Pale Blue Eyes
Eurasian Jackdaws, Corvus monedula, have pale silvery-blue eyes due to the structure and pigmentation on their irises. But why do they have such pale blue eyes?
Their light eye colour probably serves multiple purposes, and it’s difficult to measure which have been the most important factors in selecting for eye colour. Here are a few possible reasons::
- Social signalling: Jackdaws are highly social, colonial birds. Their pale eyes could help them communicate with each other, especially for establishing dominance, defending their dark cavity nest sites, or coordinating their behaviour when in groups. Jackdaw eyes are visible from distance against their dark plumage, which could make their gaze-direction obvious to other birds.
- Species recognition: Their pale blue eyes may also help Jackdaws distinguish members of their own species from others in the crow family, especially in mixed flocks with Rooks or Carrion Crows. The pale theme is carried on in the grey nape.
- Maturity indicator: Young jackdaws have darker eyes and their pale blue eyes develop as they mature, so their eye colour could also signal age or sexual maturity to others. Dark eyes mean, “Don’t bully me or attempt to mate with me, I’m only a child”.
I love the Jackdaw’s scientific name, Corvus monedula. Corvus means “crow” and monedula means “money-eating”. They love a little something shiny and bright, just like their eyes.
Here’s the classic, Pale Blue Eyes by The Velvet Underground, dedicated to every Eurasian Jackdaw lover out there: