Ramsey Island and Grassholm

Ramsey Island and Grassholm

Ramsey Island and Grassholm
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Ramsey Island and Grassholm

  • Seabird monitoring: the old and the new

    Just realised it's been 20 days since we last posted a blog! Hopefully this might explain why........

    In the 13 years since I started working with seabirds there has been a huge advancement in the technology that allows us to monitor their lives away from the colonies. Until relatively recently we could study them at their breeding colonies but were largely reliant on ringing recoveries to tell us anything about what they did whilst at sea i.e. for the bulk of their lives!

    The past few weeks on Ramsey and Grassholm has seen a wealth of modern technology used in the name of seabird research and science. But there has also been room for some good old fashioned methods too.....

    Gannets

    Exeter University led by Steve Votier are now in their 9th consecutive year of tracking gannets on the RSPB reserve of Grassholm using a range of bio-logging devices (GPS, geolocators, Time Depth Recorders (TDR's) and bird-bourne cameras). This work has led to a whole host of scientific publications which have opened our eyes to where our birds are feeding, how long they feed for, which areas are used on a regular basis, the difference strategies between males and females, how deep they dive, what they feed on, how reliant they might be on fishing discards and even what it look likes to fly with a gannet!

    Apart from valuable scientific data that enhances our knowledge of species, this work also contributes significantly from a political advocacy viewpoint too. When we campaign for increased protection of our seas (sorely needed and still desperately lacking in Wales) we can draw on this data to show politicians and decision makers hard evidence instead of just saying ‘we think’ and ‘to the best of our knowledge’ etc. Maps and graphs carry far more weight!

    One of the key aspects of this work is its longevity. Long term monitoring is key to establishing patterns and building up a more complete and compelling picture. It is vital that we keep this kind of work going but, sadly, in the current economic climate the squeeze on research funding is being felt all too keenly.

    Researchers from Exeter University attaching a GPS device to a gannet on Grassholm

    GPS tracks (S Votier)

    Tracks of multiple gannets from Grassholm (each colour is a different bird) showing foraging area (colony shown by the star) - copyright S Votier

    Manx shearwaters

    This year I took over the Manx shearwater tracking work from Holly Kirk (Oxford Uni) who has now finished gathering data for her PhD on shearwater migration strategies. It seemed a shame for 4 years of data gathering to come to an end so having assisted Holly during that time I took up the batten and volunteered for the sleepless nights alone in a shearwater colony! (there are worse places to be!)

    For this we use geolocators, tiny (2g) light logging devices that record sunrise and sunset which coupled with an internal clock can work out latitude and longitude wherever the bird is on the planet (using the same principals that mariners have used at sea for hundreds of years). Understandably these devices are not as accurate as the larger GPS units but their tiny size means they can be attached to a plastic ring on a birds leg and left on for a whole year.

    We know that our shearwaters winter off the coast of South America but this technology has allowed us observe the migration route they take, how often they stop off to rest (the device also tells us if it is salt water or not so you know when the bird is sitting on the sea), where they feed on route, how long they take to get from Ramsey to just off the Rio del Plata in Argentina (14 days in some cases!) and even when birds start incubating and how long each shift is (i.e the device records when a  bird is in 24 hour darkness in the breeding season when underground on an egg)

    So we now know a lot more about our Manx shearwaters (of which the UK is responsible for 90% of the world’s population with nearly 50% of those in Pembrokeshire) than we ever did and can say with confidence what these birds are doing when they are the other side of the world.

    It will also be interesting to compare Ramsey’s shearwaters with those of nearby Skomer. Brown rats were eradicated from Ramsey in 1999. Up until then only a small population survived on Ramsey (850 pairs in 1998) due to eggs and chicks being easy prey for the rats. Today we have just under 4,000 pairs on Ramsey. Clearly this population expansion must have involved a lot of young, inexperienced breeders, many of which will be immigrants from Skomer and Skokholm  (don’t tell the Daily Mail!). We can now compare success and strategies of these relatively young birds with the established breeding population on Skomer which numbers a staggering 300,000 pairs.

    GLS device on Manx (T Guilford)

    Geolocator (GLS) device mounted on a leg ring on a Manx shearwater - these devices remain on for a whole year and track their migration routes to the southern hemisphere (a good advert for cable ties!)

    Storm Petrels

    Due to its tiny size this is one of the least well understand of British seabirds. Only now is the technology becoming small enough to think about deploying on these birds. They have never bred on Ramsey during the time rats were present although around 150 pairs breed on the Bishops and Clerks, the small islets 2 miles NW of Ramsey and forming part of the reserve. In 2008 we discovered them breeding on Ramsey for the first time and now have around 10 pairs that we know of but there could be more.

    Last week Matt Wood from Gloucester University visited with a very fancy piece of kit, a thermal imaging camera. This is the type of kit used in disaster zones to look for buried survivors etc and works on heat radiation.

    We spent a pleasant night (regular sleep patterns are not a feature of life on Ramsey in mid summer!) walking the island looking for potential new sites. We didn’t cover the whole island but did find one potential new location where the camera picked up 2 birds flying around a rock fall area. Next week I plan to make my way down there at low tide and have a closer look around using a tape player (well MP3 these days!) and some good old fashioned sniffing of cracks! Not as odd as it sounds! Stormies have a very distinctive musky smell that are good way of locating them. I would take our sheepdog Dewi if it wasn’t so steep – he can sniff out a shearwater at a hundred paces!

