Laura Erickson's For the Birds

Friday, June 30, 2017

Review: Song Sleuth, a new app for identifying bird sounds

Song Sparrow

Two or three decades ago, I came up with an imaginary product, Earth Angel Bird Identification Earrings. Shaped like little parabolas, they collected sounds, sent them via a discreet wire to a teeny tiny microchip sewn into the birder’s wide-brimmed hat, and whispered the correct identification back into the wearer’s ears.

Many years later, a real-life app named Shazam came out—it will identify just about any published recorded music, whether you’re hearing it in a restaurant or on the radio. Shazam’s database is enormous, but the algorithm does not recognize melodies, instruments, or singers’ voices. If you go to a live concert, even if the musicians are duplicating their own recording as closely as possible, Shazam won’t recognize it, much less a hummed or keyboard version of a melody. It identifies only those specific song recordings in its database.

Shazam’s limitations are exactly why bird song identification apps have been so hard to create. Every single song a bird gives is a live performance, and for only a few species is each performance of the song essentially identical to other performances.

To make an algorithm identifying bird songs in the field even trickier, birds do not take turns singing. In spring and early summer, especially at dawn, dozens of songs can be heard simultaneously. Shazam can deal with background noise, but not with two songs playing at once. Experienced birders can tease out the identifications in a dawn chorus, but no one has figured out how to program software to do that.

Despite the difficulties, over the past decade, several groups have developed primitive programs to identify bird songs and calls. One app has come sort of close—Song Sleuth.

One of the country’s top bird illustrators and field guide authors, David Sibley, provided all the artwork, detailed species information, and range maps for Song Sleuth. The company that developed the algorithms for analyzing the songs, Wildlife Acoustics, has a long track record of helping monitor bats, frogs, and whales via acoustics. The trick for Song Sleuth is that there are an order of magnitude more bird species than bat, frog, or whale species, and the vocalizations of many individual bird species are far more variable, too.

On Monday when David Sibley and Michael Collin, another leader in the Song Sleuth team, were in town for a convention, they took me out to test Song Sleuth at one of my favorite local birding spots, the Western Waterfront Trail.

Before we started out, they helped me adjust a few of the settings of my app, and showed me how to use some features—Song Sleuth is one app that probably really does work best when you view the video tutorials first. It uses spectrographs, also called sonograms, extensively. I love that—I’ve used sonograms a lot, from the very start of my birding in 1975, thanks to the ones Chandler Robbins put in the Golden field guide.

The Golden Guide included sonagrams by the range maps for most species.
I wrote a simple but primitive tutorial for children about how to understand sonagrams when I was writing for Journey North in the late 90s. I also took the Cornell Lab of Ornithology’s field recording workshop in 2001, where we spent a couple of sessions specifically looking at them both for understanding and editing bird vocalizations. And starting in the late 90s, when I started producing my radio program digitally, I’ve been using waveforms (which show volume, not frequency, over time); when I started recording birds in 2001, I quickly adapted to using the spectrograms produced by my sound editing program, too. So I took to this element of Song Sleuth like a Northern Parula to Usnea lichen.

The process of using Song Sleuth is fun and easy. When you start the app, you click on the spectrograph icon, “Record and ID,” and Song Sleuth starts listening. Then, when you hear a sound you want to identify, you press the Record button. Sound Sleuth grabs sound starting from a few seconds before you pressed the button, giving you a fairly generous reaction time. When you press the button to stop the recording, the app gives you three choices of likely suspects, and an option to look at the spectrograph you produced. If the sound you want to identify is higher or lower than background noise or other bird songs, you can zoom in and move the spectrograph around so anything above and/or below your bird's sound won't be visible on your screen. You can also press a little scissors icon to cut out the sounds before and after the sound you want. Then when you press the arrow, it’ll base its guesses specifically on the sound you’ve selected.

How did our field test turn out?

First the bad news. It did not correctly identify most of the closest, loudest, clearest birds we heard. Its database includes only about 200 species altogether, many of them not found in Minnesota. A great many birders have found well over 300 species in the state, so there are obviously going to be a lot of bird sounds we hear that are not in Song Sleuth's database. Specifically, it does not have several of the species we most often identify by song on warbler walks at the Western Waterfront trail.

One of the first birds I got a perfect, clear recording of was a very nearby Swamp Sparrow. Unfortunately, none of the choices Song Sleuth provided was the right one. The Swamp Sparrow is a very common bird with a song people often want help with, because it’s so easy to hear but stays hidden in vegetation. Unfortunately, the Swamp Sparrow is one of many species not yet included in the Song Sleuth database. David wrote it down on their to-do list, so in future updates it should be added, but right now Song Sleuth would be worthless for working out that song, or the Marsh Wren, Brown Thrasher, Sora, or Virginia Rails that are often heard along the same trail.

Even though Song Sleuth's database does include the Song Sparrow, it misidentified just about every song produced by a nearby Song Sparrow, usually not even having the Song Sparrow as one of the three possibilities. This song is variable between populations, between individuals, and even within a single individual’s repertoire, which explains why David Sibley got the right result for one song but not for others sung by the same bird in the same spot. If the algorithm can’t work out this common species with a fairly straightforward song more consistently, I don’t see how it’s going to get other, more variable species consistently right.

