We have noticed for years that 50% of the westward-moving storks (Ciconia ciconia) of the northwest population have altered their migration behaviour significantly. A high percentage of these birds no longer fly to West Africa but instead overwinter in the south of Spain. The birds stay there to find food, mainly on large open waste disposal sites.
The question what triggers the altered migration behaviour has not been answered yet. Could past “reintroduction projects” be responsible for it? Half a century ago, white storks from North Africa were “imported” into Switzerland and indirectly also other countries in Western Europe to build up a population again that had almost become extinct by that time. The genes of the “reintroduction” birds can probably be found in many “European” storks. Do the genes perhaps have an influence on the route and distance of stork migration? What role does climate change play? The project “SOS Stork migration in the face of change” aims to address these questions.
Intensive project-based public relations work is planned to raise awareness of the “Altered Migration Behaviour” issue both among the general population and the professional community. The project is designed as a cooperation of various project partners (organisations and experts) in all countries along the migratory route of westward-moving storks.
We look forward to working with additional project partners over and above the ones listed here.
As part of the project “SOS Stork – Stork migration in the face of change”, project partners work together with sponsors each of whom finances one or more of the satellite transmitters and their running costs (see project website of Stork Switzerland “transmitting storks”).
According to an EU guideline from 1999, which is to be implemented by 2016, organic components of waste deposited in EU countries have to be gradually reduced to 3%. In plain English this means: leftover food and similar household waste will have to be separated and composted, burnt or used in biogas sites. What impact will the disappearance of the food source “waste” have on the storks spending winter in southern Spain? To what extent has the EU guideline already been implemented? What is the timescale for the implementation of the guideline for waste disposal sites in southern Spain? What is the importance of landfill sites for storks in comparison with other food resources in the region?
Project progression summary as at December 2012
After several months of planning and preparation, the actual project work began with a reconnaissance and research trip in January 2011. The project manager travelled around Spain for several weeks to determine the status quo, make first investigations and establish contact with potential project partners. Various disposal sites were visited.
In Switzerland, nine storks were equipped with GPS satellite transmitters in 2011 and 2012: originally, five young storks were fitted with satellite transmitters back in 2011: Bruno (Uznach/SG), Dani (Carthusian Monastery Ittingen/TG), Amelios (Basel Zoo), Düschess (Biel-Benken/BL) and Sämi (Murimoos/AG). Three of these storks had an accident as early as 2011. The transmitters of Amelios and Düschess were recovered and reused in 2012 on the young storks Elvis (Biel-Benken/BL) and Toni (Rothenburg/LU).
Another four transmitters were purchased in 2012 and attached to the following young storks: Sünni (Uznach/SG), Yumna (Basel Zoo), Amelios II (Basel Zoo) and Manuela (Hünenberg/ZG). One or two of these birds dropped out of the study in 2012 (Sünni and maybe Manuela). The transmitting stork Dani met with an accident in 2012.
In total, eleven young storks have been equipped with telemetric transmitters since the beginning of telemetric measuring in 2011 and 2012. At the end of 2012, only five (maybe six) storks were still alive (Sämi, Elvis, Yumna, Amelios II, Toni and Manuela) and transmitted data. At first sight, the drop-out rate of about half of the young storks seems very high, but it corresponds with the mortality rate that is to be expected for young storks in the first year of their lives.
Transmitting stork “Bruno
As early as October 2011, Bruno had an accident at the waste disposal site of the city of Kenitra in Morocco, north of Rabat. Thereafter, coordinates from his transmitter continued to be received sporadically for about a year, until 23 October 2012, always from the same place. The sensor data clearly showed, however, that the bird was dead.