    From the extremely modern to the good old fashioned – the other way we can monitor for storm petrels is by setting a mist net and ringing. Before heading to Grassholm this week we did just that with Steve Votier, setting the net at a site on east coast. We only caught two birds in an hour but it shows they are at least commuting through Ramsey Sound and there is certainly suitable habitat on this side of the island so we will check out suitable sites along here too.

    European storm petrel after being ringed on Ramsey Island. From ringing recoveries we know these tiny seabirds winter off South Africa, well some do at least! Little else is know about their migration.....yet

    I hope that has given a brief summary of the kind of research that is taking place on our RSPB reserves in Pembrokeshire and hopefully it might explain why we sometime look so bleary eyed when meeting the visitor boat! If you are visiting the island and want to know more about any of this work please feel free to come up and ask. You can also follow us on twitter at @rspbramsey or follow @SVotier, @HollyKirk and @wood_mj for further information on seabird research.

    Ramsey Island is open to the public daily (weather permitting) from 1st April to 31st October. Thousand Islands Expeditions are the only boat operator licensed to land passengers on the island. For details on this and their trips around Grassholm contact them on 014737 721721 or email info@thousandislands.co.uk

  • Ramsey Chough Summary 2014

    It has been a good season for chough on Ramsey. This year we had 9 territorial pairs (8 in 2013) of which 7 went on to nest build and attempt to breed. The other 2 were non-breeding pairs that were establishing a territory for the first time which is encouraging for the future.

    Of the 7 breeding pairs, 2 failed at the incubation stage (one to bad weather, the other for unknown reasons but they were first time breeders so this is not unusual)

    The 5 remaining pairs fledged 17 young between them (two sites fledged four young each, the other three fledged three young each)

    This gave an average of 2.43 per breeding pairs (17 / 7) or 3.4 young per successful pair

    This is slightly up on last year where 7 pairs fledged 14 young between them (2.0 per breeding pair).

     Ramsey Chough (G Morgan)

    The first of the 7 sites to start nest building did so on 9 March, the latest on 21 March.

    Incubating birds were first noted on 14 April with the first chicks being fed from 2 May. The first site to fledge young did so on 9 June with the last getting young out on 15 June

    Our oldest known chough on the island is a male bird ringed as a nestling in 2000. At 14 years old he once again bred successfully in 2014. Since he first started breeding aged 3 years old he has fledged an impressive 38 young! He is obviously seen as something special as his current partner actually jumped ship a couple of years ago and ‘divorced’ her partner at the time when the older bird's partner died and he suddenly became available! Divorce is not uncommon in choughs following breeding failure but the pair in question had been doing very well and were even  well into nest building for that year’s attempt when the female left!

    Fledging is only half the story though. The first year of a chough’s life is a difficult time and it is this ‘first year survival’ figure that is vital in terms of maintaining and ultimately increasing population levels. This spring has been encouraging with large numbers of non breeding birds (1 and 2 year olds in the main) being present on the island. They form large quarrelsome groups and prospect for future partners and nest sites whilst serving as a constant annoyance to the established breeders trying to get on with the important work of raising young!

    Our non-breeding flock this spring numbered between 15 to 30 birds but on 23rd May reached an impressive 48 birds (some of these might have been our breeding birds but the vast majority were non breeders)

     chough flock over Ramsey (G Morgan)

    large chough flock over Ramsey

    On Ramsey we try and maintain suitable conditions for chough throughout the year to give young birds the best chance of making it through the winter. They feed on soil invertebrates with beetle larvae and crane fly larvae being important components of their diet. By grazing livestock on the island year round we can help keep sward height to suitable levels in all seasons as well as providing an alternative feeding habitat in the form of animal dung.

    Sarah Beynon from Dr Beynon’s Bug Farm here in St Davids has been studying our dung beetles on Ramsey since 2009 and tells us that the population levels found on Ramsey are higher than anywhere she has studied on the nearby mainland

    You can see chough on Ramsey right through the season. Summer is a good time as the breeding groups begin to amalgamate into larger social groups, Mixed in with non-breeders this can give rise to some sizeable flocks forming (50-60 birds at times)

     young chough begging (G Morgan)

    Young chough begging to adult

    Ramsey is open to the public until 31st October – contact Thousand Islands Expeditions for boat booking details on 01437 721721 or email info@thousandislands.co.uk

  • Extreme Weather!

    Today has seen some quite extreme weather on the island. After 17 days of no rain we had 40mm of rain in less than 24 hours! (including 10mm in an epic 20 min spell this afternoon!). That is more than we have in the whole of June most years.....

    In between the monsoon like conditions we had bursts of brilliant sunshine which made for some fantastic 'sky-scapes'

    To illustrate how localised the showers were I was out attempting to do a shearwater census when Dewi and I got hit by a torrential burst (the one that gave 10mm in 20 mins mentioned above). While we took a pounding I got a text from Jess in the Thousand Islands boat office, not 2 miles away, of a picture of them in glorious sunshine!


     Worlds apart: While Dewi and I took the brunt of a cloudburst (top), St Davids looked this this! (bottom)

    30mm in the gauge when I checked it on our way out - with another 10mm in there 20 mins later! Last June we had 40mm in the whole moth!

    It's been dry for a few hours now and looks like being a glorious evening with some great clouds over the mainland. The rest of the weekend looks more settled with Sunday the best day. If you are thinking of visiting call Thousand Islands Expedition on 01437 721721 - there is an Insect Week event on the island on Sunday (29th) led by Dr Sarah Beynon from Dr Beynon's Bug Farm which I can highly recommend,. See here for further details