I'd just adjusted the settings on my camera (for gulls or terns) and the much darker jaeger was under-exposed. I had to do more post-processing with the exposure than I'd like.
It's a pretty typical looking young Parasitic with some warm tones (though they vary a decent amount in terms of light-dark spectrum and degree of warm tones), fairly heavy white flash to the underside of the wing (and an average flash to the upperside). The bird has typical proportions with medium length hand, somewhat belly heavy and a typical length tail. Long-tailed's have a longer hand giving longer thinner wings, and a somewhat longer tail. While you'll certainly see warmer colored Parasitics (and the underexposure doesn't help), it is certainly warm enough to eliminate Long-tailed just on that point alone. Some young Parasitics will have an even stronger upperwing flash, per the Olsen and Larsson book a strong upperwing flash when present is virtually diagnostic of Parasitic. It's too early to start really thinking about Pomarine; they're shorter-handed and lack tail extensions.
Here's a distant shot after I'd adjusted the settings on the camera. It gives a little better sense of the warmish tones. You can just see the pointed central tail feathers protruding an inch or so past the end of the tail.
