The Ecstatic Display given by males may be used as an honest signal of male quality for female mate choice (Sladen 1959; Marks et al. 2010). The male performs this display by stretching his head and neck up while pointing his bill vertically. He then flaps his outstretched wings while making a call that resembles the Loud Mutual Display (Jouventin 1982; Ainley 1975). The Loud Mutual Display consists of the mutual display where the Adélie raises and waves its head from side to side plus the several syllable Loud Mutual Call (Spurr, 1975a).
During non-breeding times the Adélie penguin can be found as far as 1000 km away from its breeding grounds. They leave their breeding grounds sometime during late December through early February and don’t return to their breeding grounds until 7 months later in September or October.
Adélie chicks begin life as semi-altricial and with little ability to move about or call. As they grow older they learn and display a diverse set of behaviors for feeding, comfort, locomotion, aggression, calls and displays (Spurr 1975a).
Soon after hatching most chicks will begin begging for food, but even if they don’t, parents still initiate the first feeding. Later feedings are initiated by the chick’s begging. The begging behavior begins with a chick reaching up with wobbly head movements and touching bills with their parent. They also let out a single syllable “peep” and may hold out their flippers for balance (Spurr 1975a).
Once the chicks are in the crèche stage, the second stage of parental care when both parents are away from the nest foraging so chicks gather together for safety forming a large group called a crèche, a parent returning from foraging will give the Loud Mutual Call letting the chick know it is home. This alerts all chicks in the crèche who will chase the incoming parent for food, their parent or not. Other chicks give up quickly, but the parents actual chick(s) will continue to pursue the parent sometimes right out of the colony until only one chick is left chasing. While chasing, chicks run with their flippers held up over their back and bill opening and closing while giving off “peeps” (Spurr 1975a; Boersma & Davis 1997).
Young chicks begin performing comfort activities by 10 days old. Behaviors include yawning, shaking, stretching, swallowing, scratching, and preening, all very similar to the same behaviors in adults. Unlike adults, chicks will allopreen parents or siblings. In the beginning chicks sleep lying flat on the ground, but will start standing with their bill tucked under the flipper while sleeping after 15 days old (Spurr 1975a).
Chicks being semi-altricial are unable to move out of the nest until 11 to 15 days old. By then they can move about the nesting territory but will rarely wander far away until they join a crèche around 20 days old. The ability to walk is a gradual development and is accompanied by many head-long falls (Spurr 1975a).
Adélie penguin chicks will huddle with siblings and neighbor chicks with no aggression. Around 11 days old the first sign of aggression shows, however it is more playful aggression than true aggression. Chicks will gape and bill-grip each other and may also grip one another’s feathers or beat one another with their flippers. Serious aggression begins to show after about 21 days old, usually towards unknown adult penguins or other chicks coming too close to the nesting territory. Once they are large enough, chicks in a crèche will act aggressively towards an attacking Skua. Common aggressive behavior includes physical attack with bill and flippers, charging forward, side-to-side head waving, and rolling the eyes to show the white sclerae (Spurr 1975a).
Calls and Displays
Chicks also perform a couple displays after 10 days old. An immature version of the Adult Loud Mutual Display is often performed in succession with begging when a parent comes home after foraging. They utter a several syllable call while they raise their head and wave it from side to side with bill open wide. A Quiet Mutual Display can also be performed with parents after being disturbed. This display is similar to the Loud Mutual Call minus the calling (Spurr 1975a).
An “aark call” can be heard often among crèches when chicks are alarmed by Skuas or humans. They also seem to make this call in response to novel situations, like when first dispersing on their own and entering the water (Spurr 1975a).
The Ecstatic Display in adults is a form of advertising to mates, but chicks older than 35 days will perform their own immature version. They raise their head vertically, roll their eyes showing the white sclerae and beating flippers up and down. They will emit a shrill multiple syllable call along with the physical display (Spurr 1975a).