Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.
Use sand or pebbles. Some jars can be coated with glass paint to match colored bottles. 12 quart size jars are about Suggest different sizes. Small jelly jars are "quilted" creating a faceted glow from candle.