Displays between sexes refer to the acts involved in mate acquisition and pair-bond maintenence. Some refer to this activity as courtship or "ante-nuptial" behaviour, and much of it is. However, some of these displays extend well beyond the social bond. Richdale called this activity "love habits," but this seems to connote too much emotion. And the word "habit" suggests that the activity is fixed and, as a term, "fixed action pattern" does not adequately describe these behaviours.

    By far the most dramatic display between the sexes is the Ecstatic display. The name was coined by Wilson (1907) but as it applies to behaviour, the term has been somewhat modified over the last century.

    The Ecstatic display is given typically by unpaired males attracting females. The calling may be unprovoked or incited by the approach of other penguins (and humans!) or may be a consequence of mass ecstatic displaying. The focal bird aligns his body vertically and pumps his chest several times. After this motion is complete, the individual emits a harsh, loud breying sound while arching his flippers back as far as possible. Quite audible from far distances, the ecstatic display is likened to the lone trumpet call (see Trumpet).

    There are several variations on this theme, the most common being a side to side movement of the head while calling. The call may also be used by individuals guarding chicks or by paired males.

    The Ecstatic display is also divided into two sets of varying intensity: the intention ecstatic and the imploring ecstatic. Both are similar in function to the ecstatic display, yet the former is incomplete and the latter is an amplified ecstatic display.

    If you read the FAQ and covered the section about behaviour, you saw that there was a question about a particular donkey-like noise coming from penguins. Most likely this is the ecstatic display. If you heard the call while a penguin was by his/her mate or if s/he was possibly calling his mate, this is probably what you saw and heard.

    If you feel inclined, please visit the area entitled Deconstructing Penguin Myths. One of the posts to that site is a series of observations I made regarding Humboldt penguins. There's a critical analysis of ecstatic displays in that report. You may find it interesting.

    The Bow, like most other forms of behaviour, was first named and described as an Adelie penguin behaviour. The Bow is a behaviour demonstrated most often in pairs at the nest. In a normal situation, the female will bow to the male after approaching the nest. Conversely, the male may do the same. Penguins may also walk about the area while bowing. And thus, Bowing is considered to be both a form of appeasement and a tool for maintaining social bonds.

    Divided into Loud Mutual displays and Quiet Mutual displays, these displays are seen shortly after one of a pair has returned to the nest after a time of absence.

    The focal penguin approaches the nest and calls out to its mate. The mate then approaches and leans toward its partner and calls in time; following this, the two stretch in the vertical direction to end the calling. One of the pair may shake its head during this event. For the quiet mutual display, much of the behaviour is the same, save the noise. One issue may separate the two - a loud mutual display may be given by a lone penguin.

    In my own study, I often find this hard to distinguish this from the mutual display. By comparing what Warham has to say about the trumpeting performed in the crested penguins (Eudyptes) with how Spurr describes the mutual display in Adelie penguins, I have concluded (at least for the time being) that mutual trumpeting differs in that the members of the pair stand side-by-side and may lean forward and then upwards while performing the behaviour. It is my understanding that the mutual trumpet and the mutual display serve relatively the same functions: mutual recognition and greeting after long absence.

    The vertical head sway is yet another general behaviour displayed mostly by males to indicate ownership of a nesting territory and possibly to display for females. The behaviour is initiated when a penguin bows his head toward his feet and rapidly raises it back to the vertical while emitting a growl. Once at the peak, the penguin sways his head from side to side; during this motion, sounds may be heard from the penguin.

    The vertical head sway, like most penguin behaviours, varies in intensity between penguins. Certain species greatly exaggerate the extent to which the head is swayed, while others the speed. I have noticed that the Humboldts (if indeed their behaviour is a "Vertical Head Sway") rock their heads in a rapid, albeit jerky, motion encompassing full 180 degrees of motion from the vertical.

    Two forms of preening fall under the category of behaviours demonstrated between sexes: allo-preening and mutual allo-preening. The former involves one individual preening the other. The act may be a form of recognition, reconciliation or a behaviour used between individuals of a pair.

    When the recipient penguin also preens the focal penguin, this act is known as mutual allo-preening. This event is sometimes known as the "kiss preen" since the focal penguin usually preens around the neck and beak of the recipient penguin. Most often this is done between the members of a pair and is a form of recognition.

    Of course, the goal of most sexual displays is to gain mates or to reinforce the pair bond. What proceeds is a brief summary of reproduction in penguins. Although I will present drawings that elucidate the sexual organs, I'm not going to develop them thoroughly. Besides, I don't know much about the specific physical mechanisms there. Like most birds, the reproductive cycle begins with the courting displays. You've seen those types of displays above. Now let's get into the thick of it.

    The reproductive structures in penguins do not differ extensively from those of other avian families. All birds reproduce sexually: males transfer sperm to the female through the cloaca. During copulation, the event of contact between the two cloacas is known as the cloacal kiss.

Reproductive structures of the male penguin

    The following discussion focuses on general avian reproductive structures, not penguin reproductive structures specifically. Although penguins differ quite a bit from other birds with respect to taxonomy, they are birds, and it is not unreasonable to suggest that their reproductive organs are similar.

    There are four principal parts to the male reproductive tract: the testes, the epididymis, the ductus deferens and a sperm storage location near the cloaca (the common orifice). The testes are located dorsally.

