Twirrl

Last updated 1997.

Overview:



Physical Characteristics

Twirrl are sentient avians with the following physical characteristics:

Other physical characteristics vary depending on gender and age:

Feathers

Other than their feet and beaks, Twirrl bodies are entirely covered by feathers of various shapes and colors, in three general categories:



Life Cycle

The Twirrl life cycle runs as follows:

These stages are further described below.

Courtship period

Twirrl courtship patterns are best understood in the context of instinctive reproductive patterns in their animal predecessors:

Proto-Twirrl adult females instinctively create and maintain highly defensible nesting grounds over late spring and early summer. During their fertile period (a 2-3 week period in early fall) they retreat to those nesting grounds.

Proto-Twirrl adult males become sexually aroused during this period and visit nesting grounds to seek mates. They attract the attention of potential mates by a combination of feather displays, songs, and most importantly food offerings. Once the male mates successfully, the sexual compulsion fades, although he remains fertile throughout the courtship period.

The male continues instinctive food-offerings throughout the brooding period, often malnourishing themselves. The female keeps track of this behavior, and if abandoned discards the offending mate's egg, along with a complex vocalization that typically causes other females to reject him in future breeding seasons.

Males typically take only one mate per mating season, unless foraging resources are fantastically rich. Females are more typically polygamous -- if sufficient food offerings are made, each female may accept up to six mates during a courtship period, each of which fertilizes a different egg. Otherwise, they accept only one mate and lay only one egg, which hatches precocially.

In sentient Twirrl, this pattern remains strong -- both sexes go into heat every year, females still feel the nesting instinct, and males feel compelled to provide for their mates throughout the courtship and brooding periods. These instincts can be stronger than the self-preservation urge at times. They are also reinforced by social pressures -- in effectively all Twirrl cultures, males who abandon their mates and females who unilaterally abandon their eggs are stigmatized and rejected as mates in future breeding seasons.

As with any sentient race, though, individual Twirrl can choose alternate courtship patterns. However, because failure to mate results in death for the individual as well as its genes, even "deviant" Twirrl follow some variation of the primal courtship cycle.

Gestation/brooding period

Females lay a single clutch of 1-6 eggs in their nests in early spring, after a 4-week gestation period.

The reproductive system includes six-chambered ovaries, where only one egg is fertilized per sexual act. Thus, the female controls clutch size by restricting access to mates during courtship (each egg can be fertilized by a different mate).

Egg size depends on the number of eggs: one egg averages ~3 kg/30 cm, but large clutches are significantly smaller (it's not quite inversely proportional, but it's close). Because one-egg infants are better able to care for themselves, they are more common in hard times.

After eggs are laid, they must be kept warm for a 20-week brooding period. Among the Twirrl's animal predecessors, the mother broods the egg(s) herself while her mate(s) bring food to the nest; these compulsions remain strong among modern Twirrl, but can be sublimated via indirect provisions. For example, males may purchase brooding-care plans for their mates and females may purchase adoptive brooders and caregivers, freeing them to travel during the brooding and hatchling seasons. (Adoptive brooders typically restrict themselves to a single egg and brood it along with their employer's egg(s).)

Infancy

In a single-egg clutch, the newly hatched Twirrl (known as a "chick") is precocial: covered with down, eyes open, and able to run and (within limits) to forage.

In a multi-egg clutch, the newly hatched Twirrls (known as "nestlings") are altricial: naked, born with enormous heads and abdomens relative to short and undeveloped legs and wings, and cold-blooded. They are completely dependent on the nest for warmth and food.

Consequently, if resources are limited during the courtship season, females typically restrict themselves to a single mate and raise chicks rather than nestlings.

In either case, the infant grows to hatchling status within 4 weeks.

Hatchling period

Twirrl remain hatchlings for roughly 20 weeks, growing to their full adult size during that time. Even at adult size, hatchlings do not have flight feathers; although they cannot fly, they can leap large distances and glide for short periods. Hatchlings also have significantly less endurance during the early weeks.

Although hatchlings can forage independently and evade predators (at least for a while), they are not independent. Even in wealthy cultures where little labor is required, hatchlings remain with caregivers who protect them, feed them when necessary, and teach them common cultural lore. (The caregiver is not necessarily a parent -- adoption is common among travelling females.) This is the only time when any Twirrl receives free assistance from another, and is not entirely altruistic -- hatchlings do imprint on their caregivers, and are frequently more suggestible to them as adults, which gives caregivers some political power.

After the hatchling period (in early fall) Twirrl undergo "first molt" or "fledging", obtaining their flight feathers. During this period their feet also change shape drastically, from the large, light running feet of the hatchling period to either the male's curved talons or the female's pointed ones. This process is extremely painful but doesn't last long.

Fledgling period

Fledglings are physically indistinguishable from adults, though sexually immature -- they don't experience mating urges during the courtship period -- and intellectually underdeveloped. To compete effectively in an adult world, they apprentice themselves to adult mentors. In effect, they offer untrained labor in exchange for training and (among males) assistance in gathering a nest-price for their first courtship period. (Fledglings unable to find mentors rarely survive this period.)

