deformities exceeded their expectations by over 30 times. The prevalence of beak deformity in the crows was as much as 17%, much higher than the 6.5% found in the chickadees\u00a0(Van Hemert and Handel, 2010)<\/a>.\u00a0At two of the sites with greater occurrences of deformities, eight other species of birds displayed beak deformities. These two locations were also in close proximity to where the highest occurrences of beak deformity were noted in chickadees.\u00a0Through a review of literature and observations compiled since 1980, 148 crows were \u00a0found \u00a0to have beak deformities, most of them since 1997. Sixty-four reports came from BC and Washington of crows with abnormal beaks. Only five observations were recorded from the rest of North America. This clear prevalence of occurrences since 1997 is equivalent to that of Black-capped Chickadees\u00a0(Van Hemert and Handel, 2010)<\/a>.<\/p>\n

\n

\"images\"<\/a><\/p>\n

Distribution Map of NOCR with deformed beaks<\/p>\n<\/div>\n

While no conclusions have yet been drawn, the authors have suspected both viruses and environmental contaminants and point out possible clues and directions for future research.\u00a0They suggest\u00a0the deformities are unlikely to be caused by parasites or infectious disease, because these localized avian populations are not exposed to transient agents. \u00a0They suggest that because of the overwhelming similarity of characteristics there is some factor \u2018unique to the region\u2019 causing the same disorder in crows as in all the birds studied. If it is an environmental factor or contamination then it would be diffuse because of the large geographic range of occurrences and more specific testing is necessary. \u00a0Further studies of crows living away from human habitation would provide useful comparison. \u00a0Further research into the pathology of avian keratin disorder may also be helpful in isolating the cause.<\/p>\n

References for blog posts 1 & 2:<\/span><\/p>\n

Emery N.J, Clayton N.S. 2004\u00a0The Mentality of Crows: Convergent Evolution of Intelligence in Corvids and Apes\u00a0Science<\/em>\u00a0V.302, pp.1903-1907\u00a0\u00a0\u00a0http:\/\/www.sciencemag.org\/content\/306\/5703\/1903.abstract?sid=e39eb11f-f3eb-47ff-80f3-0a2ada1b9c4b<\/a><\/p>\n

Vancouver Avian Research Centre,\u00a0Species: Northwestern Crow\u00a0Corvus caurinus<\/em>\u00a0http:\/\/www.birdvancouver.com\/b_northwestern_crow.html<\/a>\u00a0 (Oct. 27 2015)<\/p>\n

Brewer et al., Canadian Atlas of Bird Banding, \u00a02006,\u00a0Volume 1: Doves, Cuckoos, and Hummingbirds through Passerines 2nd edition,\u00a01921\u20131995\u00a0http:\/\/www.ec.gc.ca\/aobc-cabb\/index.aspx?lang=En&nav=bird_oiseaux&aou=489<\/a><\/p>\n

Sibley A.S., 2003,\u00a0The Sibley Field Guide To Birds of Western North America,<\/em>\u00a0A.A Knopf, New York, p.308<\/p>\n

Tweit B. 2015, E-Bird Northwest News and Features,\u00a0Northwestern Crows, Genetics, and eBird: New Science for an Old Problem\u00a0<\/em>http:\/\/ebird.org\/content\/nw\/news\/northwestern-crows-genetics-and-ebird-new-science-for-an-old-problem\/<\/a>\u00a0(Oct. 27 2015)<\/p>\n

Cornell University, 2015, All About Birds-Bird Guide\u00a0Northwestern Crow, Life History,\u00a0<\/em>http:\/\/www.allaboutbirds.org\/guide\/Northwestern_Crow\/lifehistory<\/a>\u00a0(Oct. 31, 2015)<\/p>\n

Marzluff J.M., Angell T.,2008,\u00a0In the Company of Crows and Ravens<\/em>, Yale University Press, p. unavailable\u00a0https:\/\/books.google.ca\/books?id=Bc5YO5PnPmMC&pg=PT244&lpg=PT244&dq=In+the+company+of+crows+and+ravens+mcdonalds&source=bl&ots=ONLek6aA6o&sig=Jf20d0ckm-XyxKE51omzjtfy0VI&hl=en&sa=X&ved=0CDAQ6AEwAWoVChMIne61wJHyyAIVxDKICh2VWwo2#v=onepage&q=In%20the%20company%20of%20crows%20and%20ravens%20mcdonalds&f=false<\/a><\/p>\n

Link R., 2005, Washington Department of Fish and Wildlife, Living With Wildlife,\u00a0Crows<\/em>, \u00a0http:\/\/wdfw.wa.gov\/living\/crows.html<\/a>\u00a0(Oct.31, 2015)<\/p>\n

Ehrlich P.R., Dobkin D.S., Wheye D., 1988, The Birder\u2019s Handbook, A Field Guide to the Natural History of North American Birds, Simon and Schuster, New York, p.416.<\/p>\n