Species that are in the database but are not listed as possibilities for Minnesota in summer even though they breed in our neck of the woods include Dark-eyed Junco, Pine Siskin, Golden-crowned Kinglet, Brown Creeper, Blue-headed Vireo, Connecticut Warbler, and Northern Waterthrush.  Species in the database that aren’t listed as possibilities for Minnesota in summer even though they breed in the south include Tufted Titmouse and Eastern Screech-Owl For large states, it might be better eventually to be able to fine-tune the state filters by region.

Due to health reasons, I haven’t done a lot of birding this year, but of the 175 species, mostly common birds, that I have seen in St. Louis and Lake Counties since January, 75 are not included in Song Sleuth's database—that’s over 42 percent. Some of them are species we don’t normally hear vocalizing anyway, but some have distinctive calls or songs that can be important for detecting or identifying them: Trumpeter Swan, Ring-necked Pheasant, Ruffed Grouse, Common Loon, Pied-billed Grebe, Sora, Wilson’s Snipe, Common Nighthawk, Eastern Whip-poor-will, Alder and Yellow-bellied Flycatcher, Marsh and Sedge Wren, Swainson’s Thrush, Northern Mockingbird, Brown Thrasher, Rusty Blackbird, White-winged and Red Crossbill, and Evening Grosbeak. Song Sleuth has a long way to go to have the ability to identify bird songs with the accuracy that Cornell’s Merlin app achieves with photos.

One irritation for me that most users wouldn't be bothered by: Scrolling through the list of birds in Song Sleuth is not easy if you’re used to seeing birds in a logical order, either taxonomically or alphabetically. As far as I could tell, we’re not given an option to list them any way except the default, which is alphabetically by an inconsistent combination of arbitrary family and order names. The Osprey, belonging to the same order but a separate family from hawks and eagles, was put under the Os, far away from the H’s where "Hawks and Eagles" are listed, but the Barn Owl is in with the other owls even though it belongs to a different family. To find the warblers, don’t look under W for “Warblers” or “Wood-Warblers”—they’re under N, for “New World Warblers.” The Gray Catbird is listed under M for "Mockingbirds and Thrashers," even though the database includes no mockingbirds or thrashers. The blackbirds are listed under O for "Orioles and Blackbirds." The Olive Warbler, now separated from the wood-warbler family, is in its own category under O for “Olive Warbler,” but a common bird in California, the Wrentit, which is the only regularly occurring member of its family in North America, is mystifyingly listed under S for “Sylviid Babblers.”

Within each family, species are arranged alphabetically, but not by the common name, as the families are arranged. They've put the scientific names in alphabetical order, which completely baffled me. I wish there were an option to list them in taxonomic order, or even in alphabetical order by common name. I found their arrangement awkward and counterintuitive. Of course, most people won’t be scrolling through the entire bird list, and there is a search box so you can type in the name of a species you’re trying to look up, so this may be nothing more than a minor personal issue.

The good news is that it’s fun to look at the spectrographs in the field, and paying attention to those spectrographs will help birders at any level notice nuances of bird sounds. "Seeing sound" is a wonderful thing; I'm overjoyed that something Chandler Robbins and I have been preaching about for decades is finally in vogue in birding circles.

David Sibley added the Swamp Sparrow to his to-do list, and the number of species Song Sleuth can identify will grow, but right now it simply does not have a big enough database to help with a sizable proportion of the birds you’ll hear, and unless you already know bird song identification well enough to not need Song Sleuth, you won’t know whether the bird you’re hearing is in the database or not. It always gives three choices, and if you don’t know any better, you’re likely to assume your bird is one of them. It never even occurred to me until we looked for it that a common bird like Swamp Sparrow, much less Brown Thrasher or mockingbird, wouldn’t be in the database at all. And in both my test use on Monday and in pulling it out a few times since, I've had very inconsistent results with common species that are in the database.

The more people buy Song Sleuth, which costs $9.99, the more Wildlife Acoustics will be able to afford to invest in improving the program, but I’m still not convinced it’s even possible, with the current size of processors in smart phones or even laptop computers, to create an app that can actually identify all the bird sounds of any single place, just like Shazam will never be able to recognize a tune except as a published recording in its database.

I’ll enjoy watching Song Sleuth continue to make improvements, and I'll love if they prove me wrong about whether it's truly possible to "turn your iPhone or iPad into an automatic bird song identifier," but for now, Song Sleuth is not an app I’ll be using.

If you want to learn bird songs, you'll be better off using Cornell's Merlin app, the Sibley eGuide to Birds app, Cornell's All About Birds website, their All About Birds bird song tutorial, or any of dozens of other ways of accessing bird songs.  At least for now.

