Migrating birds arrive at their breeding grounds earlier because of increasing global temperatures, findings of a new study have revealed.
Researchers from the Edinburgh University looked at a total of 413 species of birds across five continents and found how climate change is affecting the migration of birds. Birds arrive at their summer breeding ground about one day earlier per degree of rising global temperatures.
In the study published in the Journal of Animal Ecology, researchers looked at how various species that take flight in response to cues such as food availability and changing seasonal temperatures experience changes in their behavior over time with rising global temperatures.
By looking at the records of migrating bird species as far back as nearly 300 years ago, the researchers found that birds now reach their summer grounds at the wrong time. The data were taken from records made by amateur enthusiasts and scientists including 19th century American naturalist Henry David Thoreau.
Effects Of Early Migration
Reaching their breeding grounds even just a few days earlier could pose problems to birds. They may miss out on the best availability of crucial resources for their survival such as nesting places and food. The timing can affect the hatching of their offspring and the chances of their survival.
Birds that travel long distances and are known to be less responsive to increasing temperatures may suffer the most since other species of birds gain advantage when they arrive at the breeding grounds earlier than the others.
"We confirm earlier findings that on average birds have significantly advanced their spring migration time by 2·1 days per decade and 1·2 days °C-1. We find that over time and in response to warmer spring conditions, short-distance migrants have advanced spring migratory phenology by more than long-distance migrants," the researchers wrote in their study, which was published on Dec. 28.
Climate Change Affects Timing Of Breeding And Flowering
Study researcher Takuji Usui noted how many animal and plant species have changed the timing of their activities, which are linked with the start of spring such as breeding and flowering.
In an earlier study, researchers found that more than 600 plant species are flowering at the wrong time because of warmer winter conditions.
Usui said that their study offers detailed insight into the changes in migration timing and how this varies across species.
"These insights may help us predict how well migratory birds keep up with changing conditions on their breeding grounds," Usui said.
