Thumbnail image: Ryan Shean/Macaulay Library
[Sarah Wagner] All right, folks. We’re almost at the top of the hour. We’ll get started in just a minute. If you want to drop a note in the chat about where you’re zooming in from or tell us on YouTube if you’re watching there. It looks like we have Tennessee, Boulder, Colorado, British Columbia, home state of New York, Chicago, all over. This is fantastic. Folks are still piling in.
All right, we’ll go ahead and get started. Welcome to today’s webinar from the Cornell Lab of Ornithology where we’ll answer all of your bird migration questions or at least as many as we can get to within our short hour we have here. My name is Sarah Wagner, and I’m the public information specialist here at the Visitor Center at the Cornell Lab of Ornithology. And I’ll be facilitating today’s conversation.
With us today is Kevin McGowan, who will be joining us in just a minute. But before we get started, I have a few quick announcements I want to make. For those of you who aren’t familiar with the Cornell Lab of Ornithology, we are home to a community of researchers and supporters from around the world who appreciate birds and the integral roles they play in our ecosystems.
Our mission is to advance leading edge research, education, and citizen science that helps to solve pressing conservation challenges. Today’s webinar is the conclusion of our two-week migration celebration, which is the lab’s largest online event every year. You can check out our migration resources and tools to help you better enjoy and do your own recording of what you’re seeing with migration on our website.
So we’ll drop that link in the chat so you can see past webinars from other migration celebrations and the few that we’ve done for this year’s migration celebration. So check those out. I have a couple of quick technical notes for the audience and then we can get started. Closed captioning is available on Zoom. If you’d like to turn captions on or off, please click the captions button at the bottom of your screen.
For those of you on Zoom, click the Q&A button, and then type your question there. We’ll be answering some questions verbally, and for others, we’ll be typing in responses, which you’ll be able to see in the answer column. So that’s a great resource to check out, and you’ll get some really good information there.
Please only use the Zoom chat for technical support or to share information. I have lots of colleagues on the back end who are going to help respond to Zoom Q&As in the chat. So if you have technical issues, if you’re having trouble with anything related to Zoom, pop those questions into the chat. We’re also live streaming to YouTube.
And if you’re watching on YouTube, you can add your questions to the comments, and another colleague will relay from there. So for those of you who have attended our webinars before, today is a little bit different. We wanted to give you an opportunity to ask your burning questions about migration, especially as we enter that season this fall at least in our part of the world.
Luckily, we have Kevin McGowan with us today. Kevin, you can go ahead and turn on your camera. Hey, Kevin. Kevin not only knows the research and science very deeply, he also has a real knack for explaining it, and he’s a fantastic storyteller. To start, Kevin, thank you for being with us today. And could you tell us a little bit about yourself and what you do.
[Kevin McGowan] Sure. I’m Kevin McGowan. I’m in Bird Academy here at the lab. I write bird courses and instruct people about birds biology and identification and things like that. Basically, I’m an ornithologist. I’ve been studying birds for a very long time. I got my PhD working on Florida scrub jays. I’ve been studying American crows for the last 35 years. And I’m also an avid birder and a total bird head.
I mean, there are few of us around the lab like that. You might imagine that anything bird, I’m interested in. And so that means that I do pay attention to things. Basically I’m not a behavioral ecologist, but I like knowing all kinds of things, physiology and genetics and anything bird is good for me. So that’s why I’m happy to answer all these questions that people are wanting to know about birds.
[Sarah Wagner] Awesome. I’m excited. OK, let’s get started with some of our questions that came in from folks who preregistered So we’ll start with this question from Paula, which should set the stage for us. Why do birds migrate, and what are they searching for?
[Kevin McGowan] People should know that not all birds migrate. Some birds just stay in the same place all year long. And that’s because they can. But other birds are– other birds are feeding on food that is no longer available. So we think about the birds up in the boreal forest. The chickadees stay there all year round. They can find, believe it or not, insect eggs and little things like that in the bark that they can find enough food to keep them going during the winter.
But a lot of the other birds feed on flying insects or moving insects. And there aren’t too many of those up in Canada in the winter time, so they have to go somewhere else to find food. Migration is almost always about finding food. It’s not to get out of the cold because birds can survive cold. But there are certain inhospitable places that they need to leave, but it’s almost always about food.
[Sarah Wagner] All right, great. Food, the great inspiration. OK, Janet asks, what prompts the start of bird migration, and how do we think the birds can sense these seasonal weather changes? Additionally, why do some birds migrate earlier than others?
[Kevin McGowan] Well, the thing that starts bird migration usually is a change in daylight– day length, the length of daylight. And what that does is that starts– this is sort of the proximate mechanism that gets the birds brains changing, different hormones being produced, and the birds can sense even very small changes in daylight length.
And we find even in the tropics or the near tropics like in Panama that some of the antbirds down there can notice the change in daylight length even though it’s almost 12 hours a day but there’s a small enough change that it actually influences their behavior and their physiology.
