The blue tit (Cyanistes caeruleus) was caught in a bird banding session and, after banding the bird and taking some biometric measurements it was released. The session occurred at Parque Biológico de Gaia.
<a href="//commons.wikimedia.org/w/index.php?title=User:Gon%C3%A7alo_Vila_Ferraz&amp;action=edit&amp;redlink=1" class="new" title="User:Gonçalo Vila Ferraz (page does not exist)">Gonçalo Vila Ferraz</a>
CC BY 4.0
<span class="int-own-work" lang="en">Own work</span>