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Journal articles on the topic 'Spotted owls'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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1

Crozier, Michelle L., Mark E. Seamans, R. J. GutiÉRrez, Peter J. Loschl, Robert B. Horn, Stan G. Sovern, and Eric D. Forsman. "Does The Presence of Barred Owls Suppress the Calling Behavior of Spotted Owls?" Condor 108, no. 4 (November 1, 2006): 760–69. http://dx.doi.org/10.1093/condor/108.4.760.

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Abstract Abstract Barred Owls (Strix varia) have expanded their range throughout the ranges of Northern (Strix occidentalis caurina) and California Spotted Owls (S. o. occidentalis). Field observations have suggested that Barred Owls may be behaviorally dominant to Spotted Owls. Therefore, we conducted a test of behavioral dominance by assessing responsiveness of Spotted Owls to conspecific calls when they were in the simulated presence (i.e., imitation of Barred Owl vocalizations) of a Barred Owl. We hypothesized that Spotted Owls would be less likely to respond to conspecific calls in areas where Barred Owls were common. We used a binary 2 × 2 crossover experimental design to examine male Spotted Owl responses at 10 territories randomly selected within two study areas that differed in abundance of Barred Owls. We also conducted a quasi experiment at four study areas using response data from any Spotted Owl (male or female) detected following exposure to Barred Owl calls. We inferred from the crossover experiment that the simulated presence of a Barred Owl might negatively affect Spotted Owl responsiveness. Both subspecies of Spotted Owl responded less to Spotted Owl calls after exposure to Barred Owl calls, Northern Spotted Owls responded less frequently in areas having higher numbers of Barred Owls, and California Spotted Owls responded less frequently than Northern Spotted Owls overall.

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2

Kelly, Elizabeth G., Eric D. Forsman, and Robert G. Anthony. "Are Barred Owls Displacing Spotted Owls?" Condor 105, no. 1 (February 1, 2003): 45–53. http://dx.doi.org/10.1093/condor/105.1.45.

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Abstract Barred Owls (Strix varia) have expanded their range into the Pacific Northwest, and anecdotal evidence suggests that they may be displacing the federally threatened Northern Spotted Owl (Strix occidentalis caurina). Our objectives were to describe the current status of Barred Owls in Oregon and compare occupancy of Spotted Owls in historic Spotted Owl territories before and after Barred Owls were first detected in those territories. Between 1974 and 1998, we estimated that 706 different Barred Owl territories were located in Oregon. From 1989–1998 an average of 60 new Barred Owl territories were located in Oregon each year. In Spotted Owl demographic study areas in Oregon and Washington, Barred Owl detections increased at Spotted Owl territories from 1987–1999. Occupancy of Spotted Owl territories declined after Barred Owls were detected within 0.80 km of the territory center. When Barred Owls were detected 0.81–2.40 km from Spotted Owl territory centers, occupancy of Spotted Owls was only marginally less than at territories without Barred Owls. This suggests that the frequency and intensity of interactions between the two species is negatively associated with distance between them. Our results suggest that land managers and regulatory agencies should regard Barred Owls as a threat to Spotted Owls, particularly if Barred Owls continue to increase in number as they have during the past 25 years. ¿Está Strix varia Desplazando a Strix occidentalis caurina? Resumen. Desde su expansión hacia el Pacífico Noroeste, existe evidencia anecdótica de que Strix varia podría estar desplazando a S. occidentalis caurina. Nuestros objetivos fueron describir el estatus actual de S. varia en Oregon y comparar la ocurrencia de S. occidentalis caurina en sus territorios históricos antes y después de que S. varia se detectó por primera vez en dichos territorios. Entre 1974 y 1998, estimamos que se confirmaron 706 territorios diferentes de S. varia en Oregon. Entre 1989 y 1998, se localizaron en promedio 60 nuevos territorios de S. varia anualmente. En áreas con estudios demográficos de S. occidentalis caurina en Oregon y Washington, las detecciones de S. varia en territorios de S. occidentalis caurina se incrementaron entre 1987 y 1999. En comparación con territorios sin S. varia, la ocupación de territorios de S. occidentalis caurina disminuyó luego de que se detectaron individuos de S. varia a menos de 0.80 km del centro del territorio. Cuando se detectaron individuos de S. varia entre 0.81 y 2.40 km del centro de los territorios, la ocupación de éstos fue sólo marginalmente menor que en territorios sin S. varia. Esto sugiere que la frecuencia e intensidad de la interacción entre las dos especies está asociada con la distancia entre ellas. Nuestros resultados sugieren que las autoridades ambientales y de regulación deben considerar a S. varia como una amenaza para S. occidentalis caurina, particularmente si los números de S. varia se siguen incrementando como en los últimos 25 años.

