In our continuing series of brief examinations of the state birds of the United States we move today from Alaska to Arizona. This progression is completely random and the fact that we’ll probably cover Illinois and Delaware next is in no way connected to the current political campaign in the United States. Pure coincidence.
Arizona’s state bird is the Cactus Wren. It builds several nests, sometimes as many as seven. They use some as homes and some as decoys, although because the Cactus Wren builds its nests in thickly thorned cacti, it is unclear why it needs all those nests. One likely reason is that adult wrens allow their children to use some of the nests which gets the kids out of the way. In good years as many as three broods of wrens may fledge. Moreover, the male Cactus Wren, like a fighter pilot, mates with more than one female. All the nests separate the new broods and the females from one another. Reminds me of the old Royal Navy toast, “To wives and mistresses, may they never meet!”
It is unknown whether the males remember how many nests they have. Or, for that matter, how many mistresses.
Cactus Wren range
Noisier and larger than any other wrens in their range, Cactus Wrens live in the Chihuahuan, Mojave, and Sonoran Deserts. Like Louis L’Amour’s Apaches and desert heroes, these wrens are well adapted to the desert. They are most active during the sunrise and sunset hours when the desert has its mildest temperatures. During the heat of the day they hang out in shady spots, doing as little as possible. Because of the scarcity of available water, they evolved as xerophiles, animals which do not need free water but who acquire all their water from their food. Insects are their primary food.
By the way, insects have taken over the world, so it is a good thing that birds and fish eat them for us. Insects originated, on dry land, about 400 million years ago. (By comparison, humans have been here less than 2 million years.) At least a million different species of insects exist. According to E.O. Wilson, about a billion billion insects are alive on the planet as you read this. These insects weigh, if you put them all together — and please, don’t — about one trillion kilograms, more than all the humans on earth combined. “Insects,” according to Dr. Wilson, who has spent his lifetime studying them, “can thrive without us, but we and most other land organisms would perish without them.”
Living in the desert has its advantages. For instance, because it is warm year round, there is no need to migrate and Cactus Wrens don’t. Better yet, the beetles, ants, moths, spiders and ants don’t freeze or go dormant, so food is constantly available.
The downside for the wrens is that many other animals also like desert living. Predators such as snakes, roadrunners, and Loggerhead Shrikes are undeterred by the thorny cactus in which the wrens live. Curved-bill Thrashers compete with them for territory. Worse — for the wrens — humans also like the warmth of the desert. We build cities and bring our pet cats along with us and the cats are a significant cause of mortality among Cactus Wrens. We also destroy their habitat and that is now the leading cause of death for Cactus Wrens.
Of course, we’re not xerophiles and it is a desert. The Cactus Wrens might outlast us.
Many of the facts in this post came from Proudfoot, Glenn A., Dawn A. Sherry and Steve Johnson. 2000. Cactus Wren (Campylorhynchus brunneicapillus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/558. You should not blame the scientists for any liberties we may have taken. The photo was taken by Mark Wagner.