Guardians of black swans in a Devon town which has the birds as its emblem say they are concerned that the birds' eggs are under attack.
About 12 eggs have disappeared in Dawlish, resulting in only two cygnets having been born four weeks ago, the first for 2011.
Seagulls are believed to be to blame, and staff at the town's aviary say they have never known a year like it.
Visitors are being asked to not feed gulls because it makes gulls forage.
It is not known why the seagulls have started targeting nests this year, but Dawlish waterfowl warden Derek Porter said if the swans left an opportunity for the gulls to target the eggs, they seemed to take it.
He said: "If the swans decide to go for a swim, there are just so many gulls that they'll fly in straight away and the eggs are gone.
"Swans' eggs are fairly big, but the gulls are managing to take them and damage them, break them, and, obviously once that happens, there are no chicks."
Mr Porter added that anyone who threw bread for birds encouraged a gull "feeding frenzy", which why visitors were being asked to stop.
The two cygnets at the aviary and their parents will be looked after on site for a few more weeks before being released into the wild.
The black swans in Dawlish Water have been a major tourist attraction for decades and have been used as the town's emblem for more than 40 years.
They were brought to Dawlish from Australia at the start of the 20th Century.