Biologging around the clock

The understanding of the interplay of movement, behaviour and physiology that biologging offers has applied relevance for a range of fields, including evolutionary ecology, wildlife conservation and behavioural ecology. In recognition of this, the Journal of Animal Ecology has an upcoming Special Feature on Biologging  (submissions due 20th September).

A great advantage of biologging is that it allows data collection from some of the toughest environments on Earth. But this still creates some challenges for scientists. In this ‘field diary’ blog post, we hear from Marianna Chimienti, Jannie Fries Linnebjerg, Nicholas Per Huffeldt, and Flemming Ravn Merkel – an intrepid field team who have just returned from a seabird tagging trip in the Arctic.

Fieldwork in the Arctic. What an adventure! We, Marianna, Jannie, Nicholas and Flemming (Fig 1), embarked in a breath-taking adventure in July 2018 travelling to an island called “Kippaku” (meaning “cut in half” in Greenlandic) in Northwest Greenland, to carry out research on seabird populations. With our tents, warm sleeping bags, food and water supplies we were ready to camp for the next two to three weeks. We always camp on the island by ourselves, but this year a carpenter also accompanied us; he was to finish a small research station that was started last year. The coast of Northwest Greenland is a wild area. After leaving behind the last few human settlements, our days were characterized by 24 hours of continuous light, the roaring thunder of icebergs calving and the sounds of thousands of seabirds (thick-billed murres and kittiwakes); the reason we were there – of course! The view from the island was truly magical!

Fig 1 - Arctic seabirds.png

Fig. 1: Left: from left to right, Nicholas, Flemming, Marianna and Jannie. Right: View of Arctic fjords from Kippaku. Photos: Flemming Merkel and Marianna Chimienti

For Marianna this was the very first experience in the Arctic, she just started a post-doctoral research position at Aarhus University. She carries out research related to animal movements and behaviour analysing data collected with high resolution loggers such as accelerometers, time depth recorders and GPS. By developing and applying approaches for the analysis of movement data, her research aims to understand how and why animals make decisions while moving in their natural habitats. Ultimately, her research aims to understand and predict how populations are affected by climate change.

Jannie has been working in the Arctic for the past 10 years and is currently doing post-doctoral research at Aarhus University. Like Marianna, Jannie also uses high resolution loggers to look at animal movement. Her current research examines how diving seabirds cope with the harsh weather and low food availability they experience during winter. More specifically, she is investigating whether food availability at the different over-wintering areas for thick-billed murres breeding in the North Atlantic, can be the explanation behind the differences we see in population trends (declining vs stable).

This was Nicholas’ 8th season on Kippaku and his 9th in Greenland. He just finished his PhD at Wake Forest University, USA, focusing on the ecological and physiological mechanisms underlying biological rhythms in polar environments, and he is beginning as a post-doctoral researcher at Aarhus University. During this season, he was collecting bio-samples to identify physiological underpinnings of the sexually-segregated daily rhythms of breeding murres that were described previously from data collected on Kippaku.

Flemming is a senior researcher at Aarhus University, with more than 20 years of fieldwork experience in the Arctic. He also works for the Greenland Institute of Natural Resources where he is in charge of the seabird monitoring program in Greenland and for providing the scientific advice to the management department within the Greenland Self Rule Government. Consequently, Flemming is focused on the applied aspects of the research – how can the results add to our understanding of population trends and how can it be used to improve the management of the species.

Together our research uses bio-logging for linking thick-billed murres’ (Uria lomvia) movements and activity to physiology and population dynamics by recording foraging movements at high resolution during the continuous daylight of polar summer, behaviour across the annual cycle, and breeding success and survival (Fig 2).

Fig 2 - Guillemot and seabird colony

Fig. 2. One thick-billed murre standing on a breeding ledge on Kippaku in Greenland. (Photo: Marianna Chimienti)

3rd-6th July 2018 – We were meant to be on the island, but no! Fieldwork never goes as planned, especially when travelling to remote areas and having a narrow window of time to conduct the work

We began with a three day delay. This was due to both technical and weather problems with our flights, but we reached our final destination on the 6th of July. We always try to time our arrival at the field site around mean hatch date, when many pairs transition from incubating eggs to rearing chicks. However, guessing the timing is difficult in remote areas, and we are unable to take scouting trips to check on the breeding stage of the birds. We have to rely on data collected in previous years. Even with the best planning, we never know what to expect. Depending on the environmental conditions encountered the previous winter and those of the current breeding season, things can be very different between years. Due to a late and cold spring in western Greenland this year, and our relatively early arrival (compared to other years), all birds were still on eggs.

