Why do some birds develop so much faster than others?

In a new study from the University of Sheffield, scientists have discovered why some birds take longer to develop. The researchers found that size, safety, and parenting are all factors that influence the speed at which a particular bird species matures.

The experts set out to understand why there is so much variation in the length of time it takes birds to develop from a fertilized egg to an independent adult.

All living creatures have to strike the balance between reproduction and survival, and they have different strategies. 

The researchers found that bird species with a “live fast die young” strategy grow up faster in order to maximize the number of offspring they can produce in a short time.

The study, which was focused on thousands of bird species, revealed that birds living and breeding in safe environments with few predators took longer to develop. This is likely because they can afford to spend longer in a vulnerable state.

The research also showed that migratory birds develop much faster, which is necessary for them to be prepared for a journey to their winter habitats at the end of the summer.

It was no surprise to find that bigger birds took longer to develop, but the experts noted that even among birds of a similar size there was variation in development times.

“The amount of time it takes for a fertilized egg to develop into a fully grown adult varies hugely across the animal kingdom,” said study lead author Dr. Chris Cooney. “For instance, it takes an elephant almost 10 years to reach independence, whereas a fruit fly is fully grown after only a matter of days.”

“This extraordinary diversity is also encapsulated within birds, where albatrosses can take almost a year to develop from an embryo to an independent adult, but a typical UK garden songbird takes little more than a month. We found that certain aspects of a species’ lifestyle and environment are important in explaining how long they take to develop.”

The study is the first of its kind to consider the significance of body size, lifestyle, and environment while explaining evolutionary differences. 

“Our study on birds gives us some clues about the type of factors that may be important in other species. However, it may be that different factors are important for determining development length in other animal groups,” said study co-author Dr. Alison Wright.

“The next step is therefore to address these questions using data that covers the breadth of the animal kingdom – from fish to mammals to insects – to gain an even broader insight into the factors shaping these fundamental differences across species.”

Study co-senior author Dr. Nicola Hemmings said the research may prove crucial in understanding and predicting how organisms may respond when conditions change as the climate warms and habitats are modified. 

The study is published in the journal Nature Communications.

—

By Chrissy Sexton, Earth.com Staff