So, a robin built several nests in my carport, but only laid eggs in one of them, the middle one in the photo. They hatched about nine days ago. As you can see, the mother is not roosting in the middle nest, but that’s still where her hatchlings are. You can’t see them in the photo, but I saw them moving around in there. Is this normal? Does the mother just need her space or is she confused somehow, perhaps by the repeating joists? Is that why she built multiple nests to begin with?

If there’s another community where you think people might know better, please suggest it.

Update: all is well, apparently.

  • The_Empty_Tuple@kbin.social
    8·
    1 year ago

    I’ve had some experience with seabird and waterfowl nesting research so this caught my attention. I haven’t come across anything like this personally, but I’ve only ever worked with larger birds with higher nest building costs and greater territorial behavior across seasons.

    Apparently this is a common behavior with some bird species, and it’s baffled scientists for a while.

    I managed to find a specific explanation for American Robins (excerpt below). I can’t guarantee the validity of this author’s ‘supernormal stimuli’ explanation, but it’s a compelling one:

    A. This is a question we hadn’t been asked before, so we wrote to Len Eiserer, the author of The American Robin: A Backyard Institution. Len answered:

    "Building multiple nests simultaneously happens every now and again with robins. One started 26 different nests on roof rafters of a garage under construction; another built 8 on successive steps of a fire escape. Support from underneath is the primary site selection factor for the female robin — it’s more important than concealment. Because some human structures provide repetitive sites with strong support, the female can get seduced into building multiple nests.

    This is an example of “supernormal stimuli” — artificial stimuli that are even more effective than those provided by Mother Nature (tree limbs). Animals have a hard time resisting supernormal stimuli. There are many examples. Your robin will probably settle on one site and just lay eggs in that nest, or else just incubate eggs in that nest after laying, say, one egg in one nest and two in the other. She won’t lay two complete sets of eggs and try to incubate both of them at the same time."

    • CrimeDad@lemmy.oneOP
      3·
      1 year ago

      I can see your reply just fine, and the supernormal stimuli explanation mIakes sense. Also, I think I found my answer here:

      Q. Why has the mother stopped sitting on the nest at night?

      A. By the time the babies are about a week old, the nest is getting crowded, and the babies are capable of keeping themselves warm, all snuggled together. At this point the mother robin starts sleeping on a tree branch again.

      Like I said, the chicks are about nine days old, so the mother’s behavior appears to be normal. That’s a relief!