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3

Hamer, Thomas E., Eric D. Forsman, and Elizabeth M. Glenn. "Home Range Attributes and Habitat Selection of Barred Owls and Spotted Owls in an Area of Sympatry." Condor 109, no. 4 (November 1, 2007): 750–68. http://dx.doi.org/10.1093/condor/109.4.750.

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Abstract We compared home range areas and habitat selection of radio-marked Spotted Owls (Strix occidentalis) and Barred Owls (Strix varia) in an area of sympatry in the northern Cascade Range of Washington in 1986–1989. On average, home ranges of Spotted Owls were 3–4 times larger than ranges of Barred Owls, and there was little overlap of home ranges during the breeding season. Ranges of both species tended to expand during winter. Home range size of both species was negatively correlated with the amount of old forest, but the negative slope of the regression was much steeper for Spotted Owls than for Barred Owls. For both species, home ranges of individual owls typically had high overlap among seasons and years, indicating high site fidelity. Barred Owls generally occupied home ranges at lower elevations than Spotted Owls (mean = 386 ± 27 m vs. 750 ± 68 m). Both species tended to use old forests more than expected, but Spotted Owls tended to use other cover types less than expected, whereas Barred Owls used most other cover types in proportion to their availability. We suggest that Spotted Owls may use larger ranges than Barred Owls because they prey selectively on a few species of nocturnal mammals, whereas Barred Owls forage more evenly across a broad range of prey types, including diurnal and aquatic species. The low overlap of Barred Owl and Spotted Owl home ranges suggests that territorial Barred Owls exclude Spotted Owls from their territories, at least during the breeding season, thus reducing the amount of habitat available to Spotted Owls.

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4

Kelly, Elizabeth G., and Eric D. Forsman. "Recent Records of Hybridization Between Barred Owls (Strix Varia) and Northern Spotted Owls (S. Occidentalis Caurina)." Auk 121, no. 3 (July 1, 2004): 806–10. http://dx.doi.org/10.1093/auk/121.3.806.

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Abstract We summarized records of hybridization between Barred Owls (Strix varia) and Northern Spotted Owls (S. occidentalis caurina) in Washington and Oregon through 1999. A total of 47 hybrids were observed, including 17 F1s that were first detected as adults, 4 F1s that were banded as juveniles and subsequently recaptured as adults, 10 F1 juveniles, and 16 F2 juveniles. All confirmed cases of hybridization between Barred and Spotted owls involved male Spotted Owls paired with female Barred Owls. Ten F1 hybrids that backcrossed with Barred Owls produced a total of 15 young; 6 F1 hybrids that backcrossed with Spotted Owls produced only 1 young. Those differences may indicate that some combinations of sex and species are more compatible or more fertile than others, but more documentation is needed. Because F2 hybrids and subsequent generations are difficult to distinguish in the field from Barred or Spotted owls, genetic comparisons of blood or tissue samples may be needed to identify hybrids beyond the first generation. The small number of F1 hybrids detected during many years of extensive banding studies of Spotted Owls suggests that the isolating mechanisms that separate Barred and Spotted owls are normally sufficient to avoid hybridization between them. Direct competition between the two species for food and space is probably a much more serious threat to the Spotted Owl than hybridization.

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5

Hanson, Chad T., Derek E. Lee, and Monica L. Bond. "Disentangling Post-Fire Logging and High-Severity Fire Effects for Spotted Owls." Birds 2, no. 2 (April 14, 2021): 147–57. http://dx.doi.org/10.3390/birds2020011.

