Birds migrating to and from North America are getting smaller since has temperature risen over the past 40 years.  According to new research from Washington University in St. Louis, the sizes of birds with smaller brains reduce more than those with bigger brains.

Warbler
(Photo : Bruce Bennett/Getty Images)

How Climate Change Affect the Sizes of Bird

This is the first time cognition and animal response is associated with human-induced climate change. Singing bird species such as sparrows, warblers, and thrushes have experienced tiny but noticeable changes in body size, as per Phys.org.

In fact, some experts believe that shrinkage is a universal reaction to global warming because of how widespread the size changes are. 

A recent study published in Ecology Letters indicates that birds with larger brains can outthink those with smaller brains. 

Body sizes are shrinking as temperatures rise, says Justin Baldwin, a Ph.D. student in Carlos Botero's lab at Washington University's School of Arts & Sciences. However, the decline in large-brained species is less dramatic than the decline in small-brained species. 

Also Read: Almost 300 Migratory Birds Found Dead in New York After Smacking Into a Skyscraper

Experimental Findings

Between 1978 and 2016, Baldwin and his co-authors examined data on more than 70,000 birds that perished in Chicago after colliding with buildings.

New brain capacity measurements and lifespan data for 49 of the 52 species of North American migratory birds included in the original study were added by the researchers at the University of Michigan. 

Compared to birds with smaller brains, birds with large brains had only one-third the amount of reduction in body size, according to the Washington University researchers.  

According to Verve Times, birds' behavioral adaptability is typically equated with their relative brain size. Applied to other creatures, the concept is disputed, yet it works effectively for birds. 

In addition to better learning and memory, Baldwin found that having a larger brain led to longer lives and more stable population dynamics. 

There is a possibility that a bird with a larger brain could seek out microhabitats where the temperature is cooler, reducing its exposure to warming temperatures, according to Baldwin. 

It is the first time that scientists have demonstrated a relationship between cognition and phenotypic responses to climate change, making these discoveries crucial.

Sparrow
(Photo : ADEM ALTAN/AFP via Getty Images)

Does Climate Change Affect Brainy Birds?

The reason so many songbirds are getting smaller as temperatures rise is a mystery. This could be due to the fact that birds with smaller bodies are better able to dissipate heat.

There is evidence to support this theory, like the smaller size of birds found in the more temperate regions of their regular geographic distribution areas. 

However, reducing one's size may have a detrimental effect on a bird's capacity to compete, such as an increase in predation or a decrease in competitiveness. Being a large-brained species opens up possibilities that smaller-brained ones do not. 

There is no guarantee that brainy birds will be unaffected by climate change, or that they would fare well in the face of it. But the findings show that the less-intelligent birds may be particularly vulnerable to the effects of climate change. 

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