Tracking White Storks with GPS/GSM technology
All White Storks used to winter in Africa but in recent decades an increasing number has started wintering in the southern Europe. This major shift in migratory behaviour is the focus of this project - why have these birds suddenly changed their behaviour so radically? Is it due to climate change or due to some other anthropogenic factor? The BTO is co-supervising a PhD project based at the University of East Anglia that is tracking adult White Storks caught in winter in Portugal to try and understand why birds have changed their migratory behaviour.
Where are the birds now?
The locations are received five times each day (once at night time and 4 times during the day) and the maps are updated once a day at 10:30GMT. You can zoom in on the Google Map to look at each bird movements over the past 90 days in detail. The birds are named - a clickable point is located over the last location received for this bird.
22 April 2013 Goncalo has started transmitting again after a long period. One of our theories for the mysterious stopping and starting of the loggers is that perhaps the logger housing is not sufficiently waterproof so the logger fails after heavy rain and until it has dried out. The breeding season is in full swing so the eggs of the birds carrying logers should soon be hatching. This means the adults should now be foraging much closer to their nests as they tend and provision their chicks.
24 March 2013 As the UK shivers, the sun is shining in Portugal and breeding season is getting under way for the white storks. I have been looking in to nests with a camera pole and between 40-60% of the white storks have eggs so far, depending on the region of Portugal. As many nests are very high I was not expecting to be lucky enough to view in to the nests of any of our logged birds. Aldina has been very obliging and has chose to nest on a ruined building within reach of my pole. She is in a colony with 10 other nests amid beautiful rolling cork oak grasslands –prime habitat for storks. Currently she has 3 eggs. Storks lay up to 6 eggs over approximately a week but usually only fledge 3-4 chicks. Last year was a very bad year for breeding storks in Portugal due to poor weather. This year looks set to be a much better breeding season. As you can see from the map, Joao has also started wandering. He seemed to be on a nest south of Beja and had a regular foraging pattern in fields and on landfill. Is he a young bird or was he pushed off the nest by a migrant returning just in time to breed?
4 March 2013 This week the star of the show and the focus of much speculation has been Jose. Having spent the winter mostly feeding on landfill in central Portugal, he then moved west and fed almost exclusively on rice fields for over a week. He then made a rapid movement eastwards over the Spanish border. Reasonable numbers of birds ringed in Germany are found wintering in Portugal - was Jose headed for breeding grounds in Germany? Since then he has circled back into Portugal. Storks are long lived (25-30 years) and usually do not breed until they are 3 years old. They are difficult to age once they have molted out of their juvenile plumage so it is possible that Jose is a young bird seeking a suitable nesting site for a first breeding attempt. It will be interesting to see where he decides to settle and whether he tries to breed this year.
19 February 2013 The 14 tagged storks movements are being followed closely and the latest project news will be regularly posted here. We are following birds known to be resident in Portugal during the winter. From the data received so far, we know many of our storks (e.g. Goncalo and Aldina) are already back on their breeding territories and defending nests . Migrant storks used to return to Portugal from Africa to breed almost immediately upon arrival in March. However, in recent years migrant white storks have been returning increasingly earlier from Africa and the majority are now returning over a month earlier than they did in the 1980s. Storks usually return to the same nest but competition for the best nests is fierce. Will our resident logged birds keep their nests, or are the returning migrants the next owners? We shall find out over the next few weeks
Updates by Nathalie Gilbert