Editing Seabird (section)

=== Other threats ===
{{See also|Introduced mammals on seabird breeding islands}}
[[File:Oiledcrestedauklet.jpeg|thumb|This [[crested auklet]] was oiled in Alaska during the spill of [[MV Selendang Ayu|MV ''Selendang Ayu'']] in 2004.]]
Other human factors have led to declines and even extinctions in seabird populations and species. Of these, perhaps the most serious are [[introduced species]]. Seabirds, breeding predominantly on small isolated islands, are vulnerable to predators because they have lost many behaviours associated with defence from predators.<ref name ="Moors" /> [[Feral cat]]s can take seabirds as large as albatrosses, and many introduced rodents, such as the [[Polynesian rat|Pacific rat]], take eggs hidden in burrows. Introduced goats, cattle, rabbits and other [[herbivore]]s can create problems, particularly when species need vegetation to protect or shade their young.<ref name ="car">{{cite journal|author1=Carlile, N. |author2=Proiddel, D. |author3=Zino, F. |author4=Natividad, C. |author5=Wingate, D. B. |year=2003|title=A review of four successful recovery programmes for threatened sub-tropical petrels|url=http://marineornithology.org/PDF/31_2/31_2_185-192.pdf|journal=Marine Ornithology |volume=31|pages= 185–192}}</ref> The disturbance of breeding colonies by humans is often a problem as well—visitors, even well-meaning tourists, can flush brooding adults off a colony, leaving chicks and eggs vulnerable to predators.<ref>{{cite journal |last1=Beale |first1=Colin M. |last2=Monaghan |first2=Pat |title=Human disturbance: people as predation-free predators? |journal=Journal of Applied Ecology |date=April 2004 |volume=41 |issue=2 |pages=335–343 |doi=10.1111/j.0021-8901.2004.00900.x|doi-access=free |bibcode=2004JApEc..41..335B }}</ref><ref>{{cite journal |last1=Watson |first1=Hannah |last2=Bolton |first2=Mark |last3=Monaghan |first3=Pat |title=Out of sight but not out of harm's way: Human disturbance reduces reproductive success of a cavity-nesting seabird |journal=Biological Conservation |date=June 2014 |volume=174 |issue=100 |pages=127–133 |doi=10.1016/j.biocon.2014.03.020|pmid=24899731 |pmc=4039997 |doi-access=free |bibcode=2014BCons.174..127W }}</ref>

The build-up of [[toxin]]s and pollutants in seabirds is also a concern. Seabirds, being [[apex predator]]s, suffered from the ravages of the insecticide [[DDT]] until it was banned; DDT was implicated, for example, in embryo development problems and the skewed sex ratio of [[western gull]]s in southern California.<ref>{{cite journal|author1=Fry, D.  |author2=Toone, C.  |name-list-style=amp |year=1981|title=DDT-induced feminization of gull embryos|journal=Science |volume=213 |issue=4510 |pages= 922–924|doi=10.1126/science.7256288|pmid=7256288|bibcode=1981Sci...213..922F}}</ref> [[Oil spill]]s are also a threat to seabirds: the oil is toxic, and bird feathers become saturated by the oil, causing them to lose their waterproofing.<ref>{{cite journal|author1=Dunnet, G. |author2=Crisp, D. |author3=Conan, G. |author4=Bourne, W. |year=1982|title=Oil Pollution and Seabird Populations [and Discussion]|journal=[[Philosophical Transactions of the Royal Society B]] |volume=297 |issue=1087 |pages= 413–427|doi=10.1098/rstb.1982.0051|bibcode=1982RSPTB.297..413D |doi-access=free }}</ref> Oil pollution in particular threatens species with restricted ranges or already depressed populations.<ref name="BirdLifeMMurrelet">{{cite web |url=http://datazone.birdlife.org/species/factsheet/marbled-murrelet-brachyramphus-marmoratus/text |title=Species factsheet: ''Brachyramphus marmoratus'' |author=<!--Not stated--> |date=2021 |website=BirdLife International Data Zone |publisher= BirdLife International |access-date=March 31, 2021}}</ref><ref name="IronyGannet">{{cite news |last=Hagen |first=Christina |date=December 12, 2017 |title=The ultimate irony: Cape Gannets, famed for their greed, are now starving |url=https://www.birdlife.org/worldwide/news/ultimate-irony-cape-gannets-famed-their-greed-are-now-starving |work=BirdLife International |location= |access-date= March 31, 2021}}</ref>

[[Climate change]] mainly affect seabirds via changes to their [[habitat]]: various processes in the ocean lead to decreased availability of food and colonies are more often flooded as a consequence of [[sea level rise]] and extreme rainfall events. Heat stress from extreme temperatures is an additional threat.<ref>{{Cite journal|last1=Dias|first1=Maria P.|last2=Martin|first2=Rob|last3=Pearmain|first3=Elizabeth J.|last4=Burfield|first4=Ian J.|last5=Small|first5=Cleo|last6=Phillips|first6=Richard A.|last7=Yates|first7=Oliver|last8=Lascelles|first8=Ben|last9=Borboroglu|first9=Pablo Garcia|last10=Croxall|first10=John P.|date=2019|title=Threats to seabirds: A global assessment|url=https://www.sciencedirect.com/science/article/pii/S0006320719307499|journal=Biological Conservation|language=en|volume=237|pages=525–537|doi=10.1016/j.biocon.2019.06.033|bibcode=2019BCons.237..525D |s2cid=201204878 |issn=0006-3207}}</ref> Some seabirds have used changing wind patterns to forage further and more efficiently.<ref>{{Cite book|last1=Bindoff|first1=N. L.|title=Special Report: The Ocean and Cryosphere in a Changing Climate|last2=Cheung|first2=W. W. L.|last3=Kairo|first3=J. G.|last4=Arístegui|first4=J.|last5=Guinder|first5=V. A.|last6=Hallberg|first6=R.|year=2019|page=479|chapter=Chapter 5: Changing Ocean, Marine Ecosystems, and Dependent Communities|display-authors=4|chapter-url=https://www.ipcc.ch/site/assets/uploads/sites/3/2019/11/09_SROCC_Ch05_FINAL.pdf}}</ref>

In 2023, [[plasticosis]], a new disease caused solely by plastics, was discovered in seabirds.
The birds identified as having the disease have scarred digestive tracts from ingesting [[plastic waste]].<ref>{{Cite web |url=https://www.theguardian.com/environment/2023/mar/03/plasticosis-new-disease-caused-by-plastics-discovered-in-seabirds|title=New disease caused by plastics discovered in seabirds |date=March 3, 2023 |work=The Guardian |access-date=March 4, 2023}}</ref>  "When birds ingest small pieces of plastic, they found, it inflames the digestive tract. Over time, the persistent inflammation causes tissues to become scarred and disfigured, affecting digestion, growth and survival."<ref>{{Cite web |url=https://www.nhm.ac.uk/press-office/press-releases/new-disease-caused-solely-by-plastics-discovered-in-seabirds-.html|title=New disease caused solely by plastics discovered in seabirds |date=March 3, 2023 |publisher=Natural History Museum |access-date=March 4, 2023}}</ref>