The Ferruginous Pygmy-Owl has a long name for such a small owl, standing only seven inches tall. “Ferruginous” refers to the characteristic rusty coloration on the back and fine bars on the relatively long tail. The birds have a white circle of feathers around the eyes and in the facial disk, and fake, dark “eyes” on the back of the head. The call is a monotonously repeated poip, especially by the male in the spring. The pair of birds nest in a tree cavity where three or four white eggs are incubated. This is a desert, mostly tropical, bird found in the U.S. only in southern Arizona and the lower Rio Grande Valley of Texas. The birds are found along streams, especially in mesquite thickets (1).
The species name (second word) in Glaucidium brasilianum refers to its primarily tropical American range. Unlike the Elf Owl that also occupies the range of the Ferruginous Pygmy-Owl in the deserts along the Mexican border, the latter species is resident and does not migrate. That is likely because the Elf Owl feeds almost exclusively on insects which are not very active in the winter, so it migrates farther south. The Pygmy-Owl, on the other hand, feeds largely on warm-blooded vertebrates and stays put.
The Ferruginous Pygmy Owl is active mostly in the morning and evening (crepuscular), but also during the day (2). It has an up-and-down pattern to its flight, and it hunts for small birds, mammals, lizards, and insects. Oddly, for such a small owl, it can attract a large number of birds that harass it, called mobbing. With its wide range, there is much variation in in coloration, suggesting distinct genetic populations.
One subspecies, called the Cactus Ferruginous Pygmy-Owl, was listed as endangered in Arizona by the Endangered Species Act until 2006. Fire was the major threat to it. It was de-listed in spite of there being only twenty adults and five nests in the three prior years to 2006, but it was considered abundant elsewhere, so no longer needing special protection. These small owls are popular with birders (3).
This species is known to erect feathers on top of its head reminiscent of the “ear” tufts of some other owls according to the article, “Ear Tufts in Ferruginous Pygmy-Owls (Glaucidium brasilianum) as an Alarm Response,” published in the Journal of Raptor Research 42(2):153-155, 2008, by Miguel Angel Santillum and Jose Hernan Sarasola. These animals were photographed in Argentina where the response was elicited by humans and other potential predators.
All owls have a ruff of feathers around the eyes called the facial disk which functions to direct sound into the ear openings. Owls have no external ear and the so-called ears are tufts of feathers. Owls have exceptional hearing, especially with regard to determining direction and distance, being able to hear mice rustling under leaves or even snow. Both the Ferruginous Pygmy-Owl and a related species lack asymmetrical ear openings that help locate prey in many owl species, as these two species hunt during the day and rely more on vision. A species similar in size and habits, except lacking reddish coloration and living in conifer forests of the Rocky Mountains and along the Pacific coast, is the Northern Pygmy-Owl (4). This species is more widespread and not endangered. Both species are aggressive hunters and may take prey as large as themselves.
- National Audubon Society: Field Guide to North American Birds, Alfred A. Knopf, Inc., New York, 1998, by John Bull and John Farrand, Jr.
- https://en.wikipedia.org/wiki/Ferruginous_Pygmy_Owl
- https://www.fws.gov/external-affairs/public-affairs/April 1
- https://www.allboutbirds.org/Guide/Northern_Pygmy_Owl
