McGILL BIRD OBSERVATORY
Seasonal status at MBO:
Ageing and sexing guidelines:
Ageing and sexing details:
Male Common Grackles have glossy plumage over most of their body, but especially so on the head, which often has a purple sheen. Note the especially hefty bill on males. Age can generally not be determined without examining the underwing.
The open upper wing of a male Common Gracklee shows some of the glossy plumage present across the body, especially on the greater coverts. The second photo shows the underwing covert pattern typical of male after-hatch-year grackles, with a contrast between adjacent tracts, but no moult limits within any of them.
Female Common Grackles have the same overall pattern of plumage as males, but it is much less glossy, and the head tends to be mostly bluish, with the purple sheen of males generally absent.
The wing of AHY females is relatively uniform, with some colour on the greater coverts, but usually less so than on males. The pattern in the underwing coverts is the same as on males, though the contrast between the lightest and darkest feathers is not as great.
Second-year males typically appear identical to older males, except for the underwing coverts and occasionally a couple of other retained feathers that are best seen on an open wing.
The upper wing usually provides little information about ageing, although occasionally one or two juvenile secondaries may be retained, recognizable by their pale brown colour contrasting with the adjacent blackish feathers. More frequently, second-year grackles can be recognized by moult limits within tracts of the underwing coverts, as in the second and third photos below.
Second-year female Common Grackles are not reliably separable from older females, but it seems that some are particularly dull in plumage, as in the photo below.
In most cases age is best determined by looking at the underwing, but occasionally (as in the second photo below), there are retained brownish juvenile secondaries that contast visibly with the adjacent adult flight feathers, and these are sufficient to identify a grackle as second-year. As with males, moult limits within the underwing covert tracts also indicate the age as second-year.
As in spring, the largest and glossiest Common Grackles are after-hatch-year males. However, if observed during their body moult, some may have a scruffy appearance with some patches of brown, as in the photo below.
The glossiness of the flight feathers in the photo below is somewhat exaggerated by being taken in the sun, but nonetheless reflects the typical pattern of plumage. There are no moult limits within the tracts of underwing coverts.
As in spring, females are duller than males, with a bluish head and dark relatively dull body. However, if observed during their body moult, some may have a scruffy appearance with some patches of brown.
Hatch-year males may have a variable amount of brown in the plumage depending on the timing of moult. The first photo below is a of an individual fairly advanced in its moult, with a mostly glossy head, while in the second case a side profile reveals that wing moult has commenced, but the head remains entirely brown.
The two photos below illustrate the variability in appearance of hatch-year male wings. In the first case, the greater coverts and most of the median and lesser coverts have been replaced, as well as the inner primaries and primary coverts, which contrast with the paler brown retained outer feathers. In the second case, almost all the wing feathers have been replaced, except for three secondaries. Later in fall, there are often no juvenile feathers retained at all, and the upper wing looks the same as after-hatch-year males. At that point, the only way to recognize hatch-year birds is by finding moult limits within tracts of underwing coverts, as in the third, fourth, and fifth photos below.
Hatch-year females may have a variable amount of brown in the plumage, depending on the timing of moult. The first photo below is of an individual that has begun moulting both its body feathers and wing feathers, while the second is less advanced. However, since after-hatch-year birds may also have a mottled apperance during moult, age is best determined by examining the wing.
Retained brown juvenile feathers on the wing are indicative of hatch-year birds. If present, these most often occur among the outer primaries and primary coverts, alula, inner secondaries, and median coverts, as illustrated by the photos below. In cases where these have all been replaced, check for moult limits among within tracts of the underwing coverts.
Juvenile Common Grackles are largely brown.
© 2002- The Migration Research Foundation Inc.