Wednesday, June 28, 2017

Review: Merlin, a simple app to identify birds

Back in the ‘90s, this radio program introduced Earth Angel Bird Identification Binoculars. “With the teenie-tiny microchip embedded in the binocular housing, these binoculars can compare your bird with plumage of every known species and identify it in 12 seconds flat.”
Two decades later in the real world, we have a real-life app that helps you identify a bird based on your answers to 5 simple questions, or based on a photo you took. The app, named Merlin, was developed by the Cornell Lab of Ornithology, and it's surprisingly accurate. I tested it a few years ago, when it wasn't quite up to snuff yet. For some photos, it didn’t give the correct identification as the first choice, and it got a few photos entirely wrong, but there was a better-than-even chance that it would get any individual photo right. Based on tests I made today, the accuracy has gone up dramatically.

For a photo ID, you can use your smartphone to photograph a picture you have on your computer or camera screen, or straight from the phone. Merlin cautions, “For best results, use a photo of the bird unobstructed by vegetation or other birds. Merlin will always suggest a possible ID, but if a person can’t see the bird in the photo well enough to tell what it is, it’s unlikely that Merlin can, either.”

I just tested Merlin on two photos of a Brown Thrasher on a lawn that a person sent me this morning. She wanted to know what it was, but said these photos were “lousy,” and taken through a window screen.

I knew it was a thrasher, but the photos were not at all crisp and the color was distorted and much too red. I figured the side view, showing the bird’s distinctive shape and color pattern, would not be too hard for Merlin to work out, and sure enough, Brown Thrasher was the first choice it gave. I figured the other view, showing just the bird’s back and flanks but little of its face and none of its breast, would be trickier for Merlin, but Brown Thrasher was the first choice for that one as well.

House Wren

I then tested it on a front view of a House Wren, leaving out the distinctive wren features of the wings and tail, and it gave that as the first choice.

Red-breasted Nuthatch fledgling

Merlin also got a fluffed out baby Red-breasted Nuthatch right, even though this, too, didn't show the species’ distinctive shape—and when I zoomed in for Merlin, I even cropped out the tail.

I went through dozens of my photos of birds from Minnesota and Merlin got them all correct as the first choice for each. It did get stumped on one nice, clear photo sent to me today by someone who'd found these birds running about by his cabin on Rainy Lake.

Apparently one of his neighbors is raising Helmeted Guineafowl as free-range fowl. Of course, we could hardly expect any software to properly identify a domesticated African bird in the wilds of Minnesota.

Merlin has a button, “This is my bird!” that we click if we are certain it properly identified the photo—that’s one way crowdsourcing has improved the app’s accuracy, but the millions of checklists sent in to Cornell via eBird are a powerful source of current local information, too. If we’re uncertain even after seeing the choices Merlin presents, we can also go through the questions Merlin gives to identify a bird without a photo: Where did you see the bird? When did you see the bird? What size was the bird? (It gives four options—a tiny songbird, a robin, a crow, and a goose, offering the option of choosing in-between sizes as well.) What were the main colors? (It allows you to select from one to three choices among nine colors.) And was the bird…? (the choices are eating at a feeder, swimming or wading, on the ground, in trees or bushes, on a fence or wire, and soaring or flying).

Then it creates a list of possible birds, with several photos each, that it could be. Depending on the details, that list could have more than 20 choices, or just one or two, but the photos of each help you choose. The most probable is the first choice given.

Alder Flycatcher

Some species are too close in plumage for even an expert to be certain with just a visual representation. I put in a photo of what I knew was an Alder Flycatcher, and Merlin made that the first choice—impressive enough, but it gave the right alternate choices, Least and Willow Flycatchers, noted that Willow Flycatcher would be rare here, and said for the real bird, Alder Flycatcher, that it’s extremely similar to the other species and gave habitat and voice hints, along with actual recordings. A beginner who really didn’t know what it was would be able to verify its identification with these tools.

Yellow-bellied Flycatcher

When I gave Merlin a photo of a Yellow-bellied Flycatcher, a very similar species in the same genus, it gave that as the first choice with Alder as the second, again providing help with habitat details and recordings to verify the identification.

So Merlin is a shockingly cool app. I feel a special connection to it because many of my own photos are in Merlin’s database. And Merlin is absolutely free, for android or iPhone. Just put “Merlin bird identification” in your browser’s search box, or click here, to find it.

Monday, June 26, 2017

Where have all the insects gone?

Luna Moth

I took my first ornithology class at the Kellogg Biological Station, near Kalamazoo, Michigan, in the summer of 1975, and Russ took a water chemistry class there on the same days. At the time, we were living in East Lansing, and my class started at 6 am, so we had to leave home each morning about 4:30. We always started out with a clean windshield, but on the hour-long drive, we had to pull over at least once, sometimes even twice, to clean the windshield again, because it had become so spattered with bugs that not even the washer fluid and wipers could clean up the goopy mess. This was standard driving procedure back then. It was also common for the snowplows to have to come out to clear mayfly carcasses off bridges. There once were a LOT of flying insects.