Transmitting stork “Dani”
Having spent most of his time on the waste disposal site of Ejea de los Caballeros (north of Zaragoza) by the end of 2011, Dani remained there until the end of April 2012. He then moved east to the Mediterranean coast and had flown over the Pyrenees in northerly direction by 11 May 2012. He eventually reached Bourg-en-Bresse, located only approximately 70 km west of Geneva, in the middle of May. He stayed in the vicinity of the waste disposal site there from mid-May until the end of August, and within a few days he flew south through the Rhone Valley and stayed in the Camarque until November. In the middle of November 2012, he had an accident there, a few kilometers south of Étang de Scamandre.
Transmitting stork “Amelios”
As early as the end of November it was apparent that Amelios had died in Spain, close to the city of Teruel in August 2011. On 24 March 2012, a team of our project partner SEO (Spanish Ornithological Society) managed to recover the transmitter following an intense search. Arturo Bobed Ubé of the SEO Teruel reported the following: “Yesterday we found Amelios’ transmitter in Jabaloys (Teruel). It was located in difficult terrain. We first found a few feathers and then the transmitter close to a steep slope …” The transmitter had been attached to the young stork Toni in August 2012 (see rear cover).
Transmitting stork “Düschess”
Düschess was found dead close to the location where it had been fitted with the transmitter as early as August 2011. The transmitter was found by Beat Huggenberger (IIGSFBB Biel-Benken) and was attached to the young stork Elvis in June 2012 (see rear cover).
Transmitting stork “Sämi”
Overwintering in Senegal close to the city of Kaolack in 2011, Sämi was the stork that had travelled the furthest of all transmitting storks participating in the “SOS Stork Project”. In the middle of March 2012, it began its journey back north. A few days later, it reached the south of Mauritania. As early as 14 April 2012, it was in southern Spain and after an exemplary migration path it reached the Lerida region on 23 April 2012. It stayed in the vicinity of the waste disposal site of Castelnou de Seana, about 30 km east of Lerida, until the beginning of August 2012. In the middle of August, it migrated, via various places, to the south west as far as Zaragoza and was located about 250 kilometres south of the waste disposal site at Alcázar de San Juan. Afterwards there was radio silence. It seemed clear that the bird must have had an accident there. All the greater was the joy when, from 15 November 2012, coordinates started coming in again. As in the previous year, the signals came from Senegal, from the area of the cities Kaolack and Touba. A temporary technical defect had closed down the transmitter. Sämi continued to stay in Senegal until the end of 2012 supplying reliable data.
Transmitting stork “Elvis”
On 12 June 2012, the young stork Elvis was equipped with the transmitter that had originally been fitted to “Düschess” who later met with an accident. After spending the first week of August 2012 in Biel-Benken, the bird began its migration to the south. For comparatively short periods of time it stayed near Solothurn, Avenches and Gland and then reached the Rhone Valley and arrived at a location close to Salon-de-Provence on 21 August 2012. It continued its migration on 16 September via Zaragoza to Alcázar de San Juan where it stayed at a waste disposal site for about two weeks. Since the beginning of October, it stayed firmly located in the area of the city of Almagro, often at the waste disposal site there. Since the beginning of December 2012 its transmitter failed several times for a period of about two weeks, probably due to low battery voltage, but current data confirm that the bird is alive.
Transmitting stork “Sünni”
„Sünni“ was equipped with a new GPS transmitter in Uznach on 12 June 2012. From 26 July, it sometimes moved to Hombrechtikon for some time and began its migration on 13 August 2012. Via Lausanne, it flew to a region about 50 km south of Lyon where it stayed close to Saint Maurice-l’Exil together with about 175 other storks until it flew into an overhead line, probably on 16 August. In the evening of 18 August, Jacques Frier found the injured bird there. On 22 August 2012, Jacques Frier handed Sünni over to Pascal Tavernier, the director of the Bird Rehabilitation Station of Saint Forgeux northwest of Lyon. Sünni who had been injured by electric shock suffered a broken Coracoid bone (the equivalent of the shoulder blade in mammals) and burns. Having made a complete recovery, however, Sünni was set free again on 3 October 2012. Unfortunately, its transmitter is no longer functional.
