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Via Pontica - Myth and Reality for Birds and Wind Turbines
Tanyo Manev Michev & Pavel Zehtindjiev
Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences
2 Gagarin Street, 1113 Sofia, Bulgaria
According to the World Encyclopedia WIKEPEDIA, Via Pontica (from Latin: Via Pontica,
Black Sea Road) was an ancient Roman road in the province of Thrace, following the Black
Sea coast. It starts from Constantinople and it passes through Bourgas, Varna, Kaliakra and
the delta of the Danube called Istros in ancient times.
(https://en.wikipedia.org/wiki/Via_Pontica).. (https://en.wikipedia.org/wiki/Via_Pontica ).
Original ancient Roman map with indicated ancient road „Via Pontica“
The story is very interesting and indicative of our time marked by historical changes in
Eastern Europe.
The first reports of concentrations of migratory raptors on the western Black Sea Coast are
reported by Alleon & Vian (1869, 1870) who have established an intensive migratory
migration in the Bosphorus but they do not use the term Via Pontica.
In 1930, the great Bulgarian ornithologist, Pavel Patev, published a report on the Black Sea
coast for the purpose of searching for a suitable place for exploring bird migration. In his
report Pavel Patev writes "......... Observations on bird migration around the Black Sea have
been made so far first by Mr Braun, who has been able to observe for many years the bird
migration around Constantinople. According to his observations, a large number of birds,
mainly raptors, fly over the Bosphorus to Asia Minor. The same writer assumes that these
birds are moving along the western coast of the Black Sea and gave for the first time the name
FLY WAY "Pontius" ... "
In 1970, this Pontiac road was mentioned as Via Pontica in two scientifically popular articles
by the famous ornithologist and environmentalist Nikolay Boev (Boev 1970a, b).
Over the next decades, the term Via Pontica is becoming more and more common in the
scientific literature on bird migration on the Bulgarian Black Sea coast.
How does this historical fact come to the idea of a bird-migration migratory airspace limited
in a corridor and even to a ban on the construction of wind power facilities in the entire
Dobrudja region of Bulgaria?
In the era of socialism, revolutionary surveys of the migration of flying birds were carried out
with the help of the radar of the two airports in Varna and Bourgas. For the first time,
Associate Professor Tanyu Michev, with his team of collaborators, follows the migration of
flocks of pelicans and storks within the scope of the two airport radars and on this basis uses
the term "Via Pontica", introduced by Patev (1930) and Boev (1970a, b) borrowed from the
name of the ancient Roman road known from ancient times. In this study, it is not stated that
the flight is limited only to the radar range and there is no mention of CORRIDOR and there
is no element of spatial constraint. The study does not specify exactly the whole territory over
which Via Pontica extends (Figure 1). There are no Ludogorie and South Dobrudzha, which
play a significant role in the autumn migration of the flying birds. This is due to the specific
location of Varna Airport, located just south of a Plateau. Because of this, the airport radar is
unable to reach the small and medium heights of much of this flat elevation. However, the
map shows that the migration routes in the NE Bulgaria occupy a wide front and do not pass
directly along the sea coast.
Figure 1. Migration roads of soaring birds according to Simeonov et al. 1990 (after Simeonov
et al. 1990)
Later, with the development of the specialized bird watching tourism known as - BIRD
WATCHING
(https://en.wikipedia.org/wiki/Birdwatching#Economic_and_environmental_impact) the term
introduced by Pavel Patev and Nikolay Boev lives its own life with a variety of nterpretations,
part from which they have led to various consequences, including economic ones.
The positive consequences of Tanyu Mitchev's study and his colleagues have traditionally
been held for decades by annual autumn student brigades for nature conservation activities
and tracing of migratory birds flying over Atanasovsko lake near Bourgas. In this tradition,
hundreds of students have been brought up to date, who are today active participants and
managers of nature conservation and ornithological projects. At his initiative, a number of
bird conservation activities were carried out in Bulgaria (the census of wintering waterfowl,
the significant Bulgarian participation in the preparation of the first European atlas for the
breeding of birds in Europe, the two editions of the Red Book of Bulgaria, the foundation of
the Bulgarian Society for protection of birds, etc.)
