Found this article on-line by Oklahoma Dept. of Wildlife Conservation that states -;

"Birds that are mature enough to reproduce will develop "nuptial tubercles," or large ridges on top of their bills, and ornamental plumes atop their head. Once chick feeding begins, the ridges fall off and the birds develop black feathers on the back of the head. Their eye color also changes from dark to light as their breeding status changes."

Interesting picture you took, Thanks for posting the link. I have seen White Pelicans now and again in various locales around the country but never happened to see this phase before.

https://www.wildlifedepartment.com/wildlifemgmt/species/americanwhite.htm

Dee W
Edmonds, WA

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman11.u.washington.edu/pipermail/tweeters/attachments/20180626/75885804/attachment.html>