[CT Birds] King Eider plumage

Greg Hanisek ghanisek at rep-am.com
Thu Jun 25 17:30:08 EDT 2009

Tom deBoor asked an interesting question awhile back about the King Eider at Hammo: If it sticks around will we see a spectacular adult male in full alternate (breeding) plumage this winter? I don't think anyone responded, at least not on the list, which isn't surprising. King Eider molt isn't the easiest thing to grasp. I got sidetracked (you know, by life) and didn't have a chance to check a couple references until now, but there are two parts to an attempted answer. 

One/ The normal distribution of King Eider at out latitude. Basically, although females and immature males occur regularly but rather rarely in southern New England and the Middle Atlantic States, adult males are very rare. We get females/immatures in late fall and winter, but it's also not all that unusual to get an individual like the Hammo bird that turns up in spring and sometimes early summer. These are often young males (born during the previous summer and just going on one year old). The first good bird I found in CT when I moved here in the early 1990s was one of these young males. It was in almost exactly the same place as the one present now. I found it off the big breakwater looking from a vantage point in Clinton and it was later seen as Hammo. It didn't stick around as long as this one. Therein lies one part of the answer - despite the presence of young males here in spring/summer they don't have a history of staying through into the following winter. It will be interesting to see how long this one stays.

Two/ The molt sequence of King Eider. The bird at Hammo is in its second calendar year (born in 2008). It won't attain full alternate plumage until its third calendar year, so even if it stays, it won't molt into a pristine adult. The bird right now is probably in its first alternate plumage, which is described as highly variable. Late in the summer or early fall it will molt into its second basic plumage. That means it will actually get a bit drabber for awhile. However, the species holds this plumage for only a short time. Later in the fall they start to molt into their second alternate plumage, which can approach the look of full alternate. I think the male that was off the Brazos Road area of East Haven a few years ago was in second alternate plumage.

This progession can be a little hard to follow through the written word, but the link below also has a lot of good photos and a nice chart plotting the molt sequence over time.  


Greg Hanisek

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