Synanthrope: an undomesticated organism and especially an animal (such as a mouse, pigeon, or raccoon) that lives in close association with people and benefits from their surroundings and activities (Merriam-Webster Dictionary)
A synanthrope ……is a member of a species of wild animal or plant that lives near, and benefits from, an association with human beings and the somewhat artificial habitats that people create around themselves….. Such habitats include houses, gardens, farms, roadsides and rubbish dumps. (Wikipedia)
One of the positive spin-offs of the corona virus-induced shutdowns and travel bans is that I have been doing a lot more reading. Recently I came across this term while reading a book on bird ecology in the context of a progressively urbanizing world. I mulled it over as I was walking the Chippawa Trail from Caledonia to Albion Falls. Despite the long extent of seemingly wonderful bird habitat, I saw very few birds. This is what got me thinking. Where were they? I know that at the head of the trail in Caledonia if I had gone left (south) instead of right (north toward Hamilton) I would have run into a ton of them accessing the numerous feeders that local residents have put out. Ah ha! So this was synanthropism.
But there seem to be varying “levels” of synanthropism from the full synanthrope (species which have a major dependence – like Rock Pigeon), through casual synanthrope (birds exploit human ecology without becoming dependent), to the tangential variety (species occasionally exploit human ecology).
I think a major headache would be to put species into one class over another. Into which category would you place these species?
- Barn Swallows. Where would they nest if there weren’t man-made structures?
- Tree Swallows. I’ve seen a couple in tree nesting holes but the vast majority make use of nesting boxes.
- Purple Martins. Have never seen one not nesting in a man-made contrivance.
- Peregrine Falcon numbers are growing as some have discovered that buildings are as good as cliff faces for nesting….and there’s a large food bonanza in the form of Rock Pigeons – a full synanthrope.
- Man-generated clear-cutting of boreal forests has a similar impact as forest fires in terms of successional plant growth. Many warbler and some flycatcher species take full advantage of this.
- Larus gull numbers have been climbing due to food available in garbage dumps.
- What is the impact of feeders on wintering sparrows and finches and winter resident chickadees, woodpeckers, and nuthatches. they could survive on “natural” food well enough but would this food sustain the numbers of them that we see?
- Along this idea, we more than doubled the number of Baltimore Orioles we were catching in the Spring when we started putting out grape jelly feeders.
And the list goes on. And each species exemplifies a different level of “dependence”. But maybe, and this is more likely, much of the behaviour we’re seeing is simply birds taking advantage of what they find in their environment – feeder food sources and nesting boxes being prime examples. At what point does the relationship between birds and man-made elements of the environment become symbiotic?