The Humber Estuary has become one of the most successful breeding grounds for a rare British bird.
The Humber Estuary is a breeding ground for rare birds
More than 100 pairs of avocets have nested on Reads Island this year, raising at least 120 chicks.
Numbers should continue to grow if nesting birds are left alone, wildlife charity the RSPB said.
"Avocets are easily disturbed when they are breeding and so it is important that they are allowed to nest in peace," spokesman Pete Short said.
Avocets are black-and-white, long-legged wading birds with a distinctive upcurved bill.
Reads Island has been managed as a nature reserve and has become increasingly important as a refuge for thousands of rare birds, the RSPB said.
The reserve's Avocet colony is legally protected under the Wildlife and Countryside Act and anyone disturbing the birds could be fined up to £5,000.