Wobbling waxwings

Cedar waxwing (Photo: Eve Fraser-Corp, Creative Commons license)

By the end of winter, the fruit upon which cedar waxwings depend can pack a real punch (Photo: Eve Fraser-Corp, Creative Commons license)

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I recently came across a report that cedar waxwings (Bombycilla cedrorum) have returned to Texas. Every time I hear someone mention this species I’m reminded of  my days as director of a wildlife center in Houston. For a few weeks every year the waxwings would show up by the cardboard box-full and the rehabilitation clinic would turn into… well, a different kind of rehab center.

With their handsome, distinctive plumage, even a newbie birder can easily recognize this species. Their yellow tail- and red wing-tips look as if they’ve been dipped in sealing wax—thus the name. With a range that covers much of North America, waxwings aren’t rare but they’re not as common as some of our iconic backyard birds, so it’s always a bit of a thrill when they’re in the neighborhood.

Cedar waxwing and chick (Photo: Alan Huett, Creative Commons license)They’re one of only a handful of avian species in the U.S. and Canada whose diet is composed largely (but not entirely) of fruit, a useful characteristic when one shares a breeding territory with brown-headed cowbirds (Molothrus ater) and other nesting parasites—females who don’t bother to build a nest of their own. Instead, they leave their eggs in the nests of other birds and the cowbird chicks are cared for like biological children. In fact, the foster nestling normally out-competes the surrogate’s own offspring when food is being passed out but the high-sugar diet provided by waxwing parents, while perfect for their own kids, causes the cowbird to waste away.

Waxwing adaptability has allowed them to benefit from the introduction of non-native fruit-bearing plants used in urban and suburban landscaping. For example, they seem to love honeysuckle… and it shows. The red pigment in the exotic vine’s berries can turn the bird’s canary tail-tips bright orange, a plumage change birders and ornithologists first began to notice in the 1960s.

Waxwing flock on pyracantha (Photo: Bob Muller, Creative Commons license)Waxwings travel in flocks that may include 40+ individuals, all searching for pyracantha and privet, choke cherries, mulberries, and any other tree or shrub that bears sugary fruit. Once they’ve gobbled up every last berry, they move along without a backward glance.

Unless the fruit is spiked.

It’s not a matter of someone trying to contribute to avian delinquency. From late autumn until plants have produced new spring and summer crops, last season’s berries, drupes, drupelets, pomes, and other sweet seed containers hang on, growing inceasingly less… fresh, shall we say. Temperature fluctuations and the presence of wild yeasts often will cause fruit to ferment in situ. Migration and colder temperatures make for voracious birds and the waxwings are carbo-loading as fast as they can swallow. They don’t seem to notice some of the snacks pack a punch. When you weigh slightly more than an ounce, the alcohol content doesn’t have to be very high to knock you for a loop. Next thing you know, birds are careening around on the front lawn like New Year’s Eve.

Injured waxwing (Photo: Churl Han, Creative Commons license)It can look rather comical but it’s no laughing matter. Many inebriated birds are seriously injured or are killed when they fly into cars and windows.

Good Samaritans across the county scoop disoriented birds into cardboard boxes and head for the nearest wildlife rehabilitation center. There, the birds are given a head-to-toe, beak-to-tail examination. Most of the patients are simply allowed to safely sleep it off in a warm, dark room before being released to continue their travels… although they probably set out with a doozy of a headache.


Start your day with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to name for making their work available through a Creative Commons license: Eve Fraser-Corp (waxwing with wizened berry); Eve Fraser-Corp (waxwing with wizened berry); Alan Huett (waxwing adult and nestling);  Bob Muller (waxwings on pyracantha)’ and Churl Han (injured waxwing).

