The 60th anniversary of one of the longest ever British mammal surveys is being celebrated by the National Trust.
Since 1951, wardens have been counting and tagging seal pups born on the Farne Islands off the Northumberland Coast. During this time, the number of pups born each year has trebled, from 500 to 1499, making it the largest English colony of Atlantic grey seals.
When the survey began, scientists knew almost nothing about how seals bred, what they ate or where they went during the winter – making those early studies on the Farnes groundbreaking.
The seal colony is monitored throughout the autumn by a team of five Trust wardens. Led by NT Head Warden David Steel, this dedicated team lives on the islands full-time between October and December, when they can expect to be regularly cut off from the mainland by storms.
“Out here you’re really in the hands of nature, ” explained David. “We can go a couple of weeks without seeing anyone else, it’s just us and the seals. The young pups can cry like human babies so it can be really eerie but after 11 years I’m used to it.
“One mother seal usually has her pup about 10 feet from the door of where we live which makes life interesting. It means that once it’s dark you can’t go outside!”
The results of the Farnes Seal Survey are collected by the Sea Mammal Research unit at St Andrews University. Senior Research Scientist Callan Duck said: “The Farne Islands are an integral feature in the Berwickshire and North Northumberland Coast Special Area of Conservation and the National Trust’s monitoring of grey seal pups provides an essential component of the information required by European conservation legislation for this area.”
Seal tagging was pioneered on the Farne Islands by members of the Natural History Society of Northumberland led by Ian Telfer and Grace Hickling. The first stainless steel tags fitted to 10 pups on Staple Island were similar to cattle ear-tag clips and cost 1s 9d each.
Since then the methods and tools have improved dramatically. Today tiny transmitters like the SIM card from a mobile phone are glued to the seal’s fur. Every time the animal surfaces, its location is sent back to the researchers, allowing them to pinpoint its movements.
Only a small number of seals are electronically tagged each year. The rest are carefully counted by hand – unlike most other seal surveys which use aerial photographs to estimate the number of newborn pups.
To keep up to date with the progress of the seals on the Farne Islands go to David Steel’s blog: www.farnephoto.blogspot.com or follow him on Twitter: @NTSteely