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:

Prebiotic evolution: Hairpins help each other out
The evolution of cells and organisms is thought to have been preceded by a phase in which informational molecules like DNA could be replicated selectively.
How to be a winner in the game of evolution
A new study by University of Arizona biologists helps explain why different groups of animals differ dramatically in their number of species, and how this is related to differences in their body forms and ways of life.
The galloping evolution in seahorses
A genome project, comprising six evolutionary biologists from Professor Axel Meyer's research team from Konstanz and researchers from China and Singapore, sequenced and analyzed the genome of the tiger tail seahorse.
Fast evolution affects everyone, everywhere
Rapid evolution of other species happens all around us all the time -- and many of the most extreme examples are associated with human influences.
Landscape evolution and hazards
Landscapes are formed by a combination of uplift and erosion.
New insight into enzyme evolution
How enzymes -- the biological proteins that act as catalysts and help complex reactions occur -- are 'tuned' to work at a particular temperature is described in new research from groups in New Zealand and the UK, including the University of Bristol.
The evolution of Dark-fly
On Nov. 11, 1954, Syuiti Mori turned out the lights on a small group of fruit flies.
A look into the evolution of the eye
A team of researchers, among them a zoologist from the University of Cologne, has succeeded in reconstructing a 160 million year old compound eye of a fossil crustacean found in southeastern France visible.
Is evolution more intelligent than we thought?
Evolution may be more intelligent than we thought, according to a University of Southampton professor.
The evolution of antievolution policies
Organized opposition to the teaching of evolution in public schoolsin the United States began in the 1920s, leading to the famous Scopes Monkey trial.

Related Evolution Reading:

Evolution: The Human Story, 2nd Edition
by Dr. Alice Roberts (Author)

Theistic Evolution: A Scientific, Philosophical, and Theological Critique
by J. P. Moreland (Editor), Stephen C. Meyer (Editor), Christopher Shaw (Editor), Ann K. Gauger (Editor), Wayne Grudem (Editor), Steve Fuller (Editor), Douglas Axe (Editor), C. John Collins (Editor), John D. Currid (Editor), Guy Prentiss Waters (Editor), Gregg R. Allison (Editor), Fred G. Zaspel (Editor), Matti Leisola (Editor), James M. Tour (Editor), Winston Ewert (Editor), Jonathan Wells (Editor), Sheena Tyler (Editor), Günter Bechly (Editor), Casey Luskin (Editor), Paul A. Nelson (Editor), Ola Hössjer (Editor), Colin R. Reeves (Editor), Stephen Dilley (Editor), Garrett J. DeWeese (Editor), Tapio Puolimatka (Editor), John G. West (Editor)

Why Evolution Is True
by Jerry A. Coyne (Author)

Darwin Devolves: The New Science About DNA That Challenges Evolution
by Michael J. Behe (Author)

Evolution: A Visual Record
by Robert Clark (Author)

Dr. Gundry's Diet Evolution: Turn Off the Genes That Are Killing You and Your Waistline
by Steven R. Gundry (Author)

Evolution
by Douglas J. Futuyma (Author), Mark Kirkpatrick (Author)

The Equations of Life: How Physics Shapes Evolution
by Charles S. Cockell (Author)

The Evolution of a Girl
by L E Bowman (Author), Marie Worden (Illustrator)

The Story of Life: A First Book about Evolution
by Catherine Barr (Author), Steve Williams (Author), Amy Husband (Illustrator)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Circular
We're told if the economy is growing, and if we keep producing, that's a good thing. But at what cost? This hour, TED speakers explore circular systems that regenerate and re-use what we already have. Guests include economist Kate Raworth, environmental activist Tristram Stuart, landscape architect Kate Orff, entrepreneur David Katz, and graphic designer Jessi Arrington.
Now Playing: Science for the People

#503 Postpartum Blues (Rebroadcast)
When a woman gives birth, it seems like everyone wants to know how the baby is doing. What does it weigh? Is it breathing right? Did it cry? But it turns out that, in the United States, we're not doing to great at asking how the mom, who just pushed something the size of a pot roast out of something the size of a Cheerio, is doing. This week we talk to anthropologist Kate Clancy about her postpartum experience and how it is becoming distressingly common, and we speak with Julie Wiebe about prolapse, what it is and how it's...