For the Birds Radio Program: Great Blue Heron

Original Air Date: April 21, 2003 Rerun Dates: April 4, 2018; April 23, 2004; March 17, 2004

The enormous Great Blue Heron weighs less than most newborn babies. Learn more about this majestic bird and why monofilament line is so dangerous for it.

Duration: 4′33″

Transcript

One of the biggest birds in Minnesota, measured from tip of beak to the end of its long long legs, is the Great Blue Heron. But if you use weight as your measure, suddenly swans, geese, turkeys, hawks, and eagles dwarf this magnificent wetland bird. Despite their great size, Great Blues tip the scale at a mere six or seven pounds. One who’s eaten a lot of good meals recently might bulk out at close to 8 pounds, but even an exceptionally fat heron still weighs less than most newborn human babies.

This bird has hollow bones and an extraordinarily skinny body. Much of its weight is concentrated in the hefty beak and powerful neck muscles. So much of its weight is forward of its wings that if it flew with its neck outstretched as cranes do, it would stall out. To stay aloft, herons pull their necks in, seeming to rest their heads on their shoulders.

Herons are voracious fish eaters that take their food by spearing it with that lance-like beak. Often they spear with only the lower mandible as the upper snaps shut on the fish, but sometimes observers have clearly seen them impaling the whole fish with their closed beak. Their gangly legs and skinny toes aren’t designed for manipulating their meals, so they can’t take the fish off the beak with their foot. In this situation they must walk ashore with the fish on their bill and then throw it to the ground with an enormous jerk, usually dashing it on a rock or branch before they pick it up and swallow it whole.

No matter how big the catch, herons always down it in one huge gulp, and they always swallow head first so it will slide down smooth and easy. A baby heron might swallow backwards once or twice, but a raspy fishtail and scales as rough as sandpaper are harsh lessons. Heron eyes bulge out so they can see the sky above fairly well as they scrutinize the water beneath, and they can even cross their eyes to direct their vision to the fish in their beak, to help them figure out which end is which.

Probably the greatest danger facing herons is fishing tackle, especially monofilament line. When a line gets tangled it becomes nigh on impossible for a fisherman to retrieve it sometimes, and so the normal course of action is to simply cut it off and leave it. Some fishermen simply discard wads of tangled line right where they’re at. Monofilament line is a plastic that never breaks down. It’s out there getting more and more tangles and collecting debris, waiting like a time-bomb for some bird or turtle or mammal to entangle itself in it. I’ve heard of dozens of cases right here in the Northland where herons have been tangled in fishing line, and I’ve personally handled loons, grebes, and gulls in this predicament. Most of the birds end up dying. A loon I received last year must have gotten the line caught in its mouth and around its neck—it literally broke the bottom mandible at the base trying to extricate Itself. By the time it was rescued by some canoers, probably many days later, the whole inside of its mouth was infected and it was extremely underweight. It was sent down to the Raptor Center but it ended up dying.

Once a Pied-billed Grebe tangled in fishing line ended up grounded on the Lester Park Golf Course in Duluth. Its feet were badly abraded and it was in shock by the time some children found it and called me. That bird did recover, but think of how many birds are never found and end up dying horrible deaths or entangling a predator as well. if you fish, please dispose of discarded fishing line, preferably securing it in a closed bag so when it reaches the landfill it won’t get blown away.