This isn’t the first time Europe has heard of bird flu (or flu). The virus, which affects poultry, began to be detected in wild species in the early 2000s and spread through the birds’ migratory routes. Since then, there have been sporadic mass die-offs in wetlands across the continent, mainly of aquatic birds, and more or less seasonally. However, in 2021, the highly pathogenic H5N1 avian influenza virus jumped to seabirds, causing an unprecedented situation that continues to this day.
The rapid development of a disease without borders
In the summer of 2021, as humans slowly emerge from the worst epidemic of the last century, seabirds are also beginning to face their own epidemic. The death of several giant skuas in the Scottish colony from the highly pathogenic H5N1 bird flu virus has sounded alarm bells.
That same winter—as explained in a CMS-FAO report last July—there was a massive die-off of geese in wintering areas in the UK, and the virus was detected in North America, where it began to spread. Spread, spreading rapidly across the continent.
Early 2022 will also see mass bird deaths across Africa, such as the Juji National Bird Park (Senegal), one of the world’s most important bird sanctuaries.
In the spring of 2022, the virus had a disastrous effect on Europe’s devoured populations of pelicans, gannets and terns (the worst-affected lesser terns), with fewer than half of the breeders estimated to have returned for the winter. The site after brooding.
In late 2022 and early 2023, the virus reached the southern part of the American continent for the first time in history, affecting a large number of species, including marine mammals. In just four months in 2022, 22,000 birds, mostly Peruvian pelicans, died off the coast of Peru, and thousands of sea lions were stranded in early 2023.
The remainder of 2023 does not bring any improvement. Seabird habitat continues to be devastated by influenza. In Europe, although gannets appear to be less affected by the virus, populations of black-headed gulls and more recently kittiwakes and guillemots are most susceptible to the virus, and their rapid expansion and adaptation to new hosts is of concern.
Impact on European seabird populations
To date, avian influenza viruses have been detected in about 400 different bird species, but outbreaks over the past two years have mainly affected seabirds, which is unusual for now. The group behavior of species such as gannets and terns during breeding creates the perfect scenario for the rapid spread of the virus. Adults come ashore only once a year for several months to build nests, usually congregating on remote islets or bays. This means that these colonies house a significant portion of the world’s population for some of these species, so the impact on their global population is devastating. Some of the data gathered so far suggests a dire situation:
Atlantic gannet. At least 75% of existing colonies are affected, with an overall mortality rate of 60%. Scotland is their main nesting ground and more than 11,000 casualties are estimated. In Bas Rock, the largest gannet colony in the world, occupied territory decreased by 71% and reproductive success dropped by 66% (see graph).
Pay big money According to statistics, at least 2,700 dead bodies, the occupied territory of the British Isles is reduced by 70%, here is the world’s major colony (about 8,900 couples), and the death toll is estimated to account for 7% of the global population. In 2021 and 2022, the reproductive success of affected populations will be close to zero. Several of the dead birds were over 20 years old.
Sandwich Tern. During the 2022 outbreak, a total of 20,531 adults died in just two months in the northwestern European colony, calculating a mortality rate of 74% for the nesting population.
The frowning pelican. In 2022, influenza killed 60% of the world’s largest population in Lake Prespa (Greece), and also affected other populations in Eastern Europe. It is estimated that the European population will decrease by 40% and the global population by 10%.
laughing gull. Around 10,000 gulls are estimated to have died in the UK, accounting for 4% of its population, with hundreds more cases in several continental European countries.
These figures are likely to be vastly underestimated because it is difficult to find the carcasses of dead animals, and not all colonies have long-term population estimates that allow year-to-year comparisons. “If these populations are successful, they are expected to take decades to recover,” said Lucía Soliño, SEO/BirdLife Marine Program technical staff. He added: “Seabirds are long-lived animals with long maturation periods and low numbers of chicks. This makes the survival of the adults critical to the survival of the species. The fact that it primarily affects reproductive individuals is a serious blow to these populations, with effects that go beyond immediate mortality and appear to be will not decrease”.