Transmitting stork „Yumna“
Yumna was equipped with a new GPS transmitter at Basel Zoo on 13 June 2012. After some initial “excursions” (of 5 to 10 km) to an area south of the city, it moved southwest on 14 August 2012. From 16 August onward, it stayed in France, in the area of Bourgh-en-Bresse, for a few days. On 27 August, it continued its migration through the Rhone Valley and via Lyon and Valence to Montpellier, where it arrived on 29 August and stayed on a waste disposal site for just a day before speedily continuing its flight further along the Mediterranean coast. It flew over the eastern peaks of the Pyrenees and arrived in Spain on 1 September 2012. It then continued its journey to the landfill site in Lerida without any lengthy stay there. On the waste disposal site in Alcazar de San Juan, in the centre of Spain, however, it stayed for about one week before continuing its migration south on 9 September. It made its next stop at the refuse dump in Almagro from where it speedily moved on to the next disposal site, located in the south of Cordoba. 4 days later, it then headed south-west to the rice paddies on the isle of Mayer, in the Guadalquivir River, about 30 km south of Sevilla. It spent about one month there before visiting the waste disposal site of Dos Hermanas for the first time which is located about 20 km from Sevilla. This disposal site remained its primary place of residence, although it frequently flew over to the rice paddies on the isle of Mayor.
Transmitting stork “Amelios II”
Amelios II was also equipped with a new GPS transmitter at Basel Zoo on 13 June 2012. Apart from a time delay of several days, its migration was quite similar to that of Yumna. Amelios II left Basel on 8 August 2012 in a south west direction. However, the bird did not fly south through the Rhone Valley, but instead flew over the Massif Central a bit further to the west. In Perpignan, it reached the eastern edge of the Pyrenees and flew across the mountain range the following day. On 13 August, it was in Lerida, but did not visit the waste disposal site there. The bird flew west and spent a couple of days in the Ebro Valley east of Zaragoza before continuing its southbound flight west on 2 September. As early as 3 September, it reached Cordoba and already spent its first night on the roof of a large building of the waste disposal site. It stayed (and spent the nights) at the site until 23 September and occasionally visited the nearby valley of Rio Guadajoy, probably in order to drink water there. On 24 September, it moved southwest as far as the rice paddies on the Isle of Mayer close to Sevilla. Occasionally, it visited the dump site of Dos Hermanas, 16 km away. On 1 October 2012, Amelios II flew back to the site of Cordoba, and about two weeks later to the Isle of Mayor again. After several short stays at the waste disposal sites of Dos Hermanas and La Puebla de Cazalla, it spent ten days at the site of Cordoba again from 2 October, only to return to the Isle of Mayor on 13 October. From 24 November until 2 December, a period of time spent at the waste disposal sites of Dos Hermanas and La Puebla de Cazalla followed, then the bird returned to the site of Cordoba where it stayed until the end of the year. This means that Amelios II regularly moved back and forth between various “feeding places” up to 135 km apart.
Transmitting stork “Manuela”
Young stork Manuela was equipped with a transmitter in Hünenberg on 23 June 2012 in the presence of senior civil servant Manuela Weichelt-Picard. On 2 August, the bird left the area of Hünenberg and flew to Uznach, located at a distance of 35 km from Hünenberg. Until 17 August, it kept moving back and forth between Uznach, Lützelsee/Hombrechtikon and the southern part of Lake Zurich, sometimes returning to Hünenberg before flying on to Altreu/Solothurn on 22 August. There, Manuela started its south-west migration on 23 August, eventually reaching the south shore of Lake Geneva on 24 August. On 25 August, it spent the night in the Rhone Valley between Grenoble and Lyon. On 26 August, Manuela reached the area of Montpellier where we received the last GPS coordinates of the bird from the shore of the Etang de Thau at 14:00. At first, the sudden absence of further signals seemed to indicate that the bird must have met with an accident. However, a thorough analysis of all raw data brought to light some coordinates and sensor data which merely suggested a malfunction of the transmitter: a last (if imprecise) Doppler coordinate of 28 August 2012, 12:47 was received from a place about 50 km southwest of Zaragoza. The distance (approx. 530 km air route) to the last coordinate known to us would have been easy to manage in two days. This means that there remains hope that Manuela too may “get in touch” again at some stage in the future.
