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Looking closer into the "shit"... How much do we know about Barnacle geese from their droppings?

Ny-Ålesund is the world’s northernmost civil settlement, situated at 79 degrees North in the north-western region of Spitsbergen, Svalbard.

At present time, it is a research station with scientists from over 10 different countries. It has only around 30 – 35 residents living there throughout the whole year. But in the summertime the population count can on occasion rise to around 120 people.

Maarten Loonen is a polar researcher who has been travelling to Ny-Ålesund since 1990 to study the behaviour of migratory birds, changes in their living conditions and the consequences of climate change.

This year, there were 6 people working together in the Dutch station.

They arrive on Svalbard when the goslings are close to hatching. They check the nests, count the eggs and make maps. Maarten has been doing this over 30 years and he has wonderful data on the moment when eggs hatch.

"What we see actual that the geese do hatch now almost 10 days earlier than they did in the 90s because of climate change".

So they did adapt, but the only the moment in which they adapted is two specific years. They jumped one week and then 10 years later, they jumped another week. In that, they are following climate change.

After hatching, they go on the tundra. Whole families graze here and the science team does a lot of observations. They try to follow specific individuals and their families - they can recognise them by the rings on their limbs. Information like how many young they have and where they graze are needed to get the whole picture.
The small lake just behind the station plays an important role for geese, they always tend to come here.

For geese the summer is very short. Geese and ducks have adapted (especially geese) to change their flight feathers in a time in which they are caring for their young too.

It's an adaptation to the short season of summer. Normally a bird is changing feathers every year, but one by one after the reproduction is over. Of course, if you have to bring food to your chick, you have to be able to fly.

For the geese it works differently. They walk on the tundra and the young graze with their parents. Therefore, they can lose the feathers already in this time. Some of the geese lose them in one stroke of the wing and then suddenly they can't fly anymore. When the feathers grow this can happen really fast - seven millimeters a day!

Geese are silent when they are molting. They know that they have to be careful with being seen. After that you will hear them honk.

We know very well that the season of hatching is earlier. But what happens with the molt? It's seems like the males and females have difficulty to move the molt earlier.

So how does the fieldwork and collecting of information look like?

Researchers herd the flock into soft fence nets. Sometimes people from Ny-Ålesund are involved to help with that. They close it and wait 2 hours to let them empty their guts (to be able to inspect the cloaca without risking to be shat on).

Afterwards, if catches are without goslings, one by one (the adults) are measured and immediately released.

Otherwise, if the catch is with goslings, the young are measured first and then kept in a second soft fence net. Successively, all the adults are measured and put together with the goslings. When the process is over, the flock is released all together.

The measurements...

The measurements they take on geese during catches are: weight, tarsus length, midwing length (the length of the folded wing), bill length and primary 9th length (the longest feather, which during molt is the most visible when it falls and regrows).

One of the projects this year was to put 24 collars with GPS tracker on the geese necks.

It's not possible to read the GPS information in Ny-Ålesund, because of the radio silence. But as soon as the geese come in contact with the telephone system G4, they can send the information of all the places they've been visiting in this period.

This is a new technique for the Barnacle Geese. The collars are light, they weigh only 20 grams, they are thin and fit on the goose neck.

The reason for putting on GPS collars is connected to their droppings.

Isabella, one of the researchers, has a project where she tries to collect individual droppings. She wants to study the rhythm of hormone levels and is interested in how three different hormones are doing in constant light, during migration and on the wintering grounds when days are short.

They collect droppings every period, every three hour block of the day and as much as possible from neck banded geese.

All geese from Svalbard go to Scotland and England, but they will have some stops on the way. Because of the GPS position the team can find the exact place to try to see the bird again and collect droppings during the migration too.

An interesting thing that they found and saw in Ny-Ålesund is this interaction between geese and reindeer. If you have a chance to observe big male reindeer with big antlers, you will see that they're not eating grass and moss. They're eating goose droppings!

The team could see a few times that a reindeer walked to the young geese, chased them away and ate the droppings which they the gosling left on the ground.

In the grass are more nutrients, which the young require. After a while they produce black droppings which the reindeer love. Opposite to the droppings from adults without young, which are brown from eating the less nutritious mosses.

This is an example that shows how sensitive this system is to food quality.

With a very simple digestion inside the goose droppings is only grass or moss.

The reindeer need 48 hours to digest the cellulose (that's the main part of the energy), and this is only possible because of the bacteria in their intestines. Geese don't have those bacteria and produce a dropping one and a half hours after swallowing the grass.

Goose droppings have a huge impact on tundra as the population grows. They fertilise the tundra and make it easy for plants to grow. But on the other hand as the geese remove many edible plant species the grazed tundra has much fewer flowering plants. Only plants which are not eaten by the geese flower e.g. Saxifraga cespitosa.

"The geese can also swim in the lakes, and leave a lot of droppings inside. We study the effect of it on the lake ecosystem." Maarten and his team did many experiments and they see that with the growing temperatures the Lepidurus arcticus (small tadpole animals, full of nutrition, good food for geese) will have a much harder time to survive.

Maarten collecting Lepidurus arcticus

Predation is also very important.

One of the main predators is the arctic fox. One den with puppies can take up to 400 goslings in one summer season. They take eggs out and place them somewhere else. It's food for them to survive the long and cold winter.

But what's happening more recently is actually polar bears coming in. In the end of June/beginning of July, there has been 3 polar bears almost constantly in the fjord.

In 2018, 80 percent of the nests were taken by polar bears and this year 85 to 90 percent. This is a new fact. "We don't know what the future balance will be. Maybe barnacle geese will have to move to the cliffs as in the early days, but the cliffs do not have enough space".

These bears take the egg on the paw, press down on it to break it, and then they lick it. So these egg eating polar bears are easy to recognize because of their yellow paws. After eating 40 to 60 eggs, they tend to stop eating eggs and they need a break.

The glaucous gull also come into the picture. They can swallow a whole goose egg at once and they are companions of the polar bears.

Of all three populations, the Russia/Germany & Netherlands population is currently the largest and is expected to grow to 8.7 million birds from the estimated 1.2 million in 2014. The geese are on average 16 years old. They are reproductively active for 14 years. This equals 70 eggs (14 x 5) per female in a lifetime. If they all would grow into adults, then the world would be black and white. So it's very good that there is predation.

"Let's say we can study the system right now, but bringing history into the data is very important to understand it. When my university came here for the first time in 1979, the first conclusion was that the space is not limited, because they saw lots of place for geese and they could nest close to each other. At that time nesting space was not a problem. And then in the 80s, the amount of food during the molting period became the major limitation. But now with the polar bears which have a easy access to nests space start playing an important role. How will this be in the future? We don't know. Everybody talks about the ice retreating with not enough ringed seals to hunt. But we don't know much about polar bears living in these fjord systems, and actually there are now many harbor seals, which is a new development, too. When I came here in the 90s, we only had a few ringed seals.

It's very important to also think about how the world was 50 years ago."

Created By
Dagmara Wojtanowicz
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Dagmara Wojtanowicz