Episode 42: Eat the Invaders & Ask Sam Round-up

This week we attempt to not only eat the invaders, but drink them as well. And this time, most of us were on board. Also, the Ask Sam hotline gets some attention as Sam answers questions about bird feeders, black flies, storm clouds, and dew.

Eat/Drink the Invaders

If you have Japanese knotweed in your yard, chances are you curse at it, hack away at it, do anything to try and kill it. But we thought we should at least *try* to eat it, and we found a guy who even found a way to drink it. Plus we put some in between two slices of bread which was weird, but not that weird.


Ask Sam Round-Up

Since we launched the toll free version of our Ask Sam hotline, 1-844-GO-OTTER (844-466-8837), people have been calling day and night with all manner of questions for Sam about the outdoor world. This time we talk to two different Sarahs (Saras? Or is it Sarah and Sara? Or vice versa?) one about birds, the other about black flies. Then Sam answers a question about thunderstorms and the clouds that accompany them, plus uncovers the mystery behind dew. So pop some popcorn, settle in, and get ready for the Ask Sam round-up.

Question 1: Sarah from Albuquerque, NM asks:

"I have a lot of bird feeders in my yard and I really like to watch the song birds, and my indoor cats chatter at them through the window. But a co-worker told me that feeding the birds, even if it's high quality bird food is actually harmful for them, because it makes them stay in places longer then they normally would if they are migratory, that it disrupts their natural diet. So is that true? Am I hurting the song birds in our eco-system by putting out bird feeders? Tell me if I'm a bird killer or not."

This is a question that has preoccupied the “don’t mess with the ecosystem” wing of the environmental movement for a long time. And there are three concerns:

1. Are We Messing With Their Migration?

Are we encouraging birds that should be migrating to stay in place, when they should be migrating? We’re worried about this because if they leave their summer range too late maybe they will suffer later in their migration: starve to death… freeze to death… get eaten by winter weasels… something. The counterpoint to this concern is that birds likely start migrating based on the change of the seasons—shorter days, colder temperatures—not availability of food.

2. Are They Getting More Diseases From Hanging Out At the Feeder?

When birds are all packed together because they’re clamoring to get these delicious seeds and nuts, are they then transmitting diseases to each other that they wouldn’t normally get? The worry here is that disease might lead to higher mortality than if the birds had to fend for themselves.

3. Are We Making Them Dependent Upon Us For Food?

Finally, what if you feed birds religiously for years, and then you move away or are kidnapped by pirates and suddenly the bird feeders vanish? Will the birds be dependent on you feeding them and not know how to feed themselves while you’re away?

Thankfully this question has been studied. (Thank goodness for science, or else we would have to call this segment “How the Hell Should Sam Know?”) The study that I found that seemed to best address the first two concerns was done using data from something called Project Feederwatch, which used data from backyard birdwatchers to assess the state of bird species that regularly hang around bird feeders. Think about it, if feeding birds were causing them to die while migrating or die from disease, you would expect the populations of the birds that eat at feeders to decline… right? Because it’s bad for them, right?

But that’s not the case, usually they’re doing just about the same, or maybe slightly better than the birds that never visit feeders.

And on the last point: do birds get dependent on feeders? This was tested twice on chickadees in Wisconsin and Pennsylvania. They set out feeders for a whole bunch of chickadees and then after two years of feeding them, they took the feeders away.

The result? No effect. Chickadees in the areas that lost their feeders and the ones that kept their feeders had the same survival rates.

So, are you a bird killer? All evidence points to “No.” For now, feed with a clear conscience!


Question 2: Sara from Dunnsville, VA asks

"I have several friends who have hiked the Appalachian trail, thru-hik ed it, and another friend who's about to start, and she's starting up in Maine in June and we were talking about how she needs to get a head net to protect herself from all the black flies in Maine and in other parts of the Northeast. So my question is, why are black flies such a problem up in the Northeast, but they're not really problematic at all down here in the south?"

I love this question so much. I used to lead Wilderness Trips up in this region and I remember evenings when the black flies were so bad that we would spend the whole afternoon cowering in our tents, or cook dinner swathed in rain coats and rain pants even in the middle of summer. I remember a camper who had never been exposed to black flies before, was bit so many times her eyes nearly swelled shut the next day. So if you’ve never experienced a proper black fly swarm, be warned: when it happens, it’s intense and terrible.

The truth is, as Elmer Gray of the North American of Black Fly Association told me, there are black flies in the south, but there aren’t swarms of them. In places where the winters and therefore the streams and rivers are colder, the black fly season is short and concentrated. This is because the cold slows the development of the fly larva, and makes it so that the flies can only lay eggs once per year (they are “univoltine”) instead of the black flies in warmer parts of the world that can develop faster and have more than one generation per year (“bivoltine” or “multivoltine”).