Why do some birds migrate earlier than others? Partially because their food supply runs out or they just need to get the heck out of there. The things that we find migrating first through here in Central New York are actually the shorebirds. And the shorebirds breed up in the very high Arctic, and there’s not a long season there. So if they’ve succeeded in raising young or failed in raising young, they get the heck out of there early and move through.
And then we start to see basically the more northern birds migrate first because it’s getting cold up there already, so their food supplies are starting to decline. And so different birds migrate at different times because they’re following different resources, and some of them have farther to go than others to go to their final wintering grounds.
[Sarah Wagner] So it’s not necessarily that like all the raptors would go next it would kind of depend on where they’re coming from.
[Kevin McGowan] Certainly, that’s true. I mean, there are a few things. As I say, we see the shorebirds move early. We see the waterfowl move late, and so you can make some broad generalizations for some birds. But in general, it depends on their own personal biology what they need to keep going. So yes, we can find some. Even within a group, there will be early ones and later ones, so.
We can tell– here in upstate New York, we can pretty well distinguish the dowitchers, the two species of dowitchers that come through because short-billed dowitcher migrate through very, very early, and then late in the migration season for shorebirds, we see mostly long-billed dowitchers. And so that’s actually a key clue to their identification is when you’re actually seeing them come migrating through.
[Sarah Wagner] Super helpful. Let’s see. So this is sort of similar, but Tracy asks does the time of migration change every year? Is there a lot of fluctuation in the timing? And what are the– you already talked about birds that stick around but with chickadees if you have other examples of birds that stick around.
[Kevin McGowan] Sure. I’m trying to remember what the first part of that was. Does the time of migration change every year? No, in fact, it’s actually fairly rigorous in some species that it’s very, very predictable. Like when red-winged blackbirds turn up in Central New York is always within a two-week period. And so some of these things are very precise.
However, migration for an individual bird depends on the circumstances that that bird is in. And that includes changes in weather and local conditions and stuff like that. So there’s always that sort of fine-tuning. So it’s never precisely the same. It’s like the swallows coming back to Capistrano or the buzzards coming back to Hinckley, Ohio, the turkey vultures.
They pretend it’s a single day, but it’s usually a little slop around it. But again, it is very predictable to a certain degree if you give them the allowance of man, it’s raining today, I’ll do it tomorrow kind of thing that isn’t predictable but surprisingly consistent from year to year.
[Sarah Wagner] Yeah. We got a lot of folks asking, specifically, here’s one from Cora, why do some species age groups appear to begin migration at different times? There are also a lot about– so if you want to answer at the same time people asking why different age groups did and different sexes. Like why aren’t they all just going at the same time?
[Kevin McGowan] Yeah, that’s an interesting thing about migration is we tend to think, oh, well, yeah, they just go. But they don’t. That there are different– the sexes do different things, and the juveniles do different things. And typically, what you see going first are the males.
The breeding males of a lot of different birds leave the breeding grounds before the females and the juveniles do. And then again, as a general rule of thumb, the adults leave first and then the juveniles leave later. And it may be they just need a longer time to fatten up to migrate. But that’s a very predictable pattern that we see.
It’s easy to see in ruby-throated hummingbirds in the Eastern US and Canada that the males disappear a couple of weeks before the females. Well, the females are around. So you stop seeing male hummingbirds here and sometime in August, but the females still hang around into September although they’re pretty well headed to Texas by now so.
[Sarah Wagner] Yeah, and does that behavior look a lot different like if you’re watching your hummingbird feeder and it’s just females there? I mean, I feel like we see a lot of seasonal shifts in reports from hummingbird feeders.
[Kevin McGowan] Oh, absolutely, absolutely. Yeah, changes in behavior and changes in the sex ratios and things like that. Also, I will say on some other species in some species of birds, the males and females actually winter in different areas. And so like the females will go farther south than the males of some species like white-throated sparrows and stuff like that.
And a lot of that is tied to the fact that the males are actually coming back before the females. So like red-winged blackbirds come back to their breeding grounds in the north. The males come several weeks before the females do. And partly, that’s their biology where they’re trying to set up territories because the females are going to come and pick a male based on his territory.
And so they need to– the good males want to get there early and make sure they get the best spots. The problem with that in places like Canada or upstate New York is that we get winter storms and squalls and things early in the spring. And so you can’t go too early or you die in summer. So that’s the thing.
In some years, it’s a great strategy to be the first one there because you get the best territory, you get a couple of females, and you produce the most young. But the next year doing exactly the same thing, you may– there may be a big storm and you die. So there’s a lot of selection for taking risks but not being too risky.
[Sarah Wagner] Right. I think we’ll get into navigation in just a minute. But what about species that there’s a component of their migration where they actually need to go with parents in order to know the route. Is that something that happens?
