First experience of Bass Rock

This week I thought I’d share with you my first experience of working with the Bass Rock gannets. The photos were all taken on my phone as it was a pretty non-stop few hours but you’ll get the idea.

We didn’t get off to the best start! Our first visit coincided with some pretty windy weather which made landing on the rock impossible. After a couple of days checking out the coffee shops of North Berwick and exploring the North Berwick coastline our luck suddenly changed. The marvellous Maggie Sheddon from the Seabird Centre came to give us the word we’d been waiting for … a boat was about to go out and if we were quick we could be on it!

We ran to our cars, we didn’t want to miss this opportunity, and drove the short distance to Seacliff beach. Walking out onto the sand, we were a little puzzled as there appeared to be no sign of a harbour or boat. However, a very brisk walk across the bay brought us to the tiny Seacliff harbour (which has claim to be Scotland’s smallest), where the lobster boat Keyte and her brilliant skippers Jack and Robbie were waiting.

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My wait was finally over, after a year of talking about catching and tagging gannets I was actually going to catch and tag a gannet!

Heading out of the narrow harbour it took a minute before the first gannet appeared, cruising past low over the water, then another, and another until the haze of birds you can see from the coast surrounding the top of the rock came into focus. Literally thousands of gannets, filling the skies appearing to circle the rock but actually just arriving and departing on foraging trips. A true spectacle or “perfection” as David Attenborough would put it!

Heading out of the very narrow Seacliff harbour

Stepping off the boat and onto the steep steps of the east landing we were immediately confronted by a seal who seemed a little surprised by our appearance. That was also when the noise and the smell really hit us – 75,000 large birds constantly communicating with each other and defecating everywhere certainly know how to assault your senses.

First steps on the Bass Rock. L-R Chris Gilbert, Keith Hamer, James Grecian

After making our way through the old heavy prison gate, we headed up the old footpath to the ruined chapel. If it hadn’t become colonised by breeding gannets the same path would have continued all the way to the foghorn on the summit. The birds around the ruined chapel were to be our ‘study birds’ for the main reason than they are the only breeding birds it’s possible to access. Even getting here you have to ‘move on’ a good hundred non-breeding gannets that are trying to establish territories on the path. Walking up from the lighthouse it was like herding geese. Following my PhD supervisor Keith Hamer I was amazed that the gannets were literally at our feet, chivvying each other along trying to get out of our way without having to head into the unwelcoming colony of breeders!

Standing next to the chapel I had a quick moment to reflect; here I was on Bass Rock, just wow! Having never worked with seabirds before, here I was, face to face with about 75,000 gannets and my PhD had just become very real!

Our team for this visit consisted of me, my supervisor Prof Keith Hamer who has been studying the Bass gannets since 1998, James Grecian a research associate at the University of Leeds and Chris Gilbert an MSc student. Keith, having not caught a gannet since 2012 was super psyched and raring to go and quickly showed us how it was done by catching the first gannet using the pole and noose.

We soon got ourselves into a good catching and tagging routine. This was a relief as we had the pressure of knowing we were being joined by a film crew in the afternoon. The team from Germany were making a documentary series about Edinburgh and its surrounding area and the gannets of Bass Rock were on their wish list. Like us they had been waiting out the weather for the last few days so were also chomping at the bit to get out.

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It was a fantastic day which ended with lots of smiles. We’d caught and tagged 10 adults, not too bad for a first day’s work with a late start and a film crew thrown in. I was hooked, tired (my brain had been on overdrive taking in so many new experiences) but super excited about the next visit when we’d try to re-catch the birds we’d deployed tags on this visit and put some more out.

Big smiles after our first day on Bass Rock

Big smiles after our first day on Bass Rock

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Gannets in three-dimensions

So in my first blog I talked about how we use GPS devices to record fixes of a gannets’ location in order to create maps of where it’s been. Using the locations and the time at which they were taken we can calculate metrics such as the distance and duration of a foraging trip. A more detailed look can reveal different behaviours such as searching for food, resting and commuting to and from search areas. When combined with data sets telling us things about the environment such as wind direction, chlorophyll levels (indication of food availability) and fishing vessel tracks, we can learn more about how their behaviour is influenced by their environment.

So we’re getting pretty good at the location tracking stuff (although there’s still so much more to learn) but one of the big gaps in our knowledge about gannets is how high they fly. It’s a great research question to try and answer as not only will it help us to better understand how they search for food but it is also very relevant when it comes to their conservation.

Many of you will know something about our need to produce more renewable energy. As a member of the EU the UK Government has pledged to produce 15% of its energy from renewable sources, much of which is set to come from offshore wind farms. One of the biggest questions when it comes to birds and wind farms is how likely is it that they will collide with the rotating turbines? To answer this to the best of our ability we need to know the heights at which birds fly and until now heights used to estimate likelihood of collision have just come from visual observations. As I mentioned in my first post, visual observations have some large drawbacks, but now we can use technology to help us out.

As well as fitting gannets with GPS, this year we have also been putting small pressure loggers on the birds. These devices can record air pressure at a rate of one reading every second which can then be used to calculate altitude. By combining altitude readings with the GPS locations we will be able to analyse foraging trips in three-dimensions and provide important information about how high gannets are flying in areas proposed for windfarm development.

Here you can see the first bird we caught this year having its GPS and pressure logger fitted. Both are taped to the central tail feathers using extremely sticky tape. You can see the GPS has been completely covered in order to ensure the bird doesn’t puncture the waterproof plastic.

The loggers don’t stay on for long. After about 10 days we re-catch each bird and remove them both. It’s then back to the office, breath held, to find out whether a) we remembered to turn them on, b) we programmed them correctly, c) they recorded what looks to be sensible data!

I am very relieved and excited to say that our efforts have been very successful. You can see below an example of what our first glimpse of the data looks like when we initially download it from the devices (click on an image for a better look).

GPS locations - this bird made three trips shown in red, blue and white

GPS locations – this bird made three trips shown in red, blue and white

Pressure readings for part of a trip.

My summer of data collection on Bass Rock has sadly come to an end for this year but I’ll continue to post about my experiences of working on the largest gannet colony in the world. For now though I guess it’s time to get comfy at my desk and start to work out what it all means!