Hybrid Tern??????

[Joe Senzatimore]

Taken this AM at the local Tern Colony. Never saw one with markings like this. Am wondering if it might be a cross between a Common Tern and a Black Tern. It is banded but a very large blow up of the band doesn't reveal any info at all. I am posting this to try and determine the species/cross , and not for critique as I know it is not really fit for this forum. Hope someone can shed some light on this.

800ISO F8 at 1/2500th

[Sidharth Kodikal]

Looks like something that a nice bath would wash off?
I'd be curious to see a 100% crop of the neck/chest area.

PS: I'd post this to the "Avian: About birds" forum. They might be able to shed some light.

[Daniel Cadieux]

Thread moved to Avian: About Birds.

Looks like it may be a stain, but we'll see what others think...

[John Chardine]

It could be oil. Notice how the feathers look wet around the fouling. Oil temporarily destroys the micro-structure of the feathers thus allowing water to penetrate and otherwise waterproof barrier.

[Paul Guris]

This looks like oil to me. I've seen very strong and specific stains like this before on gulls, especially Kittiwakes, on our pelagic trips. Fortunately the sight of oil stained birds has actually become less common than it was back in the 80s and 90s.