Last summer, heavy rainfall resulted in the puffin population of the Farne Islands suffering substantial losses at a time when young puffins (called pufflings when they are still in their burrows) were at their most vulnerable.
On 13 June, more than 300 pufflings died when 5in (12cm) of rain fell on the islands in just 24 hours, flooding many burrows.
Yet even in the event of such extreme weather, the birds’ numbers have remained stable, with sufficient numbers of pufflings successfully hatching on the Farne Islands.
During last year’s puffin survey, only a marginal decrease of less than 0.5% of the 43,752 breeding pairs was revealed when compared with the results of the 2018 survey. Although this is great news for the population on the Farne Islands, puffins are in decline on a global scale.
The Atlantic puffin is listed as ‘Vulnerable’ by IUCN, and is on BTO’s Red List for conservation concern.
This decline is in large part due to the reduction in numbers of sandeels. Although puffins will also eat small squid, herring, and sardines, sandeels are the birds’ preferred food supply, and make up the highest proportion of their diet on the islands.
The ‘Puffin Census’ takes place on the National Trust owned islands every five years, where a team of rangers check thousands of burrows in search for occupied nests/Credit: Paul Kingston, NPP
A lack of the sandeels was the primary cause of the puffin population crash on the islands in 2008.
Climate change could be a key factor in contributing to such food shortages, while extreme weather, overfishing, invasive predators such as rats, and marine pollution also play a role.
Since 2008, the puffin population has slowly been recovering on the islands.
The birds have traditionally done well on the Farne Islands due to a number of factors, including the work of rangers; the protection of the marine area around the islands; the lack of ground predators; and the availability of suitable nesting areas.
But there are concerns that the puffin population here, and elsewhere, will remain vulnerable to the effects of climate change.
As well as puffins, the Farne Islands host many thousands of Arctic terns, guillemots and razorbills, plus grey seals/Credit: Paul Kingston, NNP
Because of this, the National Trust has taken the decision for their 11-strong ranger team to monitor puffins on the Farne Islands annually, rather than once every 5 years, as was previously undertaken.
National Trust ranger Thomas Hendry explains, “Switching to the annual survey in 2018 has given us year-on-year data for the first time, and it’s allowing us to monitor the puffin population and breeding behaviour much more closely.
“The annual survey is also allowing the rangers get a better picture of the causes of seabird declines, tracking puffin numbers against likely causes of population change from island-based factors such as seal distribution or predatory gull numbers to changes in the frequency of storms and summer rainfall as a result of climate change or changes in the sand eel population.”
The census takes place on the National Trust owned islands every five years, where a team of rangers check thousands of burrows in search for occupied nests/Credit Paul Kingston
During the surveys, rangers monitor puffin burrows on the eight most populated islands to check whether the holes are occupied.
The rangers look for signs of occupation which include birds returning to nests with fish in their beaks, fresh digging around burrows, puffin footprints, clearance of vegetation, hatched eggshells, and fish or guano in the entrance. If they are unsure whether a burrow is occupied, rangers will put their arm down the burrow to carefully feel for any occupants.