Supporting field research into the UK's most efficient diving bird, the European Shag
Julian Evans is a PhD student at the University of Exeter's Cornwall Campus. He is studying the behaviour of the European Shag, one of the most efficient diving birds in the world. Fourth Element has partnered with the University of Exeter to support Julian's research. Related to the Cormorant, these birds can be seen on rocky outcrops all around the British coastline, and they are remarkable underwater hunters.
Over the next three years Julian will be collecting data and analysing the foraging behaviour of a colony of these animals in the Isles of Scilly to see if and how information is exchanged between them and how they manage to be so efficient. From attaching small cameras to the birds to capture video and still images of a bird's eye view of diving and fishing, to collecting huge amounts of behavioural data. The study hopes to improve our understanding of the Shag.
Julian will also be learning to dive and recording his journey in a blog.
Check back for more details soon
While I have been on the Scillies for a week now, slowly getting a feel for the island of St Martin where I’m staying, I have yet to actually begin my work.
For the past few days I’ve been here with a group of second year undergrads practicing their field techniques out and around the Scillies. While I have been thinking about the project and making a few contacts, my time has also been taken up by demonstrating, assessments and sightseeing. Not to mention going to the pub more or less every evening with the over demonstrators and leaders of the course.
This has been a slightly surreal experience. It seems not so long ago that I was on this same field course as an undergraduate, getting my first taste of fieldwork and behavioural ecology.
I can clearly recall sitting in the back room of the Scillonian club with the rain lashing the windows. Alongside two of my friends I was attempting to describe our proposed mini-project, examining how shags might change their diving behaviour depending on environmental conditions. A panel of alternatively blank or sceptical looking lecturers sat across the table from us, occasionally nodding and taking notes.
I should have been able to read the omens back then as we tramped around the circumference of St Mary’s with telescope, binoculars, camera and stopwatch. I should have stood on a high rock (with suitably dramatic waves crashing into it) and yelled something along the lines of “I WILL RETURN” at the sky.
Not that I’d have believed you if you’d told me I would one day return to study shags on the Scillies. Back then I had every intention of leaving university after finishing my degree and attempting to get some form of conservation education job. That first Scillies field course was the first thing to suggest to me that I might like to try my hand at research.
Now it’s me sitting on the other side of that table, nodding and making notes as students describe their proposed mini-projects to me and try to read my handwriting upside down (Impossible, it can barely be read the right way up). I’m not sure how sceptical I look. Perhaps I should work on that.
We managed to see various interesting wildlife. Early morning student mammal trapping produced the elusive Scilly shrews. On Annet we saw an enormous number of seals hauled up on the beach not to mention large quantities of seabirds.
For more pictures, check out the gallery.
My tent also blew down in a 50 mph gale. Returning from the pub in the dark to find my possessions scattered and sodden caused me to swear a great deal. As I attempted to rescue my things, students battened down other tents by attaching them to as many picnic tables as possible. The end result of all this was that I and all my dripping possession spent a night on the floor of the camp sites’ washing up room. Luckily nothing was damaged by the water and I managed to dry everything out.
The tent wasn’t enormously high-quality (it had been purchased as a temporary replacement on another field course) so the chances of this sort of thing happening again are slim hopefully.
Now the field-course was over and the Scillonian III motoring out of the harbour and beginning its trip back towards Cornwall marks the beginning of my fieldwork proper. I have been left to my own devices on the Scillies.
First thing I have to do is move my tent to another field, one with electricity! I need electricity to keep various gadgets charged up, including the GPS loggers. I’ve pilfered one of the large 8 man tents which the students were using. This allows me the luxury of actually being able to stand up in the tent.
My field assistant Richard arrived on the ferry on Saturday. While I call him my field assistant, he is actually going to be teaching me an enormous amount about catching, ringing and tagging birds. Richard has carried out tagging of shags on these islands in previous years on behalf of the FAME project and is an experienced bird ringer. FAME is a project set up by the RSPB
Richard and I have a brief discussion about how the tagging had gone on previous years and the difficulties the FAME project had faced. The islands we’re going to be working on are uninhabited, exposed and only accessible by leaping from the bow of a boat onto some rocks. In order to catch the birds on the nest we have to approach them undetected and then block off their exit points. This can be very difficult, and in order to deploy and recover the tags, we’d need to do it twice! Last year only 7 tags were recovered.
Hopefully this year we’ll have a bit more success. We’re going to start a bit earlier and avoid the risk of having our tagged birds’ chicks fledge before we can recover the tags and Richard has a few ideas about how we can sneak up on birds more successfully.
