The Wildfowl & Wetlands Trust has increased its membership by a third over the past two years and signed its 100,000th member.
Members pay an average of £2.20 a month by direct debit. The conservation charity, which operates nine visitor's centres, has stepped up its training regime for workers and has invested in a merchandising programme.
The activity has increased since the arrival of Mike Daw, who joined the charity 18 months ago as marketing director, and following the launch of the award-winning developments in London and Slimbridge, Gloucestershire.
The charity, which recruits its members through its centres, introduced a professional training manual that explains how to sell the membership to visitors, as well as a twice yearly "get together
for staff and volunteers.
Merchandising material such as banners on the ramps leading into the centres ask people to "sign up today".
The trust is encouraging new members to sign up by offering the chance to win a trip to Banrock Wetlands Station in South-West Australia later this year.
It also launched an adoption initiative in June, whereby members could sponsor migrating Brent Geese for £75 and follow their progress via the internet.
The trust has also undergone a redesign to help change people's perceptions that the centres are run separately instead of being part of a major charity.