He grouse, an emblematic species of mountain habitats, is disappearing in Spain and some studies suggest this is due to its poor reproductive success. Although the common subspecies is quite abundant throughout Eurasia, in our country Fewer than 1,500 copies survive of the two peninsulas.
In the specific case of Pyrenean capercaillie (Aquitanian grouse), which occurs in Catalonia, Aragon, Navarra, Andorra and the French Pyrenees, its natural habitat is black pine forests (Crochet pine) and the population in Spain is small. This means that, just like with the Cantabrian capercaillie (Grouse urogallus cantabricus), is considered in Danger of extinction according to the Spanish Catalog of Endangered Species.
Several Spanish institutions, led by the Animal Health Research Center (CISA, INIA-CSIC), have carried out the first health survey of the species, finding that 62.5% of Pyrenean capercaillie are infected with blood parasites of the genres Haemoproteus j Leukocytozoon, related to avian malaria. In addition, they have identified a herpes virus in four of these birds for the first time.
“Knowing which infectious agents affect wild populations is essential to draw up adequate conservation plans, especially when making decisions to make translocations between different population centers or to reintroduce animals born in breeding centers,” he says. Carlos Sacristán Yagüeresearcher at CISA-INIA-CSIC and last author of the work.
“It is important to always keep in mind that when we move an animal, we also move the infectious agents it carries, and the destination populations may not have immunity against them,” Sacristán Yagüe added. The findings are published in the journal Scientific reports.
In addition, scientists have discovered the absence of genetic material of several pathogens (Newcastle virus, Escherichia coli, Salmonella sp., Campylobacter jejuni j Chlamydia psittaci) in the 30 samples of fresh capercaillie feces analyzed.
“It is vital to clarify possible causes of diseases and the factors that determine them, as an important point to carry out targeted and more effective conservation actions,” the expert added.
For Olga Nicolas de Franciscoveterinarian specialized in wildlife and first author, “knowledge of the health status of populations of wild animals in danger of extinction, such as the Pyrenean capercaillie, is essential to prioritize conservation actions.”
So much Haemoproteus as Leukocytozoon They are hemoparasites transmitted by vectors, in the first case mainly by insects of the genus Culicoides, and in the second case by blood-sucking black flies. “Discovering his presence in the Pyrenean capercaillie “It was a surprise, since these are mountain birds that live at high altitudes, where we expected the vectors they transmit to be absent or only present at low densities,” says Sacristán Yagüe.
Capercaillie: climate crisis and transmission vectors
To conduct the study, the researchers used the periodic catches in the Catalan Pyrenees to mark specimens (previously with a radio transmitter, now with GPS) and carry out their monitoring, and to find out their distribution, behavior and threats.
In recent years, the authors performed a veterinary examination at these admissions and collected blood, oropharyngeal, and cloacal samples for pathogen analysis by PCR; They also took tissue samples from Pyrenean capercaillie found dead in Catalonia and Andorra.
Finally, they prioritized the use of non-invasive methods to determine the presence of pathogens of interest in feces, by collecting fresh remains for more than two years in the forests where they still occur.
Although more research will be needed, scientists do not rule out a link with climate change in the spread of these diseases, as the Pyrenees are one of the areas where the incidence has increased the most. average temperature in recent years – at least 1.2 °C between 1949 and 2010 – and this promotes the expansion of the vectors.
“We know that other carrier-borne pathogens can increase their spread thanks to global warming and affect birds, as in the case of West Nile virus or Plasmodium left”, the researcher indicates.
The latter is a protozoan parasite, which is considered one of the main causes of avian malaria. “This disease is not transmitted to humansbut it can have dramatic consequences in birds, especially in birds that have not co-evolved with this parasite, such as birds from certain islands or from arid climates in which the mosquito that transmits this parasite is absent,” Sacristán Yagüe points out.
It is still unknown what impact the detected hemoparasites may have on the Pyrenean capercailliebut from previous studies it is known that they can cause anemia and even death in other bird species.
The first herpes virus in capercaillie
As for the herpes virus discovered, it is probably a new species, the first recorded in capercaillie, related to the species that cause respiratory diseases in domestic birds.
“Es new to science, but it has certainly been infecting these animals for thousands of years, as these viruses generally co-evolve with their hosts. From what we observed during our research, virtually all species have their own herpes viruses,” they say.
It is important to keep in mind that a large amount of wildlife still exists lack of knowledge about pathogens that influence them. For this reason, the team emphasizes the importance of conducting research that can detect new agents and thus increase knowledge about the pathogens present in the natural environment.
“Despite the compromised status of the species, recovery is still possible. There are clear examples of how establishing intensive and targeted conservation strategies can restore populations of wild species, as in the case of the Iberian lynx, even species that are extinct in the wild, such as the European bison or the stilt-footed lynx. polecat, black,” Sacristán Yagüe emphasizes.
Technicians from the Generalitat of Catalonia and the Conselh Generau d’Aran, the European University of Madrid, the University of Barcelona, the University of Lleida and the Pyrenean Institute of Ecology also took part in the work.
Human activities that disturb grouse
In the Iberian Peninsula, capercaillies are mountain forest birds and act as indicators of the health of the ecosystem in which they live, as they are very sensitive and have limited movement capacity.
One of the main threats they face, in addition to the change and degradation of their habitat, climate change or the increase in ungulate populations, is the stress caused by human presence during the mushroom season or, in winter, by mountaineering activities such as off-piste skiing and snowshoeing.
Programs are currently underway to demarcate preferred areas for the species, educate the population on the annual cycle of these birds and even provide guidance on where they are located in some natural parks, advising alternative routes to avoid these areas.
Nicholas de Francisco ensures that ski slopes can influence the Pyrenean capercaillie: “Previous studies in alpine areas have shown that the presence of skiers, especially off-piste and in the forest, is a cause of stress for the species. Currently, when constructing or expanding ski slopes, the presence of this bird is taken into account as one of the limiting factors within the environmental impact analysis.”
On the other hand, those that are already in use and include forests inhabited by capercaillies are carried out dissemination and signaling actionsto inform users of good practices to follow.
The team’s next steps will focus on expanding the number of animals sampled and analyzed. In this way, clinical symptoms of disease can be associated with infection by this virus and we can know what symptoms they cause, and even observe associated lesions.
In addition, they believe it is important to examine a larger number of animals from different populations, to know whether the herpes virus is already present in all of them. “If we manage to minimize the stress we experience urogallos By improving the quality of its habitat, we will reduce the potential impact of this virus on the species,” concludes Sacristán Yagüe.