Bufflehead courtship

November 26, 2018 • 2:30 pm

Buffleheads (Bucephala albeola) are cute diving sea ducks that have a pronounced sexual dimorphism, especially in the breeding season. Here are the males vs. females from the Cornell bird site. This will help you pick out the sexes in the video below. 

The video shows a group of bufflehead males trying to impress a few females. Note that the male display includes a lot of elements that demonstrate vigor, like head-bobbing, wing-flapping, and racing (in one case a female appears to incite a male to race). It’s hard to avoid thinking that females are looking for the most vigorous males, because those males have fewer parasites to transfer during mating (males have no parental care in this species), because the males have “good genes” that can be passed onto offspring, or a combination of these “direct” and “indirect” benefits.

But if female choice is basically random, as Richard Prum suggests, and has nothing to do with the genetic composition of the male, why are the most vigorous males always the ones who win? I suppose you cold say that they’re simply more conspicuous, but I don’t think so. These males are showing off a lot of different aspects of vigor, and the females are watching them closely before making their choice.

Anyway, enjoy the show!:

This is the 18,999th post on this site!

25 thoughts on “Bufflehead courtship

        1. Believe me, Mr Kukec: AllYa’All got it !
          Our attentions ! I ‘nd amicis ?

          We were watching YOU !

          ‘nd that high dive platform ? It took me, literally,
          from then at 14, until I was 64 and wanted
          to brag to the grandkiddos but not be l y i n g !
          to finally just climb that frickin’ ladder ‘nd
          … … walk the ‘ell off of it !

          I did ! 50 years … … it took me.

          Blue

  1. I’ve been watching the buffleheads on the Snake River beginning the mating dance. I hope to get a bit of footage.

  2. “Head-bobbing, wing-flapping, and racing (in one case a female appears to incite a male to race” would then be included in the “entended phenotype” and indicating genetic superiority. Prum addresses this issue of the quality of the “extended phenotype” regarding the Spotted Bowerbird (Evolution of Beauty, p. 197). “… there is no compelling evidence that bower decorations are costly, honest signals of male quality.”

      1. It is hard to draw any conclusions from the video, because the camera was not following any behaviours through. Toward the end one female ran down, then out-ran two males, and lost interest in both. My hypothesis: she would be that interested in the male who could beat her, since she has no other basis for comparison. None of the males shown seemed able to achieve that.
        So, a cute video if not terribly useful scientifically.

    1. “there is no compelling evidence that bower decorations are costly, honest signals of male quality”
      But it’s easy to see how they could be. Any time spent away from foraging is costly. Ability to search for and find the right decorations is, probably like foraging success, under selection. Obviously, without testing that, I have just come up with an evolutionary just-so story but there are so many analogous sexual selection examples that it would seem robust.
      I have to say I’m not impressed with Prum’s thesis from discussions I have seen and heard so far but I may track his book down and read it over the (southern hemisphere) summer and see if there is anything worth including in future lectures

      1. Not to mention that any predator with even a little intelligence might learn what a bower looks like and figure out that a tasty (male) bird could be found around one. That is a very real cost, much like the one Peacocks must pay.

        That’s a just-so too, I suppose.

        1. But a valid hypothesis. Even if bowerbirds are not sexually dimorphic – and we know that brighter/more colourful males of many species are more susceptible to predation than are females – their behaviour may indeed still make them more likely to fall prey to a predator. A female would perhaps benefit from a mating with a male who not only makes a nice bright elaborate bower but also manages to avoid all the predators too.

  3. What cute ducks! I love to see animals doing stuff like that. I know it’s a serious business, but it still looks like they’re having a lot of fun.

  4. And we also had a beautiful shot of a Bufflehead drake in today’s RWP by Colin Franks.

    And it is fitting that the 19,000 post will be Tuesday’s Hili Dialogue.

  5. Bufffleheads are a favorite of mine. Do they perform these displays only on the breeding grounds, or do they during migration? They are common in bays and coves in and around NYC during the winter, and I don’t recall seeing anything like this.

    The New York City area is a great place to see waterfowl in cold weather. High latitude nesters like buffleheads, scoters, scaup, mergansers, eiders, looks, and gannets winter there.

  6. As Helena Cronin argues (in The Ant and the Peacock) ultimately decisions about Fisherian selection and good genes sexual selection amount to the same thing because, in the limit, these are all cashed out in terms of differential reproduction and spread of the genes underlying the trait. We might look at some of those genes as being good ones–and thats fine–but we shouldnt get too hung up on that. Ultimately the decisions arent ours to make. I find her argument pretty compelling and Prums to be specious (at best).

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