Thus, the term Via Pontica comes in different versions depending on the necessity and
purpose of the specific activities to which it applies. It can be found in dozens of documents
related to the conservation of nature. It is adopted by the structures of the Ministry of
Environment and Waters, crosses the national borders and is transported in a number of
international publications in the field of birds and bird surveys as. It has reflected in
identification of Burgas lakes as a point for interesting and species-rich bird watching sites
during the autumn migration period. Burgas is referred to as an area with a concentration of
migratory white storks and a unique Bottle neck with a concentration of the species of flying
birds on the territory of Bulgaria (Figure 2).
Figure 2. Bottlenecks of White stork migration in autumn as presented by Willem van den
Bossche in “Eastern European White Stork Populations: Migration Studies and Elaboration of
Conservation Measures”.
The term "Via Pontica" is not used in a comprehensive monograph showing a 10-year period
of satellite tracking of white storks, as a migratory bird species in Europe, but Burgas is
marked as an important region.
(https://www.researchgate.net/publication/27268777_Eastern_European_White_Stork_Popula
tions_Migration_Studies_and_Elaboration_ofConservation_Measures).
This is because, through the tracking of satellite transmitters with white storks for 10 years,
none of these birds have been traversed through the same "road" for two consecutive years.
The distances of the individual routes of the same individual bird in different years reach
hundreds of kilometres and are not limited to "corridors". This and many other such findings
alter the views of scientists on bird migration as a large scale phenomenon across Europe.
Accumulation of knowledge on the migration of flying birds using the warm air masses
through Bulgaria intensifies during the development of wind power in the country. Dozens of
sites have been surveyed by ornithologists in Bulgaria during preconstrucytion studies of
wind power farms. These results are also published in a number of scientific papers, which
significantly changed the knowledge on the distribution of migratory birds over the territory
of Bulgaria. The data are summarized by Michev et al. (2012).
The accumulation of quantitative data on migratory flying birds in Bulgaria makes it possible
to identify the areas of the country with important territories for birds.
The term Via Pontica is developed by a long-term observation (1979-2003) of flocks of
pelicans and storks near Bourgas to a certain region of Bulgaria, as indicated by Michev et al.
(2012). Professor Michev gave the first definition of this concept with regard to birds in
scientific literature. Via Pontica is defined as an area of the territory of Bulgaria, including the
eastern parts of the country with borders on the west line from Ruse - Aytos - Malko Tarnovo
and the Black Sea to the east. The authors point out that for a number of species these
boundaries should be extended westwards to Karnobat (Michev et al., 2012).
Figure 3. Map of the region Via Pontica according to Michev et al. 2012.
Thus, the scientific community has established clear boundaries and defined the mythological
term Via Pontica. Although the term remains primarily for national use, the definition of a
wide territory of the country, as Via Pontica, in practice rejects obsolete perceptions of the
existence of space-bound "corridors" that birds are obliged to use during their seasonal
migration. Although these findings have led to a change in our ideas about the nature of
migratory processes in Bulgaria, the country still suffers the consequences of obsolete ideas
for this evolutionary adaptation of birds to the changing conditions of the environment. The
most significant consequence of obsolete bird's corridors is the notion of an impact that could
hinder this corridor. It is precisely on the basis of such an erroneous from the contemporary
point of view of science that Bulgaria should prohibit the construction of wind power
facilities in the vast territory of Dobroudja including the eastern coastal parts of the country
where for many years the observations have proved the absence of concentrations of soaring
birds and therefore no potential impact on their populations during their seasonal migrations.
Over the 10 years since the construction of the first wind turbines in Bulgaria, systematic
research has been carried out. Detailed surveys on the territory of the Dobrudja area in the
area between Kavarna and Shabla, comparing the number of bird species, their number as
well as their flight direction and flight altitudes, clearly indicate the absence of direct impact
through barrier effect or direct collisions on migratory populations of birds
(http://www.aesgeoenergy.com/site/Studies.html).
