Tracking White Storks with GPS/GSM technology
1 October 2013 Last week two birds, fitted with loggers that have stopped transmitting, have been sighted on a landfill in Portimao in the Algarve, southern Portugal. It is great news to know Ricardo (33+) and Brutus (3W+) are both alive and well, despite not transmitting since the the summer. Their location in southern Portugal suggests they may be about to migrate to Africa. This shows the importance of colour rings in tracking birds and I urge anyone who has sighted any storks with a leg ring containing a '+' symbol to get in touch.
Meanwhile, as you can see from the map, most of the chicks have crossed in to northern Africa. Here the GSM network used to transmit the data is rather patchy, so we dont expect updates from these birds until they move further south. The loggers can store thousands of data points and will transmit them all once the bird is back in GSM coverage.
14 July 2013 With their chicks successfully fledged, all our adults (red markers) have started post-breeding movements. Sadly, since breeding and just as things are getting interesting, several adult loggers have stopped transmitting, including Phil, Carlos and Nathalie. This is likely due to the end of their onboard batteries. Whilst the 10 transmitting adults are apparently staying in Portugal, at least for the time being, Phil moved rapidly to Southern Spain before his logger stopped. Was he a migrant? It is a shame we will probably not know. I encourage everyone visiting Africa or Portugal this winter to keep an eye open for Phil’s blue colour ring 34+ and let me know where and when you see it!
Meanwhile, the logged chicks (yellow markers) are also on the move and have headed south towards Gibraltar. Storks are soaring birds so they do not like crossing open water. Like many other migrant species they make the crossing to Africa at the narrowest possible point: Gibraltar. Migrants gather here in large numbers and may remain for some time waiting for favourable conditions to make the crossing. Will all the chicks migrate? Where in Africa will they go? Keep checking the map to follow their progress.
14 June 2013 Several of our birds failed to breed successfully this year and, as you can see from the map, these birds have already left their breeding areas and begun post breeding season movements. Phil has reached Spain whilst Sara visited Spain and then came back to Portugal. In contrast, Carlos, despite not rearing any chicks is still staying close to his nesting location. Ricardo, Nuno, Goncalo and Rosa were amongst the earliest successful breeders and their chicks have now fledged. Rosa is already on the move now that the chicks are fully independent. Rosa headed east and is currently on the rice fields of the Tagus estuary near Lisbon.
Aldina still has chicks in the nest and, very excitingly, they are being fitted with GSM/GPS loggers too. A total of 10 chicks from Nuno and Aldinas colonies have been fitted with loggers so we can follow their movements. Will they all migrate to Africa? Aldina's chicks will be particularly interesting to follow because we will be able to see how long they stay with their parent. Will Aldina teach the chicks to feed on landfill in Portugal during the winter or will the instinct to migrate be stronger? A map of chick movements will be created soon so you can follow their fascinating progress.
15 May 2013 Those of you who are following the storks closely will notice the live map has changed. The GPS points from winter have been cleared away to make it easier to follow the most recent, breeding season movements. At this time most of the storks are busy feeding their young and not travelling far from the nests. As the chicks get older they require ever more food and the adults are hard at work finding sufficient food for the hungry mouths. Brutus and Ricardo have stopped transmitting but their nest locations are known so updates on their breeding progress will continue.
13 May 2013 The breeding season is well underway. This season seems set to be a good year for breeding storks with no sign of the rain and/or low temperatures in the crucial first weeks after hatching that caused many nests to fail last year. The birds do not breed in synchrony and, so far, I have seen chicks ranging in age from just hatched to 30 days old, whilst other adults are still incubating eggs. Our tracked birds feature along the full length of this spectrum with Ricardo's chicks being oldest and Carlos perhaps still incubating eggs (or having chicks too young for their heads to appear above the sides of the nest yet). See my blog storkphdtalk.blogspot.co.uk for photos of logged birds on their nests.
Sadly, Sara seems to have failed breeding in the last few days. I visited her nest on 5th May and saw no sign of her, or chicks. After a day or so without transmitting she went to Spain but, as you can see from the movement data, she has since returned to her breeding area.
The reasons behind her breeding failure are unknown. The weather has been good and predation is unlikely because there is always an adult in attendance at the nest. It is possible that late returning migrants out-competed her for her nest however I saw no other adults there. Maybe her partner died or she is a young, inexperienced mum and was not tending her chicks with sufficient care and therefore they did not survive. It is not uncommon for first-time breeders to fail.
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.
I am heading back out to Portugal tomorrow to view in to the nests and monitor progress. I will report soon with news on how many chicks Aldina has and how the other logged birds are getting on. Meanwhile visit my blog http://storkphdtalk.blogspot.co.uk/ for pictures of logged birds on their nests and some footage of viewing into nests with a camera pole.
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?
10 March 2013 The sharp eyed among you will have noticed that Ricardo has not been transmitting since the end of January. In the last few days GPS fixes have been flooding in again from his logger as if nothing had happened. We are still trying to understand why he didn't transmit throughout February but we are delighted to have him back on-line. I leave for Portugal tomorrow to start fieldwork. I will be visiting the nesting locations of the logged birds to see if they are in a breeding pair. They may already be sitting on eggs. Next update from Portugal!
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