It's been a long summer for the seabirds and site team at the RSPB Langstone Harbour Reserve but I'm very happy to say that 2017 has been a great one. In particular it's been a much needed successful year for our breeding little tern colony. A grand total of 27 chicks fledged and are now winging their way south with their parents to their wintering grounds on the west African coast. It's certainly not been an easy year for them but thanks to their tenacity and a little helping hand from us, a new generation of Solent little terns is heading out into the world! The following blog is a glimpse into their world and the work the RSPB reserve team have carried out daily over the summer to help them..
Above: a young little tern receives a fish whilst poking it's head out from under the wing of the other parent
After a disastrous year in Langstone Harbour for little terns in 2016, with just 11 pairs attempting to breed and none managing to successfully fledge young, optimism was in short supply whilst we awaited their return this spring. Last year had seen terns struggling to feed, a large scale issue beyond our ability to resolve locally. Nevertheless, each new year brings a clean slate for our migratory seabirds and another chance for a successful breeding season. Seabird conservation is at heart a numbers game with each year being a metaphorical roll of the dice. For millennia, the chances of success & failure in any given year have added up to allow a continued population but over the last few decades we've seen a worrying decline linked to a number of human factors. Our long term work nationally & internationally is to tip the balance back in their favour and replace the loaded dice they've been metaphorically rolling with a set that will allow them to stay in the game. With that in mind, habitat preparations began in early April to offer them a perfect nesting substrate, away from disturbance and storm surges and protected from their usual predators.
Before: overgrown with a storm bashed fence & litter strewn about.
After: A layer of fine substrate with crushed shells, a working electric fence, decoys and security cameras.
Above: Circular sand patches among the larger shingle offering small, safe nesting spots to snuggle down in.
Thanks to shingle restoration work carried out in 2013 & 2014, both of the primary nesting sites in the harbour are now above the reach of all but a devastating summer storm surge. With this blank slate to work on each spring and help from our neighbours across the water at the Hampshire and Isle of Wight Wildlife Trust, habitat preparation work took place in April to recreate perfect little tern nesting habitat. Vegetation was cleared from two small areas of shoreline to give it the 'empty beach' feel that little terns prefer to settle on and anti predator fencing was erected to deter any adventurous mammals that made it across the dangerous mudflats at low tide. In addition to clearing the available small sandy areas, we also created a host of small, plate sized sand patches amongst the larger shingle so that little terns could snuggle down in the finer sediment and incubate their fragile eggs. Finally, 'decoy' model little terns were put in position to highlight the area to the arriving real terns and security/observation cameras were put in place to keep watch. The 'decoy' terns have proved invaluable at many seabird conservation sites around the world and use social attraction to encourage colonisation. If used correctly as part of a larger program, terns will be drawn to the sight (& sound) of a 'colony' forming, see how good the habitat quality is and decide to take up residence themselves.
With preparation complete, we didn't have long to wait. The first little tern touched down in the harbour on April 13th, two days early (we usually expect them on April 15th and they're relatively punctual). The question was, would they take up our offer of safe tern friendly nesting areas or go elsewhere? Worryingly, at first, a handful of terns began to nest very near the spring tide line outside the prepared colony site!
Above: A little tern adding shell fragments & sticks to it's nest (behind) whilst its partner incubates.
Although the sandy, shell covered soil between large shingle they settled on was perfect for incubating eggs, evolution has somehow not equipped them to realise that it would be under water within the month... These first colonisers nested during neap tides, the part of the tidal cycle when high tide is around 1 metre lower than it's peak in the harbour. As the earth and moon slowly moved into position with the sun over the course of the next two weeks, the tide's peak would gradually increase & most certainly wash away these lower nests. Worse news was to come and as the peak spring tides approached, a storm system formed in the Atlantic and began its slow march towards the Solent. Expecting the worst, the site team watched carefully, sat off shore in the boat, waiting to see if fast action would be needed. It was. As the tide surged in and overrun the nests, forcing parents away, the team quickly moved in and relocated the handful of affected nests just above the new tide line out of harms way (taking care to keep the 'nest furniture' of stones & shells identical so that the returning parent recognised its nest).
Above: eggs submerged at the peak of the tide prior to a small relocation.
Above: An incubating little tern watches the storm surge approach, luckily having nested just a few cm above it's final reach.
When the storm passed and the calm waters of the harbour once again allowed stable observation from the boat, we were relieved to see that the moved clutches of eggs were all being incubated. Later confirmation revealed the eggs were toasty warm and virtually all of those submerged and moved remained viable.
