You may notice something is lacking when walking through the heart of various European cities, such as London, Amsterdam, Madrid, or Prague. If you have a keen eye, you may have noticed that a certain bird is virtually gone from European skies1. The House Sparrow, a little brown bird that has been our friend for over 10,000 years, is vanishing from the ancient continent, and no one understands why.
The British newspaper "The Independent" offered to offer a prize of £5,000 to anyone who could solve the mystery of the Londoner sparrows' disappearance. Despite the lucrative prize, the riddle has remained unsolvable for over two decades. Our most dependable detectives have been researchers. However, none of the offered explanations to explain the loss of the House Sparrow have been acknowledged by the scientific community as completely legitimate. Some theories stand out and are more widely accepted: the loss of nesting sites due to new construction, the absence of green spaces linked to a decrease in invertebrates to feed hens, the increasing air pollution caused by our automobiles, the bad urban diet they encounter in the city, and an increased exposure to avian malaria. However, although it is possible that all these factors act jointly to the detriment of this small species, it would be key to determine which one has a major influence on their disappearance to ensure their conservation. Although it's likely that all of these variables work together to harm this little species, it's critical to figure out which one has the greatest impact on their extinction in order to safeguard their survival.
But, are House Sparrows really so crucial to the city and its residents? Isn't it more exciting to devote time and resources to the protection of tropical or large African animals? Is it really necessary to act now to save the species if there are still millions of people left? Allow me to provide some hints.
A Biomarker for Urban Health
The Residence Sparrow is a stationary bird that spends the entire year in the same location, the city. As a result, people and sparrows share the same environment, the urban ecosystem: sparrows nest on your tiled roof, educate their young to fly away from the automobiles on your street, and feed in the garden visible through the window (if you are lucky to have a green area in your neighbourhood) perhaps they devour the leftovers of the breakfast cupcake you consume every morning on your way to the bus station. We share the same environment and manner of life. As a result, the House Sparrow is a vital bio indicator of urban health, a species whose presence or absence indicates how well our city is doing.
Let me inform you that I don't have any good news for you: this bio indicator has been placed on the Red List for Birds in the United Kingdom (UK)8 due to its declining population. Furthermore, if the Spanish towns have ran out of nine million sparrows in twenty years9, we should be aware that danger is on the way: "Beware of your own house while your neighbour’s is on fire." Something horrible is occurring in the cities, as the world's best urban bio indicator warns us, and we must recognize the problem before it's too late. The extinction of sparrows may have broader ramifications for citizenship than we previously realized. Is there a lot of noise? Is there more pollution? Do you eat a bad diet? Is it sparrows or people we're talking about? A bio indicator functions in the same way. One of the most prominent researchers on this species, J.D. Summers-Smith, once said: “We can't rule out the idea that the House Sparrow is today's version of the miner's canary.”
Lab-related inquiries
We are concerned about the disappearance of the "urban canary" at the Cavanilles Institute of Biodiversity and Evolutionary Biology at the University of Valencia in Spain, and we are working to uncover the causes of this decline with funds from the Generalitat Valenciana and the European Social Fund. Because the behaviour of House Sparrows varies depending on the features of the metropolitan environment in which they dwell, we needed to first understand the elements that favour or hurt these populations in our research location (in our case, Eastern Spain).
While House Sparrows are more usually found in private gardens in the United Kingdom11, we discovered that this is not the case in Eastern Spain, where they occupy the city's "green islands," the parks12. We also discovered that regions with a lot of traffic and hence more pollution, as well as locations with tall structures, were practically devoid of our winged companions. Other questions developed in our lab as a result of those findings. Are the green spaces in our research area changing and having an impact on the population? Is it the urban diet or pollution that is to blame for the decline? House Sparrows are sedentary, but how closely are close groups linked? Is there a chance of decolonization if a colony goes extinct? Our team is conducting study on these issues. We've counted a lot of colonies, identified their favourite and least favourite urban elements, taken blood samples to determine nutritional and oxidative stress levels, colour-tagged individuals to track them via binoculars, and investigated their nesting sites, among other things. Hopefully, these findings will be made public.
We expect to have a sufficient scientific basis at the conclusion of the research to point to the precise cause or reasons of the species' decrease in Eastern Spain. These findings might be generalized to other Spanish areas or possibly Europe. In summary, we wish to give additional clues to help solve the mystery of the House Sparrows' disappearance. Not only that, but we will also attempt to offer political, urban planning, and wildlife management actions that should be implemented in order to ensure that we do not lose our most distinguished winged neighbours, the urban bio indicator, the House Sparrow.
