Background and context
- Natural England
- Hampshire County Council
- LPAs
- Chichester District Council
- New Forest District Council
- East Hampshire District Council
- New Forest National Park Council
- Portsmouth City Council
- Eastleigh Borough Council
- South Downs National Park
- Fareham Borough Council
- Southampton City Council
- Gosport Borough Council
- Test Valley Borough Council
- Havant Borough Council
- Winchester City Council
- Isle of Wight Council
- Conservation Organisations
The Solent coastline and its associated intertidal habitats comprise internationally designated sites due to their importance for overwintering and breeding waterbirds. The Solent itself is a tidal strait separating the mainland of Hampshire from the Isle of Wight, including coastal sections of Hampshire, West Sussex, the Isle of Wight, and the cities of Portsmouth and Southampton.
The following designated sites represent some of the most ecologically sensitive coastal habitats in southern England, providing critical feeding, roosting, and breeding areas. These designations are underpinned by Ramsar designations, a large number of Sites of Special Scientific Interest (SSSI) and Marine Conservation Zones (MCZ):
Solent and Southampton Water SPA encompasses the eastern Solent and Southampton Water, including intertidal flats, saltmarsh, and estuarine habitats, supporting internationally significant numbers of Dark-bellied Brent Goose, Shelduck, and other migratory waterbirds.
Chichester and Langstone Harbours SPA comprises intertidal mudflats, saltmarshes, and creeks along the Hampshire coast, supporting internationally important numbers of overwintering and breeding bird species such as Dark-bellied Brent Goose, Ringed Plover, Dunlin, Redshank, and Avocet.
Portsmouth Harbour SPA is a largely enclosed tidal harbour with extensive mudflats and saltmarshes, providing essential foraging and roosting habitat for internationally important numbers of birds including Redshank, Black-tailed Godwit, and Dunlin during the non-breeding season.
Ecological driver and scheme details
Bird Aware Solent is a strategy to provide mitigation to address the impact of increased recreational pressure upon the SPAs from new residential development. It is a partnership of local councils and conservation bodies, funded by fees paid by developers of new housing (Bird Aware Solent, 2024). The Solent Recreation Mitigation Strategy (Bird Aware Solent, 2017) was first developed to address the risk that increased recreational use of the Solent coast could disturb internationally important bird populations, particularly over-wintering waders and wildfowl. Research indicated that planned housing growth around the Solent would lead to a measurable increase in recreational visits to the coast, potentially threatening the SPAs qualifying features. Natural England advised that this growth would give rise to a likely significant effect “in combination”, meaning there was a real risk that residential allocations and applications would be unable to demonstrate no adverse effect on the integrity of the SPAs under the Habitats Regulations without coordinated avoidance measures. Ecologically, a strategic approach was more appropriate than case-by-case mitigation because the impact itself arises cumulatively from dispersed development across a shared visitor catchment.
The strategy focuses on influencing visitor behaviour and choices. Its primary aim is to reduce human disturbance to birds by promoting responsible recreation, providing educational materials, and creating opportunities for alternative recreational spaces. Contributions from developers are calculated per dwelling and pooled to fund ranger programmes, educational work, site improvements, and ongoing monitoring. A key principle of the strategy is that disturbance is best addressed through influencing behaviour rather than restricting access. As such, the approach prioritises positive engagement and awareness-raising over enforcement, seeking to encourage responsible recreation through education, social norms and voluntary behaviour change.
A central component of the strategy is the ranger programme, designed to engage directly with visitors on the coast. The strategy includes extensive communications and educational initiatives, targeting schools, community groups, and the general public through signage, media campaigns, and outreach activities.
The strategy also outlines practical measures to manage visitor impact on sensitive sites. These include site-specific interventions such as paths, signage, low barriers, and habitat management to separate people from feeding or roosting areas.
Additionally, alongside the strategy, the Partnership promotes Wildlife Aware guides (previously called Codes of Conduct), site-specific visitor management measures and Suitable Alternative Natural Greenspaces (SANGs) which provide recreational options away from the coast, helping to reduce pressure on SPA habitats. These measures are designed to be complementary, forming a layered mitigation package that addresses both direct disturbance and the broader patterns of coastal use.