[Kevin McGowan] It is. Actually, surprisingly, few birds do this that follow their family, but waterfowl and cranes are ones that we know that do that most birds seem to figure out their migratory route based on just instinct and wanting to go in a certain direction for a certain amount of time. But some birds actually learn their routes.
And in things like geese, the young geese follow their parents. So you’ll see a big flock of geese, and if you look in it, you’ll see juvenile geese, and there’ll be little family groups like in snow geese. Snow geese are easy to tell the juveniles apart from the adults. Canada geese, not so much. But if you look at a flock of snow geese, you’ll often see two adult birds that have a couple of youngsters hanging with them.
And then when they take off, the whole family leaves as a group. And so they lead their kids down to where they want a winter. Same thing with cranes. And we’ve been actually– people have used ultralights to ultralight planes to lead captive raised cranes to a wintering ground.
This has been done in Europe too with some ibis’s. And I forget what else I was reading about somebody in Germany who recently who was really good at leading some of these big birds around teaching them where to go to migrate. Most birds don’t do that though. Most birds find their way.
And somehow, it’s really quite remarkable. We don’t know how a lot of birds find their way to their wintering grounds or how they determine it. Certainly, a lot of them learn what to do, but other ones end up getting there on their own. And actually, this is something I have to– I have to tell this because this is one of the most amazing stories I ever heard of.
And this was like– I will say we’re getting better and better devices, smaller and more complicated devices to actually track birds on migration. And the results are thrilling. To be able to see exactly where some of these individual birds go is just really, really mind-boggling with some really fun, fun results coming out.
But some of the results are stuff that just make you scratch your head and say, what? They did what? How did they do that? And the very first talk I ever saw at an American Ornithologist Society meeting was of a guy who was putting satellite transmitters on swallow-tailed kites in Florida.
And swallow-tailed kites breed from Florida down into South America, but their resident population is in South America. So when our birds go down there, we don’t know who they are because they just blend in with a bunch of residents. And so we really didn’t know where the birds breeding in the United States spend the winter.
And so they put some satellite transmitters on a few of these birds, and they found that like we were talking about, the adults left before the juveniles did and that the juveniles kind of flocked up– get in big flocks, but they also start moving to the Southwest and end up on the West Coast of South America. And so there was one– there was a mother of breeding female at a nest and her daughter that were both tagged, and the mother left like a month before the daughter did.
And they took various routes to get down there, but they all started congregating somewhere around Columbia. And it turned out that they all went through a single pass in Bolivia into the Amazon basin. And all of the birds, the mother had gotten a month head start, but the daughter caught up to her, and they went through the pass together on the same day.
[Sarah Wagner] Wow.
[Kevin McGowan] And it’s like, what? How could they do that? Why would they do that? We don’t even have the right questions to ask yet about that is how you get something like that to happen. But that’s what birds do, and we’re finding out more and more about that stuff. And that one has just stuck with me for years because that just blew me away. It just blew me away. How did they do that?
[Sarah Wagner] That’s incredible.
[Kevin McGowan] We didn’t know.
[Sarah Wagner] Right. That needs to be a book at least. OK, let’s dig into navigation a little bit more. This is a big one. And in thinking about navigation techniques, the four and five-year-old classroom from the flora and fauna preschool wrote in to ask, how do they know where to go, and what if they forget their way?
[Kevin McGowan] That’s great. Well, some of them– as we just said, a few of them, a very few of them are taught where to go that their parents teach them. And what if they forget their way? Then they get lost. And we find this turning up– not a lot of birds get lost, but we do know that some birds do get lost.
They end up being places that none of their same species is. And that happens, and they just kind of wander around until they find their way back or they may never get to the final destination. That’s part of it. But they may find some place that’s just as good. So we’ve had some of these wayward strays and things like European birds that end up in North America.
And they’re notable because they’re rare. And they sometimes go back to the same wintering place over and over again that they never do get quite back on track. Other ones may go home and figure out how to go to take the right turn or the left turn the correct way the next year, but some of them don’t.
[Sarah Wagner] OK, lots of folks are wondering about time of day that different groups like to migrate and how on earth they keep up the energy to do that.
[Kevin McGowan] Well, different birds do migrate at different times of the day. A lot of people are surprised to know that the bulk of migration happens at night, that most birds fly at night. And there are several reasons for this. One is that there are fewer predators being able to catch you at night.
You can’t really forage that much, so you might as well fly. And as we found out, when their vision gets– when there’s not enough light to see very well, birds can actually turn on a different sense and see the magnetic fields of the earth. And so they can tell north and south because they can see the magnetic fields. We’ve known that they can detect magnetic fields for a very long time, but we haven’t been able to figure out how they did it.
And only recently did we find that there aren’t special magneto receptors in the bill or anything like that. It’s they have pigments in the eye that actually can get into– with a very low level of light, they can take the electrons on some of their atoms and get them into a quantum state that is sort of neither here nor there and that it can– they’re sensitive to magnetic fields and then they can see that.