Not all adults take apprentices, but most do, and many take several. Travelling adults often encounter more wealth than they can readily transport and adult assistance is expensive; lek-bound adults frequently take their own hatchlings as apprentices. In poor cultures, apprenticeship is a within-gender relationship, as females learn nesting techniques and males foraging skills. In wealthy cultures a wider diversification of trade is common.

The fledgling period lasts a year, until the second molt the following fall. Afterwards, Twirrl undergo their first courtship transition as sexually mature adults, at which point their apprenticeship is over (since they are largely in competition with their mentors at that point). They continue to molt annually until death.

Aging and death

Twirrl do not experience age-related senescence: a healthy 2-year-old adult is physically indistinguishable from a healthy 10-year-old adult.

Twirrl live 9 or 10 years on average, and Twirrl who die of old age do so rapidly, during molting time: their feathers fall out, do do not grow back, vital organs break down quickly, and relatively painless death ensues in a few days. This is generally known as the "final molt", and Twirrl face it with relative equanimity -- the fear of death is not nearly as universal among Twirrl as among humans.

Twirrl must mate annually or die. Twirrl who do not successfully mate during a courtship period die shortly thereafter: shortly after the "missed" period, a second out-of-phase molt occurs (this is also known as the "final molt", but with some irony). Several weeks or months of mental deterioration follow, followed by a rapid breakdown of vital organs and death within a few days. (The feathers that grow in during this out-of-phase molt are always dark green, and Twirrl in this phsae are often called "green Twirrl" for this reason.)

Green Twirrl typically exhibit psychotic behavior -- violent aggressiveness, territorial paranoia, and obsessive collecting are all common. They retain all their skills and intelligence, which can make them extremely dangerous: several mass slaughters in Twirrl histories have been initiated by green Twirrl.

A variety of sophisticated masturbatory devices and techniques can simulate the mating experience sufficiently closely to postpone the green period. Twirrl males can avoid the courtship cycle altogether this way -- if the simulated experience is sufficiently "convincing", the mating urge declines and he is safe for another year. Even so, they still experience the compulsion to provide, which expresses itself in bizarre ways depending on the nature of the surrogate mate -- this option is not common except in desperate cases. Females are even less likely to exercise this option, since those who do not lay at least one egg per breeding season run a serious risk of being unable to mate at all the following year, due to atrophying of the reproductive system.



Psychology

Although individual Twirrl vary as much as individuals of any species, certain psychological attributes are common:

Language and vocalizations

Twirrl produce a wide range of vocalizations, both intentional and instinctive. These fall into the following general categories:



Cultures

Twirrl cultures are defined by a loose network of reciprocal trade agreements and commonly known reputations among individuals. Different cultures vary along many dimensions, but most importantly by economic status -- any two individuals who can trade as equals on an ongoing basis are effectively part of the same culture. The key terms here are "trade as equals" and "ongoing basis": wealthy Twirrl often hire poorer neighbors, especially during the mating and brooding periods, but they remain from distinct cultures, since the relationship is assymetric.

That said, however, Twirrl cultures are extremely mobile... as individual fortunes change, they can move from one culture to another with ease. This is primarily mediated by shared reputations, but also by the rapidly changing private languages created by cultures and subcultures for exchanging secret information. Any individual with sufficient assets to purchase training in a culture's secret language is effectively a member of that culture, and those who can no longer afford it are effectively excluded. (Smaller associations regularly develop private languages as well, and devote a great deal of energy to protecting, stealing, and replacing them.)

On the other wing, some things are common to all cultures:

Nesting grounds and leks

Twirrl courtship takes place in established mating areas called "leks". All leks share certain geographic properties, so Twirrl can find them by navigating along magnetic lines, but not all sites with those properties are necessarily being used at any given time.

Twirrl interaction happens almost exclusively in the leks. Some Twirrl stay at the lek year-round, while others leave after mating, travelling as individuals or in small groups. Lek-bound and travelling Twirrl don't really choose their lifestyle -- some Twirrl have the wanderlust, others don't. Lek-bound Twirrl offer services such as brooding-support plans for mates and surrogate-brooding and caregiver services for hatchlings, allowing sufficiently wealthy travellers to bypass the normal brooding season.

Travelling Twirrl often amass more wealth than lek-resident ones, but this is a gamble... surrogate brooders, adoptive caregivers, and mate-support plans are all extremely expensive, so a certain initial investment is required. Also, travelling females don't participate in lek politics, and travelling males often experience psychological symptoms from sublimating the food-offering instinct via indirect brooding-support plans. Ultimately, it's a question of personal taste more than practical reasons.

Females from poor cultures often choose to stay lek-bound rather than travel -- even if inclined otherwise -- since preparing decent nesting grounds can take all spring and summer.

Travelling Twirrl return to a known lek every year -- females do so before the courtship period begins, to prepare nesting grounds; males do so somewhat later. Because males and females fly at different speeds, mixed-gender travelling groups are rare.

Twirrl nests are always easily defended, warm, provide easy access to water and basic foraging grounds, and include storage sites for the additional foods Twirrl need to survive the brooding period. Specific nesting techniques vary depending on region and culture: Twirrl may nest in caves, underground, in artificial shelters, even underwater.