Bird mortality risk: conflict mapping of birds and the grid in Hungary

Highlights

Main Information

In 2008, the Accessible Sky Agreement was the impetus for the partnership that conducted the first study to create a sensitivity map for bird risk around the electricity grid in Hungary. The legislation’s aim was to eliminate the problem of bird mortality caused by collision and electrocution by 2020. In response to this goal, MME Hungary conducted a follow-up study to identify and map critical pylon types still causing the most electrocutions. This is even more urgent, considering that unsafe grid infrastructure in Hungary has caused a significant decrease in population for two IUCN red-list species (Saker Falcons and the Great Bustard), impacting not only Hungary’s conservation goals but also those of surrounding countries like Austria and Slovakia. This legislation was the impetus behind a coordination committee for retrofitting and redesigning energy infrastructure. MME Hungary looks to continually re-evaluate goals and identify key areas to continue reducing bird mortality. The new study analyses:  

• Critical habitat areas
• Retrofitting effectiveness 
• Pylon risk level

Using these aspects, MME created a map to inform more targeted and effective actions to reduce bird mortality. To do this, the team used a four-step methodology to develop their conflict map.

1. Distribution of priority bird species.

As it is challenging to create a map based on all bird life in Hungary, the study identifies 16 key species based on their relative statistical importance, i.e. conservation status combined with the effect of powerlines on individuals and potential impact on populations (rate of mature survivors). Once identified, a distribution map is created for each species. This is done by using 2.5 X 2.5 km Universal Transverse Mercator (UTM) grid cells.  The cells are used to break up the land so areas can be easily catagorised descriptively by species use of the area. The categories are:

• not significant
• occasionally used habitat
• frequently used habitat
• most important habitat

The study was able to complete this categorisation of the grids by using data from MME, National Park Directive Cooperation, Bird Atlas Program (MAP), common bird monitoring (MMM), Waterbird database, and other specific databases on breeding and observations to create the maps, including data from citizen science. Once completed, they made a priority map of threatened species based on a formula that sums the probability values of each species multiplied by its relative weighting for each UTM grid cell. 

2. Identify the microhabitat around the pole/powerlines

The different habitats surrounding powerlines influence bird risk in different ways. For instance, grasslands makes it more tempting for birds to use a pylon as a perch or to hunt than in a forest. Using data from the Ministry of Agriculture’s national ecosystem service mapping project, MME identified five main habitats:

• Artificial (1)
• Mixed habitat (2)
• Forest (2)
• Agricultural area (3)
• Wetland (4)
• Grassland (5)

Then, these were compared with electrocution data from detailed surveys in Heves-Borsod Plain (Péter Tóth, 2012-2017) study. This data is what informed the risk category each habitat received, one being the lowest risk and five being the highest.

3. Categorisation of pole or powerline structure type.

How a powerline is designed has a significant effect on the bird population living in the surrounding area. For example, in constellations where the the live components are attached underneth the support arm, it is less likely for birds to bridge the gap between the components and create short circuit in the system. The study identified six types of pylons scored on risk level from 1-5 as above, they used the Heves Borsod Plain survey data to assess the risk levels of each pylon type.

• Suspender horizontal (5)
• Other mixed type (4)
• Suspended triangle (3)
• Switch tower (2)
• Transformer station (1)
• Normal (1).

4. Evaluation of Retrofitting on pylons.

MME has been working on retrofitting pylons with bird-safe cross-arm covers since the 1980s. In that time, they have noticed that not all retrofitting measures are implemented with the same level of care. MME used the data from a State Nature Conservancy of Hungary project to create another descriptive index stating if a pylon was using mitigation measures or not. These were again scored on a 1-5 risk scale:

• Bird-friendly design (1)
• Best-known mitigation implemented (2)
• Various solutions with limited precision (3)
• Cross arm cover (4)
• Not mitigated, or no data available (5)
  

Once all stages were completed, a risk score was created for each section of the grid. Electrocution risk was calculated by multiplying the bird weighting score by the habitat score, pole type score, and mitigation category score. The result was a heat map based on the findings which clearly showed the most critical parts of the grid infrastructure that require retrofitting or replacement.

Further Information

MME Hungary acknowledges that there are large gaps in their data, especially around the presence of birds in a certain areas due to high dispersal capacity and unequal surveying effort. This also applies to pylon surveys and has, in turn, impacted their collision study. As more data becomes available, MME looks forward to updating and making an even more accurate model to demonstrate the risk pylons pose to bird life.

MME’s conflict map revision was financed by the distribution system operators (DSOs) NKM Áramhálózati Kft.,E.On Tiszántúli Áramszolgáltató ZRt. , ELMŰ Hálózati Kft. és ÉMÁSZ Hálózati Kft. Further support was provided by the Ministry of Agriculture and 10 national park directorates in the form of data and other expertise.