What tiny bird fits in the palm of your hand, can kill a bird twice its size, nests in a hole carved out of a cactus plant by another species, and is named for earth itself?
That would be the Ferruginous Cactus Pygmy Owl, or Glaucidium brasilianum.
What a long name for an owl so small that it averages 6.5 inches in length and only weighs 2.5 ounces! But it describes this fierce little creature well.
Ferruginous refers to something containing iron oxides or rust, or to the colors rust or reddish brown. Fe is the symbol for iron, the most common element on Earth by mass, and it forms much of Earth’s outer and inner core. So it should be no surprise that it also refers to the ferruginous earth of southern Brazil, because this little owl is indeed most at home in tropical ecoregions.
Appearance
The feathers on the owl’s back are creamy-brown, and the underside is cream-colored with reddish-brown stripes. The top of their heads are slightly streaked and on the back of the head, they have two black eye spots outlined in white. Their eyes are yellow and round, their tails are longer than most owls, and they have no tufts on their ears. They have noticeably large legs and feet that are white and thickly feathered.
Check out this short video of two little owls:
Habitat
If you happen to have a calendar from Defenders of Wildlife hanging on a wall near the table where you eat, you’ll see the Ferruginous Cactus Pygmy Owl staring out at you from its cactus perch. And cactus is definitely one of this owl’s preferred habitats, making the Sonoran Desert a favorite location.
However, the bird’s habitat needs are poorly understood. In the tropics, it inhabits many distinct vegetation communities including woodlands and open forests. In the Sonoran Desert they live at elevations below 4,000 feet (1,200 m), preferring desert scrub thickets, trees and large cacti for nesting and roosting. In this habitat the owl often lives where ironwood, mesquite, acacia, saguaro and organ pipe cacti can be found.
At the northern edge of its range (northern Mexico, south Arizona and south Texas), the Ferruginous Cactus Pygmy Owl has been recorded in riparian woodlands and thickets. In fact the best place to find this little creature right now is in low stands of live oak and mesquite trees in southern Texas.
The two subspecies that have made their way into this northern range are G.b. cactorumis (found from South Arizona south along the West Coast of Mexico), and GH.b. ridgewayi (found from Southern Texas to East and South Mexico, and all the way to Panama).
They choose to live where the vegetation protects them from predators including larger raptors. The same vegetation also protects the owls’ favorite prey: birds, lizards, insects, small rodents, frogs and earthworms.
Ferruginous Cactus Pygmy Owls are fierce hunters and can kill a dove twice their size. They are crepuscular, meaning that they are most active at dawn and dusk. In an interesting display of solidarity, different songbird species have been known to gather together to mob and harass one subspecies of this Pygmy Owl when they hear its unique whistle near their homes. They even mob birders who imitate the whistle, uniting to protect themselves and their young.
Behaviors and Cycles
Cactus Ferruginous Pygmy Owls don’t migrate. In late winter or early spring they begin nesting in the cavities of trees or cacti like the saguaro and organ pipe. These holes have often been made by woodpeckers.
They lay 3 to 5 white eggs in late April, which hatch about 28 days later. The young owls are fed by both parents. They fledge, or leave the nest, 27 to 30 days after hatching and stay close to their parents until they are ready to be on their own.
Climate change and human impacts
With nearly 3500 species of plants, 500 species of birds, and 1,000 species of bees, the Sonoran is the most biodiverse desert on earth. The Glaucidium ridgwayi cactorum subspecies of the Ferruginous Cactus Pygmy Owl has been severely impacted by threats to the Sonoran. No more than 41 adult birds have been found in Arizona in any recent breeding season. Despite these dangerously low numbers it was removed from the endangered species list in response to a lawsuit by developers.
In addition to logging and direct agricultural impacts, planting invasive Buffel grass for forage led to an increase in fires. Buffel grass forms a continuous cover, allowing fires to travel across large areas. Extended droughts are increasing fire risk and further threatening this little feathered friend.
It’s clear that development has to slow down and be very carefully designed in order to minimize negative impacts on our planet’s sacred, life-giving, cooling ecosystems and the creatures that depend on them. It’s time we value our fellow creatures and their wellbeing alongside our own, and move toward a world in which we share in the beauty, diversity, and abundance of our planet earth.
For the health of the Ferruginous Cactus Pygmy Owl and its desert home,
Paula Phipps, Associate Director