But there has to be some light, but it can’t be a lot of light. And it’s kind of like if you think about when you’re in a dark situation and your eyes get adapted to the dark, you don’t see colors. You only see shades of gray. But then when the light gets strong enough then suddenly boom, you start to see colors.
And we call that the rod-cone break where you’re going from rods using the rod cells in your eyes that are really good at low light but then you’re switching on– at higher intensities, you switch on the cones, which can see color. And so it’s kind of like that that they have a threshold that they go into.
The first time I learned that this was the visual system that was using the magnetic fields, I thought to myself, I read that news and it’s like, oh, that’s why they fly at night is because then they can see. And that does seem to be the consensus is that a lot of the nighttime flying is because that allows them to use their magnetic sense to detect north and south. I forgot what the second half of the question was. It was–
[Sarah Wagner] Oh, it was about how they fuel themselves to be able to do that.
[Kevin McGowan] Right, how they fuel themselves. Some birds do this differently. There are birds that migrate during the day, and they sometimes forage during the day. Other birds will fly for a while to a destination then stop and spend two or three days eating to fill up along the way and put on fat to then go– so they put on fat, fly to use up the fat, stop, put on more fat, fly to use more.
Other birds like crows that do migrate to some extent, they will often forage during the day as they go because they’re flying by day. And an interesting switch that one that I just sort of really was thinking about when we put out our hummingbird course recently is a ruby-throated hummingbird, which is found breeding all over Eastern North America.
And they winter in Central America from Southwest Mexico down to Panama. And if you think about going from Quebec to Guatemala city or something like that, there’s a big thing in the way that’s the Gulf of Mexico. And so they could either take the short route and fly over it or take the long route and go– the easier one and go around it. And it turns out what they do is most ruby-throated hummingbirds in the fall, they take the easy route to go around it.
Like all of our birds from New York are probably in Texas right now. And they migrate through the coastal areas of Texas in huge numbers. There’s actually a hummingbird festival or several hummingbird festivals down there right now that are– you can go one place. And like in people in these towns put out hummingbird feeders, and you can go see 200 hummingbirds in one person’s yard as the ruby throats go through. It’s really quite a special thing.
And you can watch this on our status and trends maps. If somebody could throw in the link to the status and trend map for the migration of the ruby-throated hummingbird, it’s really cool to watch because what happens is so in the fall, they’re not in a hurry to get down there. They’re just going to go take vacation, so they’re just lazing it down. But in the spring, they have things to do, and they want to get back, and they want to start breeding.
And if you watch that status and trends map, what you’ll see is that all of a sudden, these birds start to congregate in the northern tip of the Yucatan Peninsula, and then boom, they’re in Louisiana and Alabama that they fly– they do fly over the Gulf in the spring completely. And that would probably take a hummingbird maybe 15 hours of flying solid straight across the Gulf.
And there’s no place to sit down and take a break when you’re flying across the Gulf of Mexico. So it’s really quite remarkable that these birds can do that. And they put on fat– they almost double their body weight in the Yucatan while they’re bulking up to make this one big, tremendous leap, but they do it.
And so, again, looking at that status and trends map, that’s the first really good definitive statement to me that this is how the hummingbirds do it. You can watch them go around through Texas on the west going south, but then nobody goes that way. They all just jump across the Gulf, really quite remarkable.
[Sarah Wagner] Yeah.
[Kevin McGowan] And the bird’s this big.
[Sarah Wagner] Yeah, they’re not hiding any weight because of–
[Kevin McGowan] They only weigh 5 grams or so. It’s like a couple of nickels. And it can make it all the way across the Gulf. It’s quite remarkable.
[Sarah Wagner] And it’s so great to be able to watch them once they’ve made it because they care less about us and more about eating.
[Kevin McGowan] Yeah, you bet. And, you know, I’ve watched– I’ve watched hummingbirds come off the Gulf on the West Coast of Florida, and they don’t go anywhere. They just sort of drop 3 feet onto shore. And the one place I was watching in Saint Petersburg, Florida was a patch– there was a big patch of thistles. And they were like 35 hummingbirds that were there claiming a thistle to sit on. And the thistle’s just behind the dunes kind of thing.
And it was really cool because I remember the one spring when I was down in Florida that the males turned up in like early April, something like that. And there was just this small patch of flowers with 35 male hummingbirds, one of which had a yellow gorget, which was really weird. All the red males and then this guy that flashed yellow.
He had some kind of problem going on with his feathers. But then about two or three weeks later, I went to the same patch, and it was full of female hummingbirds because again, the females are coming after. And it was several weeks after the males had come through. So it was really– I’m talking a lot about ruby-throated hummingbirds today but they’re–
[Sarah Wagner] We had a lot of questions so–
[Kevin McGowan] They’re just such a spectacular story.
[Sarah Wagner] Yeah, yeah. There are other groups that cross the Gulf too, right?
[Kevin McGowan] Oh, sure.
[Sarah Wagner] What’s the difference in how raptors use that area and some songbirds? So how would raptors do it differently?
