Persistent lead poisoning of waterfowl in the Camargue (southern France) 10 years after the ban on the use of lead ammunition in wetlands
Data files
Jun 12, 2025 version files 297.17 KB
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cartridge.txt
376 B
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duck_gizzard_anonym.csv
254.39 KB
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README.md
5.23 KB
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Scripts_gizzards_and_cartridges_for_dryad.Rmd
35.19 KB
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species_traits.txt
1.98 KB
Abstract
Lead pollution is a worldwide environmental and health issue causing persistent detrimental effects on humans and wildlife. Despite having been identified as detrimental to waterfowl a century ago, in France lead shotgun pellets for hunting were banned only in 2006 and only in wetlands. We used long‐term monitoring data from the Camargue (southern France) to (1) assess the local effectiveness of the French regulation at reducing the ingestion of lead shotgun pellets by waterfowl and to (2) assess local hunter compliance with the regulation. We used data on 2187 gizzards from 13 waterfowl species collected from 38 hunters in the Camargue over 20 hunting seasons (1998 to 2017). In addition, from 2008 to 2019, we systematically collected shotgun shell cases at three communal wetland hunting sites and used the ratio of cases indicating lead versus nontoxic shotgun shells to estimate hunter compliance with the ban. Across the 20‐year study period that spanned pre‐ and post‐ban, gizzards of harvested waterfowl had a mean lead shotgun pellet prevalence of 12% across the 13 species with no significant reduction over time. There was a slow increase in the use of nontoxic shot shells after the ban; lead shells continued to be used widely, suggesting inadequate policy enforcement. Because the ban was only applied for hunting in wetlands, hunters have to be caught with lead shells in the shotgun while in wetland to be fined. It is still legal to carry lead shells, favoring the circumvention of the regulation. Our results support the need for a complete ban of lead shotgun shells for both wetland and terrestrial hunting. A complete ban would facilitate policy enforcement and would favor compliance, eventually leading to a phase‐out of lead shell production and use.
Dataset DOI: 10.5061/dryad.6q573n68s
Corresponding author information
Name: Arnaud Béchet
ORCID: https://orcid.org/0000-0002-0330-6342
Affiliation: Tour du Valat, Institut de recherche pour la conservation des zones humides méditerranéennes, Le Sambuc, 13200 Arles, France
email: bechet@tourduvalat.org
Description of the data and file structure
We collected bird gizzards opportunistically from a network of hunters in the Camargue during each hunting season from 1998/1999 to 2017/2018 (Figure 1). A total of 38 hunters contributed to the sampling effort. Those hunters harvested waterfowl both on communal hunting grounds (managed by the local hunting associations) and on private hunting estates. The number of gizzards collected per winter varied from 3 to 305, with a mean of 115 ± 20 (SE). In total, we collected 2306 gizzards from 28 species, which represent well the community of wintering game species in the Camargue.
Every hunting season from 2008/2009 to 2019/2020, we collected shell cases at three public wetland hunting sites located on the outskirts of Tour du Valat nature reserve (Figure 1; 43°30′30″ N, 4°39′59″ E) where it is illegal to hunt with lead shotgun shells. We collected shell cases abandoned by hunters on the ground by walking twice during each hunting season along the 5.2 km of hunting paths (Draille du Sambuc, bordure du Fumemorte, and Draille marseillaise; Figure 1) where the communal hunters of Arles hunt (Groupe Cynégétique Arlésien). We used the same research effort and the same observer over the study period. We considered only recent, bright shell cases (no rusty marks that appear after a season). We distinguished lead and nontoxic shells from the inscription on the shell cases (Mondain-Monval et al., 2020). Shell reloading is not practiced in our region, so shell case inscriptions reflect their content.
Files and variables
File: cartridge.txt
Description:
This dataset provides the number of steel versus lead shotgun shell cases collected each year on hunting trails surrounding the Tour du Valat nature reserve
Variables
- winter: Year of shotgun case collection - from 2008 to 2019
- type: Type of shotgun cases collected, either cases that have contained "lead" or "steel" shotgun pellets
- N: Number of shotgun cases collected
File: species_traits.txt
Description:
This dataset provides the diet, family, and order of the species considered in the study
Variables
- species: Species name
- diet: Diet of the 28 species considered
- order: Species order
- family: Species family
- diet_m: Modified version of the diet pooling granivorous with vegetarian
- source_dietm: Reference for diet assignment - HBW for Handbook of Birds of Western Palearctic
File: duck_gizzard_anonym.csv
Description:
This dataset provides the data on the number of pellets of different types (lead, steel, etc.) found ingested in the gizzard of waterfowl harvested in the Camargue and the surroundings. Hunter names and observer names (who identified the number of pellets) have been anonymized.
Variables
- sample: Sample ID
- species: Species name
- sex: Species sex
- recovery_site: indicate the place of species harvest
- location: whether the harvest site is within or outside the Tour du Valat estate
- date: Date of harvest
- hunter: Name of hunter
- hunt_type: Type of hunting (Affut = Hunting from a hide neaby a wetland; passée= Hunting birds commuting from roosts to foraging areas; DSAM=Hunting walking forward in afternoon; DSM=Hunting walking forward in the morning)
- ingested_lead: Number of lead pellets found in the gizzard content
- ingested_steel: Number of steel pellets found in the gizzard content
- ingested_tungsten: Number of tungsten pellets found in the gizzard content
- ingested_bismuth: Number of bismuth pellets found in the gizzard content
- ingested_alloy: Number of alloy pellets found in the gizzard content
- lead_shot: Number of lead pellets found in the bird (outside the gizzard)
- steel_shot: Number of steel pellets found in the bird (outside the gizzard)
- observer: Name of the observer who has counted and recorded the data
In all columns, NA is for missing values.
File: Scripts_gizzards_and_cartridges_for_dryad.Rmd
Description: Markdown script used to prepare data, tables, figures, and run models presented in the paper.
Code/software
Analyses of the data were run with R (version 4.3.1) and R Studio (2023.06.0 Build 421). A commented R script in markdown is provided covering both data preparation and analysis.