Russ and I moved to Duluth in 1981, and we woke up every summer morning to dozens and dozens of moths clinging to the screens on our windows and back door.  Some were amazingly beautiful—various sphinx moths, and even an occasional luna, io, polyphemus, or cecropia moth. By mid-day they’d have fluttered away or been plucked off the screen by a phoebe or the Tree Swallows nesting two doors down. On summer evenings, we could hear Common Nighthawks overhead. They nested on flat roofs here and there all around Duluth.

Common Nighthawk

Nighthawks aren't sampled well on the Breeding Bird Survey,
but their numbers are clearly lower than in the 70s.

Back in the 80s, bug zappers suddenly came in vogue, and one of our neighbors set up a couple in his backyard. He expected them to take out the mosquitoes, but bug zappers are indiscriminate killers, and the vast majority of zapping noises we heard throughout the evening and night were much too loud for a mosquito—his lights were mostly taking out moths and other innocuous insects that had been sustaining our swallows and nighthawks. On many nights, the loud zapping seemed almost continuous.

Bug zapper lights were a short-lived fad, but they were far from the only things killing insects. Mayflies were disappearing as more and more waterfront property was developed with manicured lawns down to the shoreline, fertilizers running off into our lakes, rivers, and streams, supporting algae and other aquatic plants that ultimately depleted the oxygen levels; the most important thing mayflies need during their aquatic nymph stage is well-oxygenated water. At that same time, chemical lawn services and garden insecticides were growing increasingly popular. People who claimed virtuously to use only the relatively non-toxic Bt were a big part of the problem—the form of Bt that kills pest caterpillars kills every other lepidopteran caterpillar, too, including those of Monarch butterflies and Cecropia moths.

Cecropia Moth

Phoebes and swallows haven’t nested in my neighborhood since the 80s. I’m lucky to hear one or two nighthawks during spring migration now, and never hear them during their nesting season. Where we used to have several August evenings each year when thousands of nighthawks wended their way above Peabody Street, we’re now lucky to have one or two evenings a year when hundreds fly over.

Tree Swallows may not nest in my neighborhood anymore, but their numbers
are actually increasing in Minnesota according to the USGS Breeding Bird Survey.

Eastern Phoebe numbers are constant or even rising in Minnesota.

Last month, the American Association for the Advancement of Science’s journal, Science, published a story, “Where have all the insects gone?” summarizing several long-term studies based on bodies of data from nature reserves and other areas in western Europe and America, documenting massive and dramatic declines in insects. These studies have established that even in places where plant diversity and abundance have improved, insect numbers still declined.

One Canadian study involved probing into decades of stratified bird droppings in some old chimneys in which Chimney Swifts have nested for generations. Going through the layers of bird poop, they could track a striking change in the swifts’ diets in the 1940s, when DDT was introduced and suddenly the proportion of beetle remains dropped off. The proportion of beetle remains increased after DDT was banned in the 70s, but never reached the level it had been in the 40s. Meanwhile, most of the insects the swifts were catching were smaller than the pre-1940s species, meaning the swifts had to work harder for each calorie.

Chimney Swift

Chimney Swift numbers have been steadily declining since the 70s.

Some of the causes of insect declines scientists are looking at include habitat loss, increased use of fertilizers, light pollution, and pesticides, especially neonicotinoids. But the widespread, dramatic declines are almost certainly due to multiple factors, so even beginning to solve the problem will require multiple fronts of attack.

I’ve been talking about declining insect numbers since the 90s—that seemed quite obviously a serious factor in the declines of so many of my favorite birds that feed entirely on flying insects. And for years, people have been criticizing my conclusions because I had no proof of widespread declines in insects—just the anecdotal observations on my car’s windshield and on my window screens. I’m glad some scientists are taking these problems seriously and starting to quantify the decline. Solving the many factors that have contributed to the decline in important insects will be extraordinarily difficult as it is. It will be outright impossible until we acknowledge that there is even a problem.

Hummingbird Moth

Where are the Tree Swallows?

Tree Swallow

I just got an email from one of my friends, Jan Keough, who lives on a lake north of Duluth. Here it is, the last week of June, and she has not had a single Tree Swallow this year. She’d cleaned out her three swallow nest boxes to be ready. Last year one of the boxes attracted squirrels, which chewed up the entrance hole, but she bought a metal ring—what’s called a nest hole restrictor—to exclude birds and mammals larger than Tree Swallows from using the box. She was concerned that that might have discouraged swallows from using what had been her most reliable box, or that tiny bits of debris from the squirrel nest might have repelled the swallows, though she noted that she hadn’t seen any swallows swooping around on land or over the lake this year.

As people on my Spring Warbler Walks can attest, this spring was a pretty cool, especially in the central states but also up here. This seemed to delay migration for a great many birds. We were still wearing winter scarves and gloves at the very end of May.

Laura and Pip and Laura's car
Pip and me at our last Warbler Walk of the year on May 30. It was cold!

These temperatures, though not much below normal on average, did keep flying insects at bay, and those flying insects are what fuel Tree Swallow migration, sustain nesting adults, provide the basic building blocks to produce eggs, and keep baby Tree Swallows alive and thriving. I wonder if many swallows didn’t stay a bit further south this season?

