Age: It's safe to assume this is a 1st cycle based ont the black terminal band on the tail.
Identification: Our June bird appears to be a small, two-cycle, gull. The small, pointy bill, black pseudo-hood and thin black tips to the primaries immediately evoke Little Gull and Bonaparte's. It's difficult to judge bill proportions here, but Black-headed is safely ruled out not only by the bill's color, but also by the white under side to the primaries. As for Bonaparte's, that species would show a prominent black trailing edge running across all of the remiges. Here's an example of a typical trailing edge on Bonaparte's:
Instead, what we see here is a "spotty" black trailing edge that is discontinuous and weakly patterned, which leaves us with Little Gull.