Does Hopi Religious Harvest of Eaglets Affect Golden Eagle Territory Occupancy and Reproduction on the Navajo Nation?
The Golden Eagle (Aquila chrysaetos) has great religious importance to many indigenous North American peoples, including the Hopi Tribe and Navajo Nation of the southwestern United States. Hopi oral traditions indicate their ancestors harvested nestling Golden Eagles prior to the arrival of Europeans to the region, and this religious practice continues today. Despite contemporary conservation concern for Golden Eagles, no studies have evaluated potential negative effects of religious harvest on populations of this species. We conducted aerial and ground searches for Golden Eagle nesting territories on the Navajo Nation from 1996–2005, and monitored occupancy and reproductive rates of territories in three study areas: one area where Hopi annually harvested eaglets, and two areas without harvest. We analyzed 9 yr of data (1997–2005) using multi-season occupancy models and generalized linear mixed models to test for differences among study areas in occupancy dynamics, and production of early-season and fledging-age nestlings. We found no significant differences in probabilities of occupancy, persistence, or colonization of territories between study areas. Territories in harvest and control areas produced similar numbers of nestlings early in the season; however, significantly fewer (53%) reached fledging age in the harvested area, suggesting collection of nestlings led to locally depressed fledgling production. Given possible declining trends of Golden Eagle populations in the southwestern U.S., we recommend continued monitoring and more intensive demographic studies to better understand the effects of religious harvest on the population of Golden Eagles nesting on the Navajo Nation.
Aquila chrysaetos tiene una gran importancia religiosa para numerosas comunidades indígenas de América del Norte, incluyendo la Tribu Hopi y la Nación Navajo del suroeste de los Estados Unidos. Las tradiciones orales de los Hopi señalan que sus ancestros recolectaban pollos de A. chrysaetos antes de la llegada de los europeos a la región, y esta práctica religiosa continúa hoy en día. A pesar de las preocupaciones actuales para la conservación de A. chrysaetos, no existen estudios que hayan evaluado los efectos potencialmente negativos de esta recolección religiosa sobre las poblaciones de esta especie. Realizamos búsquedas aéreas y terrestres de territorios de nidificación de A. chrysaetos en la Nación Navajo entre 1996 y 2005 y monitoreamos la ocupación y las tasas reproductivas de los territorios en tres áreas de estudio: un área donde los Hopi recolectaban pollos de A. chrysaetos anualmente y dos áreas sin recolección. Analizamos nueve años de datos (1997-2005) utilizando modelos de ocupación de múltiples estaciones y modelos lineales mixtos generalizados para evaluar las diferencias en la dinámica de ocupación y en la producción de polluelos volantones a principios de la estación entre las áreas de estudio. No encontramos diferencias significativas en las probabilidades de ocupación, persistencia o colonización de territorios entre las áreas de estudio. Los territorios ubicados en las áreas de recolección y de control produjeron un número similar de polluelos a principios de la estación; sin embargo, una cantidad significativamente menor (53%) llegó a la edad de volantón en el área con recolección, sugiriendo que la colecta de pollos provocó una disminución local en la producción de volantones. Teniendo en cuenta las posibles tendencias de declive en las poblaciones de A. chrysaetos en el suroeste de los Estados Unidos, recomendamos el seguimiento continuo y estudios demográficos más intensivos para comprender mejor los efectos de la recolección religiosa sobre las poblaciones de A. chrysaetos que nidifican en la Nación Navajo. [Traducción del equipo editorial]Abstract
Resumen

Study area. The contiguous Navajo Nation (divided into Western, Central, and Eastern study areas), the Reservation of the Hopi Tribe, and surrounding U.S. states. Inset shows the location of the Navajo Nation in the coterminous United States.

Probabilities of persistence and colonization of Golden Eagle nesting territories in the Navajo Nation, 1997–2005. Plots depict estimates (points) with 95% CI (bars) from the best-approximating multi-season occupancy model (Table 2). Persistence probability followed a quadratic time trend, colonization probability followed an additive time trend, and neither differed among study areas.

Probabilities of annual occupancy and detection for Golden Eagle nesting territories in the Navajo Nation. Plots depict estimates (points) with 95% CI (bars) from the best-approximating multi-season occupancy model (Table 2). Probabilities of annual occupancy and detection varied among years, but did not differ between study areas.

Average number of early-season and fledging-age nestlings produced by Golden Eagle territories in the Navajo Nation, 1997–2005. Plots depict annual group means (points) with 95% CI (bars) from the best-approximating Poisson generalized linear mixed models, with random effects of nesting territory. Best-approximating models for production of early-season and fledgling-age nestlings included fixed effects of year, and the model for fledgling production included a fixed effect of study area. Both early-season nestling and fledgling production varied significantly among years, but only fledgling production varied among study areas, with significantly fewer young reaching 80% of fledging age in the West study area.
Contributor Notes
Associate Editor: Ian G. Warkentin