Friday Sprog Blogging: adaptive strategies.


Younger offspring: The bad thing about all the Canada geese on the fields this summer is that the fields have lots of goose poop.

Dr. Free-Ride: Well, geese gotta poop.

Younger offspring: I don't like stepping in goose poop when we're playing soccer.

Dr. Free-Ride: I can understand that.

Elder offspring: The Canada geese look like they mostly eat grass and weeds. There are other birds that eat lots of berries, and their poop is pretty nasty.

Dr. Free-Ride: It's true that it's not fun to be pooped on by a bird that's just eaten a lot of berries. But it's a good deal for the berry bush.

Younger offspring: How?

Dr. Free-Ride: Think of the berries you've been eating all summer. What do they have a lot of?

Younger offspring: Seeds.

Dr. Free-Ride: And what happens when critters like birds eat those seedy berries?

Younger offspring: They poop out the seeds.

Dr. Free-Ride: Sure, but probably not right away.

Elder offspring: They fly for awhile first and then poop out the seeds.

Dr. Free-Ride: Uh huh. And why is that a good deal for the plant that grew the berries?

Elder offspring: Because then the seeds can grow far away from the original plant -- farther away than they'd grown if the berries just fell off the plant -- and there will be more berry bushes growing in lots of other places.

Dr. Free-Ride: A tidy little plan for world-wide domination.

Younger offspring: Do the berry bushes want their berries to be eaten?

Dr. Free-Ride: Well, they don't have brains, so I don't think they want anything. But it does help the survival of the berry bushes to have critters spreading their seeds to lots of other places they can grow.

Elder offspring: There are some plants where the fruit is poisonous, though.

Dr. Free-Ride: That's true.

Younger offspring: It wouldn't be good for animals to eat poison fruit, so animals couldn't help spread the seeds from those plants.

Dr. Free-Ride: Hmm. Is there any way that it could be a good deal for the plant to be bad to eat?

Elder offspring: Maybe if the plant is poisonous, it won't get eaten by animals before it's done growing and making its seeds.

Dr. Free-Ride: So being poisonous or yucky-tasting could be a protection from predators.

Younger offspring: Seeds don't always need to spread in poop. Some can spread in the wind, and some can get stuck on your clothes and follow you home from the woods.

Dr. Free-Ride: So it sounds like maybe the plants that do really well have ways to spread their seeds to other places, but that different plants have different strategies for doing it.

Younger offspring: Plants have strategies?

Dr. Free-Ride: Well, since they don't have brains, they don't really plan what they'll do. But the plants that have reliable ways to get their seeds out there are the ones that are still around.

Elder offspring: Being tasty seems like a good strategy for plants but not for animals.

Dr. Free-Ride: I guess. Unless the animal only became tasty after having offspring ...

Elder offspring: Some things are tasty and hard to get to.

Younger offspring: Like honey!

Elder offspring: And artichokes. Is it a good deal for the artichoke plant if the artichokes get eaten or not?

Dr. Free-Ride: Well, humans cultivate artichokes. If the first human who ate an artichoke and thought it was tasty hadn't fought her way through all the prickly parts, who knows if there would still be artichoke plants.

Elder offspring: Humans seem less reliable than birds.

Younger offspring: (With a serious look) So when we eat berries, we poop out seeds too?

Dr. Free-Ride: Yep.

Elder offspring: Do you think there are lots of berry bushes growing in the sewer system?

Dr. Free-Ride: I'd be kind of surprised if there were.

Younger offspring: I wouldn't want to pick those berries.


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I Hate Canadian Geese for pretty much the same reason that your Younger Offspring mentioned! If their strategy is to increase Goose Haters, it's a very successful plan. And it's working.

Can we PLEASE take them off the Federal Protection list now?
(If your sprogs ask nicely and draw pictures, will the gov't listen to them, more than me?)

Re examples from the animal world: mama bird acting like she's tasty in a ploy to lure predators away from her nest. While I might ordinarily say that's different than BEING tasty, my dog has caught a bird that was running that ploy. So it isn't just a pretense at tastiness -- sometimes they actually do end up being tasty.

(Re the bird my dog caught: we intervened and rescued it.)

Canadian geese are puzzling in that they seem to be utterly recognizable as Canadian. Humans from Canada, in contrast, can blend in undetected ... which might make them much more of a threat.

I wonder if another (human) generation or two of Canadian geese being the most commonly seen goose in the US will transform them into just "geese". Verily, then the fowl poopers will have won.

It's good for a kid to have a smart mom.

Janet - Here's how you can ALWAYS tell a Canadian Goose - They always want to play hockey, and they always say "aboot", when they mean "about". They are usually polite, but gosh darnit, they need to evolve Depends, or Pampers!

Dr. Free-Ride: Well, geese gotta poop.

Hey, isn't that a line from a jazz song?

Fish gotta swim,
birds gotta fly,
geese gotta poop


It's "Canada" not "Canadian" goose. The latter is any goose of any species living in Canada.
J-Dog, only a few subspecies of Canada goose are protected - Aleutian and dusky on the West Coast, maybe one or two others elsewhere.

Geese crap in large volumes for the same reason horses do: they process a foodstuff with very low nutritional value, that is, grass, which is perforce based on economy of scale. Pretty amazing when you think about it; flying animals generally use food with a high caloric/nutritional value for the same reason aircraft are fueled with petroleum products instead of wood. Only relatively large birds can use grass as fuel efficiently, which is why geese are bigger than ducks.

It's surprising that other than parasites, basically no animals use the berry strategy to disperse their eggs/offspring/propagules. Freshwater mussels have glochidia larvae that attach themselves to fish for dispersal, for the same reason a stationary plant uses a bird to disperse its seeds. Glochidia however attach themselves to gills and fins, and are not eaten by the fish. Perhaps only autotrophs can spare the resources to make a "fruit" attractive to animal dispersers. You'd think though that there would somewhere be an animal living in some particularly rich environment that would do so.