Identification: a dark gray goose with fine silvery-white feather patterning; the wild ancestor of domestic geese.

Social Organization

Greylag Geese usually associate in flocks containing a complex mixture of pairs, families with offspring, single birds, and subgroups of juveniles. Following the breeding season, migratory flocks sometimes contain thousands of birds. The mating system generally involves long-term, monogamous pair-bonding.

Description

Behavioral Expression: Homosexual pairs made up of two ganders are a prominent form of pair-bonding in Greylag Geese. Male couples are stable and long-lasting: some have been documented as persisting for more than fifteen years, and most homosexual pairs (like heterosexual ones) are probably lifelong partnerships (Greylag Geese can live to be more than 20 years old). “Widower” ganders may even exhibit signs of “grief,” becoming despondent and defenseless upon the loss of their male partner. Most heterosexual pairs are also lifelong (and partners grieve the loss of their mates), but in many cases gander pairs are actually more closely bonded than male-female pairs, due in part to the intensity of their displays. One of these is the TRIUMPH CEREMONY, a pair-bonding behavior in which the two partners approach each other with extended necks and spread wings while making loud gabbling calls. Gander pairs spend significantly more time in this activity than do heterosexual pairs. They are also generally more vocal than male-female pairs—they often utter PRESSED CACKLING calls (rapid syllables produced with a high-pressure airstream) together in a cheek-to-cheek position and may even perform extended duets with ROLLING calls (deeper and louder notes).

Two pair-bonded male Greylag Geese performing the “triumph ceremony”

Paired ganders also sometimes engage in courtship and sexual behavior with one another. Pair-bonding is often initiated with the BENT-NECK DISPLAY, in which one male approaches and follows another with a distinct “kink” in his neck, his bill pointing downward. As a prelude to mating, both males perform aquatic displays such as NECK-DIPPING or NECK-ARCHING, in which the head is dipped below the surface while the neck is held in an elegant curve, its feathers ruffled to reveal their distinctive patterning. Following these displays, one male may mount the other as in heterosexual copulation. If there is a size difference between the two males, often the larger male mounts the smaller one. If the two ganders are equal in size, either bird may mount the other, and they often exchange positions when they copulate on different days. Following mating, the male who mounted his partner performs a display in which he lifts his head up and arches his folded wings almost vertically above his back. Sometimes, during homosexual activity one male may “masturbate” by mounting a log or some other object (a common form of masturbation in birds). In addition, a third bird—either male or female—occasionally joins a homosexual pair in their courtship activities, and may even be mounted by one of the ganders. In all cases, though, the concluding display takes place between the members of the male pair rather than with the third bird. Some gander pairs do not regularly engage in full mounting behavior, in part because both males prefer to mount each other without either one permitting himself to be mounted.

A Greylag gander mounting his male partner

Gander pairs often assume a powerful, high-ranking position within their flock, owing to their superior strength and courage. They are notably more aggressive than heterosexual pairs, frequently threatening, charging, chasing, and jointly attacking predators as well as other geese (especially unpaired males) and often appear to “terrorize” other birds. Paradoxically, each individual gander in a homosexual pair is significantly less aggressive than a male in a heterosexual pair—it is their combined strength that gives the couple its advantage. Homosexual pairs also differ from heterosexual ones in spending significantly more time on the periphery of the flock or away from it, especially during the spring breeding season. This, combined with the gander pair’s greater vigilance behavior (as well as the pair’s aggressiveness), has led some researchers to suggest that homosexual pairs may act as “guardians” for the flock as a whole. Sometimes a female is attracted to a gander pair—perhaps because of their strength and high standing—and tries to establish a bond with one or both of them. Often the males simply ignore such a female, but in some cases she is allowed to join them to form a trio. When this happens, one or both ganders may copulate with the female, although their homosexual bond usually remains primary. The trio may raise a family together, with the two ganders often searching for a nest site together and jointly defending their eggs and goslings. Occasionally, three ganders bond with each other as a same-sex trio, which may also later be joined by a female to form a “quartet”; again, goslings can be raised by all four birds together.

Although most gander pairs are stable partnerships, occasionally one or both birds may behave antagonistically toward his partner. Fights sometimes erupt when one male tries to mount the other, while occasionally the aggression aimed at an intruder is turned back on one of the partners. Bonded ganders (especially in trios) may also become “jealous” of the attentions their partner shows toward another bird. Some gander pairs are incestuous, as brothers may form long-term homosexual bonds. In addition, interspecies same-sex pairs also occur, for example between Greylag Geese and Mute Swans. Like Greylag-only gander pairs, these partnerships are long-lasting and distinguish themselves by their aggressiveness, with the two males frequently defending their territory against intruders.

Frequency: Homosexual couples constitute a significant proportion of pairs in Greylag Geese: an average of 14 percent of pairs in some populations are same-sex, and in some years this proportion can be even higher, with more than 20 percent of all pair-bonds consisting of ganders.

Orientation: Some Greylag males in gander pairs are exclusively homosexual, since they remain in a monogamous same-sex pair-bond for their entire lives (or re-pair with another gander on the death of their partner). Other males, however, are bisexual: some copulate with a female while remaining primarily bonded to a male (as described above), while others are involved in bisexual trios. Still other males alternate or switch between female and male partners over their lives—for example, ganders in heterosexual pairs sometimes find a male partner after the death of their mate. More than half of all widowers re-pair with a bird of the opposite sex, less than a third remain single, while the remainder form homosexual bonds.

Nonreproductive and Alternative Heterosexualities

Several variations on the monogamous, lifelong pair-bond occur in this species. Divorce occasionally happens: in some populations as many as a quarter of all females, for example, may abandon their mates and find a new gander, and overall, 5—8 percent of pairs divorce. Greylag Geese also sometimes form polygamous heterosexual trios, in which bonding occurs primarily between birds of the opposite sex—two males with a female or, more rarely, two females with a male. In addition, some families foster-parent chicks by combining broods with another family, while widowed ganders occasionally adopt goslings. Birds in heterosexual pairs may engage in promiscuous courtship and mating. Ganders sometimes try to mount females other than their mate, while females may pursue other males—much to the consternation of their mates, who often try to physically prevent them from engaging in “extramarital” activities. Although Greylag Geese become sexually mature in their third year, some one-year-olds form pair-bonds and even engage in courtship and sexual activity long before they begin breeding. Like homosexual pairs, heterosexual associations may also occur between related birds (especially parent-offspring), or birds of different species (e.g., with Canada Geese). However, sibling pairings are much less common among birds of the opposite sex.

CANADA GOOSE