A study coordinated by the Doñana Biological Station (EBD-CSIC) and the Pyrenean Institute of Ecology (IPE-CSIC) shows that the physical attractiveness of birds does not determine their reproductive success.
The results, contrary to expectations, demonstrated that the density of mates and competitors did not influence whether the most attractive males had more or fewer descendants .

The little penguin is the smallest and the only penguin species whose activity on land is strictly nocturnal. Thirteen years of attendance data were used to study the effects of sun, moon, and artificial light on the attendance pattern at Phillip Island, Australia.