A study reveals that to thrive in an urban environment, birds must either develop large brains like seagulls, or have more offspring like pigeons.
Researchers at the University of Gothenburg say that big brains or lots of offspring are the two strategies that are essential for surviving in an unnatural environment.
The team says that a number of bird species are threatened with extinction due to increasing urbanization, but others seem to really thrive around humans.
They discovered that larger-brained birds are able to find new sources of food and avoid human-made hazards more precisely than their smaller peers.
Those with smaller brains, like pigeons, had to rely on larger populations – therefore more offspring – to survive in an area dominated by humans.
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Pigeons on the street. Researchers say that despite their small brains, pigeons are able to thrive in urban environments by reproducing much more than in wild environments
The results, published in Frontiers in Ecology and Evolution, could stimulate conservation efforts for different species of birds as humans thrive in more natural environments through urbanization.
Lead author Dr Ferran Sayol of the University of Gothenburg, Sweden said that cities are harsh environments for most species.
He said they offer much lower biodiversity than natural environments, mainly due to the impact of humans and human obstacles.
“The species that can tolerate cities are important because they are the ones that most humans will come into contact with in their daily lives, and they can have significant effects on the urban environment in our cities,” said Savol.
Coping with the increasingly chaotic and busy lifestyles of people is difficult for birds and other creatures, making their survival more difficult.
Our feathered friends must be smarter than their rural counterparts – or have more chicks.
The same phenomenon of larger, more gendered birds thriving in front of others is not found in the country.
Understanding which bird species succeed has implications for saving them and sheds new light on those with whom we share our neighborhoods.
Previous research has shown that larger-brained birds have a number of advantages.
This includes the ability to find new sources of food and avoid human-made hazards better than its smaller brain peers.
The new study fills a knowledge gap – that’s how pigeons and other small-brained species can thrive in cities.
Dr. Sayol and his colleagues analyzed databases and museum collections containing brain and body size, maximum lifespan, global distribution and frequency of reproduction.
They contained details of more than 629 birds in 27 cities around the world and showed that brain size plays a vital role – but it’s not the only path to success.
“We have identified two ways for bird species to become city dwellers,” said Sayol.
“On the one hand, big-brained species, like crows and gulls, are common in cities because the large brain size helps them meet the challenges of a new environment.
“On the other hand, we have also discovered that small-brained species, like pigeons, can be very effective if they have a high number of reproductive attempts during their lifetime.”
The latter represents an adaptation that gives priority to the future reproductive success of a species over its current survival.
Seagulls are able to survive in urban environments thanks to their larger-than-average brains, which allow them to dodge human obstacles and search for food.
Interestingly, the study suggests that the two strategies represent separate ways of dealing with urban environments – rather than being linked.
Medium-sized birds of the brain – relative to their bodies – are the least likely to live in cities, according to Swedish researchers.
Not surprisingly, both strategies are less common in natural environments.
Researchers are trying to understand how these adaptations will change the behavior and structure of urban bird communities in the future.
Dr. Sayol said there are multiple strategies for adapting to urban habitats.
When considering the impacts of our increasingly urban future on our wild neighbors, it will be important to consider reproduction and brain size.
“In our study, we found a general scheme, but in the future it might be interesting to understand the exact mechanisms behind, for example, which aspects of intelligence are most useful,” said the researcher.
“Understanding what makes certain species better able to tolerate or even exploit cities will help researchers anticipate the response of biodiversity as cities continue to develop.”
The research was published in the journal Frontiers in ecology and evolution.
HOW DOES HEAVY METAL POISONING KILL BIRDS?
Birds are easily poisoned by the heavy metals present in their environment.
Each heavy metal causes distinct symptoms and affects birds differently.
The three heavy metals that commonly poison birds are lead, zinc and iron.
Common symptoms that a bird suffers from heavy metal poisoning are:
- Constant thirst
- Water regurgitation
- The Depression
- Loss of coordinated movements
Zinc and iron are present in food and are needed in small amounts for a healthy bird.
When abnormal amounts are present in the bird’s body, the same heavy metals can cause poisoning.
Lead poisoning is no longer as common as it once was due to increased awareness of the dangers.
Heavy metal poisoning by iron can lead to iron storage disease, which causes nutrients to deposit in the body’s internal organs.
This can cause liver problems and damage other organs.