Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (270 KB)

Title: Demography of Mexican spotted owls in the Sacramento Mountains, New Mexico

Author: Ganey, Joseph L.; White, Gary C.; Ward, James P. Jr.; Kyle, Sean C.; Apprill, Darrell L.; Rawlinson, Todd A.; Jonnes, Ryan S.;

Date: 2014

Source: Journal of Wildlife Management. 78(1): 42-49.

Publication Series: Scientific Journal (JRNL)

Description: Information on population dynamics is key to gauging the status of threatened or endangered species. We monitored demography of a population of threatened Mexican spotted owls (Strix occidentalis lucida) in the Sacramento Mountains, New Mexico from 2003 to 2011. We estimated reproductive output for territorial pairs of owls; used mark-recapture methodology and Pradel's reparameterized Jolly-Seber models to estimate annual apparent survival rates, recapture rates, recruitment rates, and annual rate of population change (lRJS) for 2005-2009; and used estimates of lRJS to assess short-term population viability. Reproductive output was highly variable for 2004­2011, whereas annual apparent survival and recapture rates were less variable among years. Annual rates of population change exceeded 1.0 for both sexes from 2005 to 2009, and empirical observations of numbers of territorial owls supported the model-based trend estimate. Abundance of territorial owls was strongly related to reproduction within the study area, suggesting that population change was driven largely by internal processes. Population viability analyses suggested that population growth was likely to continue in the short term if current conditions persist. The positive growth rates observed in our study populations are encouraging, and may indicate that current recommendations for recovering this owl are succeeding. However, our estimates of lRJS covered a very short time period, given both the potential lifespan of Mexican spotted owls and the extent of temporal variability in weather typical of the southwestern United States. Longer studies of owl demography than we present will be required to understand long-term population trends, and such studies should extend across the range of the subspecies. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Keywords: demography, fecundity, Mexican spotted owl, population trend, population viability, Pradel model, recruitment, reparameterized Jolly-Seber model, survival, vital rates

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.



Ganey, Joseph L.; White, Gary C.; Ward, James P., Jr.; Kyle, Sean C.; Apprill, Darrell L.; Rawlinson, Todd A.; Jonnes, Ryan S. 2014. Demography of Mexican spotted owls in the Sacramento Mountains, New Mexico. Journal of Wildlife Management. 78(1): 42-49.


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.