7th-9th of July – We start our work by monitoring the population

As part of the yearly monitoring programme, we estimate the survival of the breeding birds. This is done by identifying individual birds marked with unique colour rings. To make sure we cover all hours of the day we scheduled observations across the entire daily cycle. We typically sit on the top of the cliffs, in a strategic point where it is safe and observe the part of the breeding colony that we call the “observation plot”. Each of us was assigned multiple two-hour periods of observations, where our main task is to read the number on the colour ring attached to the leg of the murres.

Another task was to check and download data from a number of permanently installed time-lapse cameras.  These cameras take pictures every hour on the hour throughout the breeding season from late April until the end of August. By means of advanced digital image analysis it is possible to quantify the breeding success of the murres within these study-plots. The cameras are also used to document changes in the timing of breeding and to quantify variation in attendance patterns.

Also, there was plenty to do helping our carpenter to finish the research station!

10-13th of July – We decide to adapt our work to the weather conditions, until we are caught in a storm!

A combination of fog, clouds, light rain and sunshine is often what is to be expected in the Arctic. This year however, the metrological service also told us that several low-pressure systems with strong winds were heading our way. We had already been through some heavy rain and strong winds and apparently more was on the way! We therefore decided to begin deploying accelerometers, retrieving the TDRs deployed the previous year, and take bio-samples. We made a final check of the accelerometers’ settings and we planned our visits to the colony.

Fig 3 - Accelerometers charging and deployment

Fig. 3 Accelerometers on charge at our power station just installed inside the research station. Jannie (left) and Nicholas (right) preparing the climbing gear for safely working near the cliff edge. (Photo: Marianna Chimienti.)

Carrying out tracking work on seabirds can be very challenging and needs to be done safely, with the maximum respect toward the animals and with precise research questions in mind. Because of thick-billed murres’ sexually segregated activity cycles (males normally incubating/brooding during the day and females during the ‘night’at Kippaku (Huffeldt and Merkel Biol. 2016), we planned visits to the colony for, both deploying accelerometers and retrieving the TDRs, when we expected the best opportunity to meet males or females at the colony. This way we could get equal representations of behaviour from both sexes. Happy with our first retrieved TDRs, deployed accelerometers, and collection of bio-samples, we just had to wait for a few days for the accelerometer to record foraging trips, hope to keep retrieving our loggers, and for some good weather! Unfortunately the latter did not come. Sudden changes in weather conditions and strong storms are becoming more common as result of climate changes. We were unlucky to witness one. On Friday the 13th of July, the day started with rain, and ended with a very strong storm with large amplitude wind gusts up to approx. 65 knots. Luckily, our small research station was just finished and we took shelter. However, some of our sleeping tents sustained damage.

Fig 4 - The July Storm

Fig. 4. During and after the storm on the 13th of July. We are collapsing the tents as the wind is becoming too strong. (Photos: Flemming Merkel and Marianna Chimienti)

15th -18th of July – Recover from the bad weather and last days for retrieving our loggers. Positivity is the key!

The storm was followed by a couple of days of strong wind, fog and light rain. We had to be sure the rocks were dry enough to safely work near the cliff edge.  We were curious to see how the seabirds had coped with such weather conditions. Chicks were just hatching and some of our loggers were still out there including a video camera. Locked in the research station we were hypothesizing all possible scenarios!

Luckily when the weather was good enough for us to get around the island, we discovered that the video had survived the storm, although the external solar panel had been ripped off and later found at the other side of the island. We could also see some of the loggers still attached – what a relief! Most of all, we soon started to observe hatching eggs! We then planned the last retrieval trips.

In summary

A very unusual breeding season for seabirds, unforgettable for us, and full of surprises and many stories to tell! Surely, data collected with a combination of bio-logging technology, cameras and novel molecular techniques, as those collected during this fieldwork, will help us understand more about how these animals face both drastic and cumulative changes of environmental conditions.

More Info:

Huffeldt, N.P. and Merkel, F.R. (2016). Sex-specific, inverted rhythms of breeding-site attendance in an Arctic seabird. Biol. Lett. 12: 20160289.

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