Astonishing bloody battles play out in the nests of several species of eagles, herons, boobies, pelicans and certain other large birds. These are between their nestlings, although its more a case of the first-born Cain simply murdering the second-born Abel. The behaviour is called siblicide. Adult females of these birds lay their eggs several days apart, and so the first chick is older, bigger and stronger by the time its sibling hatches some days later. The elder Cain soon attacks and kills its sibling. Nasty stuff, but all to the good of the genes of the survivor and the genes that it carries of its dead brother or sister.

Black or Verreaux’s Eagles generally nest on cliffs, but Ongava has a pair nesting in a large mopane between Ongava Lodge and Margo House. The nest was discovered this year, but its large size suggests that it has been used for many previous years. We were delighted to observe a large chick perched on the nest in August, but then dismayed to note its apparent absence in September, too early for the nestling to have fledged.

Eventually Simeon Naholo (Ongava Research Centre’s technician) climbed to the nest, only to discover that the large chick was dead, and had been that way quite some time. What led to its death remains a mystery, but Simeon did discover the scant remains of its sibling. We hope for a happier breeding season next year