Tropic Birds More Colorful Than Avians Away from Equator, Studies Suggest

Centuries after Charles Darwin's proposed theories on evolution, many studies have aligned to prove most of the concepts to be true. In new research, experts discussed how the birds near the equator, which Darwin also encountered, have more shades of color compared to avians in other parts of the globe.

Colorful Birds Near the Equator

The analysis of each of the colors present in the wide array of bird species was made possible through the help of an artificial intelligence system. The examination processed over 24,000 preserved birds managed by the Natural History Museum, Daily Mail reports.

Tropical birds that reside in equatorial regions were found more colorful by 30 percent than any other avian species of non-tropical countries, especially those found nearer to the farthest latitudes of the northern and southern hemispheres.

The colorful feature of birds near the equator has been known for many years, but there is still no concrete evidence to explain why this biological phenomenon occurs.

Charles Darwin and other evolutionary and naturalist experts in the 18th and 19th centuries have theorized something that might shed light on the unusual development of equatorial birds, but they haven't been proven until today.

Higher Color in Tropical Birds, Gradient More Prominent in Male Individuals

The latest study was led by the University of Sheffield's School of Biosciences specialists Christopher Cooney and Gavin Thomas.

According to their investigation, a broad pattern can be observed in bird species. The colors become more abundant by up to 30 percent as the species' geographical location is nearer to the middle part of the planet.

Cooney explained that the locations themselves could hold the clue to why birds obtain such colorful physical appearances.

The study offers us a glimpse of the factors that promote and maintain global biodiversity on a different level. However, Cooney added that the board-scale associations through the dietary and habitat variances present limited data.

Cooney continued, that the information on the avian colors could be further elaborated through the evolutionary and ecological aspects, giving us more detail about the true nature of the colorfulness in these tropical birds.

The abundant color of the equatorial birds was first observed by Charles Darwin and other naturalists such as Alfred Russel Wallace and Alexander von Humboldt. All of them documented how rich the shades of the tropical birds are, specifying the features as 'rich variety' and 'mixture of colors' as they traveled across the region.

To understand more about these observations, two associated studies were carried out over 24,345 bird individuals from 4,527 species. Each of them is part of passerine avians, which include birds such as songbirds, sparrows, and finches.

Using DeepLabv3, the scholars were able to examine pixels in photographs of the birds, allowing them to procure 1,500 individual points per specimen. The loci score or the metric of colorfulness, declines as the latitudinal midpoint of the bird's locations goes further from the equator.

The latitudinal gradient and colorfulness in birds were also found more prominent in females than males. The studies were published in the journal Nature Ecology and Evolution (1, 2).

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