Seabirds

In 2017, the SAMBR synthesized data about biodiversity in Arctic marine ecosystems around the circumpolar Arctic. SAMBR highlighted observed changes and relevant monitoring gaps using data compiled through 2015. In 2021 an update was provided on the status of seabirds in circumpolar Arctic using data from 2016–2019. Most changes reflect access to improved population estimates, orimproved data for monitoring trends,independent of recognized trends inpopulation size.

What is happening and why does it matter?

• Although seabird trends are variable, many species have declined within the Atlantic Arctic, in colonies in Norway, Iceland, Greenland, and the Faroe Islands.
• The sea-ice-associated ivory gull has declined in the Arctic Archipelago and Atlantic Arctic by an estimated 80-90% over the past 20 years. In Russia, ivory gull distribution has also shrunk, which correlates with the summer ice edge moving northward.
• Some seabird species have adapted their feeding behaviours because of shifts in their food supply due to climate change and reduced ice-cover—in some cases travelling farther for food or foraging on less nutritious species. The consequences vary, but have resulted in lower breeding success for some species, including black guillemots.
• Reduced ice cover has led to increased polar bear predation on ground-nesting common eiders and cliff-nesting murres, potentially leading to local population declines.
• More southern seabird species have been more commonly reported in Arctic regions, for example, albatrosses in the Bering and Chukchi Seas and ancient murrelets in the Pacific Arctic, which are thought to follow northward-moving prey species and/or currents. There is also evidence of individuals moving between Atlantic and Pacific Arctic regions.
• In some areas, such as the Atlantic Arctic, FEC species, e.g. Black-legged kittiwakes, common and thick-billed murre populations are decreasing while in other areas such as the Pacific-Arctic, species are increasing.

Why are seabirds important?

• Seabirds link marine, coastal and terrestrial ecosystems inside and outside the Arctic because they nest on land but forage and moult at sea, and, thus, they are important components of Arctic ecosystems
• Seabirds provide valuable ecosystem services to humans, notably for food, clothing, tourism and as nutrient recyclers where they help break down organic and inorganic materials to replenish minerals and nutrients in the ecosystem.

Polar bear raids murre cliff for food in Russia. Photo: Jenny E. Ross/Naturepl.com Inuit hunter with eider. Photo: Grant Gilchrist

What should you know about the monitoring data?

• Seabird population trends are relatively well known, although not for all species.
• Some of the most widely monitored species groups in circumpolar regions include common and thick-billed murres (diving piscivores), black-legged kittiwakes (surface piscivores), and common eider (benthivores); these species groups make it possible to conduct comparative studies across circumpolar regions.
• Demographic data is lacking for most species and colony sites.

Community-based research team investigates common eider nesting colony. Photo: Samuel Iverson Kittiwakes on ice. Photo: Achim Baque/shutterstock.com

What are the most important drivers? 

• Important drivers for seabird population changes include climate change, reduced sea-ice, changes in sea temperatures, changes in food webs and species interactions, disease outbreaks, hunting, fisheries bycatch, and pollution (contaminants and oil pollution).

Murre cliff. Photo: Don Landwehrle/shutterstock.com Least and crested auklets. Photo: Ian Jones, Memorial University

Where is monitoring happening?

• Most circumpolar nations have at least one source of long-term seabird monitoring datasets, but efforts vary across regions. Colony-based monitoring occurs regularly or annually, although most sites do not have fully implemented plans, with diet and survival data often lacking. At-sea surveys are more opportunistic, and often occur in conjunction with resource exploration and extraction.
• Monitoring of seabird FECs is conducted in the Atlantic Arctic, Baffin Bay-Davis Strait, Hudson Complex, Arctic Archipelago, Beaufort and Pacific Arctic AMAs. The situation for the Kara-Laptev AMA is unknown.

Boundaries of the 22 ecoregions (grey lines) as defined in the CSMP (Irons et al. 2015) and the Arctic Marine Areas (colored polygons with names in legend). Filled circles show locations of seabird colony sites recommended for monitoring (‘key sites’). The current level of monitoring plan implementation (see 2.6.2 for criteria) are green = fully implemented, amber = partially implemented, red = not implemented. The CSMP provides implementation maps for each forage guild.

The number of key sites (monitored colonies) for seabirds (in 22 CSMP ecoregions) by country (a total of 125 sites). Sites are categorized as having fully, partially, or not met the CSMP criteria for parameters monitored (see 2.6.2). Data were from Appendix 3 of the CSMP (Irons et al. 2015); the degree of implementation may have changed at some sites since this summary was compiled. 

Advice for monitoring 2017: seabirds

• Develop methods for assessing diet to increase our understanding of changes in the ecosystem and how they affect seabird populations.
• When selecting sites for new monitoring, consider proximity to hotspots for marine activities, access to the sea, and inclusion of plankton monitoring.
• Expand colony-based monitoring and strive to include a more complete array of parameters, in particular, diet and measures of survival.
• Consider a higher frequency of monitoring as current levels make it difficult to identify mechanisms or causes of change in populations.
• Conduct targeted surveys and individual tracking studies of seabird interactions at sea to improve our understanding of seabird interactions at sea, where seabirds spend most of their time.
• Continue to conduct at sea surveys on an opportunistic basis.

Holding an eider. Photo: Grant Gilchrist Little auk. Photo: Bjorn Stefanson/shutterstock.com