The Solent coast is a popular destination for a wide range of recreational activities, whilst also supporting a large waterbird assemblage including 10% of the global brent geese population (Bird Aware Solent, 2017).
The Solent Disturbance Mitigation Project (SDMP) collected extensive research on recreational activities, and their effect on wintering birds, on the Solent Coast. The research showed that walking is the most common activity along the Solent coast, with walking, dog walking, jogging and cycling accounting for approximately 91% of all recreational use. Dog walking in particular was identified as a significant source of disturbance, with dogs off lead responsible for around 47% of recorded “major
flights” (birds flying more than 50 metres in response to disturbance). Although less frequent (around 9% of recorded activity), other activities such as watersports (including sailing, kayaking and windsurfing), surfing, horse riding and rowing were also recognised as potentially causing substantial disturbance on each occurrence.
The strategy addresses the recreational impact of new development upon bird disturbance across a defined Zone of Influence (ZoI), the area over which cumulative recreational impacts are likely, as informed by visitor survey data. The disturbance of birds when feeding and resting can lead to population declines, and the disturbance of breeding birds can lead to a decline in breeding success.
The strategy does not address the impact of existing recreational pressures, which is the role of the separate Solent European Marine Sites (SEMS) initiative, other impacts such as noise, water quality, nutrient neutrality or construction impacts.
The strategy draws directly on research and monitoring data collected over more than a decade to justify the identified impact pathways and the need for mitigation actions.
The Solent local authorities, working in partnership through the Solent European Marine Sites (SEMS) framework and coordinated by the Solent Forum, commissioned and assembled a substantial body of evidence to understand and address recreational impacts on internationally designated bird sites. This work was prompted by concerns about increasing housing growth around the Solent, evidence of disturbance to overwintering birds, and the unfavourable condition of parts of the underpinning SSSIs. Natural England advised that planned development could give rise to likely significant effects on the integrity of the Solent SPAs under the Habitats Regulations. The Partnership therefore undertook the SDMP to establish a robust evidence base to inform an avoidance and mitigation strategy.
Through the SDMP, the Partnership led a three-phase programme of research.
Phase I collated and reviewed existing information on housing, human activities and birds around the Solent, and reviewed the potential impact of disturbance on birds. It also set out a methodology for the following phases (Stillman and others, 2009).
Phase II involved a range of primary research including data collection regarding visitor rates (from current and future housing), visitor activities in the shore and intertidal habitats, and the effects of recreation on different bird species (Stillman and others, 2012). This included visitor surveys (Fearnley and others, 2010), household surveys (Fearnley and others, 2011) and modelling of impacts. Dog walking was the most frequently observed activity, with walking, cycling and jogging being other common recreational activities.
Phase III set out the proposed Avoidance and Mitigation Strategy including identification of potential mitigation measures that could be adopted (Liley and Tyldesley, 2013). This included possible options for a zonal approach to gathering developer contributions, based on the visitor draw evidence.
An independent five-year review was undertaken in 2023 (Liley et al, 2023) which resulted in an update to the Strategy (2024) to incorporate insights and experience gained from delivery of the strategy and take into consideration monitoring outputs. One such output was the study on breeding SPA birds undertaken by Liley, Saunders and Rush (2024), which provided new evidence leading to the expansion of the strategy’s scope to cover breeding birds.
The strategy has been prepared to mitigate approximately 147,500 new dwellings over the period from 2024 and 2050 (5,674 new dwellings per annum) and within a 5.6km ZoI. This estimate is derived from work undertaken with each of the LPAs within the Bird Aware Solent ZoI (Bird Aware Solent 2024). The ZoI was calculated at 5.6km of the boundaries of the SPAs, the zone from which 75% of coastal visits originate. Within this area, mitigation is required from all dwellings built (Liley and Tyldesley, 2013).
