Laridae of Lake Titicaca

Most people will tell you that Lake Titicaca has but one species of Laridae - the Q'eulla, or Andean gull (I put up a photo already a while ago). In fact, there are also at least two more rare vagrant species there, and this beautiful oddball, the Rhynchops niger, or black skimmer:

How about that for a photo? I was sure proud.

Then the two other species are Leucophaeus pipixpan, and this hyper-rarity I photographed, a first-year Leucophaeus atricilla:

Why do I say it's a hyper-rarity??? In Fjeldså, it is mentioned as seen only once in the high Andes, at 3020 meters above sea level, in Colombia. Lake Titicaca is almost 800 meters higher, which would make for a world record!

Here is a first-year Chroicocephalus serranus (The Q'eulla I already mentioned) , for comparison purposes. They're born in the austral winter, so this bird is not exactly exhibiting as advanced a plumage.

Here in Lima we see a lot of L. pipixcan, but I sold my camera in Puno, so no new photos.