[Kevin McGowan] Raptors don’t like to go fly over water because there are no updrafts. There are no thermals. A lot of raptors coast their way around the world that they try to do it with as little energy use as possible. And they have learned how to take advantage of the updrafts that are created as the sunshine heats up the land. But the sunshine does not heat up the water like that, and so there aren’t these big updrafts.
So, in fact, most raptors tend to avoid going across large bodies of water and take the around the corner thing. That’s why in Mexico especially and in Central America there like Veracruz is known for this. Thousands of raptors are concentrated coming across that spot as they go around the West of the Gulf of Mexico. Same thing in Europe and like in Israel. Some of the places the birds don’t want to fly across the Mediterranean.
They want to go around the Mediterranean. And so you end up with these fantastic migration concentration areas where you see thousands of hawks coming through at one time. It’s really quite spectacular. Songbirds, on the other hand, can handle it because they’re just getting up high and cruising for as long as they can.
And they, again, put on– sometimes they double their body weight in fat so that they can use that fat as fuel for long distance migrants. And some of them like the blackpoll warbler takes off from Maine and Nova Scotia and flies straight to South America. It flies over the Atlantic Ocean to fly straight to South America in one flight, which, again, a little bird this big can do that is just quite a remarkable story.
[Sarah Wagner] And how did they figure that out?
[Kevin McGowan] Well, we don’t know. It’s something says go that way for this long. And we know we can see– actually, we can see this in birds. There’s this cool term that’s in German called “zugunruhe” and that means migratory restlessness. And so we can– you watch this, and it’s been well studied in birds that if you keep them in captivity, as the light changes, as the days get smaller or longer, they start to get antsy.
And they just kind of move around in their cages, and they just want to go somewhere. And Steve Emlen, who used to be here at Cornell when he did his PhD research at University of Michigan, he looked at these birds and actually put these things called Emlen funnels where he has a paper funnel and the birds are standing on an ink pad, and they just jump in one direction.
And what you find is that before the zugunruhe starts, they’re just kind of hopping in random directions. But when it starts to get to be time to go, they head either north or south, whichever way they’re supposed to be going, and they just want to do it. And it’s just this need to go further, to go further, go south, go south, go down, you know. And it’s like a guide on them or whatever that makes them just want to do that for a certain amount of time.
And on the proximal scale of how do you make it happen, that’s relatively straightforward. You can imagine that if you get a direction that you want to go and you go for a long time and you may find something that attracts you to stay there or you may just run out of the urge to do it. And that’s potentially the way these things work with birds.
[Sarah Wagner] Yeah, zugunruhe, such a good word. OK, sorry. Back to questions. Sylvia has one about staging areas. So she says where do migrating birds gather in large flocks when they move south? For example, we see migrant warblers in the spring and fall in our yard, and I wonder when they meet up with a group. So this is coming from Ottawa.
[Kevin McGowan] Yeah, some things it’s obvious. I mean, waterfowl gather in lakes and ponds and along the ocean. And they like to be in flocks when they migrate. Things like warblers, it’s not so obvious. And you will find loose flocks of things like warblers migrating flock loosely together. And I don’t think that they actually necessarily go someplace to stage.
The songbirds make a lot of noise when they’re migrating. They all seem to have a chip note that they give that for some birds, it’s the only time they use that particular note is when they’re migrating. It tends to be– we tend to think of it as being something that says, I’m here. Where are you?
And you can hear this sometimes when the thrushes are migrating in the evening, you can hear thrushes start to call right at dusk. And they start to use this flight note that I think gets everybody in tune with where everybody is. And they may start to get closer together and then express some level of excitement about what they’re ready to do.
And then they all take off and sort of basically keep in touch. They aren’t necessarily in a tight flock like a bunch of geese or something like that but definitely within hearing of each other. And that’s pretty much what they do is they make these calls all night long, and I think that keeps some of the birds close to their species just by saying I’m here. Anybody else out there? Where are you?
[Sarah Wagner] I lost who asked, but someone wondered if some birds just go it solo, like if individuals migrate without a group.
[Kevin McGowan] Yes, definitely some do. There are some species I’m trying to think of. I can’t think of one right off hand, but there are some birds that are– you almost never find a bunch of them together on migration or in the wintering grounds. I mean, they’re just not social or anything. It’s like they’re standoffish. I had a cousin like that, didn’t really want to socialize with the rest of us, so.
[Sarah Wagner] Right, OK, here’s one we can dig into physiology with this one. Claire asks how much body weight is lost during migration flights? And you touched on this a little bit, but you could go into that a little bit more if you want.
[Kevin McGowan] Yeah, body weight, a lot. I mean, that’s why one of the big things is– I forget. There’s a technical term for it like hyperphagia or something like that that means eat more than you need to so that you put on weight. And birds get into this state where they are, in fact, putting on weight almost directly from what they’re eating.
