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A "two year" gull with a frequently identifiable 2nd year plumage. As an uncommon to rare, non-breeding species, numbers can be quite variable year-to-year or season-to-season. Most records involve juvenile-type birds from September through January.
Juvenile / First Cycle
June
July
August
The earliest arrival of juvenile / 1st cycle BLKI into the Great Lakes is early to mid-August; however, this is a rare occurence. Timing and numbers are variable year to year locally as an uncommon / vagrant species.
September
October
November
December
January
February
March
Although the sample size is small, the bill appears to start turning yellow in Feb-Mar.
April
Spring records are much rarer. They may be a mix of rare lingering/wintering individuals or wayward spring migrants from the east coast.
May
In spring, new feathers appear more clean/fresh than worn juvenile feathers.
Second Cycle
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 arbitrary cutoff.
June
Some "first summer" individuals appear sick, and presumably may have a delayed molt compared to healthier birds.
July
August
September
October
These "second year" birds appear much like winter adults. Weaker contrast in the wingtip, messier patterns and extra black in the wing coverts, and duller bare parts (i.e., bill) help identify them from full adults.
November
December
January
February
March
April
May
Third Cycle / Adult
Through their molt into third cycle plumage, BLKI obtain an "adult" plumage for the rest of their lives. Full adults are shown below.
June
July
August
September
October
Full adults are much rarer than juvenile birds, yet they follow a similar pattern of occurrence with most records in Oct-Jan.
November
Bright yellow bills, and clean/contrasting primary patterns identify full adults compared to "second year" birds.
December
January
February
March
April
Breeding plumaged adults obtain a clean white heads and bright bill colouration.
May
Breeding plumaged adults are quite rare locally; however, an east coast storm in early May 2023 brought several adults into the Great Lakes.
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