Duck (and virus) movements from afar

A wigeon track on the undulating tribituary of the Pechora river

Before I was a researcher, I was a birder. I spent my free time either birding, or thinking about birds. And my favorite place was Ottenby Bird Observatory. This is where my formative years took place and where I made friends for life. A focus point in my existence to this day. I spent countless mornings ringing birds at the observatory. Sleep deprived, sustained by coffee, sandwiches and tobacco we young ringers often talked about what would happen with the birds we released. Where would they go, what would they do? We marveled about the epic journeys they would undertake, connecting distant parts of the globe.

Sometimes we got answers, for one benefit of ringing is that the rings transform birds into individuals, and hence make possible to follow if they are trapped again, resighted or found dead. The downside is that these are all rare events, especially for smaller birds. For instance, the chance of getting a ring recovery of a willow warbler on wintering grounds in East Africa is very low, somewhere around 1 out of 100,000 ringed birds. For other birds like the mallard, the chance of a recovery is closer to 10% – a considerable difference. In any case, the information you get is limited and usually shown as a dot on a map.

But times have changed. I am older, greyer and possible wiser, a professor working with bird borne infections (but not birding as much as I would like to). I am still very interested in the question of where birds go, and what they do. Fortunately, tracking technology has taken giant leaps and we can now do studies that were unheard of when I was a young ringer. In recent years, my laboratory has been involved in studies investigating movement behavior of mallards. Together with Martin Wikelski’s team in Constance, we have looked at home range sizes and habitat selection of mallards during migratory stopovers, tested the hypothesis that influenza A virus infection impairs movements of mallards, and even made translocation experiments between Sweden and Germany to repeat Perdeck’s classic starling study. We have used Argos loggers, radio-frequency loggers and GSM-loggers, and for each study the loggers have become better and lighter and data ever more detailed.

Right now, we are a part of DELTA-flu, a Horizon2020 EU-project with several European partners. Our role is to investigate the migratory connectivity of waterfowl in Eurasia in light of HPAI virus transmission. Can we use loggers to answer the question about possible routes of virus transmission across continent?

An urban mallard in Roskilde, Denmark, presently hanging out on the Roskilde Festival camping site

The loggers we use come from the company Ornitela in Lithuania, and weigh 10, 15 or 25g depending on which duck species we target. The general rule of thumb is that a logger shouldn’t weigh more than 3% of the bird’s mass, as not to impair it unnecessarily. These loggers are little marvels; they transfer data via the mobile phone network and can be programmed remotely. So far we have deployed loggers in Sweden, Lithuania, Netherlands and Georgia, and are planning to work in Ukraine, South Korea and Bangladesh. We are also waiting for the next leap in telemetry: the ICARUS project onboard the International Space Station. With this technology, loggers may reach 2.5g and hence be put on a larger range of species. What all these loggers do is to provide a real-time window into birds’ movements: Where they are and what they are doing, sometimes even what they avoid or what caused their deaths. We can follow the lives of ducks in great detail.

There is a veritable flood of data, with more than one million GPS points collected already. It is easy to get lost in time just watching the latest whereabouts of the tagged ducks, from the tundra regions east of the Ural mountains to a gravel pit outside Bremen. I hope to write here more frequently, because there is a lot of exciting stuff happening in the lab at the moment – until then, have fun!

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