Hand rearing of the Hooded Grebe (<i>Podiceps gallardoi</i>) and the Silvery Grebe (<i>Podiceps occipitalis</i>) as a fundamental recovery strategy for a critically endangered species
Hand rearing of the Hooded Grebe (Podiceps gallardoi) and the Silvery Grebe (Podiceps occipitalis) as a fundamental recovery strategy for a critically endangered species
Proyecto Macá Tobiano / Programa Patagonia, Departamento de Conservación, Aves Argentinas. Matheu 1246, CABA (C1249 AAB), Argentina | Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Universidad de Buenos Aires. Instituto de Ecología Genética y Evolución de Buenos Aires (IEGEBA). Intendente Güiraldes 1260, Ciudad Universitaria, CABA (C1428EGA), Argentina | Fundación Macá Tobiano. Calle 64 #620, La Plata (1900)
Proyecto Macá Tobiano / Programa Patagonia, Departamento de Conservación, Aves Argentinas. Matheu 1246, CABA (C1249 AAB), Argentina | Fundación Macá Tobiano. Calle 64 #620, La Plata (1900) | Grupo de Conservación y Biodiversidad, Dpto. Análisis de Sistemas Complejos, Fundación Bariloche, CONICET. Av. Bustillo 9500, Bariloche (8400), Río Negro, Argentina
Proyecto Macá Tobiano / Programa Patagonia, Departamento de Conservación, Aves Argentinas. Matheu 1246, CABA (C1249 AAB), Argentina | Fundación Macá Tobiano. Calle 64 #620, La Plata (1900) | Grupo de Conservación y Biodiversidad, Dpto. Análisis de Sistemas Complejos, Fundación Bariloche, CONICET. Av. Bustillo 9500, Bariloche (8400), Río Negro, Argentina | EDGE of Existence Programme Affiliated (Zoological Society of London)
Gabarain, Gabriela T., Laura Fasola, Patrick I. Buchanan, and Ignacio Roesler. 2026. “Hand Rearing of the Hooded Grebe (Podiceps Gallardoi) and the Silvery Grebe (Podiceps Occipitalis) As a Fundamental Recovery Strategy for a Critically Endangered Species”. El Hornero 41 (1). https://doi.org/10.56178/eh.v41i1.1529.
Habitat loss, climate change, and invasive alien species have led the critically endangered Hooded Grebe (Podiceps gallardoi) to decline by 80% of its population. The Silvery Grebe (Podiceps occipitalis, least concern), is a closely related species that can be used as a biological proxy. As a complement to the in situ conservation actions developed over the past decade to protect the Hooded Grebe, we proposed hand rearing as part of the conservation strategy, given that in 97.4% of clutches, the nesting pairs abandon the second egg. Given the limited information regarding captive rearing of grebes, we evaluated variables that could affect hatching success and chick survival, including incubation stage at collection, transportation duration, temperature-humidity incubation protocol, daily egg-weight loss, and care (feeding and swimming) frequency. We collected and artificially incubated eggs from Hooded Grebes and Silvery Grebes for four breeding seasons. We achieved a 73% hatching success rate. The longest Hooded Grebe chick survival was 144 hours, and we successfully raised a Silvery Grebe fledgling, which was released into the wild after 67 days. Transportation duration, daily egg-weight loss, and incubation protocol did not affect hatching success. Eggs collected in the later stages of incubation had a higher hatching rate. We observed a higher survival time associated with the high-temperature and humidity incubation protocol. Chicks hatched from eggs with a daily egg-weight loss of more than 1% showed higher survival. This was also observed in chicks with more assiduous care. We have defined an appropriate incubation protocol for the Hooded Grebe. In the future, we will focus on determining the appropriate frequency of care and diet. The low reproductive success of the Hooded Grebe in the last years urges the need for actions aimed at increasing annual population recruitment.
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