We spent the evening in the pub, meeting up with a few other Scilly folk with an interest in seabirds. We met up with Vicky Heaney in the Atlantic Inn. Vicky is in charge of Scilly seabird counts and as such is another useful source of local knowledge. Later we move on to the mermaid inn where a band is playing and we meet up with Jim and his wife Liz who both work for the wildlife trust and are heavily involved in bird ringing on the island. We discuss various things about the project and about the fact that the wind seems to be gusting at over sixty miles per hour. And Richard and I are camping in a rather exposed field.
“If things get too bad” says Liz “You can always take shelter in the Wolpack”
The woolpack is the wildlife trust’s volunteer accommodation, an old Victorian gun battery. It is located quite close to where we are camping. I laugh and say I’m sure it’ll be fine.
I barely sleep a wink that night as the tent is buffeted by the howling gale. I must have dropped off at some point early in the morning because I am rudely awoken by the tent poles hitting me around the head. At some point during the night the wind has shifted round and is now hitting the widest part of the tent like a sail, causing the poles to almost bend double. I leap out of the tent and tie the tent to as many picnic tables as possible and repeg some of the guide ropes that have been yanked out of the ground, straightening out the pole. Surely this will hold!
After some more dozing I am once more awoken by the tent poles drumming against my skull. This time both Richard and I attempt to save the tent. There are deep scores in the ground where the picnic tables and pegs have been dragged along. It’s starting to rain heavily too.
We do our best to shore up the tent and go back inside. I decide to take the precaution of packing everything I have loose in my sleeping compartment back into bags in case we have to evacuate.
Our temporary measures don’t last long. Soon the tent is pressing down on us again and the tent is quickly filling up with water. We finally decide to abandon tent. We grab whatever we carry and run to the Wolpack. We make a few trips, rescuing as much of our gear out of the tent as we can.
We rather surprise the archaeologists staying in the Wolpack as they come to breakfast to find us and our belongings attempting to dry out in the living room. They are kind enough to offer us some of their cooked breakfast. We spend the rest of the day avoiding the horrendous weather. I return to the tent at one point to take its poles out to let it lie flat. Every pole has at least one crack in, and the entire thing is sodden. It looks like we might be sleeping on the floor of the Wolpack for a while!
Read about our arrival and day from the perspective of the Cardiff archaeologists here!
Check out the FAME website here:
Today has been a day of talking into microphones. This morning I popped down to the Wildlife trust offices to discuss a few things and ended up doing an interview for their show on radio Scilly. This interview is recorded in their (admittedly very large) cupboard. I try to explain the current aims and methods for the project without stammering too much. Hopefully this’ll prevent too many people being alarmed when they see me on islands which are closed to the public.
After this I had a phonecall from the producer of Ray Mears’ Wild Britain. He’d got in touch with the university a few weeks ago in the hope of doing something with the field course. Unfortunately their filming schedule didn’t coincide with the field course, but we still arranged to assist them in finding Scilly shrews. The undergrads had already done some mammal trapping around the campsite so I had a pretty good idea of where to find shrews. Since then I had been setting the traps every night, baited but with the doors wedged open in order to get the shrews habituated to their presence.
I arrived back up at the campsite and met up with film crew and was thus introduced to the magic of film. Repeating things to make sure they sound good, avoiding looking at the camera, pretending to carry out actions again so the crew can get close-ups, trying to think of the answers to questions on the spot and not saying “umm” every second word.
So I was filmed baiting a trap, answering a few questions from Ray Mears (who turned out to be quite a nice bloke who tried to give me advice on tents which wouldn’t blow down) and then setting it up in a hedgerow. Goodness knows how all this will look and sound when it finally reaches your screens.
The film crew then went off to film elsewhere and I waited. When attempting to trap shrews it is important to check the traps frequently as shrews have a very fast metabolism and staying in the trap for an extended period of time could be harmful to them.
Amazingly, the first time I checked the traps after setting them, I find a Scilly shrew. I get the film crew back up the campsite and we film the shrew in a polythene bag before releasing it.
The release is a bit chaotic.
I say that the shrew will likely go straight to cover upon release. It doesn’t. Instead it runs straight towards the camera, up into its rain cover.
Then it ran up the cameraman’s trouser-leg.
We panic a bit, not wanting to crush the shrew. Luckily the cameraman’s trouser legs can be unbuttoned and we manage to extract the shrew.
At which point it runs up the other trouser leg.
Once again we panic and attempt to rescue the shrew. This time it finally runs towards the hedgerow. I do hope some of this chaos actually makes it to the program.
