OK, I see where this came from now. In Ron Tozer's post to ONTBIRDS email listserver summarizing the Algonquin Park CBC, he stated that ..
"There is minimal distortion caused by feeders (only about six in the circle) which unnaturally concentrate birds and support lingerers that would otherwise depart or perish."
What I think he was trying to say is that the count results for his CBC count are a reflection of what you can find out in the bush right now, not concentrated at feeders. However, what he failed to acknowledge is that what you will find concentrated at feeders is already only a reflection of what you can find out in the bush right now. Aside from "urbanized" species like Pigeon and House Sparrow, "feeder birds" and "bush birds" are not independent of each other, and "lingerers" are generally not lingering because there was a feeder to support them, but because they got lost or were injured and could not travel when they would normally have chosen to. In these rare cases, feeders may make the difference between life and death - but usually not. A feeder by itself will not ensure the survival of a bird that is not a member of a "winter hardy" species, one that has proper winter underfeathers and heat exchange systems and other adaptations needed to survive a northern winter, including specialized biochemical and physiological adaptations to a particular diet based on the foods that are normally available in winter. And, as I said previously, birds do not generally choose to occupy an area solely on the availability of feeder rations - wild food needs to be present as well. Ron Tozer, of all people, should have known better than to say such a thing.