It’s interesting that you noticed three or four rusty blackbirds in Marcellus. They are a declining species, and biologists are trying to sort out the reasons for that. The most common issues are habitat loss (they breed in boreal wetlands in far northern Canada), and their winter habitats in the US are being lost to drainage and agriculture. Rusty blackbirds in the northeast US have also been found to have unusually high concentrations of mercury in their bodies. We only see rusty blackbirds in CNY during migration where they will often mix in flocks with grackles, red-winged blackbirds, and starlings. They will be most commonly found in wooded wetlands and swampy areas.