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The Spotted Owl is a rare and declining raptor inhabiting low/middle-elevation forests of the Pacific Northwest, California, and the Southwest in the USA. It is well established that Spotted Owls select dense, mature, or old forests for nesting and roosting. High-severity fire transforms such forests into a unique forest type known as “snag forest habitat”, which the owls select for foraging. This habitat is disproportionately targeted by post-fire logging projects. Numerous recent articles have explored the influence of high-severity fire and post-fire logging on this species. Studies have shown that post-fire logging significantly reduces Spotted Owl occupancy, but efforts have generally not been made to disentangle the effects of such logging from the influence of high-severity fire alone on Spotted Owls. We conducted an assessment of published, peer-reviewed articles reporting adverse impacts of high-severity fire on Spotted Owls, exploring the extent to which there may have been confounding factors, such as post-fire logging. We found that articles reporting adverse impacts of high-severity fire on Spotted Owls were pervasively confounded by post-fire logging, and in some cases by a methodological bias. Our results indicate a need to approach analyses of high-severity fire and Spotted Owls differently in future research.

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6

Meyer, Joseph, Larry Irwin, and Mark Boyce. "Influence of Habitat Fragmentation on Spotted owl Site Selection, Site Occupancy, and Reproductive Status in Western Oregon." UW National Parks Service Research Station Annual Reports 13 (January 1, 1989): 241–42. http://dx.doi.org/10.13001/uwnpsrc.1989.2845.

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Currently there is little empirical evidence to guide decision makers on how to manage for viable populations of the Northern Spotted Owl (Strix occidentalis caurina) and how to decide what extent and what types of timber harvesting do not adversely affect Spotted Owls. In this ongoing study we are addressing some of the urgent research needs related to Spotted Owls by testing the null hypotheses that various forms of forest fragmentation do not affect (1) site selection, (2) site occupancy, or (3) reproductive success of Spotted Owls at sites within the Bureau of Land Management (BLM) checkerboard pattern of land ownership and management in Western Oregon.

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7

Wiens, J. David, Katie M. Dugger, J. Mark Higley, Damon B. Lesmeister, Alan B. Franklin, Keith A. Hamm, Gary C. White, et al. "Invader removal triggers competitive release in a threatened avian predator." Proceedings of the National Academy of Sciences 118, no. 31 (July 19, 2021): e2102859118. http://dx.doi.org/10.1073/pnas.2102859118.

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Changes in the distribution and abundance of invasive species can have far-reaching ecological consequences. Programs to control invaders are common but gauging the effectiveness of such programs using carefully controlled, large-scale field experiments is rare, especially at higher trophic levels. Experimental manipulations coupled with long-term demographic monitoring can reveal the mechanistic underpinnings of interspecific competition among apex predators and suggest mitigation options for invasive species. We used a large-scale before–after control–impact removal experiment to investigate the effects of an invasive competitor, the barred owl (Strix varia), on the population dynamics of an iconic old-forest native species, the northern spotted owl (Strix occidentalis caurina). Removal of barred owls had a strong, positive effect on survival of sympatric spotted owls and a weaker but positive effect on spotted owl dispersal and recruitment. After removals, the estimated mean annual rate of population change for spotted owls stabilized in areas with removals (0.2% decline per year), but continued to decline sharply in areas without removals (12.1% decline per year). The results demonstrated that the most substantial changes in population dynamics of northern spotted owls over the past two decades were associated with the invasion, population expansion, and subsequent removal of barred owls. Our study provides experimental evidence of the demographic consequences of competitive release, where a threatened avian predator was freed from restrictions imposed on its population dynamics with the removal of a competitively dominant invasive species.

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8

Andrews, Lawrence S., John P. Perkins, James A. Thrailkill, Nathan J. Poage, and John C. Tappeiner II. "Silvicultural Approaches to Develop Northern Spotted Owl Nesting Sites, Central Coast Ranges, Oregon." Western Journal of Applied Forestry 20, no. 1 (January 1, 2005): 13–27. http://dx.doi.org/10.1093/wjaf/20.1.13.

