Showing posts with the label Birds of Arizona

The Phainopepla is a curious bird

The Phainopepla is a curious bird. Their tall crest and feathers of silky black or gray are accentuated by piercing blood-red eyes. They reveal luminous white wing patches in their somewhat slow yet buoyant flight. In the Sonoran Desert they fiercely defend their clumps of desert mistletoe from intruders with an inquisitive “Wert?” A charming and charismatic bird at first glance, the closer one looks into any aspect of its natural history, one realizes the veracity of Allan Philips' claim in The Birds of Arizona: "Phainopeplas have no respect for the rules."

"And there isn't any need for you to doubt it"
-Rum Tum Tugger
Pencil sketch of Phainopepla
Phainopepla nitens – sketch by the author

"Wert?" call

The Phainopepla song is a modest volume series of burry and polyphonic phrases, evocative of blackbird and shrike vocalizations in their complexity. Those that work closely with Phainopepla have noted a bizarre vocal behavior when they're distressed while being handled: they unleash a near constant stream of loud (and very convincing) imitations. These include a variety of hawk and other predator calls, perhaps in an attempt to distract or frighten, but they also mimic a wide variety of small harmless songbirds. Investigating this behavior, there is a study that shows a variety of imitations mixed with alarm calls is most effective at rallying other nearby species to help mob a predator. When threatened, the Phainopepla vocally simulates a multi-species scolding mob attempting to drive a predator away. This in turn helps manifest a real mob with real birds. Avian aural Twitter bots.

Under normal circumstances one rarely hears these imitations in the field though. I had no idea Phainopeplas were mimics at all when I encountered a lone male singing from the top of a palo verde in the Phoenix Mountains Preserve in January 2019. I could hear the louder burry phrases typical of their song but interspersed throughout were quiet sounds I couldn’t quite make out. I snuck myself under the tree where the bird was singing and with the assistance of my microphone I then could hear what he was muttering.  Listen below:

After some introductory phrases he launches into a series of imitations at around 17 seconds in what is referred to as their Quiet Song. In this two minute clip I hear imitations of at least a dozen species, from desert dwelling critters like Curve-billed Thrasher and Harris’ Antelope Squirrel to a variety of higher elevation forest birds like Spotted Towhee, Cassin’s Kingbird, Tree Swallow, and Western Wood-pewee. Unlike the famous mimic, the Northern Mockingbird, which belts out its collection of imitations at the top of its lungs, the Phainopepla whispers them. They can’t be heard from more than a stone’s throw away, so who are they for? Sometimes quiet songs serve to strengthen pair bonds when birds are in close proximity – but I didn't see any other Phainopeplas nearby. Was he practicing?  I doubt it – they sound pretty crystallized to me. When listening to the extended recording he uses the same imitations many times with very similar phrasing and delivery. Was he feeling threatened, either by me or something else? Again, I doubt it – giving quiet imitations of birds that are currently hundreds of miles away doesn't seem like an effective mob-eliciting strategy in this context. Whatever the case may be, the function or meaning of imitation seems to be flexible in different contexts. They are very impressive though, why be so coy about it?

"And there isn't any need for me to shout it"
-Rum Tum Tugger

Wait a minute, how is this desert-breeder imitating so many forest birds to begin with? Without doing any research we’re already clued-in to a fascinating aspect of this bird’s natural history just by listening to his peculiar quiet song. Clearly, this male has been around. He has seen (and heard) some things.

While Phainopepla are fiercely territorial, mistletoe berry-loving, desert-breeding birds in winter and early spring, they largely vacate the premises by early summer. Around the same time, they are found in mid-elevation riparian and oak woodland habitat, sometimes hundreds of miles away. There they are social creatures, forming loose colonies, nesting together in the same trees, eating berries from the same bushes. They incorporate many more insects into their diet. They’re like a different bird.

For almost a century people have wondered whether these were distinct populations of Phainopepla or the same birds breeding twice a year in different habitats. There are still many details to be worked out but a recent study has shown GPS-tagged desert-breeding Phainopepla do migrate to the expected higher elevation habitats each year and there is no discernible genetic difference between populations in each location. This strongly suggests the same birds breed in both habitats. Aside from a handful of very interesting outliers, most other North American birds are constrained by various environmental, physiological, and behavioral limitations and only have one chance per year to breed. If Phainopeplas are in fact itinerant or migratory double-breeders, “[They] would be behaviorally flexible –in migration, breeding, and social-structure– to a degree not documented in any other North American bird” (Chu, M. and G. Walseberg, Birds of the World, 2020). As for the rules and constructs, generalizations and metaphorical boxes we try to fit birds into, the Phainopepla indeed has no respect for them.

