Freeing gannets

Not only have we been using our gannet catching pole to good effect for deploying GPS loggers but we’ve also managed to free a couple of gannets from entanglement in fishing rope and netting.

During our first visit to Bass Rock, back in mid-June, we spotted a gannet looking like Captain Jack with 6 inches of thick, matted rope hanging from its lower bill. We had no way of knowing how long it had been living with its wasteful appendage but as happens with all the non-breeders, as we approached it, it simply jumped and flapped off out of reach amongst the breeders.

Despite its accessory, the gannet still appeared to be in good condition, and must have been able to feed, as we saw it again on a couple of occasions before we were able to get close enough to have a go at catching it.

Once in hand it was clear why it had been unable to free itself, the matted rope was wound incredibly tightly around and embedded in the end of lower bill. The inside of a gannets bill is lined with backwards facing serrations which meant that no matter how much the rope was pulled at by inquisitive gannets, it wasn’t going anywhere unless cut off.  A couple of minutes cutting and sawing at the rope and the bird was free. Happily it returned, probably a little bewildered by its experience, back to a territory, so hopefully if it returns next year it will have a chance of breeding.

At the time, we were so relieved to have caught it we forgot to take a before and after photo but here are a couple of pictures to show the rope in question and the bird post removal .

That wasn’t the only gannet we’ve managed to help. During our last trip we spotted a second gannet, this time with blue netting wrapped around the lower bill.

I can guarantee these won’t be the only seabirds that have and will become entangled in fishing debris this year but they were a couple of the lucky ones. I could write a whole new blog on the topic but for now, please remember, if you ever encounter a seabird caught up in fishing line, be extremely careful. Gannets will go for your eyes.

They will be frightened, so the best thing for you to do would be to alert the Scottish Seabird Centre, Scottish SPCA or RSPCA who will be able to take the appropriate action.

Next up … foraging in 3D!

Gannet grabbing!

How do you catch a gannet? This has to be the most common question I get asked when I tell people what I do for a living.

Prior to starting my PhD, my only experience of working with seabirds was a couple of days spent assisting researchers studying lesser black-backed gulls; my role was to help catch the chicks for ringing. This was a relatively simple task given that they seemed to be under the illusion that sitting really still, bodies in full view, but with heads tucked up under a peat hag meant that you couldn’t see them. So I knew that before I went out to catch gannets I needed some training with a larger, feistier bird.

Luckily my PhD colleague Liz Morgan studies shags on the Farne Islands, so before setting foot on Bass Rock I spent a fantastic couple of days helping her catch and fit GPS tags to shags (you can read more about what her research involves here). At the time I remember thinking shags were pretty lively and slightly intimidating with that head shake and hiss (honk if its a male), however I don’t think Liz will mind me saying that the significantly larger gannet is the next notch up the intimidating scale.

As I walked up through the Bass Rock colony for the first time, I have to confess to being quite intimidated by their size, that bright blue binocular stare and the length and pointiness of their beaks. It was time to switch on and stay focussed if I didn’t want to find out what damage 10cm of pointy bill could inflict. That said, the first rule when catching and handling a gannet is always protect your hands, arms and most importantly, eyes.

So how do you actually catch one? On Bass Rock there are so many gannets that as you make your way up the footpath from the lighthouse to the old ruined chapel, there are non-breeding birds that you could almost, if you were feeling brave and were very quick, simply grab by the neck. However, for our work we have to be selective about the birds we tag as we need to get the tags back in order to recover the data. For this reason we target breeding birds with young chicks. Gannet chicks are rarely left unattended, whilst one parent is off on a foraging trip the other will stay with the chick to protect it from non-breeders who are looking to take over unattended territories. By targeting breeding adults we can almost guarantee that they will return to their nest to take their turn at chick protection, allowing us to re-catch them and recover the GPS devices.

Many suggestions have been put to me about how we go about catching them; luring them with bait, catching with a net and trapping by the leg have all been suggested, indeed you may have thought of some of those yourself, and they are all good suggestions but we actually use a noose or crook attached to a very long pole.

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Julien Collet honing in on the target gannet

Carefully manoeuvring the pole toward the chosen bird to try not to spook it or its neighbours, the noose is gently draped over the birds head and drawn gently closed. The noose is fitted with a stopper so that it can never be pulled too tight. The bird is then pulled out of the colony, quite unceremoniously, along the ground (so it can continue to take its own weight) towards waiting assistants. Now the understandably quite angry gannet can be carefully brought under control and fastened into a custom-made gannet jacket in order to restrain it safely and comfortably for the few minutes it takes to fit the GPS device.

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This sleepy gannet was one of the easier seabirds we managed to catch!

 

Some gannets are certainly easier to catch than others. This non-breeder (right) was so unfazed by having the noose draped over its head that it tried to go back to sleep!

 

 

Catching immature gannets is certainly the most challenging task. Below you can see Jana Jeglinski from the University of Glasgow putting her gannet catching skills to the test as she attempts to catch a 3-year-old gannet from the large ‘club’ site (colony of non-breeders) around the helicopter pad on Bass Rock. As you can see, with no chick to protect, these birds have no qualms about taking off the minute it looks like someone is coming their way!

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Jana Jeglinski (centre in blue) in stealth gannet catching mode!

How do we study seabirds?

The gannets of Bass Rock have a long history of being studied; the late Bryan Nelson dedicated years of his life to watching, recording and understanding their behaviour. To someone like me, Bryan’s book ‘The Gannet’ is pretty much the bible when it comes to these incredible birds. However, once they left the colony to go on foraging trips it was really anyone’s guess as to where each individual bird went.

Having said that, we did have some idea of where they might be going as people were also making observations from boats out at sea. These sightings told us that gannets were able to travel long distances and that they visit many different areas, but they still left many unanswerable questions such as 1) which colony had the birds had come from? 2) were they male or female? 3) were they breeding or non-breeding birds? 4) what were they doing? and so this is where technology has really opened up the science.

GPS devices, which use the same technology found in your cars’ sat nav, can now be fitted to seabirds to record their locations at regular time intervals throughout day and night. This allows us to map very accurately where an individual gannet has been and what it was doing whilst knowing where it was from, whether it is male or female, breeding or non-breeding etc.

Waterproofing a GPS logger for deployment on a gannet. Photo: James Grecian

Waterproofing a GPS logger for deployment on a gannet. Photo: James Grecian

Here you can see one of our GPS loggers being prepared for deployment. This particular logger is a very affordable off-the-shelf device that we’ve simply removed from its hard plastic casing to make it smaller, lighter and most importantly to make it waterproof by shrink-wrapping it in plastic. The hair straighteners are crucial to the operation allowing us to seal the ends of the shrink wrap! Once the ends have been trimmed to size, it’s ready to go on a gannet … just the small matter of catching one then!