Threats
DISTURBANCE AND EGG COLLECTING
Description
There is potential for significant human disturbance at many roseate tern sites in the breeding season. Mainland sites are particularly vulnerable, but even island sites can be accessed using boats, jet skis and – in some cases and at low tide – on foot. In addition, the rarity of roseate terns in the UK and RoI makes this species a target for egg collectors, who have been recorded using boats to access remote island colonies.
Impact
All tern species nesting in the UK are known to be susceptible to disturbance. This threat can cause whole colonies to abandon their nests, and can also cause colonies to shrink and/or move in subsequent seasons.
Location
This threat affects all project sites, to varying degrees. Those in accessible ‘beach’ locations, such as Cemlyn Bay, are most at risk from human disturbance, and therefore require wardening to manage this issue. Furthermore, Coquet Island is known to be targeted by egg collectors, and particular efforts are necessary to protect this site from this threat.
Project approach
Disturbance and egg collecting will be tackled through increases in on-site staff presence, and through visitor management and education. At some sites, we plan to deploy wardens for 24 hours per day.
Description
There is potential for significant human disturbance at many roseate tern sites in the breeding season. Mainland sites are particularly vulnerable, but even island sites can be accessed using boats, jet skis and – in some cases and at low tide – on foot. In addition, the rarity of roseate terns in the UK and RoI makes this species a target for egg collectors, who have been recorded using boats to access remote island colonies.
Impact
All tern species nesting in the UK are known to be susceptible to disturbance. This threat can cause whole colonies to abandon their nests, and can also cause colonies to shrink and/or move in subsequent seasons.
Location
This threat affects all project sites, to varying degrees. Those in accessible ‘beach’ locations, such as Cemlyn Bay, are most at risk from human disturbance, and therefore require wardening to manage this issue. Furthermore, Coquet Island is known to be targeted by egg collectors, and particular efforts are necessary to protect this site from this threat.
Project approach
Disturbance and egg collecting will be tackled through increases in on-site staff presence, and through visitor management and education. At some sites, we plan to deploy wardens for 24 hours per day.
PREDATION
Description
Predation by foxes, brown rats, peregrines, badgers, American mink, otters and possibly large gull species is known to occur or have occurred at current and historic roseate tern breeding sites.
Impact
Predation of eggs and chicks is believed to affect the breeding success of roseate terns. In addition, nocturnal predation of breeding adults may be an important factor at some colonies. Predation is thought to prevent roseate terns from establishing new colonies on mainland sites, and may also cause them to desert from established sites.
Location
This threat applies to all project SPAs. Predation problems vary from site to site and year to year, and are often highly localised.
Approach
A variety of site-specific measures will be put in place to tackle predation. For example, we will prevent gulls from nesting close to roseate tern colonies; erect fencing to keep out mammalian predators; carry out targeted control of predators such as fox and mink; provide nest boxes or shelters; and underpin such measures with enhanced wardening.
Biosecurity measures to ensure that predator-free island sites retain this status will be introduced or upgraded. In addition, a predator eradication/management strategy will be drawn up for the Forth Islands SPA, where predation appears to be limiting the use of otherwise suitable habitat, together with large gulls (see below).
Description
Predation by foxes, brown rats, peregrines, badgers, American mink, otters and possibly large gull species is known to occur or have occurred at current and historic roseate tern breeding sites.
Impact
Predation of eggs and chicks is believed to affect the breeding success of roseate terns. In addition, nocturnal predation of breeding adults may be an important factor at some colonies. Predation is thought to prevent roseate terns from establishing new colonies on mainland sites, and may also cause them to desert from established sites.
Location
This threat applies to all project SPAs. Predation problems vary from site to site and year to year, and are often highly localised.
Approach
A variety of site-specific measures will be put in place to tackle predation. For example, we will prevent gulls from nesting close to roseate tern colonies; erect fencing to keep out mammalian predators; carry out targeted control of predators such as fox and mink; provide nest boxes or shelters; and underpin such measures with enhanced wardening.
Biosecurity measures to ensure that predator-free island sites retain this status will be introduced or upgraded. In addition, a predator eradication/management strategy will be drawn up for the Forth Islands SPA, where predation appears to be limiting the use of otherwise suitable habitat, together with large gulls (see below).
LOSS OF BREEDING HABITAT
Description
Roseate tern sites are vulnerable to habitat loss due to natural processes such as erosion, flooding and storms. For example, Tern Island, an important site in Wexford Harbour in RoI, was washed away by storms in the mid 1970s. Predicted climate change effects will increase the likelihood and severity of such events.
Impact
Evidence suggests that when roseate tern colony sites are lost, only some of the birds they support succeed in settling elsewhere, and that the overall population is therefore reduced. Habitat shortage is not thought to be a limiting factor at present. However, given the extremely limited range of the population in the UK and RoI, loss of habitat from just one or two key sites could potentially have a very significant effect. In the UK, the roseate tern already occupies just a fraction of its former range.