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Abstract The life-history requirements of northern spotted owls (Strix occidentalis caurina), a federally listed “threatened” species, are associated with late-successional habitats. Nesting sites are an important habitat requirement for spotted owls. We used an individual-tree, distance-independent growth model to explore a range of management scenarios for young Douglas-fir stands (age class 50 years) and estimated which scenarios promoted the development of forest patches that emulate the species mix and diameter distributions at known spotted owl nest sites in the central Coast Ranges of Oregon. Our modeling indicates that without silvicultural intervention or natural disturbances, the young stands (170–247 trees/ac) investigated did not develop features associated with spotted owl nest sites within 160-year total stand age. Silvicultural simulations that modeled heavy thinnings at ages 50 and 80 years, followed by tree-planting and additional thinnings developed forest patches structurally similar to our sample of spotted owl nest sites. We infer that silvicultural activities in federally managed, late-successional reserves may need to include alternatives beyond the scope of those permitted under current land use guidelines to accelerate the development of stand structures that better meet the nesting site requirements of spotted owls. West. J. Appl. For. 20(1):13–27.

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9

Seamans, Mark E., R. J. Gutiérrez, and Christopher A. May. "Mexican Spotted Owl (Strix Occidentalis) Population Dynamics: Influence of Climatic Variation on Survival and Reproduction." Auk 119, no. 2 (April 1, 2002): 321–34. http://dx.doi.org/10.1093/auk/119.2.321.

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Abstract Understanding the mechanisms causing temporal variability in demographic parameters is essential to understanding fluctuations in populations. As part of a long-term demographic study, we evaluated influence of climate on Mexican Spotted Owl (Strix occidentalis lucida) annual survival and reproduction in two study areas, one in Arizona and one in New Mexico. Spotted Owl survival in New Mexico and reproductive output in both study areas were positively related to total amounts of precipitation from the previous year, previous winter, or monsoon season. For both study areas, temporal process variation in reproductive output (CV[R] = 51.2 and 75.2% for Arizona and New Mexico, respectively) was greater than that for survival (CV[ϕ] = 12.9 and 7.1% for Arizona and New Mexico, respectively). Precipitation from the previous year explained 73% of σ̂2temporal reproductive output for Arizona owls and precipitation from the previous monsoon explained 42% of σ̂2temporal in reproductive output for New Mexico owls. Precipitation from the previous monsoon season explained 53% of σ̂2temporal in Arizona owl survival and precipitation from the previous winter explained 56% of σ̂2temporal in New Mexico owl survival. The two populations of Spotted Owls we studied appeared to have the same life-history strategy hypothesized for a population of Northern Spotted Owls (S. o. caurina), although the Mexican subspecies apparently responded quite differently to climatic variation.

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10

Kelly, Elizabeth G., Eric D. Forsman, and Robert G. Anthony. "ARE BARRED OWLS DISPLACING SPOTTED OWLS?" Condor 105, no. 1 (2003): 45. http://dx.doi.org/10.1650/0010-5422(2003)105[45:abodso]2.0.co;2.

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11

Gutierrez, R., Douglas Call, and Sarah Rinkevich. "Distribution and Abundance of Spotted Owls in Zion National Park." UW National Parks Service Research Station Annual Reports 13 (January 1, 1989): 226–33. http://dx.doi.org/10.13001/uwnpsrc.1989.2841.

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The main objective of this study is to estimate the distribution, habitat use, and reproductive status of Mexican spotted owls (Strix occidentalis lucida) in Zion National Park. This information will allow managers to coordinate park activities that potentially conflict with nest sites, roost sites, or brood rearing habitats. Other objectives of this study are to estimate spotted owl food habits and fledgling success, and to compare these findings with other North American spotted owl populations.

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12

Lynn, William S. "Bringing Ethics to Wild Lives: Shaping Public Policy for Barred and Northern Spotted Owls." Society & Animals 26, no. 2 (June 22, 2018): 217–38. http://dx.doi.org/10.1163/15685306-12341505.

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Abstract Ethics reviews are not part of environmental policy or wildlife management in the United States. This changed when, for the first time, the US Fish and Wildlife Service conducted such a review with respect to the barred and northern spotted owls. Spotted owls are endangered throughout their range by a variety of anthropogenic and natural forces. The interspecific competition between barred and spotted owls is a key factor second only to habitat destruction. A proposed lethal experiment to remove barred owls raised ethical concerns among wildlife agencies, citizens, and advocacy groups. Seeking to better understand these concerns, the Service created the Barred Owl Stakeholder Group. Using an innovative method and instrument in the form of an ethics-based policy dialogue and an ethics brief, the stakeholder group explored the ethical dimensions of the removal experiment. This process holds lessons for how public policy can bring ethics to bear on wild lives.