I don’t know how the metabolism changes exactly. I’m not a physiologist but definitely when premigration birds start eating a lot and they’re putting on a lot of weight. Some birds double their weight. I mean, I had a– I remember skinning an upland Sandpiper when I worked for the museum here that it had– I forget.
I think it hit– struck a window or something like that. But it had so much fat on it that when I took the fat off, it was basically half as much as the rest of the body. And it’s like wow, that’s a lot of fat to be carrying around. And again, some of these small birds actually double their weight. And you can see it on them.
If you’ve been to banders, you can see some of the fat in the furculum. That’s one of the standard things that you do when you’re banding a bird and assessing its condition is looking at how much fat that they have on them. But if you really wanted to see it, I mean, I’ve skinned a lot of birds. And when you take the skin off, there’s a lot of fat all over the place. You just get completely covered in it. And they’ll do these long flights so that they’re powered up to spend more than a day in flight.
And then they’ll get to another spot where they stopover spots on migration that can be extraordinarily important for migration for the birds to fuel up because some of these birds are going long, long distances from Canada to South America. And you can’t do it in one shot. You have to do your best shot and then fatten up and do it again a couple of times.
And so these places on migration, we tend to think of oh, there’s a breeding grounds and then there’s the wintering grounds, and that’s all we have to worry about. But no, there are these stopover spots that can be just as important in the survival of these birds getting from one spot to another. They have to stop and refuel. And that’s what the thing is that you’ll see along the Gulf Coast in the spring.
The birds that have come across the Gulf of Mexico, they’ll just sit in that spot for several days foraging and foraging and putting on more fat before they move on. So it’s not all– for most birds, it’s not just one shot that you just keep going. Usually, it’s fly and stop somewhere for a couple of days, fly to someplace else, stay there for a couple of days and keep moving along like that.
[Sarah Wagner] Very cool. So a lot of– there are a few questions about what folks can do to help birds during migration. And so some of that might be like planting native plants that the birds might like to eat the fruit from. But Mary Ellen asks are there particular foods and feeders that average suburbanites can put up to help migrating birds?
[Kevin McGowan] Well, hummingbird feeders, the hummingbirds really like hummingbird feeders. And you won’t make them stop migrating and stick with it– and stick with your feeder till it gets cold. They’re not going to do that. But they will use it as a source of cheap energy that they can put on and help them along their way. Suet for some of the other birds is good.
Yeah, it’s hard to put something out that the blackpoll warbler is going to want to– it’s hard to help some of these birds. It’s like oh, yeah, you know, I can’t– I can’t help you Hudsonian godwit, you know. I don’t have food for you. But you do what you can. The other thing to do to help birds along during this is turn off your lights at night. That’s a big one.
And of course, this really plays out in the cities. And then there are the programs that people have– a number of organizations are working with, including the Cornell Lab of Ornithology that are trying to encourage big cities to cut down on their light usage during peak migration time because birds get confused. If you think about moth, why do moths come to flames?
Well, because when they’re navigating in the old times, what was light– the sky was lighter than the ground. And so if you wanted to go up, all you had to do was follow the light and go up. And that doesn’t work anymore. Now that whole thing of follow the light, follow the light because that light is up, it’s not. And it gets birds confused. It gets moths confused.
And sometimes especially in really bright light situations like skyscrapers and things like that, it can cause the death of the bird by causing that kind of confusion that they fly to the light and run into the windows and things like that. And so turn off your lights at night. Plant native plants. Put up a hummingbird feeder. That doesn’t do it all, but those are a couple of tangible things that people can do.
[Sarah Wagner] Yeah, great starts. And we’ll put links to some of those things in the chat. There’s a– to the Lights Out campaign and some other things that should be helpful resources.
[Kevin McGowan] Great.
[Sarah Wagner] OK, this one’s a little bit random, but we got a lot of questions about geese, and specifically Canada geese. So a lot of people are really confused about why some are sticking around and some migrate. So do you want to give us the quick rundown of that story?
[Kevin McGowan] Sure. Yeah, it’s confusing now. 50 years ago, it wasn’t that confusing. They were mostly just migratory geese going through most of North America. And this is actually a really cool story because 100 years ago or so, there was a form of subspecies of Canada goose called the giant Canada goose. And it lived around the Great Lakes area.
And it was essentially resident. But they were hunted out and were thought to be extinct 100 years ago. And then somewhere in the 40s or 50s, somebody discovered a remnant population of them up in Wisconsin or Minnesota, I forget which. And it’s like, oh my God, this thing isn’t extinct. Here they are, and we need to save it.
And so what do we do? What can we do? Well, let’s take it and get all the eggs out of that one basket and put some over here and put some over there. And people said oh yeah, you know, like Ohio was like, sure, we’ll take some. And New York was like, yeah, we’ll take some. And we’ll see if they can live somewhere else and what we can do. And lo and behold, it worked.