In other words, we cram an entire year’s worth of black flies into one, three-week long, black fly season, as all of the black flies in the region race to come out from the rivers, find something to bite, and then mate and lay eggs so the next generation can start to mature again as quickly as possible, and do it all again the next year.

And if you start the Appalachian Trail in reverse in June, you’re headed straight into the belly of that beast. Oh, and haven’t you heard? Less river pollution means black flies are doing better than decades ago. Steel yourself.


Question 3: Margie from Concord asks

"A couple of years ago, I started noticing that the clouds just seemed enormous, just towering high. And maybe they're the same as they always have been and always will be, but my first thought was: 'There go our icebergs.' I just wondered if there is any connection between icebergs melting and cloud formation, height of clouds, volume of clouds."

Those clouds that you’re referring to are called cumulonimbus clouds: they’re the big piles of clouds shaped like anvils that create lightning storms, and while there are several ways these storms can form, the most important ingredients are hot air mass rising up through a cold air mass in a process called “convection.”

Now the question of how will climate change effect clouds is a very, very complicated one that is being worked on by lots of smart climatologists creating detailed and complicated climate models. But in general terms, the thing to remember is that warm air can hold more moisture, and so it’s a safe bet that a warmer globe will mean more clouds.

Now at the same time, we have an observed that here in the Northeast, over the past 50 years or so, the number of rain storms that drop 2 inches of rain in 24 hours have increased by 71%. And not only that, but Jonathan Winter, a Dartmouth climate scientist has looked at this data and recently found that most of this increase came in one large “step” that occurred mostly all around the late 90s. That sounds like the kind of thing that someone like Margie would notice!

Winter says a lot of these extreme rain events were in the summer, so it’s a good bet that a good chunk of them were these “convective” (*ahem* thunder) storms. BUT, his next study is to look more precisely into what kind of storms are on the rise. So we need only wait until that study comes out to answer Margie’s question for sure.

Now… are those clouds *actually* our icebergs? Meh, who knows.


Question 4: Emily from Tuscaloosa, AL asks:

"I'm a preschool teacher and I was taking my kids out onto the playground this morning, and we always have to check to see if the playground is wet, and since we go out so early, the ground is always wet because there's dew on the ground. I was just curious as to what causes the dew, because it can not rain overnight, and I know it has something to do with a drop in temperature at night, but what cause dew to fall down on our ground." 

This is one of those questions that I really like because answering it helps you to understand one of those fundamental properties of the world that shapes all sorts of little things that affect you.

So, for starters, there’s water in the air, and some days there is more water than other days. You know this as humidity. However, that dew exists flows from a single fact: the warmer the air is, the more water that air can hold.

Maybe you’ve heard of the “dew point” in some weather forecast or another. The dew point is the temperature at which dew will begin to form in the overnight hours. So say it’s summer-time in Alabama and the air is warm and humid. But then the sun goes away and that warm air starts to cool. Eventually it will cool so much that it won’t be able to hold all that water, and some of it will fall out (or precipitate!) as dew!

Graph of Dewpoint vs. Air Temperature at Varying Relative Humidities. Based on the Magnus-Tetens approximation.

Graph of Dewpoint vs. Air Temperature at Varying Relative Humidities. Based on the Magnus-Tetens approximation.

So what does this mean for your life? It means when you see a high dew point, you know that the air is pretty full of water and maybe you’re gonna want to turn on the air conditioner, or if it’s insufferably humid, you know that will be a bad night to sleep outside, because you’re going to get absolutely drenched.

Oh, and also! Once you know about dew point, you’re equipped to understand another weather number: relative humidity. When you see a relative humidity of 100%, that means you’re right at the dew point, the air can hold no more water, and water is condensing out of the air and evaporating into the air at exactly the same rate. This number is “relative” because it takes less water to fully saturate the air at lower temperatures, so 100% relative humidity when it’s 40 degrees out won’t feel particularly swampy.

What other ways does this knowledge help you? Why do your glasses get foggy when you walk inside in the winter? Moist warm air hits the cold glass and the moisture falls out all over your lenses. Why does your cold beer get covered with condensation? Warm air hits cold beer. Why is there frost on the inside of your window? I could literally keep going all day with these.


Outside/In was produced this week by:

Sam Evans-Brown, with help from, Maureen McMurray, Taylor Quimby, Molly Donahue, Jimmy Gutierrez and Logan Shannon.

If you’ve got a question for our Ask Sam hotline, give us a call! We’re always looking for rabbit holes to dive down into. Leave us a voicemail at: 1-844-GO-OTTER (844-466-8837). Don’t forget to leave a number so we can call you back.

Our theme music is by Breakmaster Cylinder

This week’s episode includes tracks from Podington Bear and Ari De Niro Check out the Free Music Archive for more tracks from these artists.

Outside/In is a production of New Hampshire Public Radio.