The nest of a Ruby-throated Hummingbird is being watched at a park location in St. Louis Park. Eggs are are close to hatching, although exactly when is unknown. Incubation takes about 16 days, young birds leaving the nest about 19 days after hatching. The nest is made of plant material and down held trightly together with spider web. It is covered on the outside with flakes of lichen. The female bird, working alone, builds the nest in about five days.