The strategy is both strategic and cross-boundary, providing a consistent approach across 14 LPAs (Bird Aware 2024) to ensure that the requirements of the Conservation of Habitats and Species Regulations 2017 (the Habitats Regulations) are met with regard to the in-combination effects of increased recreational pressure on the Solent SPAs (Bird Aware Solent 2017). The strategy enables developers to contribute to a shared scheme rather than providing their own mitigation, delivering coordinated, effective mitigation and clarity for authorities and developers.
While the strategy operates at a strategic scale, its implementation is often sitespecific, with mitigation measures tailored to the characteristics, sensitivities and patterns of use at individual locations along the coastline to ensure that interventions are proportionate and effective at the local level.
The Strategy applies to every net additional dwelling built within 5.6km of the Solent’s SPAs, with recreation mitigation measures funded by developer contributions that are calculated according to the numbers of bedrooms per dwelling. Some developments may require additional mitigation due to their size or proximity to an SPA. In this context, “dwelling” includes all net new residential units, including those created through subdivision of existing properties, second homes, holiday accommodation, self-contained student accommodation, and conversions permitted under the General Permitted Development Order (such as office-to-residential changes, including houses and flats). It also includes permanent accommodation for Gypsies and Travellers, while temporary or transit pitches are considered on a caseby-case basis by the local planning authority in consultation with Natural England.
Governance, structure and working arrangements
Bird Aware Solent is a partnership of 14 LPAs, a County Council, Natural England, and three conservation organisations, with regular reporting and five-year strategic reviews to ensure that the mitigation measures remain effective and responsive to changing patterns of coastal recreation (Bird Aware Solent 2024). Governance is provided by the Partnership for South Hampshire (PfSH). Bird Aware Solent regularly reports to PfSH, as well as having its own Project Board to oversee the strategic direction and day-to-day delivery of the project.
The Bird Aware Solent ZoI extends over multiple LPA areas and provides a strategic approach which allows a housebuilder to pay a developer contribution to cover the costs of providing mitigation instead of providing bespoke mitigation themselves. It is however noted that developers can still choose to provide their own mitigation. This approach provides clarity and certainty for both developers and LPAs.
The requirements for mitigation are secured in local plan policy wording. An example is the South Downs National Park Authority Local Plan which was adopted in July 2019 (South Downs National Park Authority, 2019). Mitigation requirements for the Solent coast SPAs are secured through Policy SD10 (part 7).
7. Development proposals resulting in a net increase in residential units, within the
Solent Coast SPAs (Chichester & Langstone Harbours SPA, Portsmouth Harbour
SPA and Solent & Southampton Water SPA) zone of influence shown on the Policies Map, defined as 5.6km from the boundary of these sites, may be permitted where ‘in combination’ effects of recreation on the Solent Coastal SPAs are satisfactorily mitigated through the provision of an appropriate financial contribution to the delivery of strategic mitigation. In the absence of a financial contribution toward mitigation, an appropriate assessment may be required to demonstrate that any ‘in combination’ impacts which are likely to have a significant adverse effect can be avoided or can be satisfactorily mitigated through a developer-provided package of measures.
The strategy includes the provision of in-perpetuity mitigation, to be delivered until 2130 (calculated on an 80-year basis from 2050).
Funding mechanisms
Funding for the strategy is derived from developer contributions, collected from new residential development within the 5.6km ZoI. Contributions are calculated per dwelling, weighted to take into account bedroom numbers for planned housing. Developer contributions are derived by dividing the total annual project costs between the expected annual housing levels, and are revised annually in line with the Retail Price Index (RPI) and rounded upwards to the nearest pound. Development includes sub-division of existing dwellings, holiday accommodation, changes of use, and accommodation for Gypsies and Travellers.
Since April 2025, there have been 2 charging schedules, reflecting the different costs for those developments needing to mitigate for overwintering and breeding birds, and those only needing to mitigate for overwintering birds (Bird Aware Solent, 2024).
Under the PfSH, involved LPAs have adopted a consistent tariff-based contribution approach so that each authority applies the same mitigation calculation method. Developer contributions are secured via planning obligations under Section 106 of the Town and Country Planning Act 1990, or equivalent legal mechanisms such as unilateral undertakings. The contributions are then pooled and transferred to the PfSH responsible for delivering mitigation measures (Bird Aware Solent, 2017).
