The survival rate of short-lived birds is higher than that of other animals in a higly dynamic environment, says a study conducted by Ben Sheldon and colleagues at the University of Oxford. The findings were published in the July 9, 2013, issue of the journal PLOS Biology.
The study was based on individual bird watcher's observations of the Great Tits near Oxford England for the last fifty years.
The researchers found that these birds have a natural flexibility that allows them to adapt and adjust fast to the changing climatic conditions.This flexibility is known as phenotypic plasticity that increases the survival rate of a population amid short-term changes in the environment. But even for fast-evolving bird species, it depends on how they can quickly identify the key factors of their environment, such as availability of food.
The scientists arrived at the conclusion after closely observing Great tits' behavioral phenotypes.
They discovered that the birds, on an average, lay their eggs two weeks earlier than they did 50 years ago because there has been shift in time for peak caterpillar numbers, spring blossoms and spring temperature. The Great Tits were able to pre-pone their reproduction period successfully through phenotypic plasticity.
Normally, the Great Tits lay eggs when their prey, winter moth caterpillars, is most abundant to feed their young. The availability of caterpillar food source is based on the bloom time in spring, which is in turn dependent on the temperature.
"Our results show us under what conditions we can expect species to be able to cope with a changing environment, and under what conditions we should be more pessimistic," said, Ben Sheldon, lead author. "We should be particularly concerned about slow-reproducing species, for which the need to show just the right response to the environment is particularly crucial. A key area for future work is to understand why some species respond by the right amount, and others show the wrong response."
The scientists also revealed that future evolution might allow individual birds to demonstrate genetic adaptation to cope with the changing climate.
On the other hand, larger birds and animals with longer life spans do not have enough phenotypic plasticity required to face climate change. The flexibility is absent because they reproduce slowly, evolutionary adaptation is far slower and they fail to save themselves from extinction caused by climate change.
