Okay, I’m guessing most serious Arizona birders know Cactus Wren, not Greater Roadrunner, is our state bird.  But here’s the thing—Cactus Wrens are ubiquitous and conspicuous so most Valley birders take them for granted and don’t bother to observe the nuances of their unique lifestyle and just how different they are from all the other wrens north of the border.

With the striking exception of our state bird, North America’s wrens are small, furtive skulkers known for their shy behavior and beautiful songs.  By comparison Cactus Wrens are large, their vocalizations are harsh and guttural, and their personality is . . . well, obstreperous.  If you hear raspy “buzzing” it is probably our state bird sassing you from the top of a desert bush, and last month I missed the shot of a lifetime because I didn’t instantly recognize what that buzz call meant.  It was a Cactus Wren fly-hopping up the spines of a Saguaro toward an American Kestrel perched at the top.  The kestrel was having none of it and abandoned its perch before the combative wren could reach it.

Our Cactus Wren is more closely related to a group of large wrens found in Central America than it is to other North American wrens, and because of its size and personality it is a delight to just sit and observe.  My interest in these wrens was piqued this past January when I discovered one working on a nest in a cholla cactus.  It seemed early to me, certainly not yet spring even here in the Sonoran Desert, so I spent the morning getting better acquainted with our state bird and discovered, of course, that it’s not my grandmother’s little ‘Jenny Wren.’

Cactus Wrens are obligate nest builders, meaning the male builds multiple nests nearly year round.  Nests are football sized masses of sticks and weeds typically in a cholla, mesquite, or the crotch of Saguaro arms, lined with feathers, the tubular entrance at one end.  The extra nests serve as dummy nests to fool predators or other desert birds, and they are used as night roosts for the male when his mate finally begins incubating in the actual breeding nest.  In January, because of the season, I assumed I was observing a dummy nest being built.

Things got interesting, though, when I saw two birds bringing nesting material at the same time.  It is thought Cactus Wrens mate for life, but the literature is unclear on whether the female helps with dummy nests.  After several days of watching this nest construction, I observed one bird pass the other an insect morsel, and this gift exchange was followed shortly by copulation.  So, maybe this nest was the conjugal nest.  Let me note here that I have observed only two other species exchange food as a prelude to sex.  Those would be Greater Roadrunners and humans.

It is well documented that Cactus Wrens often incorporate unnatural materials into their breeding nest.  These may include tissue, newspaper scraps, even rags, and I have an old slide photo of red, white, and blue party balloon streamers hanging out the tube entrance of a nest.  This January nest showed only plant material, but an oblong section of a dead palm frond seemed strategically draped over the entrance hole, perhaps to keep the morning sun out of the southeast facing door.

After taking a break from my wrens for some travel, I was anxious to return to the scene, hoping to document them raising young.  On my first visit to the site I found no activity at the nest I had observed them building, but my disappointment was soon dispelled when I found them visiting another nest in a nearby Saguaro crotch, both parents coming every twenty minutes or so with food items.  I knew I had finally located an active breeding nest.

This nest was replete with human detritus too, thin green plastic streamers from god-knows-what hanging from the entrance tube, and a stark white flap of tissue paper draped over the half of the doorway on the eastern side where the rising sun first hit the cactus.  Initially it seemed one of the pair lingered inside the nest for long periods which suggested hatched and unhatched eggs, but eventually both left the nest unattended and finally, as the morning wore on, I observed one parent leave with what was unmistakably a white fecal sac.

Monitoring the wrens’ morning feeding schedule over the next several days cleared up two mysteries.  The first was, though I could discern no difference in size or plumage of the parents, it soon became obvious the male was the one that always flew to the top of the Saguaro and “sang” briefly when it left the nest.  The one I now presumed to be the female never lingered or vocalized in the vicinity of the nest.  The second revelation was that the female often remained in the nest after a food delivery, exposed tail hanging out of the tube bobbing up and down, and I could picture her inside “slicing and dicing” the food items and literally stuffing them down nestlings’ throats.

The variety of bugs on the breakfast menu was great but not surprising, insect protein comprised primarily of moths and caterpillars and, as the sun warmed up, spiders, grasshoppers, and even bees and a dragonfly.  I marveled again at the ability many bird species have to capture and transport several prey items at once, and even vocalize while doing so, without dropping or losing anything.  We know seabirds carry multiple fish, but insectivores like wrens have sticky tongues evolved for just this purpose.