    Only in a few species of birds does the male possess an intromittent organ; these birds include ratites, kiwis, cracids, screamers and waterfowl. Penguins do not have intromittent organs. There are varying reasons as to why intromittent organs would be evolutionarily advantageous in these species, but they will not be discussed here.

· Birkhead and Moller, Sperm Competition in Birds

    The testes seem to demonstrate extensive morpholical changes throughout the year, the height of such size change during the breeding season. Dr. D. G. Ainley recorded similar data with Adelie penguins. This increase in testis volume occured over the 8 stages of spermatogenesis.

• Stage 1 (n=16 cases observed). A row of spermatogonia and Sertoli cells ring the seminiferous tubule next to the basement membrane. Primary spermatocytes are present in an irregular row toward the lumen. The lumen is filled with sytoplasm.
• Stage 2 (n=20). There is a basal row of spermatogonia and Sertoli cells. Up to one-half the primary spermatocytes in a given tubule cross section are in the stage of synapsis where chromatin is concentrated to one side of the nucleus.
• Stage 3 (n=2). A basal row of spermatogonia and Sertoli cells ring the basement membrane. Towards the lumen two to three rows of primary spermatocytes are in synapsis.
• Stage 4 (n=2). A row of secondary spermatocytes lies toward the lumina of tubules. Peripheral to these are cells of previous stages.
• Stage 5 (n=7). Spermatids are present surrounding the lumina. Intertubular cells are almost completely confined to the triangles formed by the meeting of three tubules.
• Stage 6 (n=10). Rining the lumina are bundles of spermatozoa with their heads pointing toward the basement membrane. The lumina are filled with cytoplasm. This stage represents breeding condition.
• Stage 7 (n=10). In this, the climactic stage of spermatogenesis, spermatozoa and cytoplasmic particles are present in the lumina.
• Stage 8 (n=13). The stage of degeneration where the various cells from all stages in spermatogenesis, except spermatogonia, discharge into the lumina.

· Stonehouse, The Biology of Penguins

Reproductive structures of the female penguin

    In most birds, the female has one ovary. This ovary produces ova that over the period of receptivity increase to 1000 times their original sizes. The basic female reproductive tract includes the ovary, the magnum, uterus, uterovaginal junction and the oviduct (of the cloaca).

    Shortly before the period of egg laying, the ovary carries several developing follicles, each known as the ovum. Since each ovum develops within 24 hours of the pervious, as "hierarchy" of follicles is created and the larger the follicle, the sooner it is released. This is the crucial phase of receptivity in birds, and though it may vary from species to species, it is 15-30 minutes in length (Warren & Scott, 1935). Following this stage, the perhaps egg passes through the magnum, the isthmus and through the uterovaginal junction while collecting albumen and becoming calcified.

· Birkhead and Moller, Sperm Competition in Birds

    In the Adelie penguin, birds return to the rookeries in the late "autumn" and acquire pairs. Though being early does not confer an assured mating, the early arrivals are usually the ones who do achieve mating status.

    During this time, Adelie body weight is high and over the next month or so of breeding, they can lose up to 1/3 of that weight. After the egg laying period has ceased, the female leaves the rookery for the sea while the male stays to incubate the egg; during this time, males remain faithful to their fatherhood duties and do not consume any food. Because this devotion is so extensive, succeessful breeders are the penguins who are excellent foragers and can amass sufficient fat reserves for this six week period.

    D.G. Ainley's data for the breeding Adelie show that young birds do not breed (2 years of age). Females may begin to breed at age 3, but males do not begin to be successful until age 4. By age 6, most of the females in Ainley's experiment had bred at least once but it was not until age 8 did the males breed at least once. At this point, I should point out that there is a difference between being physiologically capable of breeding and being socially capable of breeding. Young birds may have the mechanics required to produce offspring, but their relative inexperience with acquiring mates and caring for the young makes them unsuccessful breeders.

    The process of acquiring a mate may be extensive and require several displays before choice occurs. In the Adelie penguin, there are some four different displays observed in acquiring mates and maintaining the social bond: bowing, mutual displays, ecstatic displays and allo-preeing.

    Ultimately, these acts lead to coition (cloacal contact). The process involves mounting and finally copulation with the female. The mechanics are different and vary among penguin species, but that for the Adelie is explained here.

    Coition or copulation is not required for mounting to be successful. Mounting simply refers to the act of the male standing on the female's back and attempting a copulation. This mounting behaviour is typically preceded by the arms act. During this event, the male approaches the female from behind and beats his wings on her sides. During this motion, the male may also rub the underside of his head and neck on her back and on the top of her back.

    As the male continues to vibrate his wings on the female, the female typically turns her head so that their bills vibrate next to or on each other. This act is followed by the male's lowering of his tail; the female in turn raises her. If the mount and copulation is successful, the two cloacas will make contact and sperm will be transferred. In Adelies, this act will last for a minute or more.

    In the Humboldt Penguins I have observed, the arms act and copulation is very similar; however, I have not seen the female to rotate on to her back as this picture suggests. Mounting and copulation typically takes less than 3 minutes in my Humboldt group.

· Spurr, Dr. E.B., Communication in the Adelie Penguin in Stonehouse, The Biology of Penguins

This concludes penguin behaviour