Using Regurgitated Pellets from White-Tailed Sea-Eagles as Noninvasive Samples to Assess Lead Exposure Caused by Hunting in Germany
Anthropogenic lead intoxication is the most frequent cause of death of White-tailed Sea-Eagles (Haliaeetus albicilla) in Germany. Most lead fragments are ingested by eagles feeding on carcasses and viscera of game animals shot with lead-based ammunition left in the wild by hunters. We investigated how many regurgitated pellets contained metal fragments and hypothesized a correlation between the presence of metal fragments and (1) the hunting season, (2) the ban of lead in rifle ammunition, and (3) the frequency of specific prey animals in the pellets. We collected 273 regurgitated pellets, radiographed them for metal fragments, and analyzed the prey composition. The metal elements were identified using micro x-ray fluorescence. Metal particles were found in 9.2% of pellets; 24 fragments consisted of lead and one fragment was mostly copper. A higher proportion (14.3%) of contaminated pellets was detected during the hunting season from September through February. During the non-hunting season from March through August, 7.6% of the regurgitated pellets were contaminated. Furthermore, there was a significant positive correlation between the presence of mammalian remains in the pellets and metal contamination (general linear model, z=2.16, P=0.03). Our results indicate a correlation between the increased activity of hunters in winter and the occurrence of metal in regurgitated pellets of White-tailed Sea-Eagles. Uso de Egagrópilas Como Método No Invasivo Para Evaluar Exposición a Plomo de Caza en Haliaeetus albicilla, Alemania La intoxicación antropogénica por plomo es la causa más frecuente de muerte de Haliaeetus albicilla en Alemania. La mayoría de los fragmentos de plomo son ingeridos por las águilas que se alimentan de cadáveres y vísceras de animales de presa derribados con munición a base de plomo, que los cazadores dejan en la naturaleza. Investigamos cuántos bolos regurgitados contuvieron fragmentos de metal e hipotetizamos una correlación entre la presencia de fragmentos de metal y (1) la temporada de caza, (2) la prohibición de plomo en la munición de los rifles y (3) la frecuencia de presas animales específicas en los bolos. Colectamos 273 bolos regurgitados, los radiografiamos en busca de fragmentos de metal y analizamos la composición de presas. Los elementos de metal fueron identificados usando fluorescencia de micro rayos x. Encontramos partículas de metal en 9.2% de los bolos; 24 fragmentos fueron de plomo y un fragmento fue principalmente cobre. Una mayor proporción (14.3%) de bolos contaminados fue detectada durante la temporada de caza desde septiembre hasta febrero. Durante la temporada de veda de caza desde marzo a agosto, 7.6% de los bolos regurgitados estuvieron contaminados. Más aún, hubo una correlación positiva significativa entre la presencia de restos de mamíferos en los bolos y la contaminación con metal (modelo lineal generalizado, z = 2.16, P = 0.03). Nuestros resultados indican una correlación entre el aumento de la actividad de los cazadores en invierno y la presencia de metal en los bolos regurgitados de H. albicilla. [Traducción del equipo editorial]ABSTRACT
RESUMEN
Locations (gray dots) where regurgitated pellets of White-tailed Sea-Eagles were collected in northeastern Germany (n = 273). Pellets distributed as follows: Schleswig-Holstein n = 145, Lower Saxony n = 2, Mecklenburg-Western Pomerania n = 88, Brandenburg n = 13, Saxony n = 17, Bavaria n = 6, and unknown n = 2. Map was created using ArcGIS (version 10.6.0.8321, Esri, Redlands, CA, USA).
Metal fragments collected from regurgitated pellets from White-tailed Sea-Eagles in northeastern Germany. Top: Particle of tombac ammunition; Bottom: Particles of lead-based ammunition. Scale: 1 mm.
Percent of pellets containing bird and mammal remains from total pellets analyzed (n = 179) and from just those pellets that contained metal fragments (n = 25) from White-tailed Sea-Eagles in northeast Germany. Grey bars indicate regurgitated pellets containing bird remains, and black bars indicate pellets containing mammal remains. Pellets containing mammalian remains were significantly more likely to be contaminated with metal fragments than those containing bird or fish remains (z = 2.16, P = 0.03). Pellets often contained more than one species of bird or mammal remains, therefore percentages add up to more than 100%.
Contributor Notes
1 Email address: andrea.carolin@web.de
Associate Editor: Sean S. Walls