At 4 feet high, with handsome gray-blue feathers, a long yellow bill and a dramatic black head plume, the great blue heron is a striking bird.

And the only way a backyard birder used to be able to spot one would be if it flew overhead on its way to a nesting site. Herons are fish eaters, so seed-stocked bird feeders hold no interest for them.

But, as a large number of area fish fanciers have discovered, ornamental ponds stocked with koi are to herons what sugar-water feeders are to hummingbirds — bird buffets.

Terry Knauer, owner of Economy Aquatic Gardens on Preston Highway in Louisville, said he has “three or four customers a day” coming in to replace fish that have been speared by great blue herons. This can be an expensive proposition, since these fish cost from $20 to a few hundred dollars each.

“We’re pet people,” Knauer said. “People stand at my counter and cry. They get attached to their fish.”

When asked if raccoons might not be the culprits, Knauer explained that raccoons leave a mess. “They stir up and muddy the ponds. And they leave behind scales and the fish heads.”

Herons simply swoop down, spear a fish and fly off.

This bad news for fish owners is the result of good news for the birds.

Brainard Palmer-Ball Jr., terrestrial vertebrate zoologist with the Kentucky State Nature Preserves Commission and author of “The Kentucky Breeding Bird Atlas,” explained that the herons have made a comeback.

“The population of great blue herons is growing rapidly,” he noted. “They are recovering from near absence in Kentucky as a breeding bird in the 1960s and early 1970s due to the accumulation of pesticide residues in the ecosystem.”

These were chemicals such as DDT, which became concentrated in the food chain and caused declines in numbers of many species of fish-eating birds, including bald eagles as well as herons.

The pesticide residue was a second blow to the great blue herons, which had suffered a decline earlier in the century when they were hunted for their plumage.

Herons are now protected from hunting and are among the most abundant wading birds in North America, found in both coastal and inland habitats.

In fact, Palmer-Ball emphasized that their habitat in Jefferson County, “… is definitely not (suffering) a reduction.”

He said that there are “sometimes as many as 50 (herons) at the Falls of the Ohio and there are two nesting colonies known in Jefferson County, along Harrods Creek and along Floyds Fork.”

A survey in 2004 found there were about 40 pairs in those two colonies.

People are seeing more of the birds because of “increasing numbers and adaptability on the part of the great blues,” Palmer-Ball said.