Wildlife experts in the United Kingdom report that the population of large puffins living on a Scottish has significantly dropped in the last three decades, from 20,000 individuals birds down to around 10,000 in recent years.
In a long-term study featured in the PLOS ONE journal, scientists from the Fair Isle Bird Observatory noted that the dramatic reduction in the number of puffins on the island began during the 1980s. They believe that the failure of young birds to return to the island could likely be the cause of the decline.
The researchers said that the puffins could be suffering from the lack of enough fish to feed on in the area.
"We don't know exactly why they would fail to return to Fair Isle and settle to breed," Dr. Will Miles, a representative from the bird observatory, said.
"It may be due to declining local fish stocks and poor feeding conditions for seabirds in Shetland waters."
Miles pointed out the difficulty in keeping track of immature puffins once they begin to fledge because of the vastness of sea areas they have to cover.
According to the study, the quantities of fish that adult puffins have brought ashore to feed their young have substantially dropped since the 1980s.
Miles said that the reduction in puffin populations on the Fair Isle could also have been affected by the number of great skuas found in the region. These large seabirds are known to be the natural predators of puffins.
While the puffins on the island declined in numbers, the population of great skuas has increased by up to 300 percent during the same period. The predatory birds now have over 400 pairs of skuas for breeding.
Miles said he was surprised to make this discovery because even though the great skuas are on the rise, the survival rate of adult puffins on Fair Isle has remained stable and high for the past three decades.
"It seems adult puffins on Fair Isle are pretty good at avoiding skuas and do not get heavily predated by them," Miles said.
Dr. Mark Bolton, from the Royal Society for the Protection of Birds (RSPB) and an advisor to the long-term puffin study, said that the United Kingdom provides support for internationally important species of birds such as the puffin.
Bolton said that the severe population decline mentioned in the Fair Isle research is a cause for great concern.
The results of the Fair Isle Bird Observatory study are published in the journal PLOS ONE.
Photo: Eric Niven | Flickr
