Laura Erickson's For the Birds

Garbagemen of the Bird World

(Recording of a Ring-billed Gull)

When my son Joey was three years old, he announced that he wanted to be a garbageman when he grew up. We had already told him that we will be proud of him no matter whatever he becomes, as long as it’s an honorable occupation, so he explained that garbagemen were the honorablest people in the world because they keep the city clean so we don’t get diseases or trip on all the junk.

The bird world has a lot of garbagemen, too–though, unlike human garbagemen, avian scavengers actually have to eat the trash they collect. You don’t have to consider fast food junk to call a gull a junk- food junkie–when they’re not dining at McDonald’s, Duluth’s Ring-bills spend a lot of time at Superior’s Wisconsin Point landfill eating the genuine article.

When people think of scavenging birds, they usually think of vultures, crows, and gulls. But many other birds scavenge on garbage and dead animals. Bald Eagles are perfectly capable of catching their own fish, but aren’t above picking up dead fish on the shore–sort of like luckless fishermen who stop by a fish shop on the way home. And eagles also eat a lot of roadkill. Sandpipers and plovers clean up dead invertebrates washed ashore on beaches. Black-capped Chickadees and other insectivores often pick at carcasses for extra protein, especially in winter. There are even reports of Chickadees picking at the scabs of deer hunters sitting in their stands.

Scavengers have a few advantages over predators. Many roadsides provide a steady supply of fresh food. And, perhaps more importantly, already-dead animals don’t fight back. Vultures and condors search for food cooperatively–when one discovers a food source, the others notice right away and join in the feast. They have an expandable gullet to allow them to pig out when they find a carcass, in case it takes a while to find the next one. Turkey vultures have even developed a sense of smell in order to find decaying carcasses on forest floors, where the leafy canopy would make it impossible to locate food by vision alone.

But there are some drawbacks to a scavenging lifestyle, too. You can’t just sit on a tree snag waiting for a suitable lunch to pass by. Vultures and condors spend most of their lives on the wing searching for food. Many roadside scavengers end up joining their lunches on the pavement. One of the obvious hazards of scavenging is disease. Turkey Vultures, which prefer their carcasses not just merely dead, but really most sincerely dead, would seem to be vulnerable to all kinds of diseases from their bacteria-laden meals, but their digestive tracts have special adaptations to destroy most bacteria. So vultures perform a valuable service, especially in warm southern areas where decaying dead animals could constitute a human health hazard. And they probably also help us so we don’t trip over all the junk. Yes, by just about any standard, avian garbagemen lead honorable lives.

(recording of Ring-billed Gulls) This is Laura Erickson, and this program has been “For the Birds.”