1

Research Note RMRS-RN-54. 2013

Rocky Mountain Research Station

Research Note

United States Department of Agriculture

Forest Service

Rocky Mountain Research Station

Research Note RMRS-RN-53WWW

July 2013

An Apparent Case of Long-Distance Breeding Dispersal 

by a Mexican Spotted Owl in New Mexico

Joseph L. Ganey and Jeffrey S. Jenness

Citation:

Ganey, J. L., and J. S. Jenness. 2013. An Apparent Case of LongDistance Breeding Dispersal by a Mexican Spotted Owl in 

New Mexico. Res. Note RMRS-RN-53WWW. Fort Collins, CO: 

U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station. 5 p.

Authors:

Joseph L. Ganey and Jeffrey S. Jenness1, US Forest Service, Rocky 

Mountain Research Station, Flagstaff, AZ.

Current address: 1 Jenness Enterprises, Flagstaff, AZ (www.

jennessent.com)

The Mexican spotted owl (Strix occidentalis lucida) is widely but patchily distributed 

throughout the southwestern United States and the Republic of Mexico (Gutiérrez 

and others 1995, Ward and others 1995). This owl typically occurs in either rocky 

canyonlands or forested mountain and canyon systems containing mixed-conifer or 

pine-oak (Pinus spp. - Quercus spp.) forests, and its distribution mirrors the availability of such areas (Ganey and Dick 1995, Ward and others 1995, USDI FWS 

2012). Gene flow is known to occur across this fragmented range (Barrowclough and 

others 2006), but the mechanisms facilitating gene flow are poorly understood. Natal 

dispersal between disjunct mountain ranges and populations has been documented 

for dispersing juvenile Mexican spotted owls (Gutiérrez and others 1996, Arsenault 

and others 1997, Ganey and others 1998, Willey and van Riper 2000, Duncan and 

Speich 2002). In contrast, there are no documented records of breeding dispersal 

(defined as movement of a non-juvenile owl between territories where it had the opportunity to breed, regardless of whether or not breeding occurred on these territories 

[Daniels and Walters 2000]) by non-juvenile owls. Thus, the potential role of breeding dispersal in gene flow within the range of this owl is unknown.

Here, we report the circumstances surrounding recovery of a banded Mexican spotted 

owl that may represent the first documented case of long-distance breeding dispersal 

in this owl. We banded this owl on 9 August 1999, in the southern Black Range, 

New Mexico (fig.1), in conjunction with a study evaluating methods for monitoring population trend in Mexican spotted owls (Ganey and others 2004). The owl 

was identified as a female when banded based on vocalizations (Ganey 1990), and 

as an adult based on appearance of the retrices (Moen and others 1991), indicating 
2

Research Note RMRS-RN-54. 2013

Figure 1. Shaded relief map of New Mexico, USA, showing the locations where a female owl 

was banded in 1999 and found dead in 2012.
3

Research Note RMRS-RN-54. 2013

a minimum age of >2 yrs (Forsman 1981). She was resident on a breeding territory 

when captured, and successfully fledged young in 1999. Elevation at the banding 

location was approximately 2,380 m.

This owl was found dead on 22 August, 2012, approximately 8 km south of Questa, 

New Mexico (fig. 1), approximately 462 km from the banding location. Distance was 

calculated as the length of the geodesic curve connecting the banding and recovery 

locations and represents the shortest distance the owl could have traveled over the 

curved surface of the planet. Distance traveled may have been considerably longer 

than 462 km, as the actual route traveled is unknown. It is interesting, however, that 

the straight-line route approximates the course of the Rio Grande River. Also unknown is whether the owl traversed this distance in one movement event or a series of 

shorter movements separated by periods of residency, and how long it took to complete the movement. Given that 13 yrs intervened between banding and recovering 

the owl, we cannot rule out the possibility that movement occurred gradually over 

the course of several to many years.

The recovery location was in the foothills of the Sangre de Cristo Mountains near 

Lama, New Mexico, at an elevation of approximately 2,500 m, near the border between a 17-yr-old burned area (Hondo fire, 1996) and a hay meadow. The recovery 

location was adjacent to a forested canyon, and only a few kilometers uphill from the 

canyon of the Rio Grande River, and downhill from montane mixed conifer forest.

