DOI: 10.5061/dryad.63xsj3vbg
title: Regional differences in crippling rate in greylag geese Anser anser in Sweden

description: Goose populations across Europe have been subjected to long-standing
 harvest practices, which include shotgun hunting. In addition to immediate
 mortality, hunting can affect an animal’s fitness by inflicting non-lethal
 injuries, often referred to as ‘crippling’ or ‘wounding’. This could
 subsequently have negative effects on the population level and causes
 ethical concerns, ultimately challenging the legitimacy of hunting as a
 management tool. Understanding spatial variation in crippling rate can
 assist management to prioritize regions for enhancing awareness and
 implementing measures aimed at reducing crippling. We examined greylag
 geese from three subpopulations (Nyköping, Örebro, and Hudiksvall)
 breeding in three regions in Sweden (Södermanland, Örebro, and Gävleborg)
 to record prevalence of imbedded shotgun pellets and to quantify crippling
 impact. Our approach excludes birds that were wounded and subsequently
 died without being retrieved. We found that across the three
 subpopulations, 21% of the 176 x-rayed greylag geese were carrying
 imbedded pellets (average 2.33 pellets, range 1–16). Crippling rate varied
 among the subpopulations, being twice as high in Örebro and Nyköping (26.4
 and 25.0%, respectively) compared to Hudiksvall (11.7%). However, the
 probability of being crippled differed significantly only between Nyköping
 and Hudiksvall (p=0.04), but not between Örebro and Hudiksvall
 (p&gt;0.05) or between Nyköping and Örebro (p&gt;0.05). This study
 could not elucidate the mechanisms underlying the observed regional
 variations in crippling rate. Nevertheless, the regional disparities in
 these rates, and the potential links between crippling rate, levels of
 crop damage, attitudes, and hunting behaviors, present intriguing avenues
 for future exploration.
description: Greylag geese were captured and x-rayed in three study sites in
 Sweden. In June 2019–2022, breeding and moulting (flightless) greylag
 geese were caught when foraging in fields near water. They were herded by
 foot and canoes towards standing nets and corrals. The birds were kept in
 gunny bags until further handling. During ringing, geese were aged
 (juvenile versus adult) based on plumage, and the adult birds were x-rayed
 for the purpose of the present study. Juveniles were not yet fledged and
 had not yet been exposed to hunting; hence they were not x-rayed. After
 ringing, adult birds were again placed in gunny bags and fitted in a
 plastic box so that they would not move during the x-ray examination. In
 total, we x-rayed 176 individuals and they were released immediately after
 examination. In 2019, 103 geese were x-rayed using a Mars1417V-TSI
 detector plate from iRay Technology combined with a portable ACOMA
 PX-15HF. In 2021, 25 were x-rayed using a VIVIX-S 1417N detector combined
 with a portable Econet Vet20BT x-ray unit. In 2022, 48 individuals were
 x-rayed using a Sedecal SP-VET-4.0 with Beam device r 72/170A DHHS. The
 x-ray was set at 50 kW and 3 mAs.
description: # Regional differences in crippling rate in greylag geese Anser anser in
 Sweden
 [ghttps://doi.org/10.5061/dryad.63xsj3vbg](https://doi.org/10.5061/dryad.63xsj3vbg) ## Description of the data and file structure "Greylag Geese (*Anser anser*) were captured for ringing and x-rayed to detect any shotgun pellets. Three capture sites, Hudiksvall, Örebro, and Nyköping in three different regions (the counties Gävleborg, Örebro, and Södermanland) of Sweden were used in this study. The Hudiksvall site is an urban wetland surrounded by grasslands and lawns in a city park (N 61°43.96′, E 17°6.55′). Hudiksvall is located in the Southern boreal zone (Ahti et al. 1968, Hallanaro et al. 2002) and the surrounding region is a mix of forested and agricultural land. The site Örebro includes two wetland reserves (“Kvismaren” and “Oset”; N 59°9.59′, E 15°22.86′ and N 59°16.3´, E 15°15.57´, respectively) situated 13km apart in the transition zone between the Southern boreal and Boreo-nemoral zones. The area is dominated by agricultural fields and attracts large numbers of greylag geese for breeding, as well as for staging in spring and autumn. The site Nyköping (N 58°58.17′, E 17°9.07′) is a wetland surrounded by a patchy landscape of forests, extensively managed grasslands, agricultural fields, and lakes. This wetland is situated in the Boreo-nemoral zone. All three sites host a mix of breeding and moulting greylag geese. In June 2019–2022, breeding and moulting (flightless) greylag geese were caught when foraging in fields near water. They were herded by foot and canoes towards standing nets and corrals. The birds were kept in gunny bags until further handling. During ringing, geese were aged (juvenile versus adult) based on plumage, and the adult birds were x-rayed for the purpose of the present study. Juveniles were not yet fledged and had not yet been exposed to hunting; hence they were not x-rayed. After ringing, adult birds were again placed in gunny bags and fitted in a plastic box so that they would not move during the x-ray examination. In total, we x-rayed 176 individuals (Table 2) and they were released immediately after examination. In 2019, 103 geese were x-rayed using a Mars1417V-TSI detector plate from iRay Technology combined with a portable ACOMA PX-15HF. In 2021, 25 were x-rayed using a VIVIX-S 1417N detector combined with a portable Econet Vet20BT x-ray unit. In 2022, 48 individuals were x-rayed using a Sedecal SP-VET-4.0 with Beam device r 72/170A DHHS. The x-ray was set at 50 kW and 3 mAs. ### Files and variables #### File: X-ray\_data.csv **Description:**  ##### Variables * Species: Goose species x-rayed (only greylag goose in this data) * Latin-name: Scientific name of species * Ringing-date: Date for capture and x-ray examination * Ringing-place: Study site (municipality) * Province: Province of Sweden where geese were captured and x-rayed * N Pellet in xray: Number of pellets  found * Occurrence: Occurenc of pellets (1) and no pellets (0) ## Code/software For example r and open office