Transmitting stork “Toni”
Transmitting stork Toni was equipped with the GPS transmitter in Rothenburg on 18 August 2012, the transmitter used being Amelios’ old one. Toni began its migration on 27 August. It flew along the Rhone Valley to the south and, flying along the Mediterranean coast, it reached Narbonne on 5 September. After flying over the far east of the Pyrenees, it stayed, from 7 July, in the area of the waste disposal site of Castellnou de Seana, 30 to 40 km east of Lerida. On 12 September, it continued on its flight to Lerida where it stayed in the area of the city and the nearby waste disposal site Montoliu at least until 4 October. Since we did not receive further coordinates from Toni until 17 December, we assumed that Toni had met with an accident back in Lerida. New coordinates came in on 18 December (from a location approx. 45 km west of Lerida), on 29 December (waste disposal site Montoliu), and finally on 1 January 2013 (city of Lerida). These signals made it abundantly clear that Toni was still alive and active in the Lerida region.
Conclusions drawn from the insights of satellite telemetry until December 2012
Only two (!) of the seven storks equipped with transmitters in 2011 and 2012 who had survived their first autumn migration flew “normally”, i.e. via the Straits of Gibraltar down to West Africa: Sämi has overwintered in Senegal twice so far, whereas Bruno at least managed to get down to Kenitra in Morocco before he met with an accident. Two of the storks spent the winter in the Valley of Ebro in the north of Spain (Dani, Toni), one in Almagro in central Spain (Elvis), and two in the area of Sevilla in southern Spain (Yumna, Amelios II). Thus the results gained so far confirm the alterations in the birds’ migration behaviour, at least for the two thirds of the birds that have survived. One of the causes of this development may be the fact that being “nutrition opportunists”, white storks know how to make good use of the all-year-round availability of food at the waste disposal sites. What role is played by the addition of North African genes through Moroccan and Algerian birds from previous settlement projects will have to be clarified by further investigations, e.g. on the genetics of the populations concerned.
The changes of location of several birds, especially the storks Yumna and Amelios II, have shown that storks are very flexible in their choice of “nutrition habitats”. Both birds moved back and forth between the irrigated rice paddies and waste disposal sites, probably as a result of the nutrition resources available at each place. To gain reliable information on this issue, carrying out field investigations on behaviour and nutrition biology as well as nutrition availability at the various sites should be considered. These investigations could be carried out by Stork Switzerland employees and within the framework of collaboration with Spanish research institutes and universities (e.g. towards degrees and dissertations).
International field research in Spain
The predominantly non-migrating stork population of Malpartida de Caçeres ideally lends itself to investigations on the impact of altered strategies on waste disposal sites. In Malpartida de Caçeres, a large open waste disposal site was closed down in recent years and replaced by a new disposal site (Ecoparque) where waste is increasingly composted or processed in other ways. Field observations by local experts in collaboration with Stork Switzerland will reveal how the storks react to the altered availability of food.
To gain reliable data on the use of the disposal site and the natural habitat of the local stork population, data loggers are currently used there. The devices are about as large as the previously used satellite transmitters. They do not transmit data via satellite, however. Instead, they store GPS coordinates on an internal memory chip. This data is read out with a manual tool, a hand-held base station, at intervals of several weeks. The data loggers are fitted to the birds with the same rucksack harness as the satellite transmitters.
In a first phase, two storks caught with a net gun were equipped with data loggers at the Ecoparque waste disposal site on 3 December 2012. The loggers record three GPS coordinates per hour around the clock. Spanish colleagues (Manuel Giraldo / Environmental Officer, Manuel Iglesias / SEO) have already been able to read out the data. The first results, approx. 3150 data sets in three weeks, provide impressive insights. A first rough evaluation produced the following results.
