Iconic birds of the region #1

Iconic birds of the region #1 

The song of a Cactus Wren is a clattering roll with quick beats without melody. The sound carries farther than other sounds and has a hollow echo that reverberates in the heat of a summer afternoon.

Cactus Wrens seem more purposeful than other birds.  Intensity is obvious in their body language, and their actions are hyper-focused without hesitancy.  Humans can’t distinguish between Cactus Wren genders by sight.  Nor can Cactus Wrens.  Males threaten every other male they meet, spreading their wings and tail as they growl.  A female signifies her gender in such a meeting by crouching after spreading her feathers.

Territories are set by January — female owners chasing away visiting females, male owners chasing away visiting males.  Females fight female intruders, the first glancing blow of a swoop-collision resembling the battles of mockingbird versus cat, followed by a slap with a wing, and finally, if need be, a peck with the sharp beak.  Males rarely fight, since song precludes such macho behavior.

The males sing at different stations along their boundary lines.  Each station is twenty or so feet from the previous one.  First, they sing at one station, then go to the next, then double back to sing again at the first station.  An individual’s territory encompasses 10 acres on average.  If a neighboring male advances, the resident male charges and fans its feathers.  This threat usually suffices to end the incursion. The invader then exhibits displacement behavior, picking up dead grass and dropping it, or chasing the nearest smaller bird.

Cactus Wrens build three to five nests per individual.  A pair often has ten nests within their territory.  Triple clutching can occur within one mating season, producing ten to eleven babies.  One nest is used as the breeding nest, but how the other nests are utilized has never been adequately studied. Cactus Wrens spend their nights in individual roost nests, and rarely use the same nest for more than a week at a time.

Sibling Cactus Wrens stay together for several weeks after leaving the nest.  A constant quiet chatter connects the group as each object in the territory is inspected.  At the Sibley Nature Center, on hot summer afternoons, sibling trios have several times napped the afternoon away on the windowsills.  At first three little birds will line up to examine not only their surroundings, but also their reflections. Slowly their eyes close.  After a few minutes their heads begin to lean forward, ever so slowly.  Often they jerk themselves awake for a quick look around and then doze off again.  Eventually their sleep deepens, and their heads lean forward until all are propped up by their beaks.

Sometimes juveniles from a pair’s first brood allow second-brood juveniles into their roost nests at night.  Both of the first two sets of young have been observed helping to feed a third set.  Due to such cooperative behavior, clutch success in Cactus Wrens is as high as sixty-six percent — well above the avian average.  Before fledging, a baby has only snakes to fear. Roadrunners seem to be a major predator on the fledglings, but after surviving that the wrens consistently live their allotted four years.  Their alert and curious ways protect them well.

The song of a Cactus Wren is an integral part of the West Texas lifescape.  To some people the song of the Cactus Wren is harsh and rough, definitely non-musical, but why should the ethereal notes of a European Nightingale represent the pinnacle of bird song? Cactus Wrens, with all of their personality and communicative expressiveness, are rock and roll, and Nightingales are Muzak.