The barrier effect and the collision risk are mutually exclusive potential impacts. In the
presence of a barrier effect, the birds are displaced from this territory and therefore do not use
it and cannot crash into the propellers or masts of the generators. Against the barrier effect,
the risk of collision increases due to the passage of more birds through the wind park and the
use of the territory with working generators for foraging and roosting. It is important for this
assessment to clearly distinguish the different adaptive abilities of bird species to the elements
of the environment characteristic of the most mobile group of animals evolutionally
specialized in avoiding various flight-related obstacles.
The observed seasonal variations in the number of species as well as in the total number of
migratory birds do not show any barrier effect after the construction of the wind turbines
operating in the Kaliakra region (according to the 7-year monitoring of the autumn migration
provided by St. Nicholas) are presented at an international conference on Impact Assessment
of Wind Farms on Flora and Fauna https://www.cww2015.tu-berlin.de/.
Figure 4. Dinamics of the number of birds and number of species in SPA BG0002051
Kaliakra before construction of wind turbines (2008 and 2009) and after construction of wind
turbines (2010 – 2014)
No changes in bird species, bird species overboard, their height and migration direction prior
to the construction of wind turbines (2008/2009) and after their release (2010-2014) in this
territory
Figure 5. Altitudes of flights established in SPA Kaliakra before construction of wind turbines
2008/2009 and after construction of wind turbines 2010 – 2014
The variation in the mean height of migrating birds by year shows that in five years, two
before the construction of turbines and three after commissioning of the St. Nichola Wind
Farm, the height of migration was about 200 meters. In two (2010 and 2013) of the five years
of active park monitoring, the average height was between 250 and 300 meters. For these
variations in height, the predominant species composition and the meteorological situation
were likely, as there were no trends to increase the migration height of the observed birds
before the park was built and the exploitation period. The established variations in the
direction and height of migratory birds, as well as their species composition and number
during autumn migration, demonstrated in the above graphs do not reflect the presence of a
barrier effect on any of the established bird species migrating through this area before and
after the construction wind turbines.
Due to the absence of a barrier effect for migratory bird species during migration, they are at
risk of collision, especially in specific weather conditions.
This requires action to manage the collision risk for migratory birds and to monitor the
mortality of these species in all areas with active wind farms. Such measures are set as a
permanent monitoring through the permits issued for the construction of wind farms and the
preliminary assessments of the potential impacts of their construction. The results of these
studies are regularly reported in the regional divisions of the MOEW. Much of the monitoring
of the impact of wind turbines on birds migrating through Bulgaria is published and available
on the Internet (https://tethys.pnnl.gov/search/Bulgaria)
Measures related to the shutdown of individual turbines, group of turbines, as well as wind
parks under certain rules are implemented in Bulgaria. The evidence for the effectiveness of
this system is the recognition of a number of nature conservation organizations in the country
(http://lifeneophron.eu/bg/news-view/92.html and http://fwff.org/BG/Bulgarian-Global-Sleep-
K4n -objects /). Recently, in response to the European Commission's expectations for
strengthening the measures for the conservation of migratory birds in the Natura 2000 area
around Kaliakra, an Integrated Wind Turbine Warning and Winding System in this area was
developed. This system integrates specialized radars in several wind power parks
(https://kaliakrabirdmonitoring.eu/) with field observations by experienced ornithologists
working in this area for over 10 years. The system records through permanent inspections
according to a special methodology all cases of collisions of birds with wind turbines.
Recently, a methodology has been developed in Bulgaria to read data from meteorological
radars with wide coverage throughout the country. The methodology has been developed
within the framework of a doctoral program at the Institute of Biodiversity and Ecosystem
Research at the Bulgarian Academy of Sciences. It is for the first time in the country that an
analysis of the data from the meteorological radar near Aksakovo (Varna)
(https://www.youtube.com/watch?v=J7VC_2gvXC4) is implemented and a picture is
produced for the distribution of the birds on the territory of a large part from north eastern
Bulgaria –known as "Via Pontica"