The film crew’s next goal was to find a hedgehog (despite hedgehogs not being native to the Scillies, being introduced by a schoolteacher in the 80s). This led to us wandering around the campsite in the dark trying to find a hedgehog to film. Eventually I managed to spot one, and Ray got to sit with it and talk about it. I believe this segment will be the conclusion the Scillies episode. Just remember if you watch it, that it was I who found the hedgehog!
Check out the IoS wildlife trust’s radio show here: www.ios-wildlifetrust.org.uk/newswhatson/radio_scilly_wildlife_trust_shows
Today Richard and I took a trip to Annet to scout out nests. We’re not catching today as we’re still waiting for some of our ringing gear to arrive. Plus it’s still fairly early in the breeding season; most birds are still just building their nests.
To get to and from the islands we’re chartering jetboats from Bryher boats. The boatman puts the bow of the boat as close as possible to a rock that’s at about the right height, at which point we need to jump (or step depending on how well we time it) onto the narrow slippery rock, while carrying all our equipment. This felt mildly perilous.
We amble around the edges of the island, poking our heads under rocks and marking the location of nests on a GPS tracker when we find nests that have eggs or birds on them. We mentally note the position of potential future nest sites.
We found one nest that had three fairly large chicks in it! The parents obviously started well before the other birds. The risk of tagging the adults on this nest is that as the chicks get older, the adults will attend the nest less. This could make it difficult to recover the tag. This is the kind of decision we’ll have to make when we start the fieldwork proper.
There were plenty of other seabirds nesting on the island including Fulmars and lesser and greater black backed gulls.
I’m going to be spending quite a bit of time on this island, so it’s nice to start getting a feel for the place.
This weekend there have been more gigs on the island than the mind can comfortably comprehend. Not much in the way of Science this weekend as the entire island is busy with the World Gig Championship!
Check out a few of these photos!
My supervisor Steve has come to visit, bringing some extra ringing gear and to offer his advice on experimental design. We discuss the adverse weather conditions which prevent us from getting to Annet in the last few days. It is decided that it would be best to expand our study areas to other colonies. The FAME project previously also tagged birds on Samson as well as Annet. We can also look into other island colonies, depending on their ease of access and the size of their populations.
This is a good idea as not only will it increase our sample size but we can also make some interesting comparisons of the foraging behaviour of birds from different colonies. Do birds from different colonies forage in different places? Do the birds have preferred spots or do they go wherever the prey are? While these are fairly simple questions, they can tell us some interesting things about how birds share information.
Richard and I get to work on charging, calibrating and sealing up loggers for deployment in the field. (I’ll probably do a post about how this process later.) As well as assembling the loggers, we construct a crook from some old tent poles, wire, zip ties and duct tape.
We managed to get out to Samson on the 8th, despite rough weather. A landing on Annet was impossible due to the wind and swell. Visibility was terrible and a constant drizzly mist coated everything. As before, we scouted out nests and potential nest sites. On Samson this mainly involves scrambling along slippery, rocky beaches, peering under the boulders.
This led to us catching our first shag! I found it peeking out from under a boulder which Richard and Steve had already passed by. We blocked off the alternative exits from the nest using our rucksacks and then Richard extracted the bird using the crook.
Our first bird! Hooray! Steve and Richard then proceded to demonstrate how to ring the bird with both colour and metal rings, and then attach the logger to the back feathers (Once again, I’ll write a post detailing the exact methodology at some point).
We check one last time that the lights on the logger are blinking and then release the bird, which immediately flies out to sea.
As we headed back to the boat, Steve (whom I believe once won young ornithologist of the year) spotted a spoonbill! Here is my best attempt at a photo.
The weather has once again completely changed. Calm days and glorious sunshine allowed us to get out to Annet for our first day of proper capture. I have caught and tagged my first birds. My first capture was fairly dramatic. We’d scoped out a nest in a hole in an earth bank, at the top of a rocky beach. We laid low for a while waiting for a bird to come back to the nest. After a while we headed back to the nest.
I drop off the top of the bank, blocking the hole with my legs. There’s a bird in there! A slightly annoyed honking bird! (The honking means it’s likely male). I put the crook around its neck and gently drag it into arms reach.
Then I make a terrible error.
Richard has told me that the strongest part of the bird is the neck, which also deters the birds from biting. Shags can bite hard enough to draw a not insignificant amount of blood. Despite this I decide the best option is hold the bird around the body.
The bird immediately twists round and bites me on both thumbs.
This is quite painful.
With Richard’s help I managed to get the bird in the birdbag for processing. Birds calm down once they’re in the bag, but my thumbs are already bleeding. Clearly I have learned an important lesson about catching large bitey seabirds!
