Glacous-winged Gulls are the most common gulls in the BC lower mainland/ Strait of Georgia. Researchers found that the population increased steadily beginning in the early 1900s, but the population is down by 50 per cent from the 1980s
Photo Credit: Louise Blight

Sharp decline in seabird population in British Columbia


Decline in marine prey fish blamed.

They seem fairly ubiquitous, but researchers have found Glacous-wing gull populations in dropping sharply on the west coast of Canada. In fact, the gull population is down by about 50% since the 1980’s.

The new study by the University of British Columbia (UBC), says a number of factors such as protection laws, and a decline in predators like eagles, led to a marked increase in gull population since the early 1900’s to peak around the 1980’s.

The UBC researchers say ther factors including a decline in marine food sources is reducing their numbers. Peter Arcese (PhD) is the Forest Renewal BC Chair in Applied Conservation Biology in the Department of Forest Conservation and Sciences at the University of British Columbia. He supervised the research team.


The study “A century of change in Glaucous-winged Gull (Larus glaucescens) populations in a dynamic coastal environment” was published earlier this month in The Condor: Ornithological Applications.

Peter Arcese (PhD) shown holding a Pacific giant barnacle, supervised the research studyiing 100 years of data on the gulls. © Sierra McLane

Lead author Louise Blight says of the gull decline “These birds are the ultimate generalist — they can eat whatever’s around. If this extreme generalist is not doing well, it’s a pretty strong message that the marine ecosystem has changed. Not for the better.”

As the high fat, high protein diet of small fish has declined, the gulls have turned to other readily available sources on land like garbage, and earthworms.

Professor Arcese says because this is not providing the needed nutrition, it’s suspected that gulls might not be laying as many viable eggs, or the young are not surviving long, leading to the marked population decline.

Other populations like the marbled murrelet are experiencing an even steeper decline  up to 90% as have western grebes.  In the murrelet case from habitat reduction and marine food source decline.

Glacous-winged gulls on Mandarte Island, University of British Columbia researchers say the decline in the gull population reflects changes and a decline of available small marine prey fish. in the region. © P Arcese

While western grebes were  once common in winter in the British Columbia lower coastal area there numbers too have dropped almost 90% but in this case they seem to have simply moved southward to over winter in California where prey fish like anchovies have increased.

Professor Arcese says that if a generalist predator like the glaucus gull is declining, it’s undoubtedly a sign that other, less easily documented land and marine species are also in trouble.

Marbled Murrelet numbers in southern BC have declined by some 90% due to comvined forest habitat loss (they nest in the forest) and the same decline in marine prefy fish affecting the gulls. © Gus Van Vliet- Us Fish and Wildlife Service- Wiki

Louise Blight, Mark Drever, and Peter Arcese of the University of British Columbia compiled all available population counts of Glaucous-winged Gulls (Larus glaucescens) in the Georgia Basin (defined as the region around the Lower Mainland, Victoria and Nanaimo), and then used these data to examine gull population trends from 1900 to 2010.

The information they used included both their own survey data and counts that had been carried out by amateur and professional biologists. Their study revealed that from a low point in 1900, gull population counts increased after protection was afforded by the Migratory Birds Convention Act of 1916.  The population peaked in the 1980s before beginning to decline again, which correlates with the recovery of Bald Eagle populations and declines in marine food quality and availability.

With files from UBC

Tagged with: , , , ,
Posted in Environment, International, Internet, Science and Technology

Do you want to report an error or a typo? Click here!

@*@ Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

 characters available

Note: By submitting your comments, you acknowledge that Radio Canada International has the right to reproduce, broadcast and publicize those comments or any part thereof in any manner whatsoever. Radio Canada International does not endorse any of the views posted. Your comments will be pre-moderated and published if they meet netiquette guidelines.

Netiquette »

When you express your personal opinion in an online forum, you must be as courteous as if you were speaking with someone face-to-face. Insults and personal attacks will not be tolerated. To disagree with an opinion, an idea or an event is one thing, but to show disrespect for other people is quite another. Great minds don’t always think alike—and that’s precisely what makes online dialogue so interesting and valuable.

Netiquette is the set of rules of conduct governing how you should behave when communicating via the Internet. Before you post a message to a blog or forum, it’s important to read and understand these rules. Otherwise, you may be banned from posting.

  1.’s online forums are not anonymous. Users must register, and give their full name and place of residence, which are displayed alongside each of their comments. reserves the right not to publish comments if there is any doubt as to the identity of their author.
  2. Assuming the identity of another person with intent to mislead or cause harm is a serious infraction that may result in the offender being banned.
  3.’s online forums are open to everyone, without regard to age, ethnic origin, religion, gender or sexual orientation.
  4. Comments that are defamatory, hateful, racist, xenophobic, sexist, or that disparage an ethnic origin, religious affiliation or age group will not be published.
  5. In online speak, writing in ALL CAPS is considered yelling, and may be interpreted as aggressive behaviour, which is unpleasant for the people reading. Any message containing one or more words in all caps (except for initialisms and acronyms) will be rejected, as will any message containing one or more words in bold, italic or underlined characters.
  6. Use of vulgar, obscene or objectionable language is prohibited. Forums are public places and your comments could offend some users. People who use inappropriate language will be banned.
  7. Mutual respect is essential among users. Insulting, threatening or harassing another user is prohibited. You can express your disagreement with an idea without attacking anyone.
  8. Exchanging arguments and opposing views is a key component of healthy debate, but it should not turn into a dialogue or private discussion between two users who address each other without regard for the other participants. Messages of this type will not be posted.
  9. Radio Canada International publishes contents in five languages. The language used in the forums has to be the same as the contents we publish. The usage of other languages, with the exception of some words, is forbidden. Messages that are off-topic will not be published.
  10. Making repetitive posts disrupts the flow of discussions and will not be tolerated.
  11. Adding images or any other type of file to comments is forbidden. Including hyperlinks to other websites is allowed, as long as they comply with netiquette. Radio Canada International  is in no way responsible for the content of such sites, however.
  12. Copying and pasting text written by someone else, even if you credit the author, is unacceptable if that text makes up the majority of your comment.
  13. Posting any type of advertising or call to action, in any form, to Radio Canada International  forums is prohibited.
  14. All comments and other types of content are moderated before publication. Radio Canada International  reserves the right to refuse any comment for publication.
  15. Radio Canada International  reserves the right to close a forum at any time, without notice.
  16. Radio Canada International  reserves the right to amend this code of conduct (netiquette) at any time, without notice.
  17. By participating in its online forums, you allow Radio Canada International to publish your comments on the web for an indefinite time. This also implies that these messages will be indexed by Internet search engines.
  18. Radio Canada International has no obligation to remove your messages from the web if one day you request it. We invite you to carefully consider your comments and the consequences of their posting.


One comment on “Sharp decline in seabird population in British Columbia
  1. benalbanach says:

    More likely infertility is the culprit.Even gulls suffer eventually from processed ‘food ‘.