We did see a few Tree Swallows on those warbler walks. On May 18 we counted at least 100 swarming in a large migratory flock with other swallow species at Park Point. One pair seemed to be interested in nesting at the Western Waterfront Trail, but we didn’t see them at all on our last field trip there, so I’m not sure they stuck around.

My dog Pip and I came upon a small group a mile or two further down the Western Waterfront Trail on May fifth. One pair who stayed very close to a nest box seemed almost certainly to be nesting—they don’t start incubating eggs until they have a full clutch, but this pair stuck very close to the nest box, giving me splendid opportunities for photos of both of them.

Tree Swallow

Tree Swallow

Temperatures along the river in West Duluth are often milder than those near the North Shore, so it’s easy to imagine that swallows may have been gravitating to warmer spots.

I don’t think the situation is dire. I looked on the U.S. Geological Survey’s Breeding Bird Survey webpage, and the graphs for Tree Swallow population trends in Wisconsin and Minnesota don’t show any declines. Their numbers in Wisconsin swing crazily up and down from year to year, but the overall trend looks steady, their numbers fairly high.

In Minnesota, the overall numbers are a bit lower. Here we see less variation from year to year, but the overall population seems to be trending up.

It’s possible swallows rejected Jan's one nest box because of the metal ring around the entrance hole, but they didn’t use her other boxes either. Many songbirds have more of a sense of smell than people once believed, but I know of no evidence whatsoever that debris at the bottom would deter Tree Swallows from nesting. Indeed, I know people who never clean out their nest boxes and still get birds using them, including swallows. So I’m hoping this is just a one-year aberration.

If other listeners are seeing unusual numbers of swallows or other birds this year, high or low, please let me know. And Jan will let me know if any Tree Swallows show up either for late nesting or in migratory flocks as they start gathering in July.

It’s sad to not see any swallows in a given year, but it’s even sadder when they do show up and then you find adults or nestlings dead in the nest boxes. That’s not much consolation for Jan, but we at least can hope for better next year.

Tree Swallow

Friday, June 23, 2017

The last moments of a dying nuthatch

This was written on May 9, 2001, and was the transcript for this For the Birds radio program.

White-breasted Nuthatch fatally wounded by cat

I’m sitting at my computer typing with my right hand while my left hand cradles a White-breasted Nuthatch as he dies. An hour ago he was busy doing what nuthatches do, flying and feeding and helping excavate a nest. But in the next hour or so, he’ll be dead thanks to a cat.

When I was a licensed rehabber, people brought me birds hurt by their cats all the time. I never quite knew how to deal with the people. On the one hand, they obviously did care enough to go to the trouble of bringing me the injured ones, but on the other hand, you don’t have to be a rocket scientist to know that cats do horrible damage to birds. I’m too innately polite to scold them, but I do manage to get in some subtle comments about our city’s cat leash law, and how cats kill hundreds of millions of birds nationwide every year. A few people have retorted sarcastically that it doesn’t take a rocket scientist to see that this particular bird isn’t dead thanks to them saving it and bringing it to me. But when people “rescue” a bird from their cat’s mouth, these birds virtually never survive for more than a few days, with or without a rehabber. Sometimes they have internal injuries and bleed to death, as this little nuthatch is doing right now. Sometimes they last a few days before dying of a massive infection.

On TV shows, compassion and skill have at least a chance of winning the day. I wish this were TV. If this were “ER,” I could yell to a nurse to hook him up to an IV and give him 2 units of nuthatch Type A positive blood as I scrubbed and readied myself for surgery. Of course I would have all the equipment and microsurgical techniques one would need to operate on a patient that weighs three-quarters of an ounce. Five nuthatches together weigh less than one quarter pound hamburger patty. The damage a ten-pound cat can do to one is comparable to the damage a 16-ton shark could do to a hundred-and-fifty-pound human. Of course, the largest sharks on record weigh only 15 tons, but let’s not quibble.

Feathers being what they are, most of the damage on a bird isn’t visible except to a discerning and practiced eye. This nuthatch’s tail was ripped out—not just the feathers but skin and muscle and a chunk of the pygostyle, the last fused vertebrae. This damage is irreparable. But the bird’s fluffy tummy feathers cover the damage and nuthatches have a short tail anyway, so the person who brought it to me never even noticed.

I wonder if a tail being ripped out feels anything like that first victim in the movie Jaws as she felt that first tug. Of course, Jaws is fiction. This nuthatch is real. Not even George Clooney’s hands could make him better.

Most people get a false sense of complacency when a bird flies away after their cat toys with it a bit, or if they pull it out of the cat’s mouth and bring it to a rehabber. Do they believe a bird is a mechanical thing that either works or doesn’t? If it can fly away in a panic on sheer adrenaline, it must be okay, right?

I’m the one with blood on my hands, watching the life leak out. In all my years of rehab, I’ve saved only two cat-injured birds, and I know many rehabbers who never saved even one.