Data on the possible immunity of birds to the disease is still sparse. In gannets, the darkening of the iris observed in some apparently healthy individuals may be related to overcoming the disease, although it is unclear how this change in the eye affects their vision and chances of long-term survival. see picture).
spanish bird flu
Spain has a national avian influenza surveillance program aimed at early detection of the disease, which includes immediate notification and investigation by official veterinary services of any signs of illness or death in poultry, as well as regular sampling on certain farms depending on risk. During this outbreak, from July 1, 2022 to June 7, 2023, a total of 7 poultry outbreaks and 1 captive bird outbreak were detected in Andalusia, Catalonia, Galicia and the Basque Country outbreaks and 117 wild bird outbreaks. , Aragon, Castilla Leon, Castilla-La Mancha, Cantabria, Extremadura, Madrid, La Rioja, Asturias, Mu Salcia and Valencia. The outbreaks in Valencia’s Albufeira and Ebro Delta Natural Parks are of particular concern, both of which are extremely important for marine and waterfowl. More than 1,000 sandwich tern and black-billed tern carcasses have been removed in the first operation, but it’s unclear how many were due to the flu. The Ministry of Climate Action of the Autonomous Region of Catalonia confirmed the outbreak of bird flu in the Ebro Delta region, among which the National Reference Laboratory of Algate in Madrid confirmed positive results of highly pathogenic H5N1 bird flu in three places in July last year. Specimen Sandwich Tern on the Van Gaal Peninsula in the northern Ebro Delta.
Faced with this situation, poultry farms have stepped up surveillance and biosecurity measures, especially measures to avoid contact with wild birds. Surveillance of seabird populations has also been intensified to quantify the incidence of the disease. However, in the face of a pandemic of this magnitude, extreme precautions and appropriate management measures are necessary to avoid transmission to the most sensitive species.
ICAO, App to Report Coastline Marine Animals
Citizen science actions can be very useful for early detection of new bird flu outbreaks or other causes of seabird mortality, which is why SEO/BirdLife has launched the ICAO (Coastal Inspection of Coastal Birds) mobile app in 2021, available at Totally free in three languages (Spanish, Portuguese and French) for Android and IOS.
The app allows you to send data on birds and other marine animals found on the coast, dead or alive, with signs of illness/injury. Two types of observations can be selected: observations along transects (ICAO Walk) or as point observations. Observations and photos can also be uploaded through the ICAO website https://icao.seo.org/ where you can also consult all user-supplied information that has been previously reviewed and verified by professionals at SEO/ . Society for the Protection of Birds.
Since the launch of the ICAO app, as of July 2023, more than 500 users have registered, and its usage has increased significantly since the end of 2022, the most recent update being carried out within the framework of the Life Seabil project. During this period, approximately 1,500 records were uploaded for a total of 1,332 birds across Spain. The app is particularly useful for documenting mass bird die-offs, such as the winter of 2022 off the Mediterranean coast, where 158 registered razorbills were stranded, and the January 2023 event in the Atlantic, during which 359 puffins. Discover the Iberian Atlantic and Cantabrian coasts with the app.
What to do if you find a sick or dead bird
Avoid contact with birds. Although cases of transmission to humans have so far been rare and of low severity, to avoid the risk of zoonotic disease, handling and eradication of birds must be carried out by specialized personnel and personal protective equipment. If you walk with your dog, keep it on a leash and out of sight to prevent it from swallowing dead animal parts or causing discomfort to sick animals.
Call 112 or the appropriate provincial CRF Animal Recovery Center and follow the instructions. Conservation staff will go to designated locations to collect the animals or their carcasses.
If you would like to contribute to SEO/BirdLife to improve understanding of causes of seabird mortality, please send observations via the ICAO app for Android and IOS (Apple).