Peering out of the reeds, the male bittern was photographed at Blacktoft Sands, in East Yorkshire, where wardens are hoping he and his mate will produce a brood of young this year.
If they do it is thought they will be the first official successful breeding pair in Yorkshire for 50 years.
The images were shot by birdwatcher Chris Bower, from Wakefield, whose patience finally paid off when he snapped the notoriously shy bird in the reeds and in flight.
The bittern's distinctive booming call has been heard by wardens of the Royal Society for the Protection of Birds at Blacktoft over the last few months, but they had only caught glimpses of the secretive bird stalking through the reeds.
Bitterns are virtually invisible as their plumage provides perfect camouflage. Living in freshwater marshes with areas of open water, they stalk fish, eels, frogs and insects.
It is the males that boom and it was once thought that they did so by thrusting their bills into the marsh before calling or even blowing down a reed stem. But in fact, the sound is produced by vibrating air in the throat.
The latest appearance adds to an increasing presence in the Humber area, which is gaining in importance as a stronghold for bitterns.
The Far Ings nature reserve just across the Humber Bridge at Barton is credited with pioneering their comeback to the river, after the perfect habitat for them was created there. They first bred there four years ago and last year four nests are believed to have successfully produced young in the Barton Clay Pits area.
A pair of bitterns attempted to breed last year at Blacktoft Sands, but without success.
Once on the edge of extinction, the bitterns have staged an amazing comeback nationally, with five times as many nests as in 1997.
Bitterns are also winter visitors to Yorkshire from the Continent. Sightings were made last winter at Pugneys Country Park, Wakefield, the Potteric Carr reserve at Doncaster, and the Tophill Low nature reserve, near Driffield.