A manager at a nature reserve said staff have noticed birds behaving differently, which they have put down to a lack of visitors to the site during the lockdown period.
Martin Lester said some species which might usually "hide" were being seen more often at the National Trust's Wicken Fen reserve in Cambridgeshire.
"The species that are here... are kind of behaving in a way that we've not seen before, because there are no people on the reserve, so they're in areas we don't normally see them," he said.
"The blackbirds and robins - they're always fairly resistant to human intrusion, but some of the less robust species like the warblers, some of the birds of prey, owls... they tend to hide themselves away, but this year, because there are no people on the trails... the birds are coming much closer to where we are."
He described it as "actually quite wonderful".