- Ruby-throated Hummingbirds are the only hummingbird species known to nest in eastern North America

Ruby-throated Hummingbird, hatch year male - Weight of a male Ruby-throated Hummingbird: roughly the same as that of a penny
- The males only reproductive contribution is copulation
- Males arrive first on the breeding grounds with the sole objective to mate with as many females as possible
- The adult males are typically the first to also migrate south for the winter
- The females build the nest, incubate and feed the young
- Nests are typically constructed in a deciduous tree 6-30 feet high
- Nest size: approximately the size of half a walnut
- The female almost always lays 2 eggs
- Insects are an important part of the Ruby-throated hummingbird’s diet
- Average life span: 3-4 years
- Oldest male on record: 7 years, 8 month
- Oldest female on record: 9 years, 2 months
- Most frequent predator: Blue Jay, nest predator
- Less common but known predators: Chinese praying mantis, orb weaver spiders, racoon, squirrel, Common Grackle, Sharp-shinned Hawk
- Earliest Arrival Record for WI: April 12, 2002
- Latest Departure Record for WI: November 30, 2006