Friday, June 28, 2019

Bobolinks: Singing from the Same Score

It’s been five years already since I wrote about Bobolink song patterns that can identify the places where they return each summer. I thought it might be interesting to go back to a few of those locations to listen for the song patterns I recorded five and six years ago to hear if they had continued.

I picked three of my favorite NE Ohio Bobolink meadows– one in each of three counties. See (hear) what you think.

My first stop was South Russell Village Park not far from Chagrin Falls. It is adjacent to Frohring Meadows in the Geauga Park District but is owned by the Village of South Russell. In 2013 and 14, the Bobolinks at both meadows had the same songs.

I climbed up the hill from the parking area into a huge, grassy meadow with buttercups and ox-eye daisies – perfect for Bobolinks. Listen:

When I initially identified the characteristic song at this location, I heard three distinctive song patterns. In addition, there was what I call the “fancy flight” song that is too complex for me to even begin to analyze if I listen in real time. It’s sung by males as they circle slowly above the meadow, showing off their gorgeous plumage and their impressive musical skills.

Being a mere human, I’d have to slow down the “fancy flight” song quite a bit to comprehend it all and even then, I’m sure I’d miss a lot of subtlety. I have immense respect for birds who can learn and later reproduce such intricate patterns of pitches, rhythms, and tone qualities – especially since they learn it all by ear. Keep in mind that even bird songs that seem simple to us are actually far more nuanced than we realize. 

The part we can recognize by ear is the shared collection of song patterns characteristic of the South Russell and Frohring Meadows Bobolinks. Here's my 2013 recording of these song components:

So now to 2019. Have the songs been consistently transmitted to the next generation? Is the same Bobolink population returning to these meadows year after year? As someone who teaches ear training professionally, I want to know what I’m hearing and ponder what it might mean.

I heard three consistent song patterns over and over again across the entire meadow. All the males sang them. Sound familiar?

My next stop was the large meadow along Sperry Road at the Holden Arboretum in the Kirtland area of Lake County. I knew the song of this Bobolink meadow well, too. I had given Music in the Meadow bird song classes for Holden on two or three occasions in the past, and the indoor class was followed by an outdoor listening walk through this meadow. This is what the Bobolinks were singing back in 2011...

...and these were the recognizable song components in 2011, 2012, and 2013:

The last time I taught the class, I had the participants sing the primary Holden Bobolink theme in the classroom and then again at the edge of the meadow. And when they heard the first Bobolinks, they recognized those birds’ special song! They were so pleased! 

On my June 2019 visit, I didn’t hear long flight songs because it was later in the day and the males were singing from perches. Human noise was present as well. But the song patterns could not have been more clear:

The third Bobolink visit I made this June was to Bath Nature Preserve in western Summit County not far from the Medina County line. This preserve's Bobolink songs - particularly the clear, three-note motive -  had been recognizably different from the South Russell and the Holden Bobolinks, who were themselves clearly different from each other. Would that still be true here?

These were the song patterns I’d recorded five years ago. In fact, I'd recorded 10 different males all singing the same song. 

At first, the Bobolinks were were far from the trail and I didn't want to jeopardize their nesting success by going off the trail. But I recognized what I was hearing, and eventually, two males were singing close enough to record. 

Once again, the songs were the same as five years earlier!

These populations seem stable. I can count on finding Bobolinks here, and there are additional locations in our region where this is true as well.

But there are other places where habitat loss, extreme weather events, and early mowing while young Bobolinks are still in the nest have impacted these birds. The songs I recorded several years ago may no longer resonate in these meadows. I had hoped to get better recordings of two of my favorite songs, but I haven’t been able to bring myself to return to those locations to see if Bobolinks are still present. Habitat tragedies occurred on consecutive years at both of these sites, and the numbers were already rather small. Maybe I’ll go to these places next May...maybe…

I'll close with a June 2019 Bath Nature Preserve Bobolink flight song. 

Field observations are valuable - especially over time. Fascinating stories reveal themselves as we keep listening.

Sunday, June 23, 2019

Snarls and Snores

Leopard Frog? Pickerel Frog? This identification question seems to come up quite a bit for people who are listening to frog songs. Citizen scientists who participate in FrogWatch do their surveys at night, so these folks always have to gather data by ear. 

A number of frog species are quite distinct from one another, particularly with a side-by-side recording reminder. There are a few, however, that people tend to have trouble identifying. 

For example, people generally know the Spring Peeper’s common and relentlessly loud peeping calls. What they often find confusing is the Spring Peeper’s ascending trill calls and the calls of the Western Chorus Frog, especially because these two species may be found calling in the same location.

Western Chorus Frog, above and Spring Peeper, below. 

Listen to this comparison of the Western Chorus Frog followed by the Spring Peeper’s trill call. The trilling peeper is much more melodious to human ears because the pitches are not as high as those of the Western Chorus Frog and therefore sound clearer to us. In fact, they fall into the same range as many bird songs. 

