Feeding guild convenes at feeders, squabble, have each other’s back

By BILL CHAISSON
The first birds to visit my feeder when I put it out four weeks ago were black-capped chickadees. When I saw them, I knew that certain other species were not far behind because during the winter a loose confederation of birds forms to dine together at feeders and in the natural environment as well. The core members in the Northeast are the black-capped chickadees, white-breasted nuthatches, and downy woodpeckers. Tufted titmice and cardinals are also part of this group, but they tend to drop out as you move northward in the Northeast. I didn’t have either species at my feeder in the Adirondacks last winter, but I’ve got both here in Unity. I was surprised to see the cardinals because I didn’t see them or hear them singing during the breeding season. These birds are shifting out of their breeding territory to range further afield looking for food in the winter.

The technical term for this confederation is a guild. The concept was discovered and named by Richard Root, an ecologist at Cornell. It was part of his doctoral dissertation and was the focus of his first scientific paper in 1967, “The niche exploitation pattern of the blue-gray gnatcatcher.” Guilds are ecological groups, not taxonomic ones. The chickadees and the titmice happen to be in the same family, but the other species are not closely related to them, except in the sense that they are all interested in the same food during the winter. When they are at a feeder this means sunflower seeds, mainly.

While all the species are interested in generally the same food, they have different ways of foraging for it, which reduces — but doesn’t eliminate — the amount of competition among them. You can observe these varying foraging strategies most easily if you have several different designs of feeder. The chickadees and the titmice are most likely to go to the tube feeder, as they are the smallest and most nimble species. The cardinals, woodpeckers and nuthatches are either too big or not flexible enough to comfortably sit on the little peg and stick their beaks into the hole in the side of the tube.

These larger birds are more likely to go to the reservoir (“hopper”) feeders with rungs to sit on while they select a seed from the trough. The cardinals will be the most likely to go to an open platform feeder as they are also more comfortable feeding on the ground than the other guild members.

You may think, “Downy woodpeckers only eat suet,” but they do in fact eat seeds as well. I saw one on my hopper feeder this morning. This visit reminded me that I should purchase a suet cage because beef fat does provide the calories that these tiny animals need to weather the cold nights. You will see all the guild members on the suet except for the cardinals, which aren’t as agile as the others and don’t hang onto vertical surfaces as well.

Of course, this does not mean that members of the guild simply eat peacefully together at a feeder. As anyone who has a feeder has noticed, birds squabble constantly. The Cornell Laboratory of Ornithology in Ithaca, New York has collected observations from their Project Feederwatch, to determine a dominance hierarcharic relationships among 136 different species in the U.S. The general pattern is intuitive enough: bigger birds are more dominant. There are, however, exceptions. Downy woodpeckers, for example, will regularly best the slightly larger bluebirds at the feeder, simply because they are feistier. 

Other patterns are less intuitive. For example, house finches dominate purple finches, which in turn dominate dark-eyed juncos, but surprisingly juncos then dominate house finches. This was called a “rock-paper-scissors” pattern by the researchers.

There were also geographic differences; the same two bird species could have different dominance relationships in different parts of the country. Perhaps birds near the margin of their niche are less pugnacious.

One of the things revealed by this study is that it is tough to be a chickadee. They lose out in scraps with 11 other species. The only species they regularly best is the surprisingly timid American goldfinch. And the real tough guy in the neighborhood isn’t the blue jay, as you would expect, but the red-bellied woodpecker (which is now in the process of spreading north into this region). The red-bellied woodpecker stands down to no bird.

There is another evolutionary aspect to the concept of the guild: protection. There is safety in numbers and furthermore different species of bird might be keeping their eye out for danger in slightly different way, in the same sense that they all look for food in slightly different ways. When you get away from feeders and walk through the woods in the winter, you will find these same guilds sticking together as they forage in the natural environment. You can walk for hundreds of yards in the woods with not a single bird in sight or within hearing and then suddenly it will seem like you are surrounded by a swarm of several species, all hard at work looking for a meal.

In looking up references to write about guilds, I typed “feeder guild” into my browser. This plunged me into the world of role-playing games, where “feeder guilds” are apparently like the minor leagues in professional sports. So, if you want to learn about this concept, type “feeding guilds” or “guilds ecological” into your search engine, and you’ll be on the right track.