Colour-ring wear and loss effects in citizen science mark-resighting studies

Table 1 Summary of the resighting data of the Eurasian Oystercatchers for different parts of the Netherlands

Area	Ringed	Pre2008	Observed (%)	Lost (%)	Worn (%)
Delta	1855	0	88.4	9.9	4.7
Wadden Sea	2891	1840	86.2	3.2	5.1
Inland	2323	0	75.4	1.5	1.3
Total	7069	1840	83.8%	4.2%	4.0%

“Ringed” = individuals fitted with colour-rings during the current study period whilst “Pre2008” were ringed prior to 2008 and observed during the current study period. We did not include individuals ringed prior to 2008 that were not observed between 2008 and 2017 because we could not be sure about the state of the individual (alive/dead, ring lost/worn). “Observed” = percentage of individuals resighted, “Lost” and “Worn” = the percentage of individuals reported with lost or worn rings

ISSN: 2053-7166