The Great Horned Owl is one of the largest, most powerful, and widespread raptors in North America. Its breeding range extends from central Alaska across Canada to Newfoundland south throughout the Americas to Tierra del Fuego (A.O.U. 1983). Except in the extreme northern portion of its range it is a permanent resident. It is fairly common throughout the state of Texas all year (Oberholser 1974, Root 1988, Sauer et al. 1996).
It is one of the more easily observed owls because it is large, relatively common, and often quite vocal. Like most owls it is generally nocturnal. However, it can often be found hunting in the daytime, ordinarily on cloudy days.
DISTRIBUTION: In Texas, the TBBAP data show that the Great Horned Owl can be found all across the state in the breeding season. This is consistent with Oberholser’s (1974) description, calling it common to uncommon virtually throughout. It was confirmed most often in the extreme southern portion of the state, with 17 confirmed records south of Latitude 27. The only area that did not have several TBBAP records was in extreme west Texas. However, this may have been due to incomplete atlas coverage, not a lack of owls.
SEASONAL OCCURRENCE: Because they are nocturnal, most owls are difficult for atlasers to confirm. The Great Horned Owl is somewhat more conspicuous than most owls because of its size and because it often nests in an exposed location. However, of the 494 records obtained by the TBBAP, only 26% were confirmed records. These confirmations were spread throughout the state and it is likely that most or all of the possible and probable records also represented breeding pairs. The Great Horned Owl is the earliest nesting bird in many parts of its range and can often be found incubating eggs under a blanket of snow (Bent 1940, Craighead & Craighead 1956). In Texas the breeding season extends from December to late July (Oberholser 1974). The TBBAP recorded nests with eggs between 20 March and 21 May and nests with young between 31 January and 10 June. Oberholser (1974) listed egg dates as early as late December and young in the nest as late as 8 July. Apparently the latest Texas breeding record is of an individual banded on its nest on 20 July (Pulich 1988).
BREEDING HABITAT: The Great Horned Owl generally uses an abandoned nest of a Red-tailed Hawk or other large bird but will also nest in a tree cavity, in the fork of a giant cactus, in a cave, or even on the ground (Baicich & Harrison 1997, Bent 1937, Ehrlich et al. 1986). As would be expected in such a widespread bird, this owl can adapt to a variety of habitats including coniferous and deciduous forests, swamps, orchards, arid deserts, and suburban areas (Ehrlich 1986, Howell & Webb 1995). They are so adaptable that they can often nest successfully in urban areas if small woodlots are available (Minor et al 1993, pers. obs.). According to Oberholser (1974) their preferred habitat consists of semi-open country with hills, canyons, and watercourses. This habitat is abundant throughout the state.
STATUS: The status of the Great Horned Owl in Texas appears to be very good. It is common throughout the state and can survive in a variety of habitats. BBS data show a non-significant increase both in Texas and in the United States as a whole for the period 1966 to 1996 (Sauer et al. 1996). This owl can easily be missed during BBS counts however, because it is nocturnal and is not vocal when the surveys are being conducted.
The Great Horned Owl is a very powerful predator and can dominate a community of raptors (Craighead & Craighead 1956). It is known to be able to take a very wide variety of prey including some animals, such as skunks, that are larger than itself (Baumgartner & Baumgartner 1944, Forbush 1955). Its ferocity has been blamed for impeding efforts to re-establish the Aplomado Falcon in Texas (Lasley & Saxton 1986), causing the desertion of a seabird colony in Massachusetts (Cavanagh and Griffin 1993), and the destruction of numerous nests of other raptors (Bent 1937, Craighead & Craighead 1956). Ordinarily, however, the bulk of its prey is made up of mice and other small rodents (Marti & Kochert 1993, Marti & Kochert 1995). In the northern parts of its range it preys heavily on Snowshoe Hares and its survival is often linked to the density of that species (Rohner & Hunter 1996).
The Great Horned is also extremely long-lived (Housten & Francis 1995). This trait, combined with its adaptability in its choice of habitats and food, allows it to thrive in a variety of situations. Its future in Texas seems secure.
Text by David E. Fantina (ca. 1998)
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