GPS tracking of lesser black-backed gull at Stora Karlsö

At Stora Karlsö, a small island to the west of Gotland in the Baltic Sea I am studying lesser black-backed gull (Larus fuscus, silltrut). Working with researchers at Amsterdam University (http://www.uva-bits.nl/) and Stockholm University through the Baltic Seabird project (http://www.balticseabird.com/), I am putting GPS devices on breeding gulls, to study their movement behaviour and ecology. This project has now been going several weeks, with an 'advance party' in mid-April to set up the system, then the attachment of devices to the gulls occurring in late May (see my next blog post). Here I will briefly introduce the project, and talk about the April visit.

 

The boat we took out to Stora Karlsö island*

Back in mid-April, Johan Bäckman, Arne Andersson, and I travelled out to Stora Karlsö to install the base-station. I hadn’t previously been to the island so early in the year, it was interesting to see the island still so wintery, with few green leaves about, and fewer birds than usual.

In mid-April the island was still very wintery. Here we are looking back towards Gotland, with the neighbouring island of Lille Karlsö between us and Gotland on the horizon

This summer I am using a recently developed sophisticated GPS device. This records position accurate to a few metres, is solar-powered, which means the device can run indefinitely, and has wireless, Wi-Fi like, communication. With this device it is possible to gain very detailed movement data throughout the year, however data can only be downloaded when birds are in the vicinity of the island where we have a base-station for communication.

A lesser-black backed gull flies along the coast of the island

We are fortunate in having an old hut near the gulls’ nests, so we installed the system there. However this is without power or internet access, so time for Arne and Johan’s technical wizardry! Johan and Arne installed the solar panels and an antenna for a mobile internet connection, turning the hut into a small version of the International Space Station (see photo!) Once set-up we had the fastest internet connection on the island, which will allow remote access of the data from the GPS device, and allow us to change the settings on the devices.

The base station hut, with solar panels and communication antenna for internet access and communication with the GPS devices. A small version of the International Space Station!

It wasn’t all work though, we had some time to see the birds, which were starting to get ready for the breeding season. On the final morning there were many guillemots (sillgrisla) and razorbill (tordmule) on the water. We went up in the light-house lantern, which is really cosy. On the way back to take the ferry from Visby to Oskarshamn we spent a couple of hours in Visby.

In the light-house lantern!

 

In my next post I attach the GPS device to the gulls, and we see some of the exciting first data.

*Thanks to Johan Bäckman for all the images in this post.