Sunday, February 24, 2019

Common Merganser

Due to this Common Merganser’s barred sides and white wing patch, I believe this bird may be a male in basic (winter) plumage. On the other hand, I think by this time of year, mergansers should sport breeding plumage. This duck is, regardless of its sex, my first spring migrant. A pair appeared at a local Northfield pond on 22 February 2019. The birds shared a very small patch of open water with at least 55 Mallards. 

1 comment:

  1. A drake Merganser would be in eclipse (which is considered alternate, not basic) plumage from early summer into autumn, not this time of year. The white patch should be there in all plumages including first-winter, but drakes have white tertials (even in eclipse). Perhaps this could be a first-winter drake, but some of the flank feathers would be vermiculated, while these just look really worn. First-winter hen is a good possibility, and I see that first-spring birds have a pre-formative molt in February-May.

    I wonder if it might have come from further north. The Mississippi River through the metro area hosts a lot of COMEs through the winter, but the extreme cold has frozen up a lot of locations. Maybe your bird came from there? Would it still count as a spring migrant if it came from the north, retreating from lakes freezing over?

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