His comments follow the Atlantic puffin being added to the International Union for the Conservation of Nature's red list, which means it faces global extinction.
The number of birds in Norway, Iceland, Faroe Islands and Shetland has declined, but the populations in most parts of Britain are holding up well.
Until two years ago, puffin numbers in Alderney were on the rise, but severe storms in the winter of 2013 are likely to have killed many juvenile birds, which will hit the number of breeding pairs for years to come.
Burhou, off Alderney, is home to more than 100 breeding pairs during the summer, making it the largest breeding colony in the Channel Islands.
Mr Gauvain said between 2005 and 2012 puffin numbers had risen, from 120 to 170 breeding pairs.
But the bad winter of 2013 hit the birds hard.
'This year saw some improvement for breeding pairs,' he said.
'The big problem we have are these big storm events, as they can lead to a decline five years or more down the line.'
It takes five years for puffins to reach maturity.