Gullison, D. 2015, Northwestern Crow Call, (sound recording), Nanaimo, Canada.<\/p>\n

Ward M., 2013,\u00a0Crows Over Commercial Drive, Vancouver<\/em>\u00a0(video) \u00a0https:\/\/www.youtube.com\/watch?v=sgmdW_Uut1U<\/a>\u00a0(Oct. 27, 2015)<\/p>\n

Campbell W., Smith G.E.J., McNall M.C.E., Kaiser G.W., Cooper J.M., McTaggart-Cowan I., Dawe N.K., 1997,\u00a0Birds of British Columbia<\/em>, Volume 3\u00a0Passerines \u2013 Flycatchers through Vireos, UBC Press, Vancouver, p.11.\u00a0https:\/\/books.google.ca\/books?id=xynPkpa6vToC&pg=PA11&lpg=PA11&dq=campbell+northwestern+crow+population&source=bl&ots=xGLv4onQpm&sig=D6ERfD2KLeho_HtrFQdw2XQf1vw&hl=en&sa=X&ved=0CCYQ6AEwAmoVChMI7rvCp53yyAIVUKWICh3H8QII#v=onepage&q=campbell%20northwestern%20crow%20population&f=false<\/a><\/p>\n

B.C. Conservation Data Centre. 2015. Conservation Status Report: Corvus caurinus. B.C. Minist. of Environment.\u00a0http:\/\/a100.gov.bc.ca\/pub\/eswp\/esr.do;jsessionid=5pCQSVnfh3vwyxBLPbzWntmyq8KvDqhnpNV04xrGpywP3nmyprbm!1298844341?id=18443<\/a>\u00a0(Oct. 30, 2015)<\/p>\n

B.C. Ministry of Environment, 2015,\u00a0Human\/Wildlife Interactions<\/em>, Nuisance Fauna, Birds\u00a0http:\/\/www.env.gov.bc.ca\/cos\/info\/wildlife_human_interaction\/docs\/nuisance_fauna.html#birds<\/a>\u00a0(Oct. 31, 2015)<\/p>\n

Alaska Department of Fish and Wildlife, 2015,\u00a0Small Game Hunting in Alaska<\/em>, Regulations\u00a0http:\/\/www.adfg.alaska.gov\/index.cfm?adfg=smallgamehunting.regulations<\/a>\u00a0(Oct. 31, 2015)<\/p>\n

Van Hemert C., Handel C.M. and O\u2019Hara T.M., \u00a0Evidence of accelerated beak growth associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus),\u00a0Journal of Wildlife Diseases<\/em>, vol.48, p.686\u00a0http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/22740534<\/a><\/p>\n

Colleen M.H, \u00a0Pajot L.M., Matsuoka S.M., Van Hemert C., \u00a0Terenzi J., Talbot S.L., \u00a0Mulcay D.M., Meteyer C.U. and Trust D.A., 2010,\u00a0Epizootic of beak deformities among wild birds in Alaska: an emerging disease in North America?, \u00a0The Auk<\/em>, v. 127 pp. 882-898 \u00a0http:\/\/alaska.usgs.gov\/science\/biology\/landbirds\/beak_deformity\/pdfs\/Auk_Handel_beak_deformities2.pdf<\/a><\/p>\n

Marzluff J.M., McGowan K.J., Donnelly R. and Knight R.L., 2001,\u00a0Causes and consequences of expanding American Crow populations, Avian\u00a0Ecology and Conservation in an Urbanizing World, \u00a0<\/em>Kluwer Academic Press, Norwell, MA.\u00a0p.331\u00a0http:\/\/www.birds.cornell.edu\/crows\/Marzluff%20et%20al%202001%20Avian%20Urb%20Ecol.pdf<\/a><\/p>\n

J. Kay, Environmental Health News, Winged Warnings,\u00a0Twisted beaks: Scientists exploring mysterious deformities focus on new virus<\/em>\u00a0http:\/\/www.environmentalhealthnews.org\/ehs\/news\/2014\/aug\/wingedwarnings6deformed-chickadees<\/a>\u00a0 (Nov. 2 2015)<\/p>\n","protected":false},"excerpt":{"rendered":"

As I mentioned in my previous post, Northwestern Crow populations have shown a strong overall increase over the past half century, despite a 4%  (BC Conservation Data Centre, 2015) decline in BC and Alaskan records over the past 2 decades . … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":306,"featured_media":203,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","footnotes":""},"categories":[23],"tags":[15],"class_list":["post-125","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dana","tag-uncategorized"],"_links":{"self":[{"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/posts\/125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/users\/306"}],"replies":[{"embeddable":true,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/comments?post=125"}],"version-history":[{"count":3,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/posts\/125\/revisions"}],"predecessor-version":[{"id":202,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/posts\/125\/revisions\/202"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/media\/203"}],"wp:attachment":[{"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/media?parent=125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/categories?post=125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wordpress.viu.ca\/biol325\/wp-json\/wp\/v2\/tags?post=125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}