Hummingbirds, with their iridescent plumage and astonishing aerial agility, captivate observers. These tiny creatures, known for their rapid wingbeats and hovering flight, lead intricate lives, particularly concerning their reproductive behaviors. Their delicate appearance belies remarkable resilience. Their nesting habits are fascinating, offering a glimpse into the complex strategies they employ for survival and raising young.
Nesting Habits of Hummingbirds
Female hummingbirds undertake the entire process of nest building, from selecting the site to raising the young, without assistance from the male. They construct small, cup-shaped nests, typically measuring 1 to 2 inches in diameter, roughly the size of a ping-pong ball or a walnut. These nests are woven from fine plant fibers, plant down, and often camouflaged with bits of moss and lichen on the exterior. A distinguishing feature is the extensive use of spider silk, which binds materials and anchors the nest, providing elasticity that allows it to stretch as chicks grow.
Nests are commonly placed on slender, often descending branches of deciduous trees like oak or birch, or within dense shrubs, usually between 10 and 40 feet above the ground. The female carefully selects a location that offers natural concealment and protection, often blending the nest seamlessly with its surroundings. Construction typically takes five to ten days.
Nest Reuse
Hummingbirds generally do not reuse the same nest from previous seasons or even for subsequent broods within the same season. A primary reason is the fragile and flexible nature of their nests; designed to expand as chicks grow, they eventually lose their shape and become unsuitable after a single brood. The materials, particularly spider silk, can stretch and wear out due to weather exposure and the activities of growing nestlings.
Abandoned nests can also harbor parasites, such as mites, or attract predators, making them undesirable for future use. Starting a new nest minimizes the risk of exposing new offspring to accumulated pathogens or drawing attention from predators. While building a new nest requires energy, this expenditure is often less than repairing a degraded structure or dealing with pest infestations. Although rare, some species, like Anna’s or Allen’s hummingbirds, have been observed to occasionally reuse a site or build a new nest directly on top of an old one, particularly if the location is secure and successful.
Factors Influencing New Nest Site Selection
When a female hummingbird constructs a new nest, her choice of location is influenced by several environmental factors. Proximity to abundant food sources, primarily nectar-rich flowers and small insects, is a significant consideration. Having food readily available reduces foraging energy expenditure, which is important during the demanding period of raising young. They also seek locations where necessary building materials, such as spider silk, plant down, and lichen, are easily accessible.
Safety from predators plays a role in site selection. Females often choose sites well-hidden within dense foliage or thorny plants, providing natural protection against threats like jays, crows, snakes, squirrels, and domestic cats. The chosen spot also needs to offer a suitable microclimate, providing shelter from strong winds, heavy rain, and direct sunlight. While they do not reuse the same nest, hummingbirds may build a new one in the vicinity of a previously successful site if conditions remain favorable.