The great black-backed gull has been added to the list of bird species in Iceland considered to be in critical danger, according to a new Red List published by the Natural Science Institute of Iceland. Other species classified as critically endangered include the Atlantic puffin, whimbrel and Arctic skua.

In total, 91 species were assessed, with 43 now considered threatened, compared with 41 when the previous Red List was published in 2018.

Borgný Katrínardóttir, a biologist at the Icelandic Institute of Natural History, says the assessment is primarily based on population trends.

“Critical danger means that, if we look only at population changes, the population has declined by around or over 80% over a defined reference period,” Borgný told RÚV.

Nineteen species are now classified as near threatened, an increase of 11. Borgný says one of the biggest changes is that four species of waders are now considered vulnerable: dunlin, redshank, golden plover and curlew. Habitat encroachment is believed to be a contributing factor.

“These are species that are difficult to protect because they breed so widely dispersed,” Borgný says. “So it’s not enough to say, ‘Okay, we need to protect this specific area.’ Instead, we really need to ensure that development and construction do not encroach on their habitats.”

She also stresses that climate change and broader environmental changes are another major factor. While these are difficult to control, she says it is crucial to focus on what can be managed — namely, human impact on bird habitats.