Bird Migration Patterns Alter Due to Climate Changes

Researchers have finally solved the mystery behind the early migration of birds each year, they blame it on climate change.

Climate changes were always suspected for the alterations in the migration, though no links were found between the migration patterns of the birds and the climate changes, so far. Researchers from the University of East Anglia (UEA) carried out the research with Dr. Jenny Gill as the lead author.

"We have known that birds are migrating earlier and earlier each year - particularly those that migrate over shorter distances. But the reason why has puzzled bird experts for years. It's a particularly important question because the species which are not migrating earlier are declining in numbers," Lead researcher Dr. Jenny Gill from UEA's school of Biological Sciences said in a press release.

The researchers examined the population of Icelandic black-tailed godwits for around 20 years. The researchers noticed that the bird population forwarded their spring arrival by two weeks.

The experimenters expected individual birds to pre-pone their migrating schedules too, but they found that the individual birds were arriving almost punctually every year. The researchers knew the exact ages of most of the birds as they were being tracked from a long time.

"We found that birds hatched in the late 1990s arrived in May, but those hatched in more recent years are tending to arrive in April," Dr. Gill explained. "So the arrival dates are advancing because the new youngsters are migrating earlier."

The researchers claimed that climatic change appeared to be the most obvious reason for pushing forward their nesting time, which leads to hatching of eggs earlier than expected.

"Climate change is likely to be driving this change because godwits nest earlier in warmer years, and birds that hatch earlier will have more time to gain the body condition needed for migration and to find good places to spend the winter, which can help them to return early to Iceland when they come back to breed," Dr. Gill said.

Most distant immigrants were found to reach the breeding grounds late and spent very little time in warming conditions and nesting. This phenomenon points towards the adverse impact of climate changes on the bird population, leading to depletion of the species at a high rate.

Above 2000 birdwatchers  are supporting the researchers by informing them about the sightings of color-ringed black-tailed godwits in the skies from Iceland to Spain and Portugal.

The Natural Environmental Research Council (NERC) aided this research financially.