Logger Project

TRACKING WHITE STORKS WITH GPS LOGGERS
An exciting collaboration between the University of East Anglia, UK, and local researchers in Portugal to attach experimental GPS data loggers to White Storks. 

 

Kris (39+) takes flight with a logger on his back
Summary: GPS/GSM data loggers have been fitted to 15 adult White Storks (Ciconia ciconia) in Portugal during winter 2012/13. Using movement information generated by these loggers we can study the winter and breeding season habitat preferences of the White Storks and their choice of nesting location. We can then relate these to climatic factors (precipitation and temperature) and use our findings to predict the future distribution of this species as a result of predicted climatic and habitat changes.
One important habitat change of particular interest to me is the imminent closure across Portugal of the landfill sites that storks rely on heavily for food supply, especially in winter. Open landfill is gradually being replaced by hi-tec facilities where food waste is handled under cover to prevent smell. This means food will no longer be available to foraging birds, including White Storks, Gulls, Kites and Egrets. 

'Joao' (3X+) almost ready for release -you can just see the logger mounted like a backpack on his back. The hood over his head keeps him calm and stops him being frightened.
Pictured: Nathalie Gilbert, Ricardo Correia, Daniel Cadwallader, Phil Saunders
Why Study the White Stork?   
Changes in Migratory Strategy: Many species breed in Europe but migrate to Africa as a strategy to overcome the lack of food resources in winter. However, in the past few decades climatic and habitat changes have allowed several previously wholly migratory species to form partial migrant populations where some individuals remain resident all year round in Europe. I find this a fascinating research topic!

The White Stork population of Portugal is one of these species that has undergone recent, significant and fascinating changes. It used to be a wholly migratory bird but since approximately 1984, increasing numbers of White Stork are choosing to stay in Iberia continuously all year rather than migrate to Africa. The numbers of overwintering birds in Portugal has increased significantly from approximately 1,180 individuals in 1995 to over 10,000 in 2008. Being a highly opportunistic and adaptable species this trend this widely considered to be the result of i) guaranteed, abundant food supply from landfill sites and ii) milder European winter temperatures.

Iberian Distribution Changes: The white stork distribution in Portugal is also changing. This species is colonizing new areas in the North of the country, possibly because they have recently become more climatically suitable but also because of the availability of food from rubbish dumps. However, the majority of the white stork population still occurs in the south.

One of a series of colonised pylons near Coimbra
Impact of Landfill: Access to landfill ‘junk food’ has influenced White Stork nesting decisions across Iberia. Large colonies, some containing over 100 nests, have been established close to landfill sites. This has likely affected chick dispersal and population expansion patterns, as well as migratory decisions of both adults and chicks. However the open landfills of Portugal are almost full to capacity and reaching the end of their working lives. They are already being superseded by modern facilities where waste is handled inside huge covered hangars and is not accessible to scavenging birds. White Storks will likely return to foraging in agricultural fields to find an alternative winter food supply and I predict this will likely impact on their distribution, breeding location, chick fledging success and migratory decisions.

My research will investigate the link between climatic warming and habitat use to predict the white stork’s future distribution. These data are highly relevant for other species impacted by climatic change and also by the landfill closures. 


A big colony near the landfill site at Ermidas do Sado, Portugal.


Both pictured colonies are ones I am monitoring.


A logger, partially packed ready for attachment to a stork.
The Loggers: GPS/GSM data loggers have been fitted to 15 adult White Storks in Portugal during winter 2012/13. The loggers are highly experimental so we are not sure how long the batteries will last but we expect them to transmit data for up to 1 year. There is a chance they will continue to transmit after this. The loggers were attached to be carried ‘backpack’ style on the storks back. The harness was designed to degrade over time so once the loggers stop transmitting the harnesses will fall off. This means the birds do not have to carry the loggers for the rest of their lives.
Every day each logger collects 5 GPS locations; 1 by night at 5am, 4 by day at 8am, 11am, 2pm and 5pm. Each location consists of a number of GPS fixes in rapid succession that tells us the direction of movement. The logger also collects accelerometer data that allows us to determine whether the bird is in a head up (standing) or head down (foraging) position, as well as the speed. Every 2 days the data is transmitted via GSM. This will hopefully allow us to track the same individuals between their wintering and breeding habitats and record how many chicks they rear successfully. 

The British Trust for Ornithology Website: 2 location fixes per day (1 at night, the other at 11am) will be uploaded to the BTOs website for you to track their progress. We are expecting lots of exciting movement and behavioural data from the storks carrying our loggers so log on and see what they are up to!
Website: http://www.bto.org/science/migration/tracking-studies/stork-tracking
 
Ines Catry with 'Ines' (32+). Her harness being fitted to carry the logger back-pack style.

The Main Objectives: 

  • Winter: To understand the White Storks winter movement patterns in response to temperature and precipitation, and also understand their preferred foraging habitats, reliance on food from rubbish dumps and how they use nests and communal roosts. Amongst other things, I am interested to know how far do the storks travel? Do they feed on rubbish dumps more in bad weather? Do storks defending nests in winter keep those nests, or will they be forced off them by returning migrants? 
  • Summer: Once the birds are nesting I am keen to know what habitats the adults visit to find food for their young. Do birds that feed heavily on rubbish dumps in winter also nest near rubbish dumps? Do they fly a long way just to visit rubbish dumps, or do they only forage close to the nest?  
  • Predictions. All this data will help us understand responses to climatic and habitat variables and the mechanisms influencing the decision over whether on not to migrate. It will also allow us to predict future distributions and population changes based on i)global climate model scenarios for different time scales and ii)after the closure of the landfill sites. 
    'Phil' (34+) -suspected collision with a power line.
  • Electricity Pylons. The GPS data will also give fascinating insight into how the birds use their nests during both the breeding and non-breeding season. Nest defending is starting earlier and earlier, with resident birds occupying nests all year round. Storks are increasingly choosing to nest on pylons which can lead to collisions with high tension electricity cables. Several of our logged storks are using nests close to and on pylons and Phil had a recent lucky escape (see photo). Our data will allow us to investigate how the logged birds are using the nests and the frequency they go through power lines. As the stork population is changing its distribution in Portugal, this will be valuable information on where and how pylons are likely to be used by storks in the future.  The logger data shows that Phil seems to be behaving normally and is none the worse for his lucky escape.

 

Keep checking my blog and the BTOs web page and find out what the logged storks are up to! 

 

Catching Storks. Although storks are a familiar site nesting on roof tops across their breeding range, they are actually very shy of being approached, particularly in open fields. For this reason we captured them on various rubbish dumps across Portugal. Here during the winter they congregate in their hundreds and, in some sites, thousands, increasing our chances of successful captures.


Short video of 'Goncalo' (30+) being released after being fitted with a logger. 


A BIG THANK YOU 

To all the rubbish dumps for their interest in our project and for kindly permitting us to catch storks on their premises:

Aterro Sanitário Intermunicipal de Evora (GESAMB)
Aterro Sanitario de Vila Ruiva (AMCAL)
Aterro Sanitário de Ermidas do Sado (Ambilital)
Aterro Sanitário da Herdade do Montinho, Beja (Resialentejo)

Special thanks also to Kris and Luc van Uffelen at Fleetronic for adapting their loggers to suit our needs, and for all their subsequent support.
 


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