Nav: Home

Review explores how birds can stay slim, even when they overeat

September 18, 2018

Noticing that songbirds, such as finches, never seem to get fat despite overeating at bird feeders, London environmental biologist Lewis Halsey wondered whether the amount of energy birds put into singing, fidgeting, or exercising could be adjusted in ways that regulate weight. In a literature review published September 18 in the journal Trends in Ecology & Evolution, he explores whether songbirds don't need to worry about their calorie counts because they can control the way their bodies use energy.

"The passerine birds at the bird feeders near my home never seem to get fat despite having this buffet constantly available to them, but there are people who get heavy when exposed to that kind of all-you-can-eat environment," says Halsey (@lewis_halsey), of the University of Roehampton. "I wanted to investigate possible behavioral and physiological mechanisms, aside from just food consumed and exercise completed, that help animals control their energy budgets and body weights; there's more going on than just how many calories you've put into your face."

Now, it could be that we never see fat songbirds because the ones that gain too much weight are picked off by a range of predators. However, that predation pressure would eventually cause evolution to weed out such a tendency, and recent studies indirectly suggest that birds are capable of balancing energy intake by increasing their daily metabolic rate or decreasing the efficiency with which they are able to extract energy from ingested food.

"For a given amount of food, an animal can unconsciously adjust how efficiently it uses the energy from it either behaviorally, for example by changing wingbeat frequency or singing patterns to use more or less energy, or physiologically, in terms of digestive or cellular metabolic efficiency," Halsey says.

Based on the emerging evidence, he wants to reframe the way we think about the standard equation subtracting energy consumed from energy burned. "We need to remember that 'energy in' isn't what's shoved down the beak but what's taken up through the gut and then what's extracted by the cells; looking at it as just the amount of food consumed is too simplistic," he says. "And this goes for humans and other animals, not just songbirds."

Halsey has flagged some areas for further research. One such experiment might present birds that normally stay slim in the face of a bird feeder full of seeds with a more attractive, easier-to-digest option instead. "I want to give birds the equivalent of ice cream and see if that breaks their resolve and fine body mass control as it does for many humans, or if, even in the face of the ice cream equivalent, whatever that might be, the birds resolutely maintain their weight," he says. "This could be done in the lab preliminarily and later in the field to help us understand how these underlying mechanisms regulate body weight."
-end-
Trends in Ecology & Evolution, Halsey: "Keeping Slim When Food Is Abundant: What Energy Mechanisms Could Be at Play?" https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(18)30185-X

Trends in Ecology & Evolution (@Trends_Ecol_Evo), published by Cell Press, is a monthly review journal that contains polished, concise and readable reviews, opinions, and letters in all areas of ecology and evolutionary science. It aims to keep scientists informed of new developments and ideas across the full range of ecology and evolutionary biology--from the pure to the applied, and from molecular to global. Visit http://www.cell.com/trends/ecology-evolution. To receive Cell Press media alerts, please contact press@cell.com.

Cell Press

Related Evolution Articles:

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.
Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.
How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.
Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.
Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.
A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.
Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?
Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.
Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.
Evolution of aesthetic dentistry
One of the main goals of dental treatment is to mimic teeth and design smiles in the most natural and aesthetic manner, based on the individual and specific needs of the patient.
More Evolution News and Evolution Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Sound And Silence
Sound surrounds us, from cacophony even to silence. But depending on how we hear, the world can be a different auditory experience for each of us. This hour, TED speakers explore the science of sound. Guests on the show include NPR All Things Considered host Mary Louise Kelly, neuroscientist Jim Hudspeth, writer Rebecca Knill, and sound designer Dallas Taylor.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

Kittens Kick The Giggly Blue Robot All Summer
With the recent passing of Ruth Bader Ginsburg, there's been a lot of debate about how much power the Supreme Court should really have. We think of the Supreme Court justices as all-powerful beings, issuing momentous rulings from on high. But they haven't always been so, you know, supreme. On this episode, we go all the way back to the case that, in a lot of ways, started it all.  Support Radiolab by becoming a member today at Radiolab.org/donate.