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13

Alston, Jesse M., Janet E. Millard, Jessica A. Rick, Brandon W. Husby, and Laurel A. Mundy. "Observations of Notable Parental Behaviours of Northern Spotted Owls (Strix occidentalis caurina)." Canadian Field-Naturalist 131, no. 3 (February 28, 2018): 225–27. http://dx.doi.org/10.22621/cfn.v131i3.1874.

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Northern Spotted Owl (Strix occidentalis caurina) is a medium-sized forest owl of conservation concern in the Pacific Northwest of North America. We report two sightings of previously unreported parental behaviour: a Northern Spotted Owl feeding avian nestlings to its young and a Northern Spotted Owl defending a fledgling against a Black Bear (Ursus americanus). Further research may be warranted on the influence of brood size and habitat quality on dietary breadth. Although Black Bears have not been previously documented as Northern Spotted Owl predators, we suggest that they should be considered potential predators of nestling and fledgling owls.

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Zabel, Cynthia J., Kevin McKelvey, and James P. Ward Jr. "Influence of primary prey on home-range size and habitat-use patterns of northern spotted owls (Strix occidentalis caurina)." Canadian Journal of Zoology 73, no. 3 (March 1, 1995): 433–39. http://dx.doi.org/10.1139/z95-049.

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Correlations between the home-range size of northern spotted owls (Strix occidentalis caurina) and proportion of their range in old-growth forest have been reported, but there are few data on the relationship between their home-range size and prey. The primary prey of spotted owls are wood rats and northern flying squirrels (Glaucomys sabrinus). Wood rats are larger and heavier than flying squirrels, and their population densities tend to be much greater than those of flying squirrels. We present data indicating that the home ranges of spotted owls are smaller where their diet consists predominantly of wood rats than where it consists predominantly of flying squirrels, and the proportion of the diet consisting of wood rats and flying squirrels explained significant variation in home-range size. We also found a significant correlation between home-range size and abundance of wood rats. These data indicate that prey species are a better predictor of home-range size than the proportion of older forest within spotted owl home ranges in the Klamath Province of northwestern California and southwestern Oregon, an area that is predominantly late-successional forest. Differences in habitat use were also related to prey species. Where spotted owls foraged for wood rats, the results indicated a preference for habitat edges, but where they utilized flying squirrels no such patterns were apparent.

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15

Forsman, Eric D., Alan Giese, David Manson, Stan Sovern, and Dale R. Herter. "Renesting by Spotted Owls." Condor 97, no. 4 (November 1995): 1078–80. http://dx.doi.org/10.2307/1369551.

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16

Jones, Gavin, Ralph Gutierrez, Douglas Tempel, William Berigan, Sheila Whitmore, and Zachariah Peery. "Megafire effects on spotted owls: elucidation of a growing threat and a response to Hanson et al. (2018)." Nature Conservation 33 (April 4, 2019): 21–41. http://dx.doi.org/10.3897/natureconservation.33.32741.

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The extent to which wildfire adversely affects spotted owls (Strixoccidentalis) is a key consideration for ecosystem restoration efforts in seasonally dry forests of the western United States. Recently, Jones et al. (2016) demonstrated that the 2014 King Fire (a “megafire”) adversely affected a population of individually-marked California spotted owls (S.o.occidentalis) monitored as part of a long-term demographic study in the Sierra Nevada, California, USA because territory occupancy declined substantially at territories burned at high-severity and GPS-tagged spotted owls avoided large patches of high-severity fire. Hanson et al. (2018) attempted to reassess changes in territory occupancy of the Jones et al. (2016) study population and claimed that occupancy declined as a result of post-fire salvage logging not fire per se and suggested that the avoidance of GPS-marked owls from areas that burned at high-severity was due to post-fire logging rather than a response to high-severity fire. Here, we demonstrate that Hanson et al. (2018) used erroneous data, inadequate statistical analyses and faulty inferences to reach their conclusion that the King Fire did not affect spotted owls and, more broadly, that large, high-severity fires do not pose risks to spotted owls in western North American dry forest ecosystems. We also provide further evidence indicating that the King Fire exerted a clear and significant negative effect on our marked study population of spotted owls. Collectively, the additional evidence presented here and in Jones et al. (2016) suggests that large, high-severity fires can pose a threat to spotted owls and that restoration of natural low- to mixed-severity frequent fire regimes would likely benefit both old-forest species and dry forest ecosystems in this era of climate change. Meeting these dual objectives of species conservation and forest restoration will be complex but it is made more challenging by faulty science that does not acknowledge the full range of wildfire effects on spotted owls.

