Migrating birds and dragonflies are returning north

Hermit Thrush
Hermit Thrush

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This is the time of year when migrating birds are returning by the flocks-full. Warblers and the woodland thrushes can be heard throughout the forest. But birds aren’t the only creatures in flight. It’s also dragonfly time. WTIPs Jay Andersen talks with a local naturalist about birds, dragon flies, damselflies and more.
 
 
Chel Anderson is a botanist and plant ecologist for the Minnesota Department of Natural Resources. She lives here in Cook County and joins us periodically to talk about phenology or what’s going on in the woods right now. Welcome, Chel.
 
Anderson: Hello, Jay. Lucky me!
 
Well, let’s talk about new birds we should be looking and listening for this time of year.
 
Anderson: Well, the migration continues onward so birds continue to kind of trickle in. The ones that I’ve been thinking about that I’d like to remind people to be listening for, one is a group called the thrushes. Most people are very familiar with the song of the robin, and the robin in terms of its visual identifiers There’s another few species of thrushes in our forest that aren’t quite so obvious, especially visually, because they’re kind of more hideout-and-sneak-around types, and those are the hermit thrush, the veery, and the Swainson’s thrush, and a fourth one, the wood thrush, which has really become very rare in the county now, so it’s not the most likely one for people to hear or see, also very secretive. But, all four of these thrushes have in common a very beautiful, flute-like song, that’s really, in terms of this group, unmistakable. If you hear one of these flute-like songs, even if you don’t know in particular which one of the thrushes it is, it has to be one of these four. There really are no birds that sound like this. So, these are very melodic, most often heard at kind of dawn and dusk. They are forest birds, so that’s where you’re going to hear them. The veery and the Swainson’s thrush have very similar songs. The veery goes down the scale, so the notes start high and end low. The Swainson’s thrush is just the opposite; the notes start low and climb the scale, the musical scale. So, listen for a real, careful, flute-like notes going up and down the scale, those would be either the veery or the Swainson’s thrush. The hermit thrush is a much more variable song, but the same quality of tone as the other two and starts out with usually one long note then does this amazing run of notes that are very difficult to reproduce. In fact, for all of the thrushes, we’re only hearing a few of the notes that they’re actually hearing are within our range of auditory reception. Other birds coming back, flycatchers showing up now, heavily dependent on insects, along with the warblers. So, they’re all showing up now, taking part in the big insect feasts that are being provided. Along shorelines, a bird to look for now would be the spotted sandpiper. It’s a little brown bird with a spotted breast, usually very visible, hopping along the shoreline, and it does a lot of head-bobbing.
 
Well, Chel, other things that fly besides birds like dragonflies and mayflies, how are we doing with those?
 
Anderson: Yeah, this is a fantastic time of year to pay attention to dragonflies, damselflies, mayflies. One of the interesting things with the dragonflies is that here, in our part of the state, we actually have dragonflies arriving in different ways, in terms of flying adults. There are actually dragonflies that have grown up down south that have migrated up here for the summer, and they’re the first dragonflies that we see. Green darners are usually the mass migrators from the south and they show up and this year they showed up May 8, was the first day, quite early. There’s a lot of art to identifying dragonflies, but if you see a dragonfly in May and it’s a large dragonfly with basically a dark body and if you get a close look at it, some green side panels on the thorax, right behind the head on that kind of stout part of the body. They’re big, easy to spot, and they typically come right up Highway 61. Unfortunately, a lot of them are lost to vehicle collisions, but they use the migration corridor that the birds use, and then they disperse out into the woods and waters of the forest. So, they’re the first dragonflies that we see. Then, the next big event among the dragonflies is something called synchronized emergence. Of course, for lots of species of insects there’s lots of advantages to all coming out at the same time, if the idea is to procreate and make sure the next generation is ready. So, dragonflies are similar in that respect. So, June is just a fantastic time to see these big synchronized emergence of dragonflies. So, if you can find a spot along maybe a slow moving stretch of river inland or lake, and just spend some time cruising the shoreline on a nice sunny day, cruise that shoreline and keep your eyes open for dragonfly nymphs, so this is the aquatic life stage of the dragonflies, and they will be crawling out onto the rocks, onto vegetation right at the edge of the lake or stream, posing there to do their metamorphosis from nymph to flying adult.
 
What about damselflies?
 
Anderson: Damselflies are, of course, related to dragonflies, and they fly a little differently. They look more like a helicopter; they fly more like a butterfly. Their wings don’t move in the same kind of quick synchrony that dragonflies do. They generally, when they’re alighting on something, they fold their wings together over their back. Dragonflies can’t do that. Dragonfly wings are always spread.
 
Am I correct in thinking that the mayfly hatch is one of the big things that trout fisherman look for?
 
Anderson: Oh, indeed. Mayflies are hugely important to fish populations of all kinds, but particularly species that recreational fisherman are after.
 
Now, these guys aren’t anywhere near as big as a dragonfly.
 
Anderson: No, and some are really tiny. Some are smaller than your little fingernail, and then others are up to 2, 2.5 inches. Some only last as adults maybe an hour and a half, and others just a few days as the maximum life span for an adult mayfly.
 
Chel Anderson, DNR botanist and plant ecologist, thanks for helping us understand what’s going on around us this spring.
 
Anderson: You’re very welcome.


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