These "Prairie Doves" are an uncommon to rare visitor to the Great Lakes, significantly more likely to be found further west. Their molt and migration is unlike any other local gull species - as they migrate to South America and undergo two complete molts (including flight feathers) twice per year.
First Cycle
June
July
Fresh juvenile Franklin's Gulls are only "expected" far west into Minnesota; however, some records further east do exist.
August
September
Molt into a first winter plumage, with new adult-like gray mantle feathers, happens quickly in the late summer and early fall.
October
Franklin's Gulls are not an expected species in the Great Lakes; however, large numbers may be blown into our region by powerful fall storms during their peak migraotry season in October and November.
November
December
Isolated individuals, usually in first winter plumage, can be found in early winter; however, they are generally not expected to overwinter.
January
February
March
April
Franklin's Gulls migrate to South America for the winter, where they undergo a complete molt (including flight feathers) which is unlike all other local gull species. The above bird represents an anomalous individual that has retained it's older "first winter" feathers. "First spring" Franklin's Gulls are expected to look like the individuals below:
May
Rarely, "first spring" Franklin's Gulls may show signs of an incomplete winter molt - such as the bird below showing some retained outer "juvenile" flight feathers. This individual from June in Ontario appears to be particularly behind in its molt.
Second Cycle / Adult
The change from first to second cycle depends on the timing of the start of the inner primary molt. May/June is used here as an inaccurate / arbitrary cutoff.
"Second cycle" Franklin's Gulls are still detectable throughout the summer as they molt (e.g., June, July, August); however, they soon lose their distinctiveness. As such, only full adults are shown below.
One further caveat involves an "adult" Franklin's Gull photographed in Indiana in October 2017 that appears to be in a "second cycle" type plumage, with dark markings in the tail and coverts (which would be expected in a species like Laughing Gull). Perhaps isolated individuals, that possibly overwintered in North America (?), advance slowly and/or follow a once-a-year full molt cycle unlike their brethren that migrate to South America?
June
July
August
September
October
November
December
Out-of-season birds may be more likely to be in an atypical molt/plumage, such as the bird on the far left below.
January
Very rarely, adult Franklin's Gulls in full "breeding" plumage, appear in the Great Lakes in winter. It is likely that these birds have somehow "reversed" their biological cycle - perhaps somehow influenced by their migrations to South America.
It is also very rare that delayed (sick or injured?) adult Franklin's Gulls can be observed into mid-winter in the Great Lakes in their "winter" plumage, such as the individual below.
February
The differnece between "anololous winter record" and "early spring migrant" starts to blur by mid to late February.
March
April
May
It's not uncommon for spring Franklin's Gulls to show a pink wash to their underparts.
An interesting example of an "adult" Franklin's Gull with an incomplete winter molt is shown below (note the older retained outer primaries).