Meanwhile, on the prepared colony site, the main event was beginning to take shape. With the addition of more 'decoys' and a repair of the speaker which played little tern calls, the main colony was forming with the swirl and chatter of tiny seabirds overhead. Combined with a quite sudden, noticeable increase in the amount of small fish available within the harbour, the sea around the colony began to fill with feeding little terns. Within a week, courtship was being seen regularly and incubation began en-masse.
Above: Little tern and 'decoys'.
Above: Little terns and decoys at one of the colony sites.
Above: Little terns building at roosting points over high tide as courting continues overhead.
Above: "Thanks for all the fish", an adult brings in a meal for it's incubating partner.
Above: An adult incubates a clutch of eggs with a chick shelter ready nearby.
Above: An incubating little tern adds shell fragment to its scrape whilst courtship takes place in the colony behind.
With summer now reaching it's peak and everything looking rosy for the breeding colony, it was time for the weather to play yet another cruel hand. With over 30 pairs of little terns sat on eggs around the harbour, another storm system formed and worked it's way towards us. For a summer storm, this one looked pretty bad with gusts of 50 mph+ predicted, not something that's desired at this fragile stage of the breeding season. Luckily for the nesting terns, the main colony had formed on top of the raised shingle bank we'd restored in previous years and without a doubt, this fact saved them from being washed away as they had been before. Nevertheless, the wind was a significant problem and roughly a third of the nests were destroyed over the course of a few days either via the wind, blown sand & sea spray or by gulls taking advantage of an unguarded clutch of eggs once the wind had subsided and the need for food forced the parents to briefly leave. Noticeably, those adults nesting within the small sand patches fared significantly better than those on the open sand.
Above: A little tern adult at the colony site having succumbed during the storm.
With stormy weather finally out of the way and the main colony settled & continuing to expand again, the chicks from our first group of nests (including the eggs rescued from the water) began to hatch. Although in a tough location and surrounded by Black-headed and Mediterranean Gulls (both known to eat little tern chicks here), the remaining parents did a great job of protecting and feeding their young. Amazingly, despite high predation rates & flooding, this sub site where I had feared no chicks would fledge at all produced four fantastic fledglings.
Above: An adult watches as (a well camouflaged) young little tern explores the beach.
Hot on the heals (wings?) of this fantastic four, the main colony now began to hatch. As each parent began to shuffle more and more on their clutch of eggs, chicks began to pop out all over the colony. An intense avian airlift of small fish started with adults constantly flying out to the harbour, hovering above the water and elegantly snatching a fish with their beak before circling back. As each parent returned and gave a call, chicks would come running from shelter to respond as loud as possible, mouth open, waiting for a meal.
Above: The very first chick to hatch on the main colony site. Safe in the middle of its small sand patch.
Above: A small forage fish delivery for a hungry chick.
Above: A long distance view of a chick (top left) breaking shelter to beg for fish.
Above: A chick takes shelter by one of our cameras whilst it's parent stays at the nest site behind.
As the days passed and summer grew old, a close daily watch was kept on each nest hatching and chicks beginning to explore their immediate area. Little terns grow at speed and are often capable of flight within just 18 days of hatching. Gradually, despite the constant need for food, the ever present possibility of being eaten and frequent downpours of rain, chicks began to spread their wings and take those first few short fumbling flights away from the colony. Within a week, these little aviators less than a month old were learning to fish for themselves and becoming increasingly confident in the air, finally leaving with their parents to begin the long journey south and a lifetime across Europe, Africa and the Atlantic.
Above: a little tern chick flaps it's developing wings.
Above: Getting bigger by the day, a pair of little tern chicks await a fish delivery.
Above: Successful siblings almost ready to take flight.
Above: A fledgling little tern, just a few weeks old, rests on the shoreline between flights.
After a long breeding season, an estimated 36 pairs of birds managed to raise and fledge 27 successful chicks, making 2017 a great year for little terns in the harbour and we look forward to seeing this years young return in the future to continue the cycle. With help from the EU Life Little Tern project, our neighbours at the Hampshire & Isle of Wight Wildlife Trust and all of our supporters and harbour users, the RSPB will continue to give migratory seabirds a home here in the Solent each year. With a successful year behind us, there's little time to rest and between monitoring our wintering birds, we'll be preparing for next spring, another seabird summer and hopefully, another new generation.
Above: a newly fledged little tern receives a fish from its parent, surrounded by adults ready to leave Langstone Harbour at the end of a successful year