 |
|
|
Swallows Arrive in European Winter |
|
Many
bird species are migrating early to Europe from Africa. Ornithologists
believe climate change is the cause behind the new travel habits
of swallows, ducks, storks and geese, and could be a threat to their
reproductive cycles.
PARIS - The workers at Marquenterre nature
park in northern France began noting a decade ago that the springtime
arrival of migrating swallows and other birds began to occur weeks
earlier than normal, a change that experts attribute to global warming.
Among the species migrating to Marquenterre, in the delta of the
Somme River, there are not only swallows (of the Hirundinidae family),
martins (Butorides virescens), nightingales (Luscinia megaryhnchos)
and larks (Alaudidae family), but also such exceptional birds as
the beautiful avocet (Recurvirostra avosetta), with its silky black
and white plumage, long blue legs and a long, slender curved beak,
whose movements are reminiscent of a ballerina.
But over the past 10 years, members of this species and others began
to move their arrival date to early February, the middle of the
European winter, when they should have remained at their warm and
sunny winter homes in Africa. Other birds noted in this phenomenon
include the Eurasian spoonbill (Platalea leucorodia) and the grey
heron (Ardea cinerea).
The change has fed concern among ornithologists and other European
researchers, who fear that the intensification of the greenhouse
effect has already had a decisive impact on the behavior of migrating
birds, and of animals in general.
The greenhouse effect is a natural atmospheric phenomenon that helps
maintain the Earth's surface temperatures by retaining energy from
the Sun, but most scientists in the international community agree
that the increased concentration of carbon dioxide from the burning
of fossil fuels has intensified the effect, gravely altering average
temperatures and causing the polar ice caps to melt and ocean levels
to rise.
"For the past 10 years we have seen that the increased clemency
of the European winters has modified the behavior of many migratory
species," Marquenterre ornithologist Philippe Carruete told Tierramérica.
"Many birds, including ducks, storks and geese, which normally migrated
from Northern Europe to Africa in the autumn, now spend half the
winter in our nature park," he said.
Scientific studies conducted in other European countries suggest
similar circumstances associated with climate change, said Carruete.
"In the countries of Northern Europe, the tundra is diseappearing,
threatening the survival of many species that inhabit that region.
In Africa, desertification is also reducing the habitat of migratory
birds during the northern hemisphere winter."
"Because the birds have memory, after years of suffering the consequences
of those changes in the vegetation of Northern Europe and of Africa,
they have learned to save themselves the trip, and to search for
appropriate habitat in Europe during the winter," said the expert.
Storks (Ciconia ciconia), ducks (Anatidae family), grey heron and
other migratory birds do not flee the cold, but rather the lack
of food that arises towards the end of Boreal summer. To reach Africa,
they are guided by the Sun, the stars and by the Earth's magnetic
field.
The findings of the Marquenterre ornithologists coincide with those
of scientists from the Max-Planck-Gesellschaft, a German research
institution, and from the Sempach Ornithology Institute in Switzerland.
In a study conducted in the Bretolet Pass in the Swiss Alps, Lukas
Jenni, director of the Sempach, established that many birds have
begun to fly to Africa in the middle of the summer, and return to
Europe in the middle of the winter, among them the bird of paradise
(Apus apus), the warbler (Sylvia borin) and the pied flycatcher
(Ficedula hypoleuca).
Jenni, who published his findings in the journal Proceedings of
the Royal Society, based his conclusion on Bretolet Pass observations
since 1965 of some 350,000 migratory birds representing 65 species.
By influencing the migration habits of different species, climate
change reduces their incubation and reproductive periods, threatening
their survival, according to the expert.
Ornithologists from Max-Planck-Gesellschaft also have found that
many birds are returning to their European habitats an average of
five days earlier than they used to.
Species like the trumpeter finch (Rhodopechys githaginea), European
bee-eater (Merops apiaster) and even parrots are leaving their normal
African habitats and are settling in the Mediterranean region, and
even in Central and Northern Europe.
Despite the evidence that confirms the consequences of carbon dioxide
emissions for the Earth's climate -- such as drought, forest fires,
heat waves, torrential rains, floods and severe storms -- climate
change continues to be a subject of much controversy.
There are some scientists who have called into doubt the climate
change phenomenon itself, while the United States, the world's leading
producer of greenhouse gases, refuses to ratify the Kyoto Protocol,
established in 1997, which obligates industrialized countries to
cut their emissions 5.2 percent by 2012, based on their 1990 levels.
* Julio Godoy is an IPS correspondent
|