Location
All project sites.
Approach
Restoration work will be carried out at sites under immediate threat of significant habitat loss – e.g. Cemlyn Bay, the Solent and Larne Lough. In addition, we will carry out an assessment of long-term options for tern colony maintenance and establishment in the three relevant sea areas in NW Europe – i.e. the North Sea, the English Channel and the Celtic Sea. This assessment will inform the long-term recovery strategy that we plan to develop.
Description
Roseate tern sites are vulnerable to habitat loss due to natural processes such as erosion, flooding and storms. For example, Tern Island, an important site in Wexford Harbour in RoI, was washed away by storms in the mid 1970s. Predicted climate change effects will increase the likelihood and severity of such events.
Impact
Evidence suggests that when roseate tern colony sites are lost, only some of the birds they support succeed in settling elsewhere, and that the overall population is therefore reduced. Habitat shortage is not thought to be a limiting factor at present. However, given the extremely limited range of the population in the UK and RoI, loss of habitat from just one or two key sites could potentially have a very significant effect. In the UK, the roseate tern already occupies just a fraction of its former range.
Location
All project sites.
Approach
Restoration work will be carried out at sites under immediate threat of significant habitat loss – e.g. Cemlyn Bay, the Solent and Larne Lough. In addition, we will carry out an assessment of long-term options for tern colony maintenance and establishment in the three relevant sea areas in NW Europe – i.e. the North Sea, the English Channel and the Celtic Sea. This assessment will inform the long-term recovery strategy that we plan to develop.
COMPETITION FOR NESTING SPACE
Description
Breeding gulls can reduce the viability of roseate tern colonies by taking over space formerly used by the terns. In addition, other tern species may have a similar competitive impact. Roseate terns dislike breeding in the open; as a result, they usually site their nests under protective cover such as rocks, or in nestboxes when these are provided.
Impact
The impact of large gulls is thought to be one of the key factors causing the decline of roseate terns in the UK and their complete extinction at sites such as the Forth Islands. Moreover, it is an ongoing issue at the principal UK colony on Coquet Island.
There is also evidence of interspecific competition when roseate terns try to establish nest sites within colonies of arctic terns or common terns, and between late-nesting roseate terns and early-nesting common terns in other situations, especially at sites with few crevices. It is not thought that this threat is preventing the species expanding its range, but it may be an important issue within certain colonies. The provision of nest shelters and boxes has proved to be very successful at both Coquet and Rockabill.
Location
This threat applies to all project sites, to varying degrees. On Coquet Island, for example, lesser black-backed gulls and herring gulls compete for space with roseate terns, and also form an additional predation threat. Expansion of large gull populations in the Firth of Forth is believed to have limited the availability of otherwise suitable breeding habitat for terns. Gulls are believed to be a contributory factor in roseate tern decline, and to restrict space for terns more generally at most project sites.
Approach
In order to provide greater nesting opportunities for roseate terns, nest shelters and nest boxes will be placed within selected colonies prior to occupation each year. Management of gull colonies will also take place to limit the size and/or control the location of these colonies. Additional on-site presence is key to this, particularly early in the nesting season when gulls are establishing territories. In the Firth of Forth, we will trial the use of tern rafts to create additional space for nesting terns. These rafts will be put in place after gulls have already settled on their territories.
Description
Breeding gulls can reduce the viability of roseate tern colonies by taking over space formerly used by the terns. In addition, other tern species may have a similar competitive impact. Roseate terns dislike breeding in the open; as a result, they usually site their nests under protective cover such as rocks, or in nestboxes when these are provided.
Impact
The impact of large gulls is thought to be one of the key factors causing the decline of roseate terns in the UK and their complete extinction at sites such as the Forth Islands. Moreover, it is an ongoing issue at the principal UK colony on Coquet Island.
There is also evidence of interspecific competition when roseate terns try to establish nest sites within colonies of arctic terns or common terns, and between late-nesting roseate terns and early-nesting common terns in other situations, especially at sites with few crevices. It is not thought that this threat is preventing the species expanding its range, but it may be an important issue within certain colonies. The provision of nest shelters and boxes has proved to be very successful at both Coquet and Rockabill.
Location
This threat applies to all project sites, to varying degrees. On Coquet Island, for example, lesser black-backed gulls and herring gulls compete for space with roseate terns, and also form an additional predation threat. Expansion of large gull populations in the Firth of Forth is believed to have limited the availability of otherwise suitable breeding habitat for terns. Gulls are believed to be a contributory factor in roseate tern decline, and to restrict space for terns more generally at most project sites.
Approach
In order to provide greater nesting opportunities for roseate terns, nest shelters and nest boxes will be placed within selected colonies prior to occupation each year. Management of gull colonies will also take place to limit the size and/or control the location of these colonies. Additional on-site presence is key to this, particularly early in the nesting season when gulls are establishing territories. In the Firth of Forth, we will trial the use of tern rafts to create additional space for nesting terns. These rafts will be put in place after gulls have already settled on their territories.
