Lesser black-backed gulls make daily trips to Mouscron | Flanders Marine Institute

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Lesser black-backed gulls make daily trips to Mouscron

Oostende, 2013.06.18 - A research project initiated this spring by the Research Institute for Nature and Forest (INBO) has revealed that the behaviour of 5 herring gulls and 22 lesser black-backed gulls fitted with a GPS transmitter is highly varied. The herring gulls look for food at sea as well as in farmland. But 7 lesser black-backed gulls make a daily trip to Mouscron via the Baudouin Canal and Leopold Canal, a distance of no less than 65 kilometres, while it has been assumed that this species mainly forages at sea.

Press release by: Research Institute for Nature and Forest (INBO) & Flanders Marine Institute (VLIZ)

It is still too early to draw far-reaching conclusions since only a limited number of birds has been tagged with a transmitter so far, and because their behaviour may change once they have chicks. Nevertheless, these first results are very interesting. They may help to answer important questions in the future: where do gulls find their food and to what extent do they make use of the urban environment? Do they run the risk of flying into the windmills on the Thornton Bank and what impact does this have in terms of population? What is the potential effect of the impending ban on fishing waste discharge on the large gull population?

INBO has conducted research on gulls since 1999. Their population trends, their feeding habits and their migration patterns have been closely monitored for many years. More in-depth knowledge can now be gained with the help of funding from LifeWatch and in partnership with the Flanders Marine Institute (VLIZ). The LifeWatch project is a European initiative which centralises and develops innovative observatories, databases, web services and modelling tools with regard to fauna, flora and ecosystems with a view to specific monitoring over time. VLIZ and INBO provide the Flemish input to this European initiative. Within this scope, VLIZ concentrates on marine areas and is building the taxonomic backbone of the entire system. INBO takes care of the terrestrial and freshwater component.

In addition, INBO is conducting research on the migration patterns of gulls in collaboration with Ghent University (Terrestrial Ecology Unit). Some lesser black-backed gulls fly all the way to Morocco to spend the winter, while others stay much closer to home. Through GPS technology we want to investigate how their migratory and feeding habits are connected to their breeding success.

The first research results

The amount of data is huge and it will take some time before any detailed information can be deduced from them in order to come to reliable conclusions.

However, the first patterns are already becoming apparent, and they do not always match our expectations. The five herring gulls that have been fitted with a transmitter on the roof of the Ostend fish market all have clearly distinct characters. Jurgen, for instance, the male that was the first to be tagged with a transmitter, adores seafood. He can be found at sea every day. He also regularly forages in the farmland in the vicinity of Zedelgem. He literally and figuratively passes over the city of Ostend. Anne, by contrast, appears to prefer shellfish and mainly forages on the groynes in Ostend.

In case of the lesser black-backed gulls, we also see individual differences among the 22 GPS-tagged birds. For example, Hans visits the Spaanse Loskaai street in Bruges almost every day, while Billie prefers to hang around in the vicinity of Oostkamp and Beernem. While it was previously thought that lesser black-backed gulls spent most of their time at sea, it now turns out that this species also regularly forages in agricultural areas. It is quite remarkable that many lesser black-backed gulls make use of the canals in the neighbourhood of Zeebrugge to travel inland. The Baudouin Canal and Leopold Canal serve as a kind of highway. It is also remarkable that the destination of 7 out of 22 lesser black-backed gulls is Mouscron and in particular a site next to a large crisp factory.

Future analyses

The data will be analysed in greater detail towards the end of this year. The way in which the gulls use their habitat will be looked at in detail and the extent to which they make use of agricultural areas, urban environments and the marine ecosystem will be calculated. GPS positions and flying speeds will be collected and data from speed detectors will provide additional information on the specific behaviour of the gulls (roosting, foraging, flying). In about March of next year the first winter data will become available – the data are stored in winter, but they cannot be transmitted because the birds are too far away. The migratory routes and wintering areas of the lesser black-backed gulls are of particular interest, as this species migrates all the way to West- Africa to spend the winter.

Innovative technology

The choice was made to use innovative GPS loggers of the UvaBits type (developed by the University of Amsterdam www.uva-bits.nl). These loggers have the advantage of being light enough to be used for large gulls, having a long working life (they provide data for up to 3 years) and allowing to be remotely programmed. The positions are stored on an internal chip (8 MB) that can be remotely read out via Bluetooth. This requires the GPS-tagged bird to come near an earth station or aerial. This is not a problem during the breeding season when the gulls return to their nest several times a day, but it also means that no data can be read out in winter. However, the stored winter positions can be read out in the next breeding season when the bird returns from its wintering area. The transmitters are equipped with a solar panel so that the battery does not die. In addition to the GPS position they also measure the ambient temperature. On the basis of the measured flight altitude and flying speed (measured by means of an accelerometer) certain aspects of bird behaviour can be mapped.

Keep track yourself

Anyone can keep track of the flight paths of the herring gulls and lesser black-backed gulls. Via the web page www.lifewatch.be/birds you can access the flight path of each one of the 27 GPS-tagged gulls. Via this web page you can also see the gulls on their nest in real time by means of webcams installed on site.

Press contacts

Jan Seys (VLIZ)
GSM: +32-(0)478-37 64 13
E-mail: jan.seys@vliz.be

Koen Van Muylem (INBO)
GSM: + 32-(0)473-81 49 28
E-mail: koen.vanmuylem@inbo.be

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