This year's seabird surveys are well under way with lots of fantastic information and data collected and crunched by our Seabird Ecologist, Vickie, with the assistance of the Rangers.  Scilly is regionally, nationally and internationally important for breeding seabirds & this year's data has answered some questions and revealed some surprises about our much loved and visited feathered beings.

This work is kindly funded by DEFRA through the Isles of Scilly AONB 

From April to September each year Seabird Ecologist, Vickie, rejoins the Isles of Scilly Wildlife Trust Team to begin the annual routine seabird surveys across our Islands.  Starting in late April with the breeding population of the iconic Scilly Puffin, before the non-breeders return to the Islands in June, and concluding with the Manx Shearwater & Storm Petrel fledgling chicks in late September.

Surveying takes place throughout the breeding season, with regular return visits to a number of colonies, recording both breeding numbers (pairs) and productivity (number of eggs, number of chicks, number of fledglings) using a variety of methods.  This year we've also done a little investigative work (using trailcam recording equipment) to try and discover what, or who, is having an impact on some of our breeding colonies (including our colonies of Lesser black-backed gull, Kittiwake & Storm petrel).  

This interim update comes before survey work on Fulmar, Manx shearwater and Storm petrel has been fully completed, in terms of fledgling success, but there's still plenty to tell you! 

Start of the Season:

The Seabird Survey season started in late April with boat trips to count returning breeding adult Puffins on land, at sea and in the air; the counts are done at this time to ensure accurate records of breeding adults prior to the juvenile, non-breeding Puffins returning to the Islands in June. 

Outcome:  Initial counts have indicated that numbers of breeding Puffins around the Islands remain stable for another year which we have to take as incredibly positive given that numbers in other locations across the UK are reported to be in decline.

As we moved into May surveying of our Gull species (Herring, Lesser & Greater black-backed) began, along with visits to various nesting sites to begin Shag and Manx shearwater counts, as well as the first of the years visits to the closed Island of Annet (one of the highlights of their job for our Ranger Team but more about that later)!

Scilly is internationally important for the Lesser black-backed gull, holding just over 10% of the UK's breeding population.  We know that gulls as a group can be incredibly unpopular with residents and visitors but as a species their numbers are in decline globally (like most of our seabirds) and consequently they are protected.  They have a bad reputation due to their opportunistic, scavenging nature and often get the blame for any multitude of problems; many of which can be traced back to humans in origin.

Following a shaky start at the beginning of the season, particularly on Gugh where there seemed to be a high mortality rate amongst the Lesser black-backed colony, trailcams were installed to try and identify the cause of the issue.  Sadly, we didn't get any answers to the "what is killing the gulls question" but the number of dead birds reduced to "normal" levels and we did get some brilliant footage of life within the colony.    

This short clip shows a pair of Lesser black-backed gulls doing their thing.  On Gugh this year a total of 422 nests were recorded with 216 chicks fledging from 382 nests in the main colony viewed here.

Seabird surveys, especially around the Gull colonies have their hazards; surveys are carried out as calmly and as quickly as possible in order to minimise disturbance and their can be some interesting equipment choices (as shown here).

Ordinarily the team are equipped with bamboo canes, decorated with fluttering brightly coloured tape, lodged in back-packs to ensure dive-bombing Gulls don't make successful head strikes.  This day however natural resources were utilised.

Outcome:  Gull chicks are just starting to fly now and again it seems that numbers are looking good and in some cases up on previous years, another success story in the making for Scilly this year!  Details regarding Shags and Manx shearwater will be shared at a later date.

As we moved into June we added Fulmar, Kittiwake and Common tern to our survey trips and for us the biggest shocker so far has come from the Kittiwake colony.

All Kittiwake sub-colonies across Scilly have been surveyed annually since 2006.  Over this period dramatic declines have been recorded; 87% drop in numbers, loss of 5 sub-colonies and total breeding failure in 7 of the last 13 years.  In the last 6 years only one sub-colony site has been occupied by all of the remaining birds; below the Turk’s Head on St Agnes between 2014-16 with no chicks fledging in 2015 or 2016 (it is likely this site was abandoned as a result of human disturbance).  The Kittiwakes then moved to Gugh 2017-19 with a total of 9 fledged chicks in 2017 and none in 2018.  This year we added a trailcam to the colony site on Gugh in an effort to find out why the Kittiwakes were failing, as we thought it unlikely to be as a product of human disturbance, and the results was surprising.

There has been talk locally and a lot of speculation that the Gulls are responsible for the loss of Kittiwake eggs and chicks; additional factors which are known to be having an impact on their success (not just in Scilly but globally) are related to changes in weather patterns, changes in sea temperatures resulting in shortages of appropriate food and human disturbance (as became evident whilst nesting near the Turks Head; we had many reports of people disturbing the Kittiwakes and even throwing stones at them prior to them abandoning the site).

As a result of the trailcams being in place we can now say with some confidence that the Gulls are not a part of the problem, and in fact the ones nesting around the Kittiwake site on Gugh are helping to protect them from other predators.

We captured evidence of Kittiwakes & Herring Gulls teaming up to chase off a predating Crow (as seen in the first image); it's a fascinating picture which clearly shows how much smaller than the Gull species the Kittiwake are, as well as how feisty they are.  

We also have photographic evidence of repeated visits from a Peregrine(s); on average one or two visits a day.  Sadly, not even the Gulls stood up to the raptors and both Kittiwakes and Gulls abandoned their nests as soon as the Peregrine arrived.

Peregrines have been successfully breeding on the Islands for a number of years now and this summer as a result of a breeding pair on Annet (who have reared one chick) survey work was disrupted slightly. 

In the UK Peregrines have been given full legal protection under the Wildlife & Countryside Act 1981. This means that it is a criminal offence to intentionally or recklessly kill, injure or take a Peregrine.  Peregrines are included in the list of species in Schedule 1 of the Act, which also means that they are given more protection than other species; as a Schedule 1 species, Peregrines are also protected from intentional or reckless disturbance at their nest sites and very specific reasoning/licencing is required in order to warrant any type of disturbance.

Outcome:  There were around 20 nests recorded on Gugh this year, with chicks growing throughout June.  However, through early/mid July they began to fail and chicks started to disappear; there was a single remaining chick during our last checks.  Following our investigative work we now know with some certainty why the Kittiwake's are failing in this location but we are also aware and pleased that the Gulls, for once, are the good guys! 

From sightings during Seal Survey work the Kittiwake's may also be scoping out other (more remote) locations and we plan to follow these leads and see if we can discover a little bit more.

Moving forwards: 

This year we have learnt a lot and made some interesting discoveries; this is just a small portion, there is still more to come!  Make sure you check back and watch this space to discover how our other Seabirds have fared during 2019 as well!

For full details of of most recent whole Island Seabird Survey and the valuable conservation work that is taking place to support and protect our Seabirds please have a look at the Isles of Scilly Seabird Conservation Strategy (2018-2023) for the results of last years Seabird Surveys please read the Seabird Monitoring & Research Project 2018; once the 2019 report is completed it will also be available to view on our website.