LACK OF FOOD
Description
Like many seabirds, roseate terns feed mainly on sand-eels. There is increasing evidence that climate change is affecting marine ecosystems, and that these impacts are reducing the abundance and/or availability of sand-eels and other prey species.
Impact
Low abundance or availability of sand-eels and other prey has the potential to lead to sustained poor productivity at current colonies and ultimately to the desertion of these colonies. We should note, however, that food availability is certainly not the only factor affecting roseate terns in the project area. The other, site-based issues described in this section are definitely major problems, and the actions we plan to take to address them will definitely bring major benefits to this species.
Location
All project sites.
Approach
We will carry out demographic studies to improve our understanding of the importance of changes in productivity at UK/RoI colonies in driving population and distribution trends in roseate terns. We will also seek to increase our understanding of how we might affect the abundance/availability of sand-eels in order to mitigate against any negative effects of climate change within key areas. We will track breeding roseate terns at Rockabill and Coquet to identify important feeding areas during the breeding season. Finally, we will advocate for the protection and management of sand-eels around the British Isles, particularly in key areas for breeding terns.
Description
Like many seabirds, roseate terns feed mainly on sand-eels. There is increasing evidence that climate change is affecting marine ecosystems, and that these impacts are reducing the abundance and/or availability of sand-eels and other prey species.
Impact
Low abundance or availability of sand-eels and other prey has the potential to lead to sustained poor productivity at current colonies and ultimately to the desertion of these colonies. We should note, however, that food availability is certainly not the only factor affecting roseate terns in the project area. The other, site-based issues described in this section are definitely major problems, and the actions we plan to take to address them will definitely bring major benefits to this species.
Location
All project sites.
Approach
We will carry out demographic studies to improve our understanding of the importance of changes in productivity at UK/RoI colonies in driving population and distribution trends in roseate terns. We will also seek to increase our understanding of how we might affect the abundance/availability of sand-eels in order to mitigate against any negative effects of climate change within key areas. We will track breeding roseate terns at Rockabill and Coquet to identify important feeding areas during the breeding season. Finally, we will advocate for the protection and management of sand-eels around the British Isles, particularly in key areas for breeding terns.
CATCHING IN AFRICA
Description
The catching of terns for sport or food in West Africa was believed to be a significant issue in the 1990s. It is no longer thought to be so important, but good data are lacking. Various methods of catching are used, including snaring, trapping and ‘fishing’ for terns using baited hooks on nylon lines.
Impact
It has been suggested that catching in West Africa may be the main recorded cause of death of roseate terns outside the breeding season. Surveys in the early 1990s found that six species of tern were affected by this threat, with roseates appearing to be particularly susceptible to snaring. Monitoring of tern catching at important coastal sites carried out in 2006 revealed that this activity was still widespread in most of the communities surveyed. More recent observations indicate that it may continue at a low level, despite legal protection of the species and key sites involved.
Location
Catching is known to occur throughout coastal West Africa. However, ringing returns suggest that the major problem for roseate terns lies in Ghana, where most of the inshore-wintering individuals of this species are found. This issue is likely to affect birds at all UK/RoI project sites.
Approach
In collaboration with local NGOs, we will assess the current scale and impact of tern catching by gathering up-to-date information on this threat. This information will allow us to develop proposals to reduce the incidence of tern catching, as necessary, through education and advocacy.
The demographic study we plan to undertake will also reveal the relative importance of issues operating on the breeding grounds and wintering grounds – and therefore the urgency with which we need to address any issues in West Africa.
Description
The catching of terns for sport or food in West Africa was believed to be a significant issue in the 1990s. It is no longer thought to be so important, but good data are lacking. Various methods of catching are used, including snaring, trapping and ‘fishing’ for terns using baited hooks on nylon lines.
Impact
It has been suggested that catching in West Africa may be the main recorded cause of death of roseate terns outside the breeding season. Surveys in the early 1990s found that six species of tern were affected by this threat, with roseates appearing to be particularly susceptible to snaring. Monitoring of tern catching at important coastal sites carried out in 2006 revealed that this activity was still widespread in most of the communities surveyed. More recent observations indicate that it may continue at a low level, despite legal protection of the species and key sites involved.
Location
Catching is known to occur throughout coastal West Africa. However, ringing returns suggest that the major problem for roseate terns lies in Ghana, where most of the inshore-wintering individuals of this species are found. This issue is likely to affect birds at all UK/RoI project sites.
Approach
In collaboration with local NGOs, we will assess the current scale and impact of tern catching by gathering up-to-date information on this threat. This information will allow us to develop proposals to reduce the incidence of tern catching, as necessary, through education and advocacy.
The demographic study we plan to undertake will also reveal the relative importance of issues operating on the breeding grounds and wintering grounds – and therefore the urgency with which we need to address any issues in West Africa.
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