An African Black Oystercatcher chick with the numbered colour rings that are used to follow its survival and migratory movements over several years.
(Photo: Doug Loewenthal)
CC BY 2.5
<i>South Africa – Serious about Biodiversity Science.</i> Cherry M., PLoS Biology Vol. 3/5/2005, e145 <a rel="nofollow" class="external free" href="https://dx.doi.org/10.1371/journal.pbio.0030145">https://dx.doi.org/10.1371/journal.pbio.0030145</a>