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  • Writer's picture@ Cynthia Adina Kirkwood

White Storks’ Population Soars in Portugal

Updated: Feb 14, 2023


White storks in the municipality of Alvito, Beja District, in the Alentejo (Photo by Ines Catry)

 

Thirty years ago, the white stork was a threatened species in Portugal. Today, its numbers have not only rebounded many times over, but many birds choose not to winter in Africa, as in the past, and stay year-round.


“In Portugal, the winter population has skyrocketed, now being 14 times larger than it was a decade ago. And the numbers are growing. Thanks to the GPS monitoring study, we now know that many birds no longer complete the migration to Africa,” said ecology professor Aldina Franco to National Geographic: Portugal (August 9, 2020).


In a winter census of 1995, there were 1,187 white storks compared with 14,434 in 2015, and 19,289 in 2020, reported SIC Noticias (February 4).


“The success of any bird population depends on three factors: food availability, safety and nesting sites,” said Caroline Walta of STORK (the Dutch Stichting Stork Research & Know-How Foundation) to National Geographic: Portugal (August 9, 2020). “The lack of any of these will alter the equation irreversibly. If we want to maintain stork populations, we must continue to invest in improving their habitat.”

 

Ascendi, the concessionaire of the A25, moved 20 stork nests that were near the Angeja interchange in the municipality of Albergaria-a-Velha, Aveiro District, for the safety of the birds and the drivers in January 2014. (Photo by Fernando Timoteo/Global Imagen)

 

In Portugal, two of those factors led to the white stork success: food at landfills and increased numbers of nesting sites built by ordinary residents.


The storks’ imposing size calls for huge nests, which are made of twigs and sticks. The birds build nests on any supporting structure, such as chimneys, and on telephone and electricity poles.


In 1993, preparatory work began for a census of the white stork for the municipality of Mertola, Beja District, in the Alentejo region. After a sharp decline, the stork’s population was on an increase.


Manuel Costa, an agricultural land owner in Monte Navarro, Mertola, was a visionary. Costa was a pioneer in the conservation of white storks, reported SIC Noticias (February 4).


He built the first additional platforms for the birds to make their nests. As attested by his daughter and grandson, Costa’s commitment inspired others.

 

Influenced by her upbringing in Indonesia, Geraldine Zwanikken saw the human connection with biodiversity. She built platforms to attract white storks to her family’s land in the Alentejo.

 

Antonio Araujo, an ornithologist who was working at the Serviço Nacional de Parques, inspired Geraldine Zwanikken, a former dancer at the Dutch National Ballet and owner of Convento de Sao Francisco (Mertola). In 1980, Zwanikken, her husband, and two sons had moved from the Netherlands. The family renovated the 400-year-old Convento themselves into an artistic retreat, an art gallery and organic gardens. In 1994, they began working on providing and maintaining nesting places for the white stork and lesser kestrel, a migratory falcon.


Zwanikken, now a visual artist, was told that once they know the place, they will return to it. While white storks nest in the open on supporting structures, lesser kestrels nest in the cavities of walls of old and abandoned barns.


“We opened holes. We made nests. We made everything,” she said, with Antonio Araujo, now president of the Portuguese Society for the Study of Birds, or SPEA, by her side.


“It worked. It worked. Incredible.


“We have here the largest colony of falcons in the country.”


At Convento Sao Francisco, nesting structures for the lesser kestrels and the white storks are built along the Guadiana River.


In urban areas, the food in landfills helped increase the number of white storks. In rice paddies, the red crayfish, an invasive species that arrived in 1979, also contributed to the stork’s food source, reported Wilder (February 18, 2021).


The red crayfish has spread across at least 11 river basins from North to South: Douro, Leça, Vouga, Mondego, Lis, Ribeiras do Oeste, Tejo, Sado, Mira, Ribeiras do Algarve and Guadiana.

Eradication of the crayfish is considered to be practically impossible.

 

“We can say that the birds are addicted to junk food,” said ecology professor Aldina Franco.

 

In urban areas: “We can say that the birds are addicted to junk food,” said ecology professor Aldina Franco to National Geographic Portugal (August 9, 2020).


There are 32 active landfills in Portugal, reported SIC Noticias (February 4). If the national and European goal of waste reduction and closure of some landfills is achieved, the effect on storks would be high, said the ornithologist, Antonio Araujo, to SIC Noticias and biologist, Bruno Martins, who is affiliated with the University of Porto and the United Kingdom’s University of East Anglia, said to Wilder. It could lead to decreased births and increased migration of the “very adaptable and opportunistic species”.


The ornithologist, Antonio Araujo, also pointed out that the increase of intensive olive grove cultivations affects biodiversity and, therefore, the populations of white storks and other birds.


Is the growth in the population of storks in Portugal too high?


Martins, who is on the Birds on the Move stork research team, said that it is possible that the maximum capacity has been reached in the territory.


However, Martins added: “Usually a species begins to be problematic when studies are presented with proven results of its impacts on ecosystems, on public health or on significant damage to human activities. . . . There is currently no indicator or study that demonstrates this”.


In coming years, researchers will continue to study the evolution of the population of white storks in Portugal. The next spring census is scheduled to take place in 2024.


A decline in the general population of white storks began in the 19th century due to industrialization and changes in agricultural methods. White storks no longer nest in many countries. Besides Portugal, current strongholds are in Spain, Ukraine and Poland.

 

White storks fly with their necks outstretched.

 

Because of the white stork’s large size, its predation on vermin and nesting near human settlements, the bird has an imposing presence in human folklore and mythology.


In ancient Egyptian mythology, a person’s soul was believed to be a stork, and the return of the stork in the spring meant that the soul had returned to the person, according to Dr. Roger Lederer, ornithologist and emeritus professor at California State University, Chico, on the Ornithology: The Science of Birds website. A Greek myth told of storks stealing babies after Hera, the goddess of women, marriage, family and childbirth, turned her rival into a stork and then that stork-woman tried to kidnap Hera’s son.


European folklore says that the stork brings babies to their new parents, which was popularized by 19th-century Danish writer, Hans Christian Andersen, in his short story, The Storks, according to the ornithologist, Lederer. German folklore holds that storks find babies in caves and marshes, and deliver them to the mother or drop them down the chimney. Slavic mythology says that storks carry unborn souls from Vyrai, where birds fly for the winter and souls go after death, to Earth in spring and summer. Storks bring luck: killing one would bring misfortune. The stories have spread around the world.


The stork is so big that it is bound to be noticed by those grounded below them.


The white stork is mainly white, with black on the wings. Adults have long spindly legs and long pointed red beaks. They measure on average 100-115 centimeters (39-45 inches) from beak tip to end of tail, with a wingspan of 155-215 centimeters (62-85 inches).


The adult white stork’s main sound is bill-clattering, which sounds like distant machine gun fire. The bird makes these sounds by rapidly opening and closing its beak. The only vocal sound adult birds make is a weak hiss. However, young birds can generate a harsh hiss, cheeping sounds and a cat-like mew to beg for food.


Although the white stork lacks a song or call, there is a song in the Cante Alentejano polyphonic tradition, that sings to and about the stork:

 

Refrão: "Senhora Cegonha, Como tem passado? Não há quem a veja. Não vai p'r'a igreja. Pousar no telhado. No seu velho ninho, Ponha ovos, ponha, Que seja bem-vinda. Branquinha, Tão linda. Lá vem a cegonha." Chorus: "Lady Stork, How have you been? There is no one to see her. She doesn't go to church. She lands on the roofs. In your old nest, Lay eggs, lay. You are welcome. White, So beautiful. Here comes the stork."

 








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