Urban Birds Are Evolving to Be Fed | Hacker News Reader

Urban Birds Are Evolving to Be Fed

theatlantic.com

104 pointsnz37 comments

Tl;dr - birds that eat at feeders a lot are evolving beaks that are better suited to eating the sort of nuts that people put in such feeders.

That wrapped in a tale of angst about conjunctivitis, losing touch with nature, and change in general.

I did look up the bird feeders that are inset in your window frame to allow for better visualizing. They are pretty cool.

I had one of those inset bird feeders. They work, but being in a urban environment I ended up attracting pigeons...

My cat loved the one way plexiglass in the feeder and would watch the birds seated on back of a chair. The birds really can't see through it.

The title is a little disingenuous: the author concludes that while city birds are evolving to be fed, it's not necessarily detrimental as studies show that birds constantly seek backup food sources.

Interesting article nonetheless and it certainly makes me reconsider my own bird feeding practice. It's been years at least, since I gave bread to ducks - I'd love nothing more than to see permanent signs at lakes and ponds pointing out how bad bread is for ducks.

https://www.popsci.com/feeding-ducks-bread

In larger sense, if fed birds are more successful, it affects the distribution of species (favouring fed part of the ecosystem). Not that it's necessarily a bad thing, and city environment does that anyway.

The article does mention how their beaks are changing to better retrieve and eat the larger sunflower seeds commonly found in feeders.

and as usual with any news headline involving evolution, it's worded the wrong way round. It should say something like "Fed urban birds have tended to survive more" i.e. looking back, not looking forward as though birds are capable of intentionally changing the genes of future generations

>White bread in particular has no real nutritional value

I've never understood this claim that a lot of people seem to make. There's plenty of starch and protein in it, two vital macronutrients. Same with the bizarre claim some people make about breakfast cereals, that you're better off eating the box it comes in. No, you're not, humans cannot digest cellulose.

If you consider that the cereals are made of wheat and corn that with traces of pesticides, sugar, synthetic ingredients, and so on, all of which cause health problems, the cardboard box starts to seem more appealing.

considering i ate almost entirely cereal growing up and was much healthier than most of the people i grew up with, that claim is not worth its weight in font.

One data point? Are you sure most of the people you know were eating healthier than you?

One is more than none.

One is a data point. You can draw any line you feel through it but that doesn't mean it's a trend. You need more data.

It wasn't an argument about a trend. The question of whether you can drive a car by filling its gas tank with cola instead of gasoline is answered after you fill a car with cola instead of gasoline, then drive it. There's no need to establish a trend.

yes, having 0 nutrition would mean that i could not have possibly survived. and if you want to be in the group that thinks eating indigestible cardboard is a possibility because 'there wasnt enough data', have at it.

you do realize, you dont need a ton of data in everything to draw conclusions.

Yeah... the cardboard not made for consumption is definitely safer.

> ...made of wheat and corn that with traces of pesticides, sugar, synthetic ingredients...

Have you looked at what is in most of the things that are on grocery store shelves?

> ...the cardboard box starts to seem more appealing.

You go ahead and eat a cardboard box every morning for breakfast for a week and tell me how much better it was than a bowl of cereal. I'll wait.

Aaaand have you considered all the shit that might be in that cardboard?

In the context of the article, I'm pretty sure this relates to nutritional value for ducks, not humans. Birds and people can eat a lot of the same food but our metabolisms are optimized very differently. I read one article that compared raising horses on a diet of corn to raising children on a diet of chocolate. After all, horses' metabolisms are optimized for extracting nutrition from grass. I would imagine ducks are on the opposite end of the spectrum.

It's more about having enough fiber, chewing and overall time spent eating (which is good both for their intestinal tract and their wellbeing) than about extracting nutrition from grass.

Sure, I don't dispute the health risks of excessive starch and sugar consumption for either ducks, horses or children, but the nutritional value of starch and sugar is very real indeed. Animal cells rely on glucose as their primary source of energy, you can't get more real than that.

I get what they intend to say, but when they use categorical language like that at least one word has to yield its actual meaning, whether it's 'nutrition', 'real' or 'value'. It's a bit like the Clintonian interpretation of 'is'.

You're making an assumption that because glucose is part of the process, it is essential to ingest it through sucrose, fructose, starches, etc. For humans at least, this isn't really the case as it's possible for the body to produce glucose from fat and protein when no polysaccharides are being ingested, and function normally and indefinitely doing so. Without water, vitamins, sodium, iron, etc., the body will experience problems it cannot compensate for.

Starch(in general) is considered a nutrient, but not because it can be used to produce glucose.

>You're making an assumption that because glucose is part of the process, it is essential to ingest it through sucrose, fructose, starches, etc.