This dying nuthatch is making me feel more bitter than usual, because this one wasn’t brought to me by some well-meaning but ignorant person. It was brought to me by a friend—one who I know cares about birds, and one who is certainly aware of my city’s cat leash law. Maybe when she sees her cats looking out the window, she interprets it as a desperate longing for freedom. Maybe she’s tired of hearing them meow at the door. Maybe she’s just tired of cleaning the litter box.

I should have told her that I’m tired, too. I’m tired of explaining over and over that cats are subsidized killers, fed and sheltered by us humans, their population maintained at far higher levels than any natural predators could be. I’m tired of reminding them that cats allowed outdoors have an average life span of less than five years, while indoor cats often live to be 17. And I’m especially tired of witnessing the irregular, weakening gasps of a dying nuthatch, as I watch the sparkle of light in its tiny eyes suddenly dim, as its body shudders one last time, cradled here in my hand.

Wednesday, June 21, 2017

Of Bald and Toupee-Wearing Birds

Feathers are one of the most wonderful adaptations in the animal world. They’re considered the most complex integumentary structures found in vertebrates; apparently, as far as the skin goes, the Therapod dinosaurs and birds are the most evolved creatures on earth. Feathers provide extraordinary insulation and waterproofing, which is why more species of birds than mammals survive in the most extreme climate conditions on earth. And feathers are exceptionally lightweight even as they provide insulation and waterproofing, allowing birds to be the most numerous and widespread vertebrate fliers on the planet.

Those benefits exact a cost—feathers degrade and wear out with time, so all bird species replace their body and flight feathers periodically in a process we call molt. Many of our songbirds molt just once a year. Chickadees time this molt for summer after the young no longer depend on the adults. Adult chickadees wearing their year-old feathers are run ragged by their chicks. By mid-summer, some look extraordinarily bedraggled and even pathetic, especially compared with their fledglings, wearing spanking new feathers.

Bedraggled Black-capped Chickadee

Black-capped Chickadee--fledging day!

But soon all those worn out adult feathers will be pushed out by new ones, leaving the adults in fine fettle before the coming winter. Most birders call the new body feathers molted into in late summer basic plumage.

Some songbirds have a second partial molt each year, replacing their body feathers before the breeding season. We can watch goldfinches make the transition from dull winter plumage to bright spring plumage—as they molt, their body feathers look very patchy. If we were in the tropics, we could observe tanagers go through that same patchy process before they head up here for the breeding season. The feathers giving this different appearance for the breeding season are called the alternate plumage.

American Goldfinch

Some birds manage to enhance or change their appearance before the breeding season while only molting once, in late summer. In the brand new feathers of their basic plumage, a Northern Cardinal's body feathers are edged with brown, giving them a dullish look in late summer and early winter. Those feather edges improve insulation and weather proofing at least a bit during the coldest season, but by winter’s end are wearing off so that the more brilliant part of the feather is exposed, giving the male his most spectacularly red plumage right when he needs it.

Timing the molt for summer’s end is ideal for many of our eastern songbirds, which have plenty of food resources in mid-late summer, right when they’re done with egg production and all the high-energy costs of incubating those eggs and raising young. As temperatures start dropping in fall, most songbirds grow additional down feathers in preparation for winter, but these inner feathers don’t change their appearance at all. For example, redpoll feathers weigh 31 percent more in winter than in summer because of this increase.

No bird drops all its body feathers at once during molt—new feathers push the old ones out little by little.  Oddly enough, some individual jays and cardinals do seem to molt all their head feathers at once.

Northern Cardinal

In rare cases, according to a few authorities, this may involve lice or mites, but I suspect it’s normal individual variation. The Blue Jay entry in The Birds of North America notes “All capital-tract feathers dropped nearly simultaneously, resulting in individuals being nearly bald for about a week,” but there is some individual variation: when I was rehabbing, I had two Blue Jays that I kept in adjoining cages. Every summer Sneakers lost all her head feathers at once, while BJ’s head molt was far less noticeable. Tragically, I never took photos of Sneakers during her head-feather molt.

The sturdy wing and tail feathers are lost and replaced in sequence. These feathers must be pretty much perfect to support the bird in flight, so some birds replace only some of them each year. With a close look or a look under a black light at a bird such as an owl in hand, bird banders can identify which feathers are fresh and which are faded to figure out how many times a bird has replaced these feathers, providing a solid guess about the bird’s age.

Loons and some other species that are exceedingly heavy relative to their wing size can’t afford to lose any flight feathers from spring migration through fall migration—any reduction in wing surface area impairs their ability to fly. This is why loons molt all their wing feathers simultaneously while they’re on the ocean in winter. They can swim anywhere they need to find food during the weeks when they’re unable to fly, and will have fresh, sturdy new feathers by the time they head back to their freshwater breeding lakes.

Right now I’m thinking about molting birds because Lisa Johnson has been taking photos of American White Pelicans this summer. These birds live up to their name—their adult plumage is white with gleaming black flight feathers. But weirdly, breeding adults in summer grow patchy black feathers on their crown, nape, and along the back of their necks.

