Project LOMVIA

Despite the amount of species and sights I have described in my previous blogs on Iceland I spent the majority of my time there working on the LOMVIA project; a study of Brunnich’s and common guillemots by BAS and its partners. More details can be found here but I will explain it briefly:

Common guillemots.

As climate change impacts the oceans via warming temperatures the distribution of species alters. This has been noted in the movement of prey fish species, such as sandeels and capelin, whose distribution changes can disrupt seabird populations.

Common guillemot with capelin.

As prey species distribution changes the distribution of seabirds may change as well, causing competition between species that wasn’t so prevalent in the past. The LOMVIA projects aims to ascertain if there is any competition caused between two closely related species – the common guillemot and the Brunnich’s guillemot – brought about by these changes in the environment.

The two guillemot species, Brunnich's sat just above the common.

Common guillemots are a temperature species; spread across the North Atlantic and North Pacific they live in areas closer to warmer waters but do range far north to places like Iceland and Norway. Brunnich’s guillemots are a colder water species, preferring the temperatures of the Arctic and so have a more restricted range. But the two species do overlap in areas where warm and cold ocean currents pass each other and mix – this is very noticeable in Iceland and our reason for being here.

Spot the Brunnich's!

Common guillemots are a very dark chocolate brown colour and have a long, pointed beak. Brunnich’s are darker, closer to black, have a pointy beak but one that is noticeable shorter and have a white stripe along the edge of the beak (to me, Brunnich's look like a common guillemot has dressed up as a razorbill for a fancy dress party but not done a very good job!).

The study we conducted collected a lot of data, focusing on where the two species were foraging for their food and what they were eating. We collected the data in a number of ways, predominantly through tagging work and diet observations; but first we had to find suitable locations to work in.

A guillemot colony on the edge of a heavily populated puffin area. Some work could be carried out here but another location was better.

The main common guillemot study ledge on Papey, birds were accessible for deploying tags and observations of diet - a perfect combination.

The tagging work consisted of deploying devices on the birds for a short period of time. These devices are carefully attached to a few feathers, can be simply removed and are incredibly light – all so as to not harm the bird in any way.

Devices deployed on common guillemots.

We utilised two types of device: GPS and TDR (time-depth recorder). The GPS tells us where the bird is and the TDR tells us its depth in the water. More specific information can be gleaned by combining the two on one bird, thereby establishing its behaviour along the entirety of its journey from the colony and out to sea to fish.

TDR attached to the belly so as to be in contact with water more often, GPS attached to the back to map the constellations.

Each bird was given a unique mark; a coloured shape on the GPS tag, which was repeated on a bit of tape covering a few feathers on the head. This head flag allowed us to see which of our birds were present in a busy colony, even if the tags themselves were not visible, so we could watch their behaviour and recover the tags.

For some birds the devices couldn't be seen from the vantage point, but the head flags could.

Once the tags were removed from a bird the head flags remained so that we could identify individuals we had already studied and so did not bother them again later in the season when deploying more tags. If we were unable to recover a tag the birds would gradually preen them off anyway, in this way no bird was left with devices on it after a week.

The tagging work was one main focus, the second was diet observations.

Studying diet is primarily done by direct observation; then, by combining such observations with the tagging data we get a fuller workup of what the birds are doing away from the colony. The adults bring a whole fish back to their chicks in their beaks. By watching the colony the species of fish can be identified as we watch the adults bring back a meal. Each fish has its own characteristics that we look out for.

The wide silver body, blue edge and (out of sight) forked tail of a small herring.

The thin silver body, forked tail and brassy sheen at the base of the tail of a capelin.

The thick body and orange/brown colouration of a gadoid (a young cod).

The brown speckling of a benthic fish, most likely a blenny.

By being able to observe the birds we were working with we could at times get a full dataset for one individual. The tags tell us where the bird went and when and how deep it dived, and the observation of it bringing a fish back to the chick tells us what it caught on the last dive it did in the foraging trip. So much vital information in understanding the ecology of these birds for conservation purposes!

The perfect sight, a tagged bird bringing back an identifiable fish (a capelin) for its chick!

By ascertaining the foraging range and diet of the two species we can determine if the distribution of the temperate species – the common guillemot – is altering as the seas warm and, if these changes are occurring, are they causing clashes with the arctic species – the Brunnich’s guillemot.

Initial results are interesting but for that information you will have to watch out for publications from the LOMVIA project over the next year or so. For now though, it was a privilege to be involved in a study at the forefront of this area of research, with a great team in a stunning country. And of course, working with such amazing birds is always the highlight!

Brunnich's guillemots with chick.

Common guillemot chicks ready to fledge.

The chicks fledged at the end of the season and hopefully they continue to grow well!