No, that's not what I'm assuming or implying.

I'm saying because starch is a highly efficient source of glucose, it has nutritional value.

Nobody who are saying citrus fruits have nutritional value because they are high in vitamin C are implying it's essential to ingest vitamin C through citrus fruits. You can't blame a lemon for not being the exclusive source of vitamin C, neither can you blame white bread for not being the only way to increase your blood sugar.

>Starch(in general) is considered a nutrient, but not because it can be used to produce glucose.

What else is it good for but to be converted into glucose?

"nutritional value" is shorthand for "practical nutritional value in this context"

Chocolate is actually a surprisingly good food, being one if the few providing carbohydrates, protein, and fats all by itself.

It’s obviously not advisable for a regular diet. But in a strNded-on-an-island scenario, you could easily survive on chocolate alone for years.

Bathroom time must be interesting.

One of my friends found a whole carton of chocolate eggs while dumpster diving at college, and spent his break living off of the eggs.

> you could easily survive on chocolate alone for years

Seems like quite an extreme claim. I'm not disagreeing, I simply don't know, but is this surviving with no ill effects (rickets for example) or surviving in the sense of just being alive?

Do you have any references?

I suspect it would be "just being alive" because I imagine eating chocolate alone would come with a whole host of other problems over a long period of time (including scurvy). I'm not sure vitamin D deficiency would be an issue if you were stranded on an island with limited shelter.

However, there is something to be said for chocolate's nutritional value in special circumstances. Most modern military rations include chocolate or chocolate-flavored items in some form as a significant part of their caloric value (predominantly fats and carbohydrates, even for the flavored items, as your OP mentioned). Aside from its propensity to melt, its size and weight make it somewhat convenient to carry on patrol and for lightweight rations, calorie-dense items are important.

I'm sure there's probably some literature on its use in rations that may be a good starting point, but as far as I remember from watching far too much Steve1989 on YT [1], most of the historic survival rations--think plane crashes--tended to rely on candy, malted milk tablets, or compressed oatmeal/cornflake bars rather than chocolate.

I've linked his channel below because I think you might find it fascinating.

[1] https://www.youtube.com/channel/UC2I6Et1JkidnnbWgJFiMeHA/vid...

My favorite park has signs all along the water, warning people not to feed the animals, but they use an image of an alligator for the signs.

I think you missed the part about how feeders contribute to the spread of disease like conjuctivitis.

The authorities where I live are trying to dissuade people from feeding birds, due to a rat problems, and instead focus on putting out clean accessible water or growing bird-atttacting plants.

I couldn't help but think of "Pigeon House" [1] in Stoneybatter, Dublin, renowned among the city's residents for the roost of pigeons that sit on its roof [2] waiting to be fed, and by the locals trying to avoid them.

https://www.dublininquirer.com/2017/11/15/in-stoneybatter-am...

https://twitter.com/ciarancuffe/status/689492575460421632

A dozen paragraphs in, still no sign of what the title claims, only storytelling about the author's life.

Can anyone that read it summarize or copy the actual "birds are evolving to be fed" part?

So when one of Badyaev’s undergraduate students, Clayton Addison, noticed that the male finches on campus in central Tucson were not singing a rapid trill that’s essential for attracting females in the nearby desert, the lab was able to dig into the data for answers. Comparing the beak sizes, bite forces, and diets of the two populations, the researchers showed that the urban finches rely so heavily on feeders that their beaks have adapted: they’ve become longer and deeper to accommodate the sunflower seeds typically on offer, which are much larger and harder than the small cactus and grass seeds that rural finches eat. This adaptation has altered not only how urban males sing, but also what urban females prefer in a mate. It’s a pattern that Badyaev has since found in other places where finches live in the shadow of humans, the same large beaks arising from a surprisingly diverse array of developmental pathways. Such varied routes to an identical end—a beak strong enough to crack sunflower seeds—may be one way that nature hides variability from the swinging axe of natural selection.

Evolutionary theory aside, however, I was stuck on one point: There’s such a thing as a finch Brooklyn accent—thanks to feeders like mine.

My neighbor maintained a bird feeder which brought in tons of different species. He moved and we're back to sparrows / pigeons / redwing blackbirds (summer) and the occasional crow .

Ironically the birds I was most enjoyed watching at the "bird feeder" were the red wing hawks that would sometimes come in for a meal

Number of times I've seen something pretty amazing. Here in Portland I've seen little birds, like sparrows, picking and eating squashed insects from front bumpers of the cars. They just fly up and pick those insects that stick to cars when cars drive at night.

Maybe we can learn to cultivate tick and mosquito hungry birds.

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