Hi, Every Oct - Nov I start filling two birdfeeders. One with regular song bird seeds for the huge population of sparrows. And another with black oil sunflower seeds. That one I usually add unsalted peanuts, raisins and dried cranberries for tuffted titmouse, chickadees, nuthatch, etc.. The feeders usually attract enough activity that they need to be filled 2-3xs each week. This year - nothing. The feeders are still full 3 months later. Where are the birds? Is this a result of global warming, too much air polution (I live just inside the city line)? There was a greater variety and population of insects in my vegetable garden last year. The side walks are turning black. Everything else is turning green (with algea?). Not sure why. I'm really getting worried. What's happening and what can I do? Thanks for your help.
We can see how that could be concerning and disappointing.
If the general area is the same, without big changes to surrounding habitat- trees, shrubs etc., we'd expect them to be back. Are you using the same brand of foods? Do you hear them or see them nearby?
The black oil sunflower seeds can feed all of the birds you mention. You might consider adding a hanging suet feeder as well.
If they aren't there, it's possible that they are still feeding on the remains of weeds and other plants nearby, and haven't yet needed to find yours.
You could try visiting the Bird Lab at Cornell University here: http://www.birds.cornell.edu/Page.aspx?pid=1478 for further hints or even to try playing bird calls which can pull them closer sometimes.
Is the black on the sidewalk under a large overhanging tree? Send us a photo of the sidewalk and the tree during the growing season. It could be honeydew from a feeding insect, which falls and then grows what is called sooty mold.
You can send photos of the green stuff as well. It likely has a natural explanation that is not concerning. Last year was very wet, and that encourages the growth of fungi, mosses and algaes in some areas.