The cormorants, of a couple different varieties, have been in Delta Ponds for a while this spring. They seem to stop by each year in the spring and again in the fall, when they migrate. I believe this might be a Double-crested Cormorant.

From a distance the cormorant may look black, but up closer lighter colors can be seen. This is what is said in a Cool Fact from 'All About Birds' - "•From a distance, Double-crested Cormorants are dark birds with snaky necks, but up-close they’re quite colorful—with orange-yellow skin on their face and throat, striking aquamarine eyes that sparkle like jewels, and a mouth that is bright blue on the inside." https://www.allaboutbirds.org/guide/Double-crested_Cormorant/lifehistory)