31 May 2011

30 May: Fridtjof takes a surprising route over the mountains

Fridtjof comes with a big surprise. All birds we have tracked so far have taken a route along the coast around Norway, just as Ebbe did - and the vast majority of observations from Norway is likewise from the coast. Fridtjof however migrated via Oslofjorden, climped over the mountains, flew down via Sognefjorden to the coast, and then followed the 'normal route'. Departed 26 May in the morning and arrived at Svalbard 30 May 9:00. The journey included several short stops and two longer stops, one i Oslofjorden and one in Barentshavet 118 km W of Bjørnøya. 

29 May: Why names?

When we followed the Light-bellied Brent Geese with satellite transmitters back in 2001 we named them just to give them a bit of personality – instead of just using the ringcode ”white DY” seen above on this beautiful more than 15 year old female goose, still going strong in 2011. To keep up this tradition, we would like to introduce you to:

Magnar is named after Magnar Norderhaug from Norway, who worked for many many years with birds on Svalbard, and amongst other wrote the nice book ”Svalbards Fugler”.

Fridtjof is named after Fridtjof Mehlum from Norway, who together with Jesper Madsen took the initiative to start studies of the breeding biology of the Light-bellied Brent Geese in Svalbard, and also published data about their distribution prior to and after breeding.

Steve is named after Steve Percival from England, who initiated large-scale colour-ringing of Light-bellied Brent Geese. He caught and ringed 333 geese during 1991-98 in Lindisfarne, the only regular wintering site of international importance for birds from our study population in the UK.

Ebbe is named after Ebbe Bøgebjerg from Denmark, who fired the cannon-nets and caught the first 11 Light-bellied Brent Geese we followed by satellite telemetry in 1997 and 2001. Before his retirement he also lead our catch-teams when we colour-ringed 140 Light-bellied Brent Geese in Denmark during 1997-2006.

Caretaker is named after BirdLife Denmarks local caretaker group of EU Special Protection Areas no. 27 and 25, the two areas where we caught the Brent Geese. The combined area annually holds about half of the flyway population is spring. The caretakers contribute to our studies of Light-bellied Brent Geese by counting them, reading their rings, and also acted as handymen during the 2011 captures.

Niels is named after Niels Søndergaard from Denmark, who together with his 140 dairy cattle and their calves takes care of most of the saltmarshes on Agerø. Without grazing management the marshes would be overgrown with reedbeds or very tall marshes – and the geese would loose one of their most important spring-fattening areas.

Loff is named after Longyearbyen Feltbiologiske Forening (LoFF)– a dedicated group of primarily amateur naturalists but also professional biologists, many of which over the years have contributed with important knowledge about the Brent Geese in Svalbard. http://www.loff.biz/LoFF_Om_oss.html

Jan Ove is named after Jan Ove Bustnes from Norway, who came down with the first handful of satellite transmitters in 1997 – and helped us to start studies of Brent Goose migratory behaviors with modern technologies.  

29 May: Ebbe first goose to arrive in Svalbard

As mentioned previously Ebbe was among the first departing geese from Agerø, and indeed the first to set foot on Svalbard, where he arrived 29 May at 9:00. Having departed in the morning of 26 May - the journey took him three days, and included a 2 hour rest near Jomfruland (just after having passed Skagerak), an 8 hour rest near Toftøya in Nedstrandfjorden, and a 5 hour rest at near Håsteinen i Ryggsteinhavet.

26 May: First mass migration

26 May 2011 in the morning the first larger flocks of Light-bellied Brent Geese took of from the Agerø island and its vicinities in the Limfjord area. This was witnessed by Erling Andersen, one of our volunteer bird counters from the local BirdLife Denmark caretaker group - who saw five flocks with a total of 933 Brent Geese departing on northbound migration between 5:18 and 6:07 in the morning.

Later during 26 May well over 2,500 Brent Geese were reported on northbound migration over Norway by local observers - typing their data into the fantastic Norwegion citizen science portal Artsobservationer.

Four of the PTT birds, Jan OveEbbe, Niels and Fridtjof also took off this morning and the question now is - how will the satellite tagged Brent Geese fly up to the Arctic - and where will they end?

4-25 May: Waiting for migration to begin

Although the main purpose of our project is to follow the long-distance migrations and site-use of the Light-bellied Brent Geese in the Arctic - we've been surprised and pleased to see a load of new information are coming out of the satellite PPTs well before migration. We had no clue that birds behave so differently in the spring staging areas - with some being very site-faithful to a corner of the general spring staging area, like the gander Ebbe (upper map), and others 'moving all over the place' like gander Caretaker (lower map).

3 May: Catching and handling - isn't that harmful?

Truly - it seems obvious. The birds must be scared by a big bang, a cannon-net flying over their heads, a herd of people running over the marshes to pull the geese out of the nets, and some hours of handling.

We do our utmost to harm the birds as little as possible. When they are in the net we cover them with a tarpaulin cloth so they can't see us, and that makes them calm down. In between handling they are stored in tents on the marshes or in wooden storing boxes lined with hay, again so they can't see us. When we catch the geese, an average bird is handled less than 10 minutes (we handled 60 birds between 7:00 and 12:00 3 May). All birds are released together, so paired birds and goslings have a chance to find each other soon after release.

But perhaps the best evidence for a low impact is that hundreds of geese including several of the newly ringed geese have been seen almost daily on the catchsites after our intervention, that birds easily can manage to fly 2,500 just a few weeks later - and that we still can find live birds in the flocks, we ringed 15-20 years ago. Additionally seven of the eight transmitter birds were observed in the field between 4 May and 25 May, six of them with a female we also ringed, and one with an unringed partner.

Why Brenttags?

The main purpose of the Brenttags study is:
·       to revisit our previous 1997 and 2001 studies of their migratory behavior and energetics - now hopefully both in spring and autumn
·       to look much more into details about how the Brent Geese spend the summer in the Arctic.

We can improve the knowledge from the previous studies because we now use PPTs with GPS accuracy (i.e. much more precise locations, and including altitude also, so we can study how they respond expected variable wind conditions along the route). 

The PTTs are also with solar panels, so we hope they will maintain their batteries much longer than previously studied birds.  

30 May 2011

3 May: Why not catch some more?

And so we did - another 60 birds were caught at 3 May in the morning, now at the Boddum Peninsula in Thy, Denmark. Again all were individually colourringed and 4 males were fitted with PTTs

27 April: First you have to catch them

And that is not always easy. In 2010 we tried for two weeks without luck - so it was a great pleasure when our chief cannon-net technician Jens Peder Hounisen pressed the button and caught the first 19 geese at Mågerodde on the island of Mors, Denmark, in the evening of 27 April 2011. All were ringed with an individial colour-ring combination and 30 g solar GPS PPTs from Microwave Telemetry was fitted to four selected males.

Why Blog in English

As a matter of fact: More understands English than anything else. The Brenttags project is funded by the Norwegian Directorate for Nature Management - so perhaps we should develop this in Norwegian. But this sounds simpler than it is if you are Danish - because our languages are quite similar yet so different that one would be doomed to present some poor Norwegian on this Blog. Our Brent Geese also winters in England, the Netherlands and Germany, so even more languages at stage. Hence English.