The Postnatal Development of Two Broods of Great Horned Owls (Bubo virginianus)

Nestlings of the great‑horned owl were studied right from the moment the eggs were laid on a metal‑capped ledge high above the University of Kansas Museum. The parents chose a modest platform of bare vines and excrement, with the eggs resting directly on the metal, while a nearby cottonwood tree offered a convenient perch whenever they were displaced. Researchers could watch the owls through a laboratory window, noting that incubation began shortly after the first egg appeared in early February and lasted about a month.

From March onward, three chicks hatched in 1945 and a single one in 1946, allowing daily records of their growth, feather emergence, and the parents’ feeding patterns. The observations capture the early stages of owlet development—how they move within the shallow nest, the shift from dependence on brooding to self‑support, and the subtle interactions that prepare them for fledging. These detailed notes offer a rare glimpse into the first weeks of life for a species usually observed only from a distance.