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Jones, Gavin M., R. J. Gutiérrez, H. Anu Kramer, Douglas J. Tempel, William J. Berigan, Sheila A. Whitmore, and M. Zachariah Peery. "Megafire effects on spotted owls: elucidation of a growing threat and a response to Hanson et al. (2018)." Nature Conservation 37 (October 1, 2019): 31–51. http://dx.doi.org/10.3897/natureconservation.37.32741.

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The extent to which wildfire adversely affects spotted owls (Strix occidentalis) is a key consideration for ecosystem restoration efforts in seasonally dry forests of the western United States. Recently, Jones et al. (2016) demonstrated that the 2014 King Fire (a “megafire”) adversely affected a population of individually-marked California spotted owls (S. o. occidentalis) monitored as part of a long-term demographic study in the Sierra Nevada, California, USA because territory occupancy declined substantially at territories burned at high-severity and GPS-tagged spotted owls avoided large patches of high-severity fire. Hanson et al. (2018) attempted to reassess changes in territory occupancy of the Jones et al. (2016) study population and claimed that occupancy declined as a result of post-fire salvage logging not fire per se and suggested that the avoidance of GPS-marked owls from areas that burned at high-severity was due to post-fire logging rather than a response to high-severity fire. Here, we demonstrate that Hanson et al. (2018) used erroneous data, inadequate statistical analyses and faulty inferences to reach their conclusion that the King Fire did not affect spotted owls and, more broadly, that large, high-severity fires do not pose risks to spotted owls in western North American dry forest ecosystems. We also provide further evidence indicating that the King Fire exerted a clear and significant negative effect on our marked study population of spotted owls. Collectively, the additional evidence presented here and in Jones et al. (2016) suggests that large, high-severity fires can pose a threat to spotted owls and that restoration of natural low- to mixed-severity frequent fire regimes would likely benefit both old-forest species and dry forest ecosystems in this era of climate change. Meeting these dual objectives of species conservation and forest restoration will be complex but it is made more challenging by faulty science that does not acknowledge the full range of wildfire effects on spotted owls.

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18

Blakesley, Jennifer A., David R. Anderson, and Barry R. Noon. "Breeding Dispersal In the California Spotted Owl." Condor 108, no. 1 (February 1, 2006): 71–81. http://dx.doi.org/10.1093/condor/108.1.71.

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Abstract Spotted Owls (Strix occidentalis) are territorial, generally nonmigratory, and strongly philopatric. Nevertheless, California Spotted Owls (S. o. occidentalis) exhibited breeding dispersal during 7% of interannual observations of banded individuals (n = 54 of 743 occasions). Based on ecological theory and published literature, we made a priori predictions about the factors associated with the probability of breeding dispersal and breeding dispersal distance, and about the consequences of dispersal. Breeding dispersal probability was higher for younger owls, single owls, paired owls that lost their mates, owls at lower quality sites, and owls that failed to reproduce in the year preceding dispersal. Sex had little effect on the probability of breeding dispersal. Dispersal distance was similar for female and male owls (median = 7 km, range = 1–33 km). We found no strong relationships between dispersal distance and any of the conditions that were associated with the probability of breeding dispersal. Dispersal resulted in improved territory quality in 72% of cases. These results indicate that breeding dispersal was condition-dependent and adaptive.

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19

Pearson, Robert R., and Kent B. Livezey. "Spotted Owls, Barred Owls, and Late-Successional Reserves." Journal of Raptor Research 41, no. 2 (June 2007): 156–61. http://dx.doi.org/10.3356/0892-1016(2007)41[156:soboal]2.0.co;2.