“For he will do as he do do
And there's no doing anything about it”
-Rum Tum Tugger

Whitewater Draw Mystery

Listen to this:

(Headphones recommended)

It's been over a year since I recorded this in March 2019 and I’m only just beginning to understand what it is.

We arrived in the dark of night, the graded dirt road violently vibrating my Honda Fit. After a few minutes of straining to hear, I turned off the radio and listened to the sound of every piece of my car and body rattle.  We pulled into the dirt parking area, shut off the engine and stepped outside. Suddenly free from the confines of the car, our ears began to open up beyond the immediate vicinity, expanding outward in every direction into the darkness...until we heard them.

My girlfriend Nell and I had come to Whitewater Draw on the last night of February to experience the Sandhill Cranes that winter at this 600-acre wetland in the southeast corner of Arizona. A huge striking bird, I had only previously seen handfuls of migrating cranes off rural county roads outside Phoenix. Hearing tens of thousands of them at night though, distant, yet filling the darkness with their prehistoric trumpeting croaks and screams was awe-inspiring.

In the morning, we were posted up by the wetland before sunrise, soaking in the sights and sounds before the cranes took off to forage in nearby agricultural fields for the morning.

Sunrise at Whitewater Draw 3/1/2019

Fun fact about Sandhill Cranes: their tracheas are elongated and coiled into their sternum. This tracheal elongation allows the cranes to have deeper, more harmonically rich voices with lower formant frequencies, making them sound even larger than they already are. The coiling around the sternum, a clever way to fit this elongated trachea into a crane body, is also thought to allow the sternum to act as a amplifying resonator. In other words, it helps the cranes croak and scream at ear-shattering volume. Cranes are amazing.

Once most of the cranes had departed for the morning we were left to wander the grounds to see what other birds and critters were around — which brings us to the aforementioned recording that has transfixed me ever since. In a tiny murky pond opposite the cranes were a pair of Northern Shovelers, striking ducks with large spade-shaped bills, and an interesting sound. I pointed my parabolic microphone towards the shovelers, slipped on my headphones and pressed record. Here it is again:

So good. A low clucking sound, sometimes phoneticized as ‘Tsook’ is the most common Northern Shoveler vocalization so that seemed to account for some of what can be heard. The grunty-smoochy sounds, however, were something I was unfamiliar with. I chalked it up to a high-intensity courtship vocalization that is only given at specific times of year (by exceptionally horny birds) and filed it away.

In the coming months, I would return to the recording and try to find any mention of this grunty-smoochy Northern Shoveler vocalization. The excellent Peterson Field Guide to Bird Sounds curated by Nathan Pieplow is my go-to resource for a concise yet near-comprehensive recorded catalogue of bird vocalizations in North America — but this sound was absent. I browsed the extensive offerings at the Macaulay Library and Xeno-Canto but still could not find this vocalization. Even the Birds of the World account had no mention of this vocalization as far as I could tell, though I often find text descriptions of bird vocalizations a bit inscrutable:

McKinney (McKinney 1970) recorded rhythmical wheezy whe or thic or quiet took notes by males during copulation; also recorded one male giving a long sighing noise at copulation. Postcopulatory behavior by males usually includes a loud, nasal paaay, followed by a series of repeated calls.

Audio recording of birds is still a relatively young pursuit. While it is quickly gaining popularity, it is still not widely adopted by the birding world so the possibility of recording an uncommon or cryptic vocalization for the first time is a real possibility (especially when you add state or county location qualifiers). I excitedly wondered if I had made such a recording breakthrough. It wasn’t until early the next spring when I heard the sound coming from the edge of a mucky pond with not a duck in sight that I began to suspect this was no shoveler sound at all.

Growing up in Phoenix, I rarely had occasion to listen to frogs and until recently have not given them much thought. With a sneaking suspicion I got ahold of Lang Elliott’s beautiful Frogs and Toads of North America and listened to all 99 tracks and 70 minutes. I was floored. The diversity of frog sounds and their charming wonkiness were completely entrancing. Still new to frog sound ID, I could say my grunty-smoochers were probably one of a handful of leopard frog species found in Arizona. A quick perusal of the Arizona Game and Fish Department website revealed Whitewater Draw is home to the Plains Leopard Frog.

It turns out my “Northern Shoveler” recording is almost entirely non-avian. The frogs that I failed to notice were likely giving what is referred to as an advertisement call. Frog advertisement calls function similarly to bird song: establishing territory, attracting females, repelling rival males. As with most animal vocalizations though, more nuances are likely to be found with closer study. These advertisement calls were apparently ineffectual on me but through sheer bizarreness eventually drew me into the wonderful world of amphibian acoustics. This is why I love paying attention to sounds, whether they’re birds, frogs, music or especially unknown sounds, you might learn something. And it is fun.