Raptor Odd Couple Spotted at Pinnacles

Great horned owl and red-shouldered hawk nestlings in their shared nest in early May. NPS / Gavin Emmons

May 2018 - Regular raptor surveys in April revealed something very unusual indeed: a red-shouldered hawk (Buteo lineatus) nestling in a great horned owl (Bubo virginianus) nest! Park biologists watched the resident great horned owl nestling and its new foster sibling preen each other, check out their surroundings, doze together, and otherwise behave very much like normal nestmates. The adult great horned owl that initially flushed from the site also finally returned and settled to sit with both nestlings.

Park raptor biologist Gavin Emmons speculates that the great horned owl adults originally snatched the young hawk from its nest and brought it back as food for their own nestling. For some reason, they then decided to adopt and raise the hawk rather than eat it, a behavior that has only infrequently been seen with certain eagle species adopting rather than eating hawk, osprey, or kestrel nestlings. However, park staff had never heard of this rare event happening between owls and daytime raptors.

Great horned owl and red-shouldered hawk nestlings the day before their nest tree unexpectedly fell over. NPS / Gavin Emmons

This unlikely family continued to live together, with the owl parents caring for both young birds, until their gray pine nest tree unexpectedly fell over on May 11th. Neither nestling was found after the tree collapsed. Although it is possible that the young owl fledged early—it was within a week or so of flying for the first time—the hawk nestling was still three weeks away from fledging, and very likely perished.

Despite the abrupt and tragic end to this unusual story, it still provides a fascinating look into the lives of nesting raptors, and reveals how much more there is to learn about these remarkable creatures. To learn more, contact Gavin Emmons.

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