Q36 — Aethia cristatella — Courtship Display on Rocks

Theoretical 1 Real exam question — full text reproduced under IBO's CC BY-NC-SA 4.0 license

Aggression, Territoriality & Social Structure Mating Systems & Sexual Selection

Aethia cristatella are strictly monogamous birds, forming colonies during the breeding season and laying one egg in a nest under rocks after mating. Mated males occupy a highly positioned rock with surrounding area, spending most time on their own stone but temporarily occupying other males’ stones too, trying to prevent invasion of their own area while displaying themselves in rivals’ territory. This behaviour increases with local bird density.

Figure 1. Aethia cristatella with courtship feathers. Figure 1. Aethia cristatella with courtship feathers.

Figure 2. Diagram of courtship-game movements between rocks at high bird density. Figure 2. Aethia cristatella courtship game diagram in areas with high bird density; a — males displaying themselves in their own territory, b — females searching for a mate, c — mated pairs, 1–4 — rocks. Arrows indicate the movements of males between rocks.

Using the information and figures, determine whether the following statements are true or false:

A. Active males of Aethia cristatella display themselves on rocks, preferred by other active males, to attract and mate with other females.

B. Active males of Aethia cristatella display themselves for social interactions.

C. The behavior of the males is aimed to dominate other males and outcompete them from their territory.

D. For females of Aethia cristatella, observing the active and regular display behavior of different males is important to evaluate their capacities for caring for the offspring.

← Previous: Q35 Next: Q37 →

Question reproduced from IBO 2022, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 — attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)