Backyard Pond Losing Fish? Try Looking To the Skies

By Scott Shalway
IF YOU HAVE a fish pond in the backyard, sooner or later you will have a problem. Your fish will disappear and you will be upset.

The culprits could be Raccoons, mink or Snapping Turtles, but more likely fish-eating birds are to blame. Great Blue Herons, Green Herons and Belted Kingfishers raid even small, hand-dug backyard water features that are the pride and joy of many homeowners. Eventually, it becomes clear that a pond without protection is simply a sushi bar for birds…

Protecting small ponds from piscivorous birds is relatively easy. One solution is to place netting over the pond to physically exclude the birds. A better and simpler option is to provide underwater cover for the fish. Add a few eight-inch concrete blocks or several lengths of six-inch PVC pipe. When danger threatens, the fish can quickly retreat inside these structures.

On the other hand, fish-eating birds might be welcomed at farm ponds, streams and lakes. I often get mail from readers who are thrilled when a Bald Eagle, Osprey or Kingfisher dines on their property. It’s all a matter of perspective.

Most small backyard fish ponds are built for the fish. If the pond had a sign and birds could read, the sign might read, “Birds keep out.” Bigger ponds, streams and lakes are typically viewed as natural systems where predators are welcomed.

Larger ponds and lakes attract occasional bald eagles, ospreys and great blue herons. Each is primarily a fish eater. But many other water birds include fish as a part of their normal diet. Loons, grebes and even ducks make short migratory stops on ponds and lakes and eat small fish.

Mergansers (Common, Hooded and Red-breasted), in fact, are ducks specially adapted to eat fish. Their bills are long and narrow with serrated edges, a perfect tool for grasping and holding slippery fish.

On big lakes and rivers, Double-crested Cormorants dive and fish for extended periods of time. When not fishing, cormorants are often seen sunning themselves with wings extended.

Along smaller streams and river banks, a less familiar bird can often be seen foraging among the rocks for aquatic invertebrates and small fish. The Spotted Sandpiper looks out of place along wooded waterways, but it nests in shallow scrapes under shrub or next to fallen logs. Spotties are easy to recognize by their spotted breast and the way they bob their rear end up and down as they walk along the shore.

Wooded streams are also home to a peculiar warbler with an identity crisis. It looks like a thrush, eats like a trout and walks like a spotted sandpiper, bobbing its tail up and down. As Louisiana waterthrushes forage along the edges of streams, they flip fallen leaves in search of aquatic invertebrates and small fish. When males sing, they fly to an elevated perch so they can be heard above the roar of flowing water.

My favorite fish-eating birds require a major trip to see and enjoy. Boobies, gannets and Brown Pelicans are sea birds that fish by plunge-diving. From as high as 60 ft. above the water, they fold their wings and plunge into the water like speeding bullets.

Finally, on the few occasions I’ve spent time along cold, swift streams in the Rocky Mountains, I’ve always found time to watch dippers. These odd birds, sometimes called Water Ouzels, actually forage underwater. Whether wading, walking on the bottom or “flying” through the water like penguins, dippers eat all kinds of aquatic insects, snails, fish eggs and small fish.

The dipper’s nesting habits are equally fascinating. They build large mossy domes behind waterfalls or under bridges, where stream spray keeps the nest damp. The one nest I found many years ago was on a massive boulder in the middle of a small, raging river.

The female incubates four or five eggs for up to 17 days. The extended incubation period is probably due to the chilling effect of the stream spray. When young dippers fledge at about 24 days, they can swim and dive almost immediately. –Pittsburgh Post Gazette