The pattern of these black feathers varies crazily from one bird to another, and there is no consensus on what to call them or whether it’s a true molt that produces them, or if they’re produced by either an early part of basic molt or a delayed part of an alternate molt. Most people just call this supplemental plumage. But since the odd feathers are found primarily on the top of the head, Lisa decided to call them a toupee, which seems as accurate and descriptive as anything ornithologists have come up with.

This pelican toupee grows in during the nesting season, at the same point in the nesting cycle that Royal, Elegant, and Sandwich Terns of the coasts are molting into dark head spotting that also varies widely among individuals.

Royal Tern

In these terns and the American White Pelican, the young gather into large groups called crèches, quite similar to what young sea ducks, mergansers, and geese form. But baby waterfowl feed themselves—they can follow any adult to a good feeding spot. Pelican and tern chicks depend on their parents to bring food and feed them. These chicks may memorize the unique spotting on their parents' heads during their time in the nest so they can recognize their parents when they join these crèches.

A lot of birders put away their binoculars in summer as birds stop singing, grow secretive to raise their young, and look most bedraggled. For me, summer is when birding grows the most interesting, when we get fascinating glimpses into avian family life as well as peculiar things like bald jays and toupee-wearing pelicans. A year of bird watching is best enjoyed all in good time. For the most aware birders, every moment of every day, it's all a good time.

Monday, June 19, 2017

My sound recording equipment

Laura recording birds

Right after my last program aired on KUMD, about my sound recordings, I got a couple of emails asking what recording equipment I use. I can't make fair endorsements or recommendations about sound equipment because I'm only familiar with what I use, so can't compare it with anything else available, but I can at least describe my own set up.

I started out on Christmas 2000 with a Sennheiser omnidirectional microphone and Telinga parabola system (pictured in the photo above). Parabolas magnify the sound they’re directed at while reducing other sounds, which is perfect when you want to get a clean recording of a single bird. But the recording doesn’t sound so good if you aren’t aimed precisely at the bird—that’s why parabolas are usually clear plastic, so you can see through them. The trick is that you need to be wearing headphones, and it’s impossible to gauge direction to find a tiny, often hidden bird when wearing headphones linked to a single microphone. It’s amazing when you’re moving the parabola around hoping to find the bird and suddenly there it is—the sound pops.

A couple of years after I got my parabolic system, I saved up the money to get a nice Sennheiser directional microphone, which is way more forgiving about where it’s pointed than a parabola is.

The problem with this mic is that, no matter what, it doesn’t amplify the call I want as my parabola does. But it captures the ambient sound better, doesn’t get hit by flies and mosquitoes with thuds, and is the simplest, easiest microphone to bring on trips. I started out with a small foam windscreen for this microphone.

Last summer I bought one of those ridiculously fuzzy wind screens, which are more effective at screening out background noise, though they somewhat lower the volume of the sounds I want, too.

From the start, I recorded onto minidiscs except for a few days during the week in June 2001 when I took the Cornell Lab of Ornithology’s natural sound recording workshop and was expected to use a tape recorder for part of the session. Minidisc recorders had the great advantage of being wonderfully small—mine fit inside a perfect little wrist pack as pictured in the photo at the top of this post—and they didn’t have any of the hiss of audiotape. But minidiscs also had a problem—they compress the sound. The recordings sound wonderful to my ears, but some of the spectrograms don’t look like the spectrogram of the same sound recorded onto tape or uncompressed digital recorders. That’s because the digitally encoded audio signal onto a minidisc was data-compressed using the Adaptive TRansform Acoustic Coding formula also called ATRAC, which is what they call a 'psychoacoustic' data reduction system, omitting some of the content that is ostensibly inaudible to our ears anyway, to make a smaller file size. The Cornell Lab of Ornithology’s Macaulay Library of Natural Sounds needs what are called lossless recordings that haven’t been compressed at all.

The Lab got away from tape recorders as soon as lossless digital recorders became available. When I started working at the Cornell Lab of Ornithology, Greg Budney of the Macaulay Library of Natural Sounds helped me select a good Marantz digital recorder—which is what I usually use now, not only for natural recordings but also to create my radio program and podcast. This records sounds as uncompressed .wav files onto an SD card. To record my voice, I use a fairly inexpensive studio microphone, but for natural recordings of birds, I use the directional microphone or parabolic microphone, and for ambient nature sounds I use the omnidirectional mic.

Last summer, in anticipation of my trips to Peru, Cuba, and Uganda, I bought a more portable little recorder made by Olympus. This was a disappointment—it works on a rechargeable battery, but the battery life is only a few hours, and it doesn’t record when connected to an external power source. It’s also not nearly as intuitive to use as the Marantz, and had I realized the battery issue, I’d not have bought it, though now that I’m stuck with it, I’m trying to make the best of it in some situations.

Every now and then, I hear an amazing sound when I don’t have any of my recording equipment. That’s when I pull out my smart phone and use the voice recorder app. The results are not as good as what I’d get with my professional equipment, but if I’m close enough to the bird, I can get some decent memories, like when I was on a field trip in the Little River National Wildlife Refuge in Idabel, Oklahoma and came upon a singing Swainson’s Warbler at close enough range to get this recording. Not bad for using a free app built into my phone. It may not be perfect, but what is?