Another point of confusion can be the Gray Treefrogs. Up here in NE Ohio, we have Gray Treefrogs but not the visually identical Cope’s Gray Treefrog. Southern Ohio residents have Cope’s Gray Treefrog AND there are locations where both species are present. 

If that’s true for you – or if you’re visiting Cope’s country – you can learn the difference if you’ll graciously grant yourself a little patience. I’ll include an example below and also this link to the Listening in Nature post that features both calls if you’d like to do some additional listening.

And then there’s Leopard and Pickerel Frogs. Some people say, “I don’t even try.” So let’s spend a little time with this comparison and experiment with some approaches you might find helpful in separating these two species. 

First, a quick reminder of some visual similarities and differences. These frogs are about the same size. Leopard Frogs are generally green and the Pickerel Frogs tan, and both have prominent dark spots. The Leopard Frog’s spots appear more random than the paired rows of Pickerel Frog spots. I find this distinction to be very helpful.

Here are Leopard Frog spots...

 ...and here are Pickerel Frog spots.


Both species call in April after the Wood Frogs have finished and the Spring Peepers and Western Chorus Frogs have already been calling for perhaps a month. It seems to me that the Pickerels start a little later than Leopards, though I don't know if that's consistently true. I also have not heard both species in the same places, though again, that may not be true elsewhere.

Although The Ohio Frog and Toad Calling Survey states that Pickerel Frogs “utilize the margins of clear, cool streams, woodland springs and seeps, fens, and wet meadows,” this isn’t necessarily true in my corner of NE Ohio. I’ve only found them in lakes, ponds, and marshes so far, so keep that possibility in mind. 

Now about listening. Let’s start with the Leopard Frog. 

They can call underwater, as can Pickerels, so you may not always know exactly where the sound is coming from. Although their calls are often described as sounding like snoring, listen for variation. I’ll give you some examples.

They can make grunting sounds, and sometimes their “snore” can be a rather dramatic roar instead.  

You may hear a relatively smooth, continuous sound or one that has lots of tiny separations in the sound’s flow. I describe it as "eh-eh-eh-eh-eh" and you can see the separations on the sonogram. 

I’ve focused on individual calls and small groups for detail. Now here's a large, glorious chorus at Killbuck Marsh Wildlife Area near Shreve (a little south of Wooster). When I recorded this inspiring chorus (photo below), I was literally standing in the water with them. Could I see them? Not really, but they were never far from my boots as I slowly sloshed through the water.

OK, got it? Now on to the Pickerel Frogs.

Brad Phillips at Erie (County) MetroParks described their song to me as a “snarl,” and I think that’s useful to remember. It’s definitely a smoother sound than those of the Leopard Frogs. (Personally, I think Pickerel Frogs can also sound at times like a growling stomach.)

The songs start softer and quickly become louder. (Imagine snarling "Nyeeaaahh!" at someone.) You can see the contour on the sonogram I’ve included.  The steady band of sound that runs through this sonogram (and recording) is that relentlessly loud chorus of Spring Peepers I mentioned earlier.

Now here's a chorus of several Pickerel Frogs and, of course, Spring Peepers.

A useful way to remember similar calls like these is to try imitating each one. 

If I were to imitate the Pickerel Frog, I would say “errrahh” beginning with my jaw clenched and lips apart, then gradually open my jaw a little and slowly closing it again. "Nyeeaaah" works pretty well, too.

But for the Leopard Frog, I would open my jaw farther before closing it, and I’d also do a “rrrah-ah-ah-ah-ah-ah” at times for the call type that has more spaces.

For both species, try to make the sound as guttural as you can. Don’t sing it; you are growling and snarling. 

Now go back and listen to the frog calls and imitate them as best you can. Improvise as needed - you may find it amusing as well as useful to find the sounds that work best for you. 

Then try immediately to recall what you did and how you did it. You don’t have to do all this in front of anyone, though if you do, you can both break down into uncontrollable laughter afterward. But you will remember the songs better!

Here's a practice track for you: Pickerel Frogs first (accompanied by Spring Peepers) followed by different Leopard Frog calls. 

What was similar? Different? What did you do to create those songs, and can you recreate them now? Actually making similar sounds yourself can be very helpful in remembering because you didn’t just listen - you did something with your own body to create a similar sound. It involves muscle memory. 

OK, Frog Watchers – or should I say, Frog Listeners! Refer back to this post next April if it's beneficial. In the meantime, we still have Green Frogs, Bullfrogs, and the lovely Gray Treefrogs calling, so keep listening...

The Ohio Frog and Toad Calling Survey

I’ll include a Google map of where I’ve recorded them so far and also reports from naturalists in the region. I’ll update the map as I get more information. I’m interested in where we have Pickerel Frogs in our region, and you’ll probably want to know where this is an option when you’re doing surveys.