Hummingbird behavior can be thought of as being in one of three very broad categories. First of all, many of the complex and fascinating activities of hummingbirds are directed toward the survival and maintenance of the individual bird. These include respiration, eating, and defecation, preening, stretching, oiling, bathing, sleeping, and shaking. A second category of behaviors is basically self-directed but tends to bring groups of hummingbirds to a common area. For example, hummingbirds congregate at feeders and bathing areas. Their constant need for new and rich food sources also results in the hummer’s great curiosity. They will closely investigate any bright red object, be it a hat or tie, and seem to immediately notice a new feeder placed close to where they are used to feeding. The third, and perhaps most delightful, group of activities are the social behaviors - those directed toward and dependent upon the presence of other organisms for their expression.
Related to their curiosity, the excellent memory of the hummingbirds is one aspect of their social behavior. They can locate food sources apparently remembered from previous years. Being able to associate food sources with color and location aids in survival. An amazing example of a hummer’s memory and ability to recognize individual humans was recounted in 1966 by the artist Arthur Fitzpatrick. While he was recuperating from tuberculosis in a California sanatorium, he hung a hummingbird feeder outside his window. Quickly, a Rufous Hummingbird claimed it as his own personal feeder. Over the next several months, the man felt that observing the hummer’s indomitable spirit while feeding at and defending the feeder helped to hasten his recovery. On his first wheelchair journey outside the hospital, he was instantly greeted by the hummer, who buzzed around his head and hovered in front of his eyes. After about a year, Fitzpatrick was able to return to his home, some eight miles away. Somehow, the Rufous followed. The bird became a companion on his daily walks that he took to regain his strength. The hummer hovered over whatever interested him, alerting Fitzpatrick to an animal he might have overlooked: once a family of quail, complete with chicks and strutting parents, once seven young skunks, once a large rattlesnake lying half hidden on the path. When he was fully recovered, Fitzpatrick left to return to work in the city for about a month. Only a few minutes after he returned to the mountains, there was the Rufous, circling his head and hovering in front his eyes!
Hummingbirds also demonstrate altruistic social behaviors in actions between parents and their offspring, and a few cases of feeding of youngsters other than their own. But this is not true in regard to adults. They do not preen each other. In fact, they rarely touch each other. Photos do exist of two Andean Emerald Hummingbirds partaking in what appears to be courtship feeding. However, this is considered to be so rare that the existence of true courtship feeding among hummers is still unproven.
Most social activities are either aggressive attack-escape interactions between birds or mating activities. Indeed, it is difficult to tell the difference between hummingbird fighting and loving. For example, the male hummer defends a territory that is centered on a food source, not on a nesting site or resources for the female and the young. Much of the swinging pendulum displays may be to intimidate rather than to seduce. Likewise the vocalizations heard during courtship, may be viewed as announcements of territorial ownership. It is also thought that the females will tend to favor mating with more dominant or conspicuous males. In 1954, after many years of observing Mexican hummingbirds, the ornithologist H. 0. Wagner concluded that the female hummer only searches for a mate after her nest is completed. Then, she is likely to mate with the first hummer of her kind that she encounters, and their union lasts for only a few hours.
The male courts in two ways. First, he charms the females that are ready to mate with a plumage display specific to his species. He follows this with a nuptial flight, sometimes in conjunction with a female, before consummation. The posturing of the luring phase is usually accompanied either by songs or by sounds produced either mechanically or by vibrating feathers during wild pendulum flights. The songs range from short offerings by a single bird to group singing in some South American species. The nuptial flight phase is initiated by the male, but the female determines the place. In some species, this phase consists only of an intensification of the luring phase, but in others it is comprised of entirely different movements.
Hummingbirds include dive displays and shuttle flights in their social interactions. In a 1982 study of the Anna’s Hummingbird, it was reported that the dive displays are essentially aggressive displays undertaken in defense of the breeding territory. But it is also noted that they may also play some role in the initial phase of courtship. The close range, back and forth, shuttle style flights of the male, complete with species specific sounds, are performed directly in front of the female. The rate, direction, and height of these shuttle flights also vary from species to species. These displays precede mating in nearly all cases, but they remain vague as to details because they usually happen in dense cover.