Duck and Goose Nurseries or Crèches

Listening carefully

When I was living in Madison, Wisconsin, in the 1970s, I used to love seeing baby ducks. Ducklings are so cosmically innocent, their big, soft eyes looking out at the world with such open curiosity and trust. It’s logical that we’d find the tiniest baby ducks and geese appealing: as a mammal species wherein adults of both sexes instinctively protect dependent young for many years, and with our babies completely helpless for over a year, we instinctively respond with warmth to beings with large, open eyes and relatively oversized heads.

With my own eyes newly opened to the wonder of birds, how could I not thrill the one time I once witnessed baby Wood Ducks jumping, one by one, from their warm, secure nest high in a tree down to their mother, softly calling from the unknown depths. I saw them, one by one, their tiny legs and feet extended, tiny flippers for wings fluttering madly in that literal leap of faith all the way down to the hard ground below. Each one seemed as light as a marshmallow as it bounced on the ground, scrambled to its feet, and headed straight to its mother.

The first day or two after Wood Duck babies left the nest, the broods contained eight or ten tiny baby ducks, sometimes even a dozen. I could often find the same families day after day, but invariably, as the babies grew, I’d count fewer and fewer in each brood. I’d feel a visceral sorrow for the existence of foxes and raccoons, though ironically, the reason those hunters were so hell bent on raiding duck families was to raise their own little baby foxes and raccoons, which elicit the same tender feelings in us humans.

Mario, Luigi, and Princess

But having tender feelings toward specific baby ducks, I wasn’t much interested in taking that broad and sympathetic a view toward the animals that killed them. And as a warm-blooded mammal, I wasn’t the least bit sympathetic toward snapping turtles and large-mouthed fish. One morning as I watched a long line of tiny ducklings following their mother across a pond, the one I was specifically focused on through my binoculars was suddenly grabbed in the middle. Its tiny mouth opened in what had to be surprise and pain as it was jerked straight down into the water. Ever since that horrifying moment, I can’t see baby ducks without fear for them overshadowing my delight.

I hardly ever saw baby geese during the 1970s, which marked the very beginnings of when their population started mushrooming, but by the time we moved to Minnesota in 1981, baby geese were a regular, and now a too-common sight. Well, too common in the detached, long view of bird populations and how one over-populated species interacts with our own over-populated species. To my eyes, each individual tiny gosling is every bit as adorable as a baby duck.

Canada Goose

This year during our spring warbler walks, we started seeing baby geese in May. The first family groups we saw all included two adults, presumably the parents, and four to six tiny, fluffy goslings.

Canada Goose

By the end of May, though, what looked like family units had grown dramatically, the goslings not just bigger in size, but much more numerous as well. One group at Park Point had over forty goslings attended by a single adult.

Canada Goose

This is not evidence of super-fertile females or that predation has declined. No, the geese are doing what a lot of ducks, especially diving ducks, do, combining families into large broods of young, forming what are often called “nurseries” or “crèches.”

The very first time I saw Common Eiders, off the coast of Maine in 1993, I saw a single mother with at least 70 ducklings. I was shocked—I’d never seen anything like that before! That’s when I learned about ducks doing this. Female ducks are pretty depleted by the time their young hatch—they’ve used up vast resources to produce their large clutch of eggs, and incubating eggs is extremely energy intensive, too. Before their bodies are dense enough to dive well, the babies get their food in the shallows. When families combine resources, the mothers can take turns feeding in deeper water.

Common Eider
This photo, taken in 2016 before most eider broods had hatched, shows adult females
attending a single clutch. A week or two later, what we'd see would be many more ducklings
and only one female at a time.

I’ve hardly ever seen dabbling ducks combine broods like this—the mothers can get plenty of food right where their ducklings are—but this happens a lot with mergansers. David Harrington of KBXE sent me an amazing photo of a female Common Merganser with 23 adorable ducklings, and generously gave me permission to post it.  

Copyright 2017 by David Harrington
When a mother diving duck doesn't have a nearby neighbor to share duties with, she will sometimes have to leave her ducklings unattended for brief periods.

KBXE's David Harrington came upon this single brood of baby Common Goldeneyes. He
writes, "The  mother had completely 
left the kids to babysit themselves.  I don’t know how
long she  was gone but she was back after 
about 5 minutes."  

Canada Geese are more and more forming crèches, too, probably to allow parents to take turns feeding and resting away from their broods. Like ducks, the youngest, tiniest geese are still seen in small family groups, but after a few days, the parents are ready for a few breaks. This keeps the young in the safest places, away from lurking predators that could never manage the huge adults, even as the adults go off to their favorite feeding places to rebuild their strength.

Canada Goose

Watching how resourceful birds can be in ensuring the world has a continuing supply of baby birds is ever so much more lovely and pleasant than watching baby ducks disappear into the depths, never to be seen again.