Ruby-throated Hummingbird - Reproduction

Reproduction

Ruby-throated hummingbirds are thought to be polygynous. Polyandry and polygynandry may also occur. They do not form breeding pairs, with males departing immediately after the reproductive act and females provide all parental care.

Males arrive at the breeding area in the spring, and establish a territory before the females arrive. When the females return, males court females that enter their territory by performing courtship displays. They perform a “dive display” rising 8 – 10 feet above and 5 – 6 feet to each side of the female. If the female perches, the male begins flying in very rapid horizontal arcs less than 0.5 m in front of her.

If the female is receptive to the male, she may give a call and assume a solicitous posture with her tail feathers cocked and her wings drooped.

The nest is usually constructed on a small, downward-sloping tree limb 3.1 to 12.2 m (10 to 40 ft) feet above the ground. Favored trees are usually deciduous, such as oak, hornbeam, birch, poplar or hackberry, although pines have also been used. Nests have even been found on loops of chain, wire, and extension cords. The nest is composed of bud scales, with lichen on the exterior, bound with spider's silk, and lined with plant down (often dandelion or thistle down). Most nests are well camoflauged. Old nests may be occupied for several seasons, but are repaired annually. The female constructs the nest, as the male has left by this point.

Females lay two (with a range of 1 to 3) white eggs about 12.9 mm × 8.5 mm (0.51 in × 0.33 in) in size, and produce one to two broods each summer. They brood the chicks over a period of 12 to 14 days. The female feeds the chicks from 1 to 3 times every hour by regurgitation, usually while the female continues hovering. When they are 22 to 25 days old, the young leave the nest and make their first flight.