The red-throated loon (Gavia stellata) is a migratory aquatic bird found in the northern hemisphere. It breeds primarily in Arctic regions and winters at sea, diving to catch fish. The red-throated loon has experienced population declines in recent decades, leading to conservation concern. Understanding the current status of this species can inform protective measures. This article reviews the red-throated loon’s population trends, geographic range, habitat requirements, and major threats. Key questions addressed include:
- What is the population size and trend for the red-throated loon?
- What is the geographic breeding and wintering range of this species?
- What habitats does the red-throated loon rely on?
- What factors threaten the red-throated loon population?
- What conservation efforts currently support this species?
Population Size and Trends
The red-throated loon has an extensive breeding range across northern North America, Europe, and Asia. However, its global population size is estimated at only 600,000-1,200,000 mature individuals. In North America, breeding bird survey data from 1966-2015 indicate a population decline of 2.2% annually, equating to an overall decline of 68% during this period. The table below summarizes population size and trend estimates for the red-throated loon by region:
Region | Population Estimate | Population Trend |
---|---|---|
North America | 200,000-500,000 | Declining at 2.2% annually |
Europe | 110,000-220,000 | Declining but varies by country |
Russia | 250,000-1,000,000 | Likely declining but uncertain |
These data indicate substantial population declines for the red-throated loon in North America, with uncertain but likely declines in Eurasia as well. Conservation groups have designated the red-throated loon as a species of moderate conservation concern. Ongoing monitoring is needed to track future trends, especially in Russia, which hosts a large portion of the global population.
Geographic Distribution
The breeding range of the red-throated loon extends across northern regions of North America, Europe, and Asia. In North America, it breeds from Alaska across Canada to Greenland and also winters along both coasts. In Eurasia, its breeding range stretches from Scandinavia and Britain eastward through Russia to the Pacific coast. It winters as far south as the Mediterranean, Black Sea, and China coast. The map below depicts the circumpolar distribution of the red-throated loon throughout its breeding and wintering range:
Key breeding areas in North America include Alaska, central Canadian Arctic islands, Hudson Bay, and Labrador. In winter, important areas include the Atlantic coast from Newfoundland to North Carolina and the Pacific coast from southern Alaska to Baja California.
The extensive migratory movements between Arctic breeding areas and more southerly wintering areas along both coasts and offshore makes the red-throated loon vulnerable to threats across its migratory flyways. Conservation must therefore consider protection of key sites throughout its full geographic range.
Habitat Requirements
The red-throated loon depends on specific aquatic habitats throughout its life cycle. For breeding, it requires open lakes, ponds, rivers, and coastal lagoons with abundant small fish populations. Nesting occurs very close to shorelines, on small islands or shoals. Crucial features are sparse short vegetation for nesting and clear waters allowing for visual foraging on fish.
On coastal wintering areas, the red-throated loon inhabits nearshore waters typically within 2 km of shore. It shows particular preference for shallow bays and inlets with calm waters. It avoids areas with intensive boat traffic or human disturbance.
On migration, this species relies on coastal stopover sites with productive feeding areas. It primarily migrates within 50 km of shorelines. Wetlands, estuaries, large lakes and rivers also provide migratory habitat.
Loss or alteration of breeding ponds, reduced water clarity, shoreline development, and human disturbance all pose threats to red-throated loon habitat. Maintaining high quality coastal and inland aquatic ecosystems is key for this species’ survival.
Major Threats
Several factors have contributed to the red-throated loon’s population decline and continue to pose threats:
- Oil spills – Oil spills on coastal wintering areas can kill significant numbers of loons. Spills also impact fish prey populations.
- Fishing bycatch – Accidental drowning in fishing nets is a known source of mortality for wintering and migrating red-throated loons.
- Habitat loss – Human disturbance, wetland drainage, and shoreline development have reduced suitable breeding and wintering habitats.
- Contaminants – Buildup of heavy metals like mercury and ingestion of lead fishing tackle can accumulate in tissues and reduce loon survival and reproduction.
- Climate change – Changing water levels, precipitation, and temperatures may alter breeding and wintering habitats. Migratory timing may become mismatched with food sources.
Conservation efforts to date have included oil spill response planning, outreach to reduce fishing bycatch, and protection of key breeding lakes and coastal habitats. Addressing all threats across the full annual cycle of the red-throated loon is needed to allow for population recovery.
Conservation Status and Efforts
The red-throated loon is protected under the Migratory Bird Treaty Act in North America, prohibiting harm or harassment. It is listed as a species of Least Concern globally by the IUCN Red List but has been identified as a species of moderate conservation concern by Partners in Flight and a U.S. National Bird of Conservation Concern.
Various measures have been implemented or proposed to support red-throated loon populations:
- Designation of protected breeding areas in Alaska, Canada, and Russia
- Restrictions on development along sensitive coastal habitats
- Requirements for oil spill response plans to protect wintering loons
- Outreach programs to fishermen to minimize bycatch
- Monitoring and research on migration routes and wintering sites
- Banning of lead fishing tackle in some areas
Continued habitat protection, education on reducing disturbance, and monitoring of wintering and migrating populations will be important conservation approaches for the red-throated loon. Addressing threats across political boundaries is needed, given this species’ expansive range across the northern latitudes. With appropriate conservation action, the red-throated loon can be restored to healthier global population levels.
Conclusion
In conclusion, the red-throated loon has experienced concerning population declines and faces ongoing threats to its breeding, migratory, and wintering habitats. Conservation groups have designated it as a species of moderate concern, and it receives legal protections in North America. Measures to date have included habitat protection and outreach to reduce bycatch and contamination. Further efforts are needed to monitor wintering and migrating populations and protect key coastal and inland wetland habitats across the full geographic range of the red-throated loon. Addressing multiple threats across its life cycle and range will be key to stabilizing and recovering populations of this iconic northern diving bird. Continued conservation action and cooperation can help ensure the long-term survival of the red-throated loon.