Cause of death was not determined. The carcass was described as being in relatively 

good shape, and the finder believed the owl had not been dead long (D. Hutchison, 

personal communication). These observations suggest the owl was at least 15 yrs of 

age at time of death, was present in the recovery area during the breeding season, a 

period during which adult Mexican spotted owls typically are resident on breeding 

territories, and was adjacent to suitable breeding habitat (incised rocky canyons and/

or montane mixed-conifer forest) at the time of death.

Although we believe this may be the first documented case of breeding dispersal in 

Mexican spotted owls, it is not the first documented case of long-distance movement by non-juvenile Mexican spotted owls. Gutiérrez and others (1996) reported a 

case involving an adult female owl banded in the Tularosa Mountains, New Mexico, 

during summer 1994. This owl was found dead in Jan 1995 in Chihuahuan desert 

grassland near Deming, New Mexico, approximately 187 km from the banding location. This case clearly demonstrates long-distance movement, but does not appear to 

meet the definition of breeding dispersal. Seasonal migration has been documented 

in Mexican spotted owls, with some radio-marked owls from all populations studied 

migrating during winter, typically to lower elevation desert or semi-desert habitats 

(Ganey and Block 2005, USDI FWS 2012). Thus, the observation by Gutiérrez and 

others (1996) could represent either an unsuccessful dispersal event or seasonal migration, given the time of death and habitat in which it was found.

In contrast, the owl we banded was known to nest successfully near the banding location, and was found dead at a distant location during the breeding season and adjacent 

to the types of habitats (incised rocky canyons, montane mixed-conifer forest) typically used by breeding Mexican spotted owls (Ganey and Dick 1995). Consequently, 

this observation appears likely to represent breeding dispersal as typically defined, 
4

Research Note RMRS-RN-54. 2013

even though successful reproduction was not documented at the recovery site. The 

behavior of this owl suggests that movements of non-juvenile owls as well as juveniles 

may contribute to gene flow among Mexican spotted owls, at least occasionally.

Acknowledgments

We thank the many dedicated field personnel who helped locate, capture, and resight 

banded owls during the study in which this owl was banded. We extend a special 

thanks to Daniel Hutchison, Sangre de Cristo Youth Ranch, for reporting the band 

recovery. Major funding for the owl banding effort was provided by the Southwestern 

Region, USFS, with additional funding from the Rocky Mountain Research Station, 

USFS. We thank Don DeLorenzo (USFS, SW Region) for his support and assistance 

with securing funding. W. M. Block, L. Eskew, D. W. Willey, and S. J. Hedwall provided helpful suggestions on an earlier draft of this paper.

Literature Cited

Arsenault, D. P.; Hodgson, A.; Stacey, P. B. 1997. Dispersal movements of juvenile 

Mexican Spotted owls (Strix occidentalis lucida) in New Mexico. Pages 47–57 in

Duncan, J. R.; Johnson, D. H.; Nicholls, T. H. editors. Biology and conservation of owls of the northern hemisphere. USDA Forest Service General Technical 

Report NC-190.

Barrowclough, G. F.; Groth, J. G.; Mertz, L. A.; Gutiérrez, R. J. 2006. Genetic 

structure of Mexican spotted owl populations in a fragmented landscape. Auk 

123:1090-1102.

Daniels, S. J.; Walters, J. R. 2000. Between-year breeding dispersal in red-cockaded 

woodpeckers: multiple causes and estimated cost. Ecology 81:2473-2484.

Duncan, R. B.; Speich, S. M. 2002. Inter-and intra-mountain movements of Mexican 

spotted owls in southeastern Arizona: Results of a multi-year banding study, 

1991—2001. Abstract, Annual meeting, Western Bird Banding Association. 

Bisbee, Arizona, USA.

Forsman, E. D. 1981. Molt of the spotted owl. Auk 98:735-742.

Ganey, J. L. 1990. Calling behavior of spotted owls in northern Arizona. Condor 

92:485-490.

Ganey, J. L.; Dick, J. A. 1995. Habitat relationships of Mexican spotted owls: Current 

knowledge. Chapter 4:1-42 in: USDI Fish and Wildlife Service, Recovery plan for 

the Mexican spotted owl (Strix occidentalis lucida), Vol. II—Technical supporting 

information. USDI Fish and Wildlife Service, Albuquerque, New Mexico, USA.