They did reproduce, and they kept reproducing, and they kept reproducing, and they kept pooping all over the golf courses. And it’s like, oh, wait, wait. We don’t need this many of them. And for a lot of parts of the country, they are the predominant form that you see are these giant Canada geese.
And they are– they don’t migrate. They move around a little bit as they have to if the water freezes and things like that, but they typically are resident. But still the Arctic breeding Canada still pass through, but they’re just so not noticeable compared to the residents that people have transplanted all over the place.
So it does get a little bit confusing. But we have like in New York, there’s a migratory hunting season or I mean, they actually regulate the hunting seasons differently for the residents and the migrants. And we do recognize the fact that migrants are coming through and are probably going further south than here to spend the winter.
But the other thing that’s changed with goose migration is back in– again, a fair number of years ago, I think this was starting to happen maybe 50 years ago in the ’60s or ’70s that the birds from Canada started what we call short stopping. And they were coming across, especially in Central US and Canada that there were so many farm fields that the geese instead of going down to Louisiana for the winter, they started stopping in Iowa.
And it’s like, meh, there’s a lot of food here. We don’t need to go any further south. So they actually changed some of the migratory pathways of the birds by providing them some brand new huge food source further north so that they didn’t end up going as far. So birds apparently are very dynamic in the way they live their lives.
And they will change their movement patterns and their distribution patterns based on the conditions at hand. And we’ve seen this by watching it closely over the last 60 years or so, and we’ve seen a number of these stories that birds change where they live based on what’s going on.
[Sarah Wagner] Right, there are lots of other questions about just exactly how they do it. But I feel like this is a good segue into– we got a lot– I would say like 70% of the questions we got are about response to climate change and natural disasters. So this one’s kind of relevant, especially right now. Wendy asks, do hurricanes affect fall migration, especially thinking of Lee that just went through the– went up the East Coast during peak migration?
[Kevin McGowan] Yeah, I was thinking about Lee too because it was coming– I was on the Coast of Massachusetts last week when it came through, and they canceled my flight to get out. So does it affect migration? Well, it affected me. I had to delay the day. And that’s kind of the thing that happens with birds is yes, birds pay attention to the weather.
Yes, they are sensitive to changes in the weather. They do somehow seem to be able to recognize changes in air pressure and barometric pressure. How they do that we have no idea, but there is evidence that they change their behavior based on what the air pressure is. And so they will be affected by this.
They notice it, of course, but it depends on which way the winds are going and what exactly that– if they smack right into it if it’s coming straight up their migratory route, that’s a bad thing. And some birds can actually get what we call entrained into the hurricane itself and carried far off course like the flamingos that are currently all over Pennsylvania and New Jersey and–
[Sarah Wagner] Kentucky.
[Kevin McGowan] –stuff like that and Kentucky, yeah, I saw that in Kentucky too. I left Ohio like the day before a couple showed up in southwestern Ohio. I was visiting family, but missed the flamingos. So those things are obvious kinds of displacements of birds, but yes, the other stuff happens too. But the other thing to know is it’s not– a hurricane is not just a wind all in one direction. It actually spins.
And so in the northern hemisphere, they spin counterclockwise. And so what that means is the– so Lee was coming up the East Coast from the south going north, north to northeast but where I was in Massachusetts on the west side of that hurricane, the winds were from the north because that’s moving north, but it’s spinning, and we’re getting those winds that are coming off the top of the hurricane that were blowing from the north into New England.
And I was hoping that maybe that wasn’t going to bring any Caribbean birds up with it. Those are on the east side of the hurricane. But on the west side, I was hoping maybe something like some storm petrels or something might be pushed closer to land or maybe a gannet or a kittiwake or something like that from Nova Scotia would be blown down here. But I didn’t find anything like that.
[Sarah Wagner] All right, so a lot of questions about the fire that we experienced this summer– this past summer especially. So Debbie asks, do we know how the forest fires in Canada and the Pacific Northwest and West have affected the timing and distance for migration this year with respect to smoke?
[Kevin McGowan] It’s an obvious question to ask because the birds definitely had to have been affected by the fires. I heard reports of some migrants coming through early that boreal breeding birds that might have been affected, but I don’t know any real hard evidence for that yet.
So it’ll be interesting to see how the eBird reports shake out after the season’s over and whether we can actually detect an early migration because if your breeding habitat burns down, it’s like oops, it’s July, might as well go back– go south and get started on the vacation there and beat the rush and get moving south.
[Sarah Wagner] Yeah, we will have to see.
[Kevin McGowan] Yeah, as I say, obviously, a huge event like that that covered the entire Northeast, we have yellow skies that has to have affected the birds in some way. And now it’s not in a good way I’m pretty sure. So except for the black-backed woodpeckers and three-toed woodpeckers, they’re happy to go in and use the burn stubs as nesting and find– and the beetles that go in and love the dead trees.
And trees can’t defend themselves anymore, so the beetles can take over. And that is a food bonanza for these woodpeckers and some other animals too. So those burned areas are not ruined. They’re changed, and birds will take advantage of the changes as best they can.