Communication and engagement
Communication forms a major element of the strategy, aiming to reduce recreational disturbance to protected bird populations by influencing visitor behaviour rather than restricting access. The strategy targets a range of audiences, including coastal visitors, dog walkers, recreational clubs, local residents within the 5.6 km ZoI, schools, and volunteers, focusing on those whose activities have the greatest potential to disturb birds. Its objectives are to educate visitors about the sensitivity of SPA habitats, promote responsible recreation, and guide recreational activity toward less sensitive areas or alternative greenspaces (Bird Aware 2017, Bird Aware, 2024).
Communications are delivered through multiple channels. Rangers engage directly with visitors at peak times, signage, printed materials, and online resources reinforce key messages, and targeted campaigns promote specific behaviours like keeping dogs on leads or alongside in sensitive areas through the ‘Coast and Country Canines’ initiative (Bird Aware, 2017).
Messaging is deliberately framed in a positive and accessible way, focusing on encouraging responsible behaviour rather than discouraging access. Campaigns are tailored to specific user groups, such as dog walkers and watersports users, recognising that different activities create different disturbance pathways. Rangers play a key role in both delivering and informing communications, providing feedback from on-the-ground engagement to refine messaging and ensure it remains relevant and effective.
Monitoring
Effectiveness of the strategy’s mitigation measures is monitored through visitor surveys, ranger observations, and data on engagement with educational initiatives and alternative sites. This evidence informs ongoing adaptation of the strategy, ensuring that communications remain effective and focused on behaviours that reduce disturbance.
Monitoring is not solely used for reporting purposes, playing an active role in shaping delivery on the ground. Evidence from monitoring is used to target ranger effort, refine site-specific interventions, and identify where measures are effective or where displacement of recreational pressure may be occurring. This enables a genuinely adaptive approach, where mitigation is iteratively adjusted in response to observed visitor behaviour and site conditions.
The Partnership commissions periodic independent reviews of the strategy, typically every five years (Liley et al., 2023). The Partnership publishes regular monitoring reports summarising data on visitor numbers, mitigation activity, and site impacts. These reports are considered by the partnership board and feed into governance and planning decisions for the following year, ensuring that lessons from monitoring inform ongoing delivery.
Links to multifunctional benefits
The Bird Aware Solent strategy explicitly notes that it delivers multiple benefits beyond reducing recreational disturbance to SPA birds. Measures such as alternative greenspaces, ranger engagement, and educational programmes provide enhanced public access, recreational opportunities, and community engagement, while habitat management and buffer zones support broader biodiversity and ecosystem services (Bird Aware, 2017, Bird Aware, 2024). Its strategic, crossboundary design also streamlines mitigation delivery for developers and local authorities, ensuring consistent, legally compliant, and multifunctional conservation outcomes.
Good practice highlights
The scheme is delivered through a formalised cross-boundary partnership of 14 local planning authorities and the broader County Council working alongside Natural England and other stakeholders. Governance is provided through the Bird Aware
Solent Partnership Board, which oversees implementation, funding and monitoring. This style of governance and the PfSH ensures a coordinated approach across administrative boundaries and a consistent evidence base for decision-making. The mitigation framework is embedded within Local Plan policy and is used by participating authorities to support project-level Habitats Regulations Assessments relating to the Solent and Southampton Water SPA, Chichester and Langstone Harbours SPA and Portsmouth Harbour SPA. This ensures the strategy functions as a formal mechanism for addressing cumulative recreational impacts from residential development.
Mitigation is funded through a per-dwelling developer contribution applied to residential development within the ZoI, providing clarity and predictability for applicants and decision-makers. Securing contributions through standard planning obligations ensures a consistent funding stream for mitigation delivery and long-term management
A key strength of this strategy is its evidence-led approach and ability to update and adapt its mitigation measures to remain proportionate and effective. The 5.6 km ZoI was established using extensive visitor survey data and modelling, and reflects observed travel distances of 75% of visitors to the Solent coast. This provides a robust, evidence-led approach to identifying residential development that may contribute to recreational disturbance. The evidence base supporting the strategy is continually growing, and monitoring is embedded as a core part of the strategy, including repeat visitor surveys, bird disturbance monitoring and ongoing evaluation of mitigation effectiveness. Findings are reported through the Partnership and used to refine implementation, ensuring the strategy continues to respond to changes in visitor behaviour and development patterns.
