Nightingale Wing Spans the Latest Victim of Climate Change

(CN) — The common nightingale, one of the most well-known and musically enchanting songbirds in the world, have begun to suffer from shorter wing sizes — and climate change may be the culprit.

A study published Tuesday in The Auk: Ornithological Advances details how a team of researchers broke down data from a roughly two decades-long observational effort on two common nightingale populations in the heart of Spain. The researchers sought to better understand how the songbirds are responding to Earth’s consistently changing global climate and possibly adapting to climate change factors, but what they discovered could prove troubling to nightingale survival.

The common nightingale. (By OrchiSelf-photographed, CC BY-SA 3.0, Link)

Researchers found the ongoing influence of climate change seems to have had a noticeable influence on the evolutionary patterns of common nightingales, notably through a small change in average wing sizes. Researchers say that since observations began in 1995 before concluding in 2014, many nightingale wing sizes have slowly decreased in proportion to the body by around a quarter of an inch, a small but potentially consequential change. 

Researchers suggest the likely driver behind this wing reduction is the changing conditions of nightingale habitats. With most common nightingales breeding throughout Europe and certain sections of Asia, their populations have been subjected to severe drought conditions and narrowing springtime windows that have plagued these areas in recent years. These factors make it more difficult for nightingales to raise their young in optimal conditions and produce more abundant offspring, resulting in more nightingales with natural selection traits that favor smaller populations.

Researchers believe these natural selection traits, through a series of biological chains, are responsible for the gradual reduction in the wingspans of nightingales in recent decades, and it is reduction that could gravely threaten their populations.

While a small reduction in wing size for the songbirds may not sound like a serious problem to many, researchers warn it could have major repercussions on migration. Every winter, the songbirds make a great migration to the warmer weather of sub-Saharan Africa. Like many bird species, this yearly pilgrimage south is central to their survival and is their primary tactic to avoid the harsher winter months.

But researchers discovered this fundamental voyage does not always go as planned for the smaller winged songbirds. The study reveals that when winter gives way to spring and it’s time for the nightingales to come back to their breeding grounds, fewer of the shorter winged birds returned. Scientists say that birds with shorter wings are at a distinctive disadvantage when making their roundtrip migration each year, making it less likely that the birds can survive the journey that takes them thousands of miles around the globe.

This decrease in survival rates could prove challenging to the long-term populational stability of common nightingales, particularly as climate change has no end in sight.

Lead author Carolina Remacha of the Complutense University of Madrid said that as evidence points to climate change being the culprit behind shorter nightingale wing sizes, it becomes even more imperative for scientists and researchers around the world to bring these problems to light.

“There is much evidence that climate change is having an effect on migratory birds, changing their arrival and laying dates and their physical features over the last few decades,” Remacha said with the release of the study. “If we are to fully understand how bird populations adapt to new environments in order to help them tackle the challenges of a rapidly changing world, it is important to call attention to the potential problems of maladaptive change.”

The study notes many sizeable knowledge gaps continue to hold back scientists in this field and stresses future research efforts focusing on the relationship between bird populations and climate change are needed to achieve a more comprehensive understanding of these problems.

Only through these efforts, researchers say, will we become better prepared to combat the problems of a consistently changing climate and help to protect the world’s precious supply of avian vocalists.

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