The roseate tern (Sterna dougallii) is a seabird found across temperate and tropical oceans worldwide. This elegant tern is known for its long, forked tail and its namesake pinkish breast feathers during breeding season. The roseate tern population declined significantly in the late 19th and early 20th centuries due to hunting for feathers for the millinery trade. While some populations have rebounded, the roseate tern is still considered threatened globally and is protected under various conservation laws and treaties.
Population Status and Conservation Status
The global population of roseate terns is estimated to be 87,000-110,000 mature individuals. The species is classified as Near Threatened on the IUCN Red List. Some regional populations are endangered, like the northeastern U.S. and Canadian Atlantic coast population which is listed as Endangered under the U.S. Endangered Species Act.
Key threats to the roseate tern include:
- Habitat loss from coastal development
- Disturbance of nesting colonies
- Competition and predation from gulls
- Oil spills
- Entanglement in fishing gear
Conservation efforts aim to protect key breeding and feeding areas for the remaining roseate tern populations.
Breeding Habitat Protection
Roseate terns nest colonially on coastal islands, beaches, and salt marshes. Protecting these sensitive breeding habitats is crucial for the species’ survival. Some key conservation measures include:
Designation of Protected Areas
Many tern nesting sites have been designated as protected areas at various levels, including:
- State and national wildlife refuges
- National and state parks
- National seashores
These protected area designations limit human disturbance and development at roseate tern colonies. For example, Cape Cod National Seashore in Massachusetts protects important nesting habitat for the northeast U.S. population.
Restricted Access to Colonies
Access to tern nesting beaches is restricted during breeding season. Symbolic fencing, signage, and patrolled buffer zones around colonies help reduce disturbance. For example, Bird Island in Marion, Massachusetts is closed annually from April to August to allow terns to nest safely.
Habitat Creation and Enhancement
Creating artificial nesting habitats has helped establish new roseate tern colonies in some areas. Habitat enhancement like clearing vegetation, deploying decoys, and using audio playback has also boosted nesting at some sites. For instance,a abandoned barge was converted into a man-made tern colony site in Long Island Sound.
Predator Control
Increased gull populations pose a major threat to roseate terns through nest competition and chick predation. Nonlethal predator control such as egg oiling in gull nests, gull nest removal, and wire enclosures around tern nests help reduce this pressure.
Foraging Area Protection
Marine Protected Areas
Establishing marine protected areas around important tern feeding grounds can reduce disturbance and bycatch. For example, the Skerries Islands off northwest Ireland were designated a Special Protection Area due to their use by feeding roseate terns.
Fishing Gear Regulations
Regulations on fishing methods and gear can help reduce tern bycatch and entanglement. For instance, seasonal nighttime fishing bans around tern colonies in the Irish Sea gillnet fishery have reduced tern bycatch mortality.
Pollution Control
Oil spills are a major threat to foraging terns. Shipping management and preparedness measures help reduce this risk. The roseate tern is also vulnerable to bioaccumulation of toxins like mercury. Tighter emissions regulations help limit exposure.
Direct Population Management
In some cases, targeted management of roseate tern populations is needed to aid recovery. This can include:
Nest Translocations
Moving tern eggs or chicks from dense, threatened colonies to areas with better habitat can boost productivity and survival. For example, nests are translocated from Great Gull Island in New York to nearby artificial sites.
Captive Rearing
Rearing roseate tern chicks in captivity and releasing fledged juveniles has helped supplement wild populations. For instance, the U.S. Fish and Wildlife Service has operated a captive rearing program for roseate terns in the northeast.
Predator Control
Lethal removal of certain egg and chick predators like owls, minks, and rats has been used in some cases to protect colonies. Live trapping and relocation of problem predators is preferred when feasible.
International Cooperation
As the roseate tern migrates across oceans, international cooperation is crucial for effective conservation. Key agreements include:
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA)
This treaty under the Convention on Migratory Species guides coordinated management of roseate terns and other migratory waterbirds that use sites across Africa, Europe, the Middle East, Central Asia, Greenland, and Canada.
Trilateral Action Plan for the Roseate Tern
This agreement between the Canadian Wildlife Service, U.S. Fish and Wildlife Service, and U.K. Joint Nature Conservation Council aims to recover the declining northwest Atlantic population of the roseate tern through synchronized conservation action across the species’ Atlantic range.
Partners in Flight
The roseate tern is designated as a Priority I species under this cooperative bird conservation initiative between federal agencies, NGOs, academia, and industry in the U.S. and Canada. The program facilitates range-wide monitoring, research, and conservation planning for landbirds and seabirds like the roseate tern.
Monitoring and Research
Ongoing monitoring and research help track roseate tern populations, refine conservation measures, and identify new threats. This includes:
Breeding Surveys
Regular breeding colony surveys monitor roseate tern abundance, productivity, survival, and habitat use at nesting sites across the species’ range. For example, the Northeast Colony Assessment Program monitors all seabird colonies from North Carolina to the Bay of Fundy.
Banding Studies
Banding roseate terns with unique leg bands allows tracking of migratory paths, lifespan, survival rates, and other population data when birds are resighted or recaptured. There are several long-term banding programs ongoing for roseate terns.
Foraging Studies
Research on diet, foraging behavior, habitat use, and at-sea distributions helps identify important marine habitats for conservation. Techniques include GPS tags, radio telemetry, stable isotope analysis, and pellet analysis.
Genetic Studies
Genetic analysis elucidates population structure, diversity, connectivity, and demographics to support management units. For example, genetic evidence helped identify unique subspecies of roseate tern in the Atlantic and Indian Ocean.
Challenges
While considerable progress has been made in roseate tern conservation, significant challenges remain:
- Climate change impacts like sea level rise threaten nesting habitat.
- Increased storms and flooding jeopardize breeding success.
- Coastal development pressures continue in key areas.
- Gull competition is still problematic at many colonies.
- Fisheries bycatch remains a threat, especially on wintering grounds.
- Limited funding and resources hamper implementation of conservation plans.
Addressing these challenges requires continued coordinated efforts across the roseate tern’s range between governments, scientists, conservation groups, industry, and local stakeholders.
Conclusion
The roseate tern has been protected through a mix of habitat protection, targeted management, policy regulations, and scientific research. However, integrated, collaborative action across the species’ migratory range is still needed to ensure the long-term viability of remaining roseate tern populations. Ongoing monitoring, adaptive management, and commitment to conservation goals will be key to the future of this iconic seabird. With appropriate protection, the graceful roseate tern can once again flourish along shores around the globe.