[Sarah Wagner] Yeah, all right, a lot of questions about climate change. Here’s one pretty specific one. Are waterfowl flyways geographically shifting from their historic locations due to climate or other changes?
[Kevin McGowan] Well, I don’t know of anything changing dramatically other than the short stopping example that I gave that happened with Canada geese and snow geese and some other birds. And that again changes that historic changes that we made with our farming practices. But I don’t know about waterfowl specifically changing courses. They still seem to be traveling in most of the same places that they have. Certainly a possibility, but I don’t know of any evidence of that at the moment.
[Sarah Wagner] What are some changes we’ve seen with bird migration in general with climate change?
[Kevin McGowan] Well, there does seem to be some advancement of birds moving northward with some species. This isn’t as widespread or as hard and fast as some people seem to think, but there is evidence that some birds are showing up earlier because the temperatures are getting higher earlier. And that could be a good or a bad thing. As I said, birds change their distributions in their habits depending on the circumstances. They adapt.
And this could be good for some birds that they get to have a longer breeding season because they get up there earlier or it could be bad because it might not be met– we worry about the fact that what was an indicator of food abundance coming may not be anymore, that the insects and the flowers may not have– may not be advancing the same way that the migration would.
And so if you get there and get your timing wrong, then that could be a problem because again, birds are using cues that aren’t direct cues of here’s the food, make your babies. It’s if you start now kind of thing that by the time your chicks are big enough that they need to be– that they hatch and need to be fed, there will be insects around. So get started while there’s still snow on the ground. That’s those things if those get disconnected, that could be a problem.
And so we’re watching for that. But we haven’t seen any– I don’t think we’ve seen big successes and big failures yet from this mismatch or not of these changes. If that changes, the birds will change. But exactly how that’s going to play out, we’re watching. We’re looking at it to see. People are interested in exactly these questions.
[Sarah Wagner] Right, I’m trying to figure out what to ask you with only five minutes left. Let’s see. Someone asked what distance is considered a migration because obviously, there are all different kinds of movements that birds make, but what is the distance that qualifies as a migration?
[Kevin McGowan] That’s a fair question and because birds move from everywhere from a matter of miles to a matter of thousands of miles. And some birds are like, say, American robins at the north end of their range around– we’ll have robins. We always have robins on our Christmas count here in Ithaca, and we’re pretty far north.
But most of the robins move as they have to. So it looks like the snow cover is a good indicator of when robins move. They like to forage on the ground, and they’ll– a lot of robins only go when they need to. If the berries run out or if there gets to be too much snow cover and they can’t find food, then they’ll move further south. Some of them go, they just go and head to Georgia from Ontario or something like that.
And you don’t get them sticking around. But some do. And I remember the– sometimes it’s hard to know. When I was doing my dissertation work in Central Florida at Archbold Biological Station, we had the red-headed woodpeckers that were breeding in the scrub. They would fly south in the winter to the south end of the station and hang out in the longleaf pines during the winter.
And it’s like what? But it was. It was an honest to God southward movement. Was it migration or was it just changing, you know, where their habitat? But it was– that always struck me as like, yep, they fly south for the winter, and they only fly 10 miles. But hey, they’re still going south. I wouldn’t call that migration, but it’s hard to say.
And then there’s some birds like crows and blue jays where some birds stay put and other ones go somewhere else. And for the crows, for our crows, I should say a lot of the crows north of us are mostly migratory, and almost everybody gets out of the cold north in the winter and come somewhere around here.
Some of our birds that I’ve marked and followed them have followed some of those birds down to Pennsylvania, Western Pennsylvania from here. I’ve gotten reports of tags being seen there. And we’ve gotten a few birds from Montreal and stuff like that. But most of my known birds, the breeders, they just stay put all winter.
So this is a mixed migration strategy where some birds move and some birds don’t. And for the crows, it appears that it’s mostly non-breeders that are moving. But that’s not necessarily the case because sometimes birds just disappear for a while and then come back. So there are different strategies of migration with different birds all over the place.
[Sarah Wagner] Very cool. All right, well, I think that’s about it, Kevin. Thanks to the audience for such great questions today. This was really fun. Thank you, Kevin, for taking the time to talk to us and sharing all of your fascinating stories about bird migration.
Tomorrow, we will be emailing our Zoom attendees with the recorded webinar and some of the resources that we discussed today. If you’re watching on YouTube, check the comments for those links and resources. Those will stick with the video. And that’s all for today. Thanks again to Kevin and the audience, and have a nice day.
[Kevin McGowan] Thank you all for coming and participating. It’s a lot of fun to talk birds.
[Sarah Wagner] Yeah, enjoy. Thank you.
End of transcript
Have you ever wondered what triggers migration, how birds navigate, or the challenges they encounter? Join us for a Q&A focused on bird migration, featuring the expertise of ornithologist Dr. Kevin J. McGowan.
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