DOI: 10.5061/dryad.qbzkh18rf
title: Blood lead levels in an endangered vulture decline following changes in hunting activity

description: Lead ammunition stands out as one of the most pervasive pollutants
 affecting wildlife. Its impact on bird populations has spurred efforts for
 the phase-out of leaded gunshots in several countries, although with
 varying scopes and applications. Ongoing and future policy changes require
 data to assess the effectiveness of adopted measures, particularly in the
 current context of biodiversity loss. Here, we assessed the long-term
 changes in blood lead (Pb) levels of Egyptian vultures from the Canary
 Islands, Spain, which have been severely affected by Pb poisoning over the
 past two decades. During this period, the reduction in hunting pressure
 and changes in legislation regarding firearms usage for small game hunting
 likely contributed to a decrease in environmental Pb availability. As
 anticipated, our results show a reduction in Pb levels, especially after
 the ban on wild rabbit hunting with shotguns since 2010. This effect was
 stronger in the preadult fraction of the vulture population. However, we
 still observed elevated blood Pb levels above the background and clinical
 thresholds in 5.6% and 1.5% of individuals, respectively. Our results
 highlight the positive impact of reducing the availability of Pb from
 ammunition sources on individual health. Nonetheless, the continued use of
 Pb gunshot remains an important source of poisoning, even lethal, mainly
 affecting adult individuals. This poses particular concerns for long-lived
 birds, compounding by potential chronic effects associated with Pb
 bioaccumulation. Our findings align with recent studies indicating
 insufficient reductions in Pb levels among European birds of prey,
 attributed to limited policy changes and their uneven implementation. We
 anticipated further reductions in Pb levels among Egyptian vultures with
 expanded restrictions on hunting practices, including a blanket ban on Pb
 shot usage across all small game species.
description: 344 blood samples (1 mL) of Canarian Egyptian vultures were
 collected between 1999 and 2022. Samples were stored in tubes containing
 lithium-heparin and immediately frozen at -20ºC for blood Pb analyses.
 Samples were analysed by atomic absorption spectroscopy with a graphite
 furnace (GF-AAS) after diluting whole blood samples in Triton at 0,1% with
 standard addition calibration. The limits of quantification of Pb obtained
 in the different years ranged between 0,1 and 0,6 µg/dL. For blood samples
 collected in 2021 and 2022, analyses were performed by ICP-MS after the
 digestion in a microwave oven with nitric acid and hydrogen peroxide. The
 limit of detection obtained with this technique was 0,1 µg/dL.
description: # Blood lead levels in an endangered vulture decline following changes in
 hunting activity The Excel file (.xlsx) contains blood lead (Pb)
 concentration data from Neophron percnopterus majorensis specimens sampled
 in the Canary Islands in the period 1999-2022. The file contains 8
 columns: 1. Id. The unique identification code (plastic ring number) of
 each individual. 2. Pb (µg/dl ). The concentration of lead (Pb) in the
 blood of each specimen is indicated in µg/dl. 3. Year. The year of
 capture. 4. The age (adult or per-adult) of each individual at the time of
 capture. 5. The sex (male/female). 6. Shotgun. Indicates whether the
 sample was taken before or after the ban on rabbit hunting with firearms
 on the island (yes - &lt;2010 / not ≥ 2010). 7. Season. The period in
 which the sample was obtained (hunting season or outside the hunting
 season). 8. Licenses. The number of hunting licenses issued in the season
 immediately preceding the capture of the bird.