Rosie is Dorothy!

March 8, 2021 • 9:15 am

After careful comparison of bill patterns between Honey’s companion this year—a hen we called “Rosie”, or “Rosalind” (after Rosalind Franklin)—and the patterns of Dorothy’s bill last year, the members of Team Duck concur in judging that Rosie is actually Dorothy, and has returned with Honey this season.

You can be the judge (for yourself), but we declare that the two hens here now are Honey (fifth season) and Dorothy (second season).  As you recall, Dorothy and Honey bred within two days of each other last year, and there was a huge kerfuffle in the pond, with Honey eventually absconding with all eight of Dorothy’s ducklings, giving herself a brood of 17 (all fledged). It was sad for Dorothy, and Dorothy used to walk around the pond, disconsolately quacking for her brood.

And then, mirabile dictu, Dorothy RE-NESTED, sitting on her eggs for another month (a total of two months without much food or water), producing a brood of seven babies (one went missing). The six survivors all fledged, and Honey left them alone because of the age difference of the broods. Dorothy’s tenacity and determination endeared her to all of us, even if she was a pretty lousy mom at the beginning, abandoning her babies for an hour at a time. (She improved greatly after that one duckling disappeared.)

So, here are the photos of Dorothy’s bill. There have been more changes in the pattern than have occurred in Honey, but not enough changes, I think, to efface Dorothy’s identity.

Last year: Dorothy, right side of bill:

Last year: another shot of the right side. Note the prominent dot directly below the right nostril, a smaller dot at about 7 o’clock to that one, and a faint pair of dots right below the nostril.

Dorothy, left side of bill, last year: There is a pattern of speckling below the nostril, both fore and aft.

“Rosie”, right side of bill, this year (a few days ago!). The same irregular dot is below her nostril (that’s why she was named “Dot”, or “Dorothy”) as well as the faint dot to its lower left and two faint dots right below the nostril. Note as well the darker patch curving around to the right in front of the dot, which Dorothy had last year.

“Rosie,” another shot of right side of her bill this year:

“Rosie,” left side of bill, this year:

The dots on her bill are more visible here, but note the one below her nostril toward the head, and the one above that (barely visible in picture below but visible above). Those appeared on Dorothy’s bill last year.  The general pattern of dark shading also matches. No other hen comes even close to having a bill like this.

I don’t believe this is wishful thinking; the pattern is similar among years and no other hen has a pattern like this. Ergo, the provisional but strong conclusion is that this is Dorothy.

This raises several questions:

a). I don’t think Honey and Dorothy left at the same time last fall, though I can’t be sure. But if they did, did they migrate south together, or simply stay in the Chicago area? If the latter, why didn’t either of them visit the pond in the winter when many ducks showed up sporadically (I checked bills when they did)?

b.) If they migrated South together, how did they manage to stay together during both flights and during the winter season?

c.) Will they both breed this year? I’m pretty sure they will, as I’ve seen Shmuley, the drake, mate with both of them. And if that happens, will they produce ducklings at about the same time? And if THAT happens, will Honey kidnap the ducklings again?

There is much to ponder here, but it seems clear that these two hens are bonded, something I didn’t know happened in mallards. They are always together—just as they were always together last year until they separated to breed on different window ledges. After that they were not BFFs any more! Ducklings change everything.

What this also means, of course, is that it will be an interesting duck season, with lots of ducklings in our future.

27 thoughts on “Rosie is Dorothy!

  1. Good grief! Botany Pond really is the best soap since er… Soap! Talk about “Confused? You will be…”

  2. They are bonded… for now. But other instincts will override that of course. I wonder if there is a way to get them to brood at different times. Just several more days difference between them might make all the difference.

  3. How nice to have more repeat visitors! A tribute to your attentiveness and your tasty duck morsels.

    I think both ducks independently returned to their previous home territory; that’s what ducks do. No need for them to have stayed together during the winter, or to have migrated together.

    1. But how did they find each other? Did they just meet by accident when they both came to the pond on the same day? And, if that’s true, did they recognize each other from last year as friends?

      1. If I had to guess, the answers are yes and yes.

        It seems unlikely that they would stay together for an entire season. We don’t really see ducks stay in tight-knit groups of adults, as far as I know. They don’t leave Botany Pond on the same day, right? And, we assume, they have no way of locating each other once separated.

        It is also my guess that they recognize each other. Animals that have friends, enemies, and chosen mates would need to have that ability. I wonder if they use dot patterns on their beaks to do this.

      2. Animals surely recognize each other; parrots recognize their owners, crows recognize people who have been mean to them in the past, hawks in falconry recognize their trainers.. I am not sure how long they “remember” but a few months doesn’t seem unreasonable.

  4. Is the pattern on the bill of a mallard hen unique to her, like a finger print, I wonder? If so, perhaps a searchable database could be created that could track their whereabouts, as an alternative to banding.

  5. “Like sands in the hour glass, these are the days of our lives….. ”
    I shall be checking in daily to the Duck Soup Opera. There’s never a dull moment with those two Madames Mallard in town. Best thing on the intarwebs!

  6. Forgive me if Professor Ceiling Cat has answered this before and I just missed it, but is there some explanation for *why* a duck would “steal” another duck’s brood? Is it somehow adaptive, or is it just a behavior that doesn’t happen often enough and/or isn’t sufficiently maladaptive for natural selection to have eliminated it?

    1. The answer: I don’t know if Honey stole the brood or the ducklings gravitated to her more as the dominant hen. Unless Honey and Dorothy are related, there is no advantage, and a palpable disadvantage, of adopting another duck’s brood (unless there is random predation on ducklings). It happens with other waterfowl in nature as well, as Bruce Lyon tells us.

  7. Dorothy used to walk around the pond, disconsolately quacking for her brood.

    I can’t say that I’ve been following the soap opera on Botany Pond terribly closely (does the Pond have an eponymous Bay, I wonder?), but since the players have clearly done King Lear (“How sharper than a serpent’s tooth it is / To have a thankless child!”), what are they working on this year? The Tempest? The Scottish Quack? Taming of the Drake? Two Drakes of Verona?

  8. What makes you say they’re bonded to each other? Isn’t the evidence equally consistent with the hypothesis that they each think Botany Pond is an excellent breeding ground (which, what with free food and all, it is), so much so as to overcome any resistance they might otherwise have to sharing it with another hen?

    1. They are always together, as they were last year, swimming about with ech other and the drake. There are other hens there, too, but none of them behave like this. Your “alternative” hypothesis does not account for the data.

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