Stork “Lola” (2381), data from 3 to 28 December 2012:
Despite the presumed unproductiveness of the waste disposal site as a nutrition resource, the stork mainly spent its time at the site to find nutrition. It moved to waters approx. 600 m west of the site in order to drink. On some days the places it stayed at were situated 10 or 14 km north-east of the site. Nevertheless, the landfill site continued to be the centre of the bird’s activities.
Stork “Pepa” (2382), data from 3 to 28 December 2012:
This stork mainly fed at the waste disposal site from 3 to 8 December and from 24 to 28 December. However, it often left the site in search of agrarian country and pasture approx. 2.5 km south-west of Malpartida. The bird mainly spent its nights in its nest in the centre of Malpartida de Caçeres, approx. 10 km north of the disposal site. From 9 until 23 December 2012, Pepa stayed about 60 km south of the Ecoparque waste disposal site, in the south and the east of Merida, mainly on the large waste disposal site of Merida and from time to time in agricultural country, e.g. close to Puebla de la Calzada. The bird mainly spent its nights in a pool close to the shore of the reservoir of Alange.
Both birds prove that waste disposal sites are also of great significance for the non-migrating birds of Malpartida. The fact that the birds flew to disposal sites long distances away in order to find nutrition was a new discovery. In the coming weeks and months the data loggers are sure to continue to supply us with valuable data on habitat use of the two birds.
On account of the good experience gained with data logger technology, two additional older storks will be equipped with data loggers in Malpartida in January 2013. Moreover, young storks are to be equipped with loggers or satellite transmitters in Malpartida. In the long term, ecological mapping according to biotopes and land use in the storks’ habitat is planned. This will permit “intersecting” the data of the birds’ locations with the habitat visited, and thus provide extensive information on the ecology of storks and on the significance of the various types of waste disposal sites.
The first results of three Swiss storks are rather alarming: they show how much time the storks actually spent on waste disposal sites in search of food.
In Dani’s case it was 73% of all days, in Elvis’ case nearly 90% (!), and in Yumna’s almost 60%. This is not guesswork but facts that can be reliably proved by means of the GPS data collected! This means that during their migration, our transmitting storks mainly or even exclusively feed on waste.
A study was recently begun in central Spain by the “National Wildlife Research Institute” (Instituto de Investigación en Recursos Cinegéticos, IREC). It compares animal weight, blood test results and the presence of various pathogens for stork living on landfill sites to stork colonies in their natural habitat. This comparison yielded surprising (preliminary) results.
As expected, stork fledglings hatched in the vicinity of landfill sites are considerably heavier and larger than their counterparts born in, say, a national park. However, the former have a significantly damaged immune system and show after-effects such as blood pigment changes which may be related to poisonous substances. Although this appears to have little effect on their state of health in terms of stork-specific pathogens, such storks harbored bacteria in their intestinal flora which, even if initially harmless, show a high degree of resistance to antibiotics. Resistance, if transferred to other bacteria, can result in dangerous combinations. Hardly any of these dangerous pathogenic agents are found in storks that grew up in the national park.
The Spanish Wildlife Research Institute (IREC), a research organization conducting a wide variety of activities nationwide, is the only scientific institution in Spain in which biologists, veterinarians and representatives of many other disciplines collaborate under one roof. The task force “Bird Pathology” is part of the SABio Department; it will actively collaborate in the project “Stork migration in the face of change”.
Since the beginning of the new project phase of “SOS Stork – Stork migration in the face of change” in January 2011, there have been regular reports on the progression of the project and new discoveries either on project blog (www.storch-schweiz.ch or directly on http://www.projekt-storchenzug.com) All reports published there are still accessible. An important part of the website is the illustration and continuously updated migration movements of the storks equipped with transmitters.