Delivery of the strategy also highlights the importance of adequate resourcing and specialist expertise. The ranger service operates as part of a wider multidisciplinary team, including roles focused on monitoring, communications and project delivery. This reflects the complexity of managing recreational disturbance across an extensive and varied coastline, and demonstrates that effective implementation requires not only strategic planning but sufficient capacity and expertise to deliver targeted interventions at a local level. The dedicated ranger service is responsible for visitor engagement, awareness raising and promoting responsible recreation. Using
a clear public-facing campaign identity helps reinforce messaging and encourages behaviour change among visitors to sensitive habitats.
A notable aspect of the strategy is its deliberate emphasis on managing recreational disturbance through engagement, education and voluntary behaviour change rather than enforcement-led measures. At the outset, participating local authorities favoured a model based on engagement, education and voluntary behaviour change, rather than enforcement or punitive measures such as fines or restrictions on access. Evidence from monitoring and the subsequent five-year review indicates that this approach has been effective in influencing visitor behaviour without the need to introduce formal enforcement mechanisms. This demonstrates that, in this context, positive engagement and clear messaging can achieve meaningful behavioural change, while maintaining public support and avoiding the potential conflict associated with more restrictive approaches.
Bird Aware Solent (2024). Revised Strategy. Available at:
https://birdaware.org/solent/wp-content/uploads/sites/2/2025/02/BAS-five-yearstrategy-proposals.pdf (Accessed: 09/02/26)
Bird Aware Solent (2017) Solent Recreational Mitigation Strategy. Available at: https://birdaware.org/solent/wpcontent/uploads/sites/2/2021/10/Solent_Recreation_Mitigation_Strategy.pdf (Accessed: 18/02/26).
Fearnley, H., Clarke, R. T. and Liley, D. 2011. The Solent Disturbance and Mitigation Project. Phase II – results of the Solent household survey. ©Solent Forum / Footprint Ecology. Available at:
www.solentems.org.uk/natural_environment_group/SRMP/SDMP/Reportphase2Hou seholdSurvey.pdf (Accessed: 18/02/26)
Liley, D., Panter, C., Saunders, P., & Caals, Z. (2023). Initial review of the effectiveness of the Bird Aware Solent strategy. Report by Footprint Ecology
Liley, D., Saunders, P., and Rush, E. (2024). Review of the likelihood of impacts on breeding birds around the Solent from increasing recreational disturbance from new housing. Available at: https://www.push.gov.uk/wp-content/uploads/2024/09/SolentBreeding-Bird-Report-January-2024-Final.pdf [Date Accessed: 20/03/26]
Liley, D. and Tyldesley, D. 2013. Solent Disturbance and Mitigation Project: Phase III. Towards an Avoidance and Mitigation Strategy. Footprint Ecology/David Tyldesley and Associates. Available at:
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South Downs National Park Authority (2019) South Downs Local Plan (2014 – 33). Available at: https://www.southdowns.gov.uk/planning-policy/south-downs-localplan/local-plan/ (Accessed: 18/02/26).
Stillman, R.A., Cox, J., Liley, D., Ravenscroft, N., Sharp, J. and Wells, M (2009). Solent disturbance and mitigation project: Phase I report. Report to the Solent Forum Available at:
www.solentems.org.uk/natural_environment_group/SRMP/SDMP/solent_disturbance _phase1.pdf (Accessed: 18/02/26)
Stillman, R.A., West, A.D., Clarke, R.T. and Liley, D (2012). Solent Disturbance and Mitigation Project Phase II: Predicting the impact of human disturbance on overwintering birds in the Solent. Report to the Solent Forum. Available at:
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