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Crowned Eagle Incubated Two Egyptian Goose Eggs Alongside Its Own

Adult Crowned Eagle perched in a tree in KwaZulu-Natal, South Africa
Research · Behaviour

An unusual nesting event in South Africa documented a crowned eagle (Stephanoaetus coronatus) incubating a mixed clutch containing one of its own eggs and two eggs laid by an Egyptian goose (Alopochen aegyptiaca). Crowned eagles normally lay only one or two eggs, and strong sibling aggression means that usually only one eagle chick is raised, making a three-egg nest especially unusual even before the foreign eggs hatched.

The case arose after Egyptian geese used the eagle nest during the breeding attempt. Rather than removing or abandoning the foreign eggs, the crowned eagle incubated all three eggs together.

Both Egyptian goose eggs hatched

Both Egyptian goose eggs hatched. The adult eagle continued to brood the newly hatched goslings alongside its own unhatched egg and even attempted to feed them. This was particularly unusual because Egyptian goose young are precocial: unlike an eagle chick, they hatch relatively well developed and normally leave the nest with their parents soon after hatching.

The mixed brood ended without an eagle chick

The mixed brood did not persist for long. One gosling jumped from the eagle nest and was later found by people after the adult geese had left the area. The second gosling remained with the crowned eagle for longer, but was eventually killed and eaten by the eagle. The crowned eagle’s own egg did not hatch, so the breeding attempt ultimately failed.

The authors describe the observation as a previously undocumented example of a crowned eagle accepting and incubating Egyptian goose eggs. They note that Egyptian geese do not build their own tree nests and can use or aggressively take over nests built by other large birds, including raptors.

In this case, the crowned eagle did not appear to recognise or reject the foreign eggs after regaining the nest. The authors highlight the event as an example of how nest competition between the two species can interfere with raptor breeding, particularly in human-modified landscapes where Egyptian goose populations and large raptors increasingly overlap.

The study was published in the Journal of Raptor Research in April 2026.

Sources and image credit

  1. Sumasgutner, P., Smith, B., & Sumasgutner, S. (2026). Extraordinary case of nest usurpation and mixed clutch: Crowned Eagle incubates two Egyptian Goose eggs plus its own. Journal of Raptor Research, 60(1), 1–6. https://doi.org/10.3356/jrr2577Primary peer-reviewed article documenting the mixed Crowned Eagle–Egyptian Goose clutch and its outcome.

Image: Bernard Dupont — Crowned Eagle in Hluhluwe-iMfolozi Park, KwaZulu-Natal, South Africa; high-resolution wild image from South Africa, not from the reported nest. Source: Wikimedia Commons. · CC BY-SA 2.0 · Source

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Behaviour

SPECIES IN THIS STORY

Species in this story

Crowned Eagle Stephanoaetus coronatus Explore species Egyptian Goose Alopochen aegyptiaca Explore species

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