Ganey, J. L.; Block, W. M. 2005. Winter movements and range use of radiomarked 

Mexican Spotted Owls: An evaluation of current management recommendations. 

U.S. Forest Service General Technical Report RMRS-GTR-148-WWW.

Ganey, J. L.; Block, W. M.; Dwyer, J. K.; Strohmeyer, B. E. 1998. Dispersal movements and survival rates of juvenile Mexican Spotted Owls. Wilson Bulletin 

110:206-217.
5

Research Note RMRS-RN-54. 2013

Ganey, J. L; White, G. C.; Bowden, D. C.; Franklin, A. B. 2004. Evaluating methods 

for monitoring populations of Mexican spotted owls: a case study. Pages 337-385 

in: Thompson, W. L., editor. Sampling rare and elusive species: Concepts, designs, 

and techniques for estimating population parameters. Island Press, Washington, 

D.C., USA

Gutiérrez, R. J.; Franklin, A. B.; LaHaye, W. S. 1995. Spotted Owl (Strix occidentalis). The birds of North America, No. 179. The Academy of Natural Sciences 

Philadelphia, and The American Ornithologists Union, Washington, D.C., USA.

Gutiérrez, R. J.; Seamans, M. E., Peery, M. Z. 1996. Intermountain movement by 

Mexican spotted owls (Strix occidentalis lucida). Great Basin Naturalist 56:87-89.

Moen, C. A.; Franklin, A. B.; Gutiérrez, R. J. 1991. Age determination of subadult northern spotted owls in northwest California. Wildlife Society Bulletin 

19:489-493.

U.S. Department of the Interior Fish and Wildlife Service [USDI FWS]. 2012. 

Final Recovery Plan for the Mexican Spotted Owl, First Revision. U.S. Fish and 

Wildlife Service. Albuquerque, NM, USA.

Ward, J. P., Jr.; Franklin, A. B.; Rinkevich, S. E.; Clemente, F. 1995. Distribution 

and abundance of Mexican spotted owls. Chapter 1:(1-14) in: USDI Fish and 

Wildlife Service, Recovery Plan for the Mexican spotted owl (Strix occidentalis 

lucida), Vol. II—Technical supporting information. USDI Fish and Wildlife 

Service. Albuquerque, New Mexico, USA.

Willey, D. W.; van Riper III, C. 2000. First-year movements by juvenile Mexican 

spotted owls in the canyonlands of Utah. Journal of Raptor Research 34:1-7.
The Rocky Mountain Research Station develops scientific information 

and technology to improve management, protection, and use of the 

forests and rangelands. Research is designed to meet the needs of 

the National Forest managers, Federal and State agencies, public and 

private organizations, academic institutions, industry, and individuals. 

Studies accelerate solutions to problems involving ecosystems, range, 

forests, water, recreation, fire, resource inventory, land reclamation, 

community sustainability, forest engineering technology, multiple use 

economics, wildlife and fish habitat, and forest insects and diseases. 

Studies are conducted cooperatively, and applications may be found 

worldwide. For more information, please visit the RMRS web site at: 

www.fs.fed.us/rmrs.

Station Headquarters

Rocky Mountain Research Station

240 W Prospect Road

Fort Collins, CO 80526

(970) 498-1100

Research Locations

The U.S. Department of Agriculture (USDA) prohibits discrimination against its 

customers, employees, and applicants for employment on the bases of race, 

color, national origin, age, disability, sex, gender identity, religion, reprisal, and 

where applicable, political beliefs, marital status, familial or parental status, 

sexual orientation, or all or part of an individual’s income is derived from any 

public assistance program, or protected genetic information in employment 

or in any program or activity conducted or funded by the Department. (Not all 

prohibited bases will apply to all programs and/or employment activities.) For 

more information, please visit the USDA web site at: www.usda.gov and click on 

the Non-Discrimination Statement link at the bottom of the page.

Reno, Nevada

Albuquerque, New Mexico

Rapid City, South Dakota

Logan, Utah

Ogden, Utah

Provo, Utah

Flagstaff, Arizona

Fort Collins, Colorado

Boise, Idaho

Moscow, Idaho

Bozeman, Montana

Missoula, Montana

To learn more about RMRS publications or search our online titles:

www.fs.fed.us/rm/publications

www.treesearch.fs.fed.us

Federal Recycling Program Printed on Recycled Paper