Village voice

white-crowned sparrow by KaCey97007, Creative Commons license

A white-crowned sparrow trying to get a date (Photo: KaCey97007, Creative Commons license)

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seagull (Photo: Dani_vr, Creative Commons license)How can one small voice cut through the cacophony of modern metropolitan life? A recently published study, combined with some earlier work, suggests that contrary to what you might assume, the secret to city communication isn’t shouting.

Urban background noise is heavily weighted toward the lower sound frequencies of 20 to 200 Hz—think diesel engines (50-60 Hz).  That’s not to say there aren’t a lot of higher frequency noises in the concrete jungle but, compared to say, the rain forest’s tenor voice, cities sing baritone… and with enough projection to reach the last row of the balcony. Depending on the location and the time of day, your city may be belting out it’s theme song at anywhere from ~45-90 decibels (dB). Ever try to tweet over a lawn mower (and I don’t mean with your smart phone)?

People who haven’t yet experienced any hearing loss can detect activity in the 20 to 20,000Hz range. The faintest sounds we’re likely to hear register at about 0 dB. By 120 db we begin to experience discomfort or even pain. Now, as someone who loves to listen to nearly every kind of music, laughter in all its forms, Japanese prayer bells playing with a breeze, and rain bouncing on a tin roof, I’d be the first to agree that the human ear is a marvel. But compared to many of our fellow Earthlings, it’s… well, it’s pitiful. My wire fox terrier puts me to shame, easily picking up sounds from 40-60,000 Hz. The super-sensitive hearing of a bat, used for echolocation, ranges from 20-120,000 Hz.

common blackbird (Photo: Oystercatcher, Creative Commons license)

common blackbird

According to the ever-useful Birder’s Handbook, we have more auditory commonality with birds, whose ability to discriminate between frequencies and degrees of loudness is on a par with our own. So perhaps we would be well served to take a page from the songbird songbook when trying to be heard in our rapidly urbanizing modern life. Researchers at the Universities of Copenhagen and Aberystwyth found that great tits (Parus major) living in urban habitats sing at a significantly higher frequency than their rural relatives. This finding coincides with previous studies reporting the same phenomenon for house finches (Carpodacus mexicanus), song sparrows (Melospiza melodia), white-crowned sparrows (Zonotrichia leucophrys), dark-eyed juncos (Junco hyemalis), and common blackbirds (Turdus merula).

European robin (Photo-Steve Harris, Creative Commons license)

European robin

Of course, going all Bee-Gees isn’t the only way a guy can get some attention from the talent scouts.  A 2007 study from the University of Sheffield found that European robins (Erithacus rubecula) living downtown changed their performance times, from doo-wopping during the day to crooning almost exclusively after sundown when the din dies down a bit. In Berlin, nightingales (Luscinia megarhynchos) take the less subtle approach and just turn up the volume, at least on weekdays. But there’s a price to be paid for setting the amps to 11—a greater metabolic demand and more attention from predators. By broadcasting on a different frequency, some city songbirds have stumbled onto a low-risk solution to a major challenge of city life.

song sparrow (Photo: TC Davis, Creative Commons license)

song sparrow

There’s incentive for avian adaptation (let’s not call it selling out) to make it onto the airwaves. You see, in the bird world the divas are all, um… divos. No, they don’t wear red plastic wedding cake hats and ill-fitting 1980s MTV fashion—that’s Devo. Let me put it another way: boy birds are the rock stars, girl birds are the groupies. Males warble (or learn to shred the guitar, or maybe groove a bass line) to get noticed by the ladies. If a gal likes a guy’s song she’ll hook up with him and probably become his baby-mama. But there’s a lot of competition out there and before you can score, you’ve gotta get heard.

Hey, singing falsetto to some chick may not be the most macho thing a fellow can do, but it beats spending Saturday night getting drunk at the karaoke bar with your buddies and going home alone.

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Start your day with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license:  KaCey97007 (white-crowned sparrow); Dani_vr (seagull); Oystercatcher (common blackbird); Steve Harris (European robin); and TC Davis (song sparrow).