What determines the speed at which birds fly?

Jul 17, 2007
Mistletoe bird

Aerodynamic scaling rules that explain how flight varies according to weight and wing loading have been used to compare general speeds of a wide range of flyers, from the smallest insects to the largest aircraft.

In a paper published this week in the open access journal PLoS Biology, Thomas Alerstam, Mikael Rosen, and colleagues from the University of Lund in Sweden analyze the flight speeds of 138 bird species and overturn the general assumption that maximum flight speed of a species is solely determined by such rules. Flight speed doesn’t just depend on the size of the bird (mass and wing loading), but also reflects functional constraints and the evolutionary lineage of the species in question.

The authors argue that only empirical measurements of flight speeds enable you to evaluate how general such aerodynamic rules really are. They used tracking radar measurements of the cruising speeds of migrating birds (collected by themselves and others) to do the analysis and provide the comprehensive dataset with the paper (e.g. this contains the flight speed of approximately one-third of all European bird species).

Their analysis reveals that the difference between the speed of small and large birds is not as great as expected; they suggest that this surprising result is likely to be the result of disadvantages associated with very slow speeds among smaller birds and with very fast speeds for larger birds. They also show that the evolutionary history of the species helps explain much of the variation in flight speed: species of the same group tend to fly at similar characteristic speeds. For example, birds of prey and herons had slow flight speeds, on average, given their mass and wing loading, whereas the average speed for songbirds and shorebirds was faster than would be predicted.

This study suggests that there are different functional adaptations affecting flight differently among different types of bird, and that there exists a diversity of cruising flight characteristics among birds that remain to be explored and understood.

Source: Public Library of Science

Explore further: Sheep flock to Eiffel Tower as French farmers cry wolf

add to favorites email to friend print save as pdf

Related Stories

How the hummingbird achieves its aerobatic feats

Nov 23, 2014

(Phys.org) —The sight of a tiny hummingbird hovering in front of a flower and then darting to another with lightning speed amazes and delights. But it also leaves watchers with a persistent question: How ...

Tricky take-off kept pterodactyls grounded

Nov 06, 2014

A new study, which teamed cutting-edge engineering techniques with paleontology, has found that take-off capacity may have determined body size limits in extinct flying reptiles. The research simulated pterodactyl ...

Bird brains may help drones fly and avoid crashing

Nov 05, 2014

Imagine a sky full of autonomous flying machines delivering anything from fast-food to important documents, medical supplies or just a surprise gift for someone special. How do you stop them all colliding ...

Recommended for you

Genomes of malaria-carrying mosquitoes sequenced

1 hour ago

Nora Besansky, O'Hara Professor of Biological Sciences at the University of Notre Dame and a member of the University's Eck Institute for Global Health, has led an international team of scientists in sequencing ...

Bitter food but good medicine from cucumber genetics

1 hour ago

High-tech genomics and traditional Chinese medicine come together as researchers identify the genes responsible for the intense bitter taste of wild cucumbers. Taming this bitterness made cucumber, pumpkin ...

New button mushroom varieties need better protection

6 hours ago

A working group has recently been formed to work on a better protection of button mushroom varieties. It's activities are firstly directed to generate consensus among the spawn/breeding companies to consider ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.