Farlington marshes, Improvements for Breeding Seabirds
- Josh Pritchard
- May 18, 2022
- 6 min read
Updated: Aug 8, 2024
Farlington marshes sits on the south coast in Langstone Harbour. It is managed by the Hampshire and Isle of Wight Wildlife Trust and is one of the most significant sites for overwintering waders and wildfowl on the south coast. It is also an especially important breeding wader site, focused on Lapwing, Avocets and Redshank.
In October 2023, Groundlord Environmental undertook a project to increase the productivity of the small seabird colony that was present in the southern lake, known as The Deeps. This was made possible through funding from the RSPB and the Life on the Edge project as well as the Solent Seascape Project, managed by Blue Marine.
The plan was to restore two very eroded islands and create two new ones from some existing features. This would create secure islands within the harbour for nesting on, safe from predators and early season storms that are now more frequent with climate change.
In a natural coastal system, new habitat for these birds would be constantly created as the coastal sediments naturally shift over time. Smaller species, such as the terns, would colonise first and eventually get pushed off by the more aggressive gulls, by which time new habitat would have formed for them. Unfortunately, nowadays most natural processes are halted by hard infrastructure and sea defences. Sea level rise exacerbates this in a process known as coastal squeeze, meaning increased habitat is being lost, especially roost sites and nesting sites for seabirds and waders. So, projects such as these are very important, especially on the south coast, one of the busiest and most built-up areas in the country. They provide much needed space, secure from tides and disturbance.
The ecology
The target species were predominantly terns, to be precise common terns, Sandwich terns and hopefully, little tern. All these species are doing very poorly in terms of breeding on a national scale and a new Special Protection Area (SPA) has recently been developed in the Solent for these birds. Little tern is really on its last legs, especially on the south coast. The project would also produce habitat for black headed and Mediterranean gulls as well as ringed plover and oyster catcher.
These species all like shingle. To be exact, fine shingle. When creating seabird habitat, we always use 10mm shingle and sometimes we add in sand. We have even added crushed oyster shells and a fake seaweed strandline, anything to replicate the natural habitats that these birds use.
Terns are tough. They lay their eggs directly onto fine shingle, in a little scrape that they create with their feet. Four eggs are laid and incubated. At this point they are very vulnerable to predation, especially from foxes, who can wipe out a colony in a night. This had to be considered in the design.
It was also important to us to factor in more facets to the scheme than just breeding seabirds. The shingle islands would also be fantastic for overwinter wader roosts, another important threatened habitat. We were also keen to produce good feeding habitat for the autumn migrant waders. This meant designing it so that mud would steadily be exposed at various levels throughout the summer as species like common sandpiper start to appear.
How it actually worked
Firstly, with the design came the necessary consents. The site is highly designated, so a SSSI consent was obtained, with discussion with Natural England. There was, however, lots of support for the scheme. It is important in this phase to build a lot of redundancy into the consent to allow for delays, and unknowns such as the amount of material being moved.
The first hurdle was to get the machinery and aggregate onto site. This was down a heavily overgrown cycle track, through multiple gates. We had to do a few hours of vegetation clearance to make sure that the lorries were able to access. This was done with a three-man team, a chipper and a couple of pole saws. The turning into site which limited the size of lorry we could use was looked at in detail and widened where possible.
We made a compound with security on site to keep the machinery safe but for this site, one of the main reasons for this was to stop the cows tampering with the kit. They love to chew rubber when they get a chance and I've lost many window seals on trucks over the years.
Prior to the work commencing the lake that we were working on was drained by Trust staff. Despite a wet year, the levels receded enough to work on, but a large gauge diesel pump was on standby if needed.
The work was done with a 15tonne excavator and a large, tracked dumper. To keep costs down, we opted for one excavator for the works and the loading of the shingle. The excavator spent the first 4 days on the lake creating the outline of the islands. This focused on the two at the far side of the lake, as we needed to maintain ground to work from as we moved back.
Two islands were formed from existing spits of land which had the necks of them removed and added onto the remaining section. A deeper trench was then cut around each island that was not uniform in depth. This created the muddy margins that we wanted for autumn migrants, whilst also creating deeper water for added predator protection.
The next stage was to add the shingle. The first layer was made of larger aggregate known as rejects. These are cheap and mainly from dredged sediment. They range from about 4cm up to 15cm. These were used to key the aggregate in, meaning the finer top level does not move around as much. The excavator pushed the first layer into the newly shaped islands.
The second layer was the 10mm shingle, which was again pushed into the surface to slightly compact it and allow it to stabilise. In total its was 360 tonnes of the combined aggregate, coming in 20tonne deliveries by lorry. It was logistically complex as there was not a lot of space for the shingle and tracking between the shingle pile and the site required time.
Luckily, the weather stayed dry for the two and a half weeks build time. The pump was therefore not needed. At the end of the island creation, there were deep channels of varying levels around the islands and some scraped areas. These were connected to the water that was left in the lake and flooded on the last day. This immediately created feeding habitat and secure roost space.
There were a couple of bonus builds as well. A causeway that allowed access across the lake was reinforced with spoil left from cutting the channels. This helped secure access for the future to the southern portion of the site. A lot of the edges around the lake were graded out as well. This produces better feeding habitat for waders and wildfowl throughout the year.
A small island was created with some left-over shingle and some ‘beaches’ were created around the periphery of the lake. The island was aimed at oyster catcher, who like smaller spaces to nest on and the beaches were for ringed plover. This is a species we are particularly keen to help in the Solent due to their poor breeding numbers
Results
Four large islands, capped with shingle, one smaller island and four small beaches were created in the end, with some improvements made to access along the way. Two weeks later the weather had become so bad that the whole lake had filled up and the islands looked fantastic. They also immediately hosted roosting dunlin, oyster catcher and grey plover.
During its first breeding season, the site was occupied by ringed plover who attempted to nest on the islands. Unfortunately they were predated by black headed gulls, which is quite common in this situation. It gives hope for the future though, with terns and gulls showing interest, so fingers crossed for 2025.
The work on the causeway in between the water bodies also allowed water to more effectively collect in the upper section, providing much better breeding habitat for the lapwing. Breeding occurred though this section with a record number of birds fledging in 2024.
The project represents a fantastic bit of work that we are enormously proud of. It highlights the need for a contractor that understands the ecology of the species that are being targeted so opportunities are made the most of during the build process. We hope to be involved with many more going forward.
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