We’ve managed to catch three birds on Annet, which is pretty good. Hopefully we can keep this up over the following weeks.
The fantastic weather continued over the following few days as we spent a couple of days catching on Samson. This turns out to not necessarily be a good thing. With still air and calm seas birds on Samson can hear us crunching along the rocky beaches. This led to a day with no captures. We decide that in future we should only attempt to catch on Samson on days when the sea and wind can mask the sound of our approach.
We also decide to acquire a blanket to make blocking off exits to nests easier, hopefully reducing the mad dash when we attempt to sneak up on a nest.
On the 15th wind picks up again and we return to Samson. This time we manage to catch three birds, mainly around the rocky beaches, which seems to confirm the idea that calm days are no good for catching on Samson. Our blanket also proves useful. We can toss it over rocks, easily blocking off exits. It’s also useful to keep chicks in the nest calm and protect them from potential predators while we process the parents away from the nest.
The cliffs on top of these rocky beaches are also frequented by fulmars, which we must avoid disturbing. Not least because their preferred method of defence is to spit a foul smelling liquid all over you!
It’s been cold and drizzly day on Annet. However we have successfully recaptured our first bird! Not only that, but this was a bird we were particularly worried about as it had some fairly well developed chicks! I have chopped the logger out of its waterproof seal and downloaded the data to the computer. It’s a fairly meaningless mess of tracks at the moment, but when I get back to the University I should be able to break this down into individual foraging trips which we can analyse. I can see that this bird seems to spent all its foraging trips foraging between Annet and St Marys.
We also captured another new bird in a rocky outcrop at the north-east tip of Annet. This bird proceeded to make a mess of my waterproofs while I was holding it.
Today we landed on the Ganinicks for the first time. This proved quite difficult. The Ganinicks are actually two islands, Great and little Ganinick, joined by a rocky causeway at low tides. Finding somewhere the boat could safely approach where we could scramble down the bow ladder and onto the rocks is rather tricky. Eventually we manage to get off somewhere in the middle of the very slippery causeway.
These islands are by far the most difficult we’ve had to navigate so far, with birds building nests high up in rocky outcrops, as well as in beaches densely packed with boulders. Great Ganinick also has a colony of cormorants sitting on top of it, which we have to endeavour to avoid disturbing as black backed gulls lurk amongst the nests, ready to grab and eat any unattended chicks.
We managed to catch a couple of birds, one from each island. The shag we caught on little Ganinick was hiding at the back of a long smelly cave and took quite some time to extract. At the end of the day we had to be picked up from a high tide point, round the back of little Ganinick, once again requiring a slightly perilous feeling jump to the boat.
There is a rather alarming trend developing on the islands. Many nests, including ones we’d captured birds on appear to have been abandoned. Nests which previously had eggs in are now empty and often destroyed as well. We have passed a nest in the morning with an egg in and would return to find it empty in the afternoon. Seemingly healthy nests with three eggs have failed within a few days. We have also noticed that even the birds that are still on nests are attending chicks far less regularly than we might expect.
While this appears to be occurring on all islands over the last few days, Annet is by the far the worst.
Some of this might be put down to poor nest location choice and violent sea. I suspect some abandonment may be due to the exceptionally poor weather forcing parents to spend more time out at sea foraging, leaving eggs unguarded. This allows the gulls (who are also suffering due to the poor weather) easy access to eggs on the nest.
It is also possible that shags have simply chosen to abandon their nests due to breeding being too much effort in these conditions. Like most seabirds, shags live quite a long time. A failed breeding season isn’t the end of the world to them.
There are other potential reasons including depleted fish stocks, but everything is just guesswork at this point. None of this bodes especially well for the shag population or for us. We have definitely lost a few loggers already (unless the birds return and attempt to lay eggs again).
After some discussion we have therefore decided to leave Annet alone in favour of Samson and the Ganinicks. There is a seabird count on Annet on the 29th which we’re going to assist in. We shall reassess the situation then.
Re-evaluating the situation this morning, I don't think we're doing too badly. We've deployed 12 loggers in the 10 days we've been working (some of which have been off-days and a couple of complete failures across Annet, Samson and Great and Little Ganinick. While we've recovered only one of those so far, I'm fairly confident we can recover the others as long as the nests don't fail. We've only definitely lost 3 devices due to nest failing, and there is a chance individuals might return to re-lay.
So the main message is, shags are terrible parents, but I think we'll do alright. I'm hoping we can do a little better than FAME's six recovered loggers last year, a one in three recovery rate.
