Nav: Home

Birds fly faster in large flocks

August 16, 2016

New research at Lund University in Sweden shows that the flight speed of birds is determined by a variety of factors. Among the most sensational is that the size of the flock has a significant impact on how fast the birds can fly. The larger the flock, the higher the speed.

Researchers at the Faculty of Science in Lund have now shown how several factors, working simultaneously together, determine the birds' flight speed. Their morphology, that is, the bird's weight and the shape of its wings, is one factor; wind direction and speed is another; and the situation (searching for food or travelling long distances) is a third.

However, what surprised the researchers the most was that the flock size has a major impact on the birds' speed.

"I was surprised that it is such an important factor. It has usually been neglected in studies of bird flight", says Professor Anders Hedenström who conducted the study together with Professor Susanne Åkesson.

This is the first time that researchers have successfully proven that the flight speed increases as the flock becomes bigger.

The measurements were taken on the Swedish island Öland, where the researchers evaluated the birds' morphology and counted the number of birds in different flocks. Subsequently, with the help of an ornithodolite - a measuring instrument that can be described as a telescope with a laser rangefinder that also records the speed and direction, as well as the height and side-angle of the wind - they were able to measure the speed of various large flocks.

The result is clear: bigger flocks travel faster, no matter what species they belong to. What remains unclear is why. One theory is that in large flocks, there are more heavy birds, which fly faster than those that are lighter. In a large flock, it is easier to take advantage of the turbulence that occurs behind other birds, especially when flying in formation, like geese and other birds do. Utilising the turbulence makes it easier to maintain higher speed.

In addition to the study on Öland, the researchers studied common swifts as they cross the Sahara in autumn and spring: their various flight routes and speed, how they find food, and how efficiently they use their energy.

The results show that common swifts, on their way from Sweden to Sub-Sahara and back, choose the most efficient route. Their migration routes across the Sahara are strongly linked to the access to food during different times of the year, and to the wind conditions that vary between spring and autumn in different areas.

"Common swifts choose to move with the wind. In the autumn, a central route across the Congo Basin is the most favourable; in spring, it is the longer western route through Liberia where, in addition to downwind, there is plenty of food", says Susanne Åkesson.

The results are published in two articles in the scientific journal Philosophical Transactions B. One article focuses on the study on Öland whereas the other article focuses on the common swifts' migration across the Sahara.

1) Ecology of tern flight in relation to wind, topography and aerodynamic theory -

2) Negotiating an ecological barrier: crossing the Sahara in relation to winds by common swifts -

Further information

Anders Hedenström Professor of Theoretical Ecology
Lund University, Department of Biology
+46-46-222 41 42 // +46-70-543 19 36

Susanne Åkesson, Professor of Zoology
Lund University, Department of Biology
+46-46-222 37 05 // +46-46-70 245 04 23

Lund University

Related Birds Articles:

Birds become immune to influenza
An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.
Even non-migratory birds use a magnetic compass
Not only migratory birds use a built-in magnetic compass to navigate correctly.
When birds of a feather poop together
Algal blooms deplete oxygen in lakes, produce toxins, and end up killing aquatic life in the lake.
Birds of a feather mob together
Dive bombing a much larger bird isn't just a courageous act by often smaller bird species to keep predators at bay.
Monitoring birds by drone
Forget delivering packages or taking aerial photographs -- drones can even count small birds!
The color of birds
New research provides insight into plumage evolution.
Migrating birds speed up in spring
It turns out being the early bird really does have its advantages.
Birds on top of the world, with nowhere to go
Climate change could make much of the Arctic unsuitable for millions of migratory birds that travel north to breed each year, according to a new international study published today in Global Change Biology.
City birds again prove to be angrier than rural birds
The researchers' observations shed light on the effects of human population expansion on wildlife.
Teaching drones about the birds and the bees
Unmanned Aerial Vehicles (UAVs) of the future will be able to visually coordinate their flight and navigation just like birds and flying insects do, without needing human input, radar or even GPS satellite navigation.

Related Birds Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".