We have another 3 weeks (After which Richard switches to catching Kittywakes on St. Agnes for FAME) and hopefully with the weather improving the birds on Annet will get going properly. We're learning which days are bad and good for the other islands. I think we'll be avoiding days which are too nice. Luckily wind is something the Scillies have plenty of!
We have managed to tag four more birds, and recapture two, including the awkward bird hiding at the back of the cave on Little Ganninick. The weather remains extremely changeable, with bad weather preventing us from landing on any island for several days. Nest failures appear to be increasing on the less sheltered parts of Samson too and shags on both islands appear to seldom return to their nests. Nevertheless, we only need three more recaptures to match FAME’s success rate last year. We currently have 12-ish tags out in the wild (some may have been lost by now)
of which I am hopeful that at least 6 are on birds
still attending a nest.
Tomorrow we shall go to Annet for the bird count and see how things are going there.
The swallows are getting very cheeky. This is a swallow hanging out in the shower room of the Wolpack.
Today seven of us jump off the boat onto Annet rather than two. Today we’re taking part in the seabird census of Annet. We form a line and walked transects as a group, shouting out the species and number of eggs on the nests we found. The coast is swept first, then inland through the gull colonies.
Also surveyed are sensitive areas which Richard and I usually avoid, such as the South East tip of Annet where fulmars nest on the cliffs and puffins build their burrows. We also climb down into caves at the bottom of cliffs, where there are several shag nests we’d never discovered before.
With regards to the shag nests we’d already discovered, things look grim. Though a few new nests have been built, most nests seem to have failed. We find very few eggs, and virtually no chicks. There were shag egg-shells scattered about several nests, and I saw a gull with an egg in its mouth that looks suspiciously like a shag egg.
Richard and I had thought to attempt to recapture some birds today, but it is clear that this isn’t going to happen.
Annet is clearly not going to give us any more data this year.
After a somewhat depressing day on the 29th we have a fairly successful few days, catching two birds on the Ganinicks, two on Samson and recapturing a bird on Samson. If we manage to recapture these birds (or any of the other birds that we’ve tagged) then we will have matched FAME’s total from last year.
Richard has officially moved on to his RSPB contract, tagging kittiwakes for FAME, but is still helping me with fieldwork. In return I’m lending a hand with kittiwake tagging. It’s great to get some experience at ringing different types of birds.
The kittiwake colony we have been working on is just below the Turk’s head on St. Agnes. Catching Kittiwakes is a bit different to catching shags. For one thing kittiwakes nest on small ledges quite high on the cliffs. In order to reach the birds we use a noose on a telescopic pole. The noose is slowly raised towards the bird and then dropped over the head of a bird, allowing it to be lifted off the nest and swung down to where I was usually standing with a bird bag.
Kittiwakes are significantly easier to handle than shags, being small enough to hold in one hand. They also can’t
break the skin when they bite! They do however make far more of a mess. My shorts have been covered in muck from both ends of the bird while I’m ringing.
The next few days will decide how much shag tracking data we end up with. All four of the birds we’ve recently tagged have got chicks, which hopefully means they will return to the nest, though as I’ve mentioned before birds have not been attending chicks like we’d expect.
While we did manage to recapture one of the birds, the tag had been damaged by seawater.
I’ll quote the e-mail I sent Steve on the 12th.
“Unfortunately these last few weeks have not been good for the birds on all islands with more bad weather. Most of the nests we tagged at failed and those few that didn't fail did not behave normally in terms of incubating, guarding and feeding chicks. They are simply barely attending the nests, I suspect because they are out feeding themselves. The number of days when we staked out nests only to find the birds did not attend the nests all day was extremely depressing.
As such, out of 19 deployed tags we only managed to recover 4 tags, one of which was damaged by sea water.
Needless to say, I'm not at all happy about the time, effort and money put in producing so little in the way of data. I'm also exceedingly worried about the future of the project.”
Steve tells me not to worry, and that there’s nothing I can do about the fact that it’s been a terrible spring.
I do have other types of data. I’ve had an Msc student helping me gather observational data about shag foraging rafts. While I won’t be able to match this data with tracking data quite like I’d hoped, it is nonetheless useful information for informing next year’s fieldwork.
And while I don’t have as much data as I’d like, I do have some data. Once again this can give me some idea about the direction future research is going to take.
So having learnt the lessons of this first year, I will come back to the Scillies again.
In the meantime, I’m going to do a little more voluntary kittiwake work, before heading back to Falmouth. I imagine in will be quite pleasant to get back to the mainland after two months!
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