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20

Loehle, C., L. Irwin, D. Rock, and S. Rock. "Are survival rates for northern spotted owls biased?" Canadian Journal of Zoology 83, no. 10 (October 1, 2005): 1386–90. http://dx.doi.org/10.1139/z05-137.

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The northern spotted owl (Strix occidentalis caurina (Merriam, 1898)) is listed as threatened in both Canada and the United States. As part of a 1998–2004 study of habitat usage, we attached radio tags to 197 northern spotted owls. Owls that died or emigrated from the study areas could be identified with high certainty. The long-term data we obtained enabled us to estimate survivorship using multiple statistical methods. Using a pooled data set, we estimated annual survivorship at 0.927. Using a year-by-year analysis, we obtained some variation in survival by year, but the same overall mean. Using a staggered-entry cohort approach, we obtained an estimate of 0.934. Mean annual survival estimated by program MARK was 0.927. These estimates are outside the confidence intervals of prior studies that used capture–recapture methods. Capture–recapture methods are based on the assumption that birds remain within a demographic study area, but our data suggest that owls may disperse or remain undetected within a study area often enough that capture–recapture methods may overestimate mortality. Our results imply that the true finite population growth rate, λ, may be higher than estimated in prior studies that used capture–recapture methods.

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21

Nadeem, Muhammad Sajid, Syed Israr Shah, Amjad Rashid Kayani, Syed Muhammad Khalid Imran, and Tariq Mahmood. "A comparative study of the diets of barn owl (Tyto alba) and spotted owlet (Athene brama) inhabiting Ahmadpur East, Southern Punjab, Pakistan." Animal Biology 62, no. 1 (2012): 13–28. http://dx.doi.org/10.1163/157075511x597593.

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AbstractThe diets of the barn owl (Tyto alba) and the spotted owlet (Athene brama) inhabiting the periphery of the Cholistan Desert at Ahmedpur East, southern Punjab were compared. Pellets of the two owl species were analyzed to learn more about their diets. The barn owl mainly consumed Suncus murinus (60.2%), birds (24.1%) and rodents (12.7%), while the spotted owlet depended on Mus species (36.8%), Suncus murinus (20.1%), birds (14.1%), reptiles (8.9%) and insects (6.7%) for its food. There was a low degree of food overlap of the two owls among the seasons.

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22

Hunter, John E., Colin Jewett, and Antonio Padilla. "Kleptoparasitism of Northern Spotted Owls." Northwestern Naturalist 74, no. 1 (1993): 28. http://dx.doi.org/10.2307/3536581.

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23

Ganey, Joseph L., William M. Block, and Steven H. Ackers. "Structural Characteristics of Forest Stands Within Home Ranges of Mexican Spotted Owls in Arizona and New Mexico." Western Journal of Applied Forestry 18, no. 3 (July 1, 2003): 189–98. http://dx.doi.org/10.1093/wjaf/18.3.189.

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Abstract As part of a set of studies evaluating home-range size and habitat use of radio-marked Mexican spotted owls (Strix occidentalis lucida), we sampled structural characteristics of forest stands within owl home ranges on two study areas in Arizona and New Mexico. Study areas were dominated by ponderosa pine (Pinus ponderosa)–Gambel oak (Quercus gambelii) forest (Arizona) or mixed-conifer forest (New Mexico). We describe structural characteristics of forest stands used by spotted owls for both foraging and roosting, in terms of central tendencies and variability in structural characteristics among stands. Our results indicated that stands used for foraging were more variable than stands used for roosting. Observed distributions of structural variables were consistent with recommendations in the recovery plan governing management of owl habitat with a few potentially important exceptions. We also provide additional recommendations for application in forest management, based both on observed data and on extensive collective experience with the owl and its habitat. West. J. Appl. For. 18(3):189–198.

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Washburn, Brian E., Douglas J. Tempel, Joshua J. Millspaugh, R. J. Gutiérrez, and Mark E. Seamans. "Factors Related to Fecal Estrogens and Fecal Testosterone in California Spotted Owls." Condor 106, no. 3 (August 1, 2004): 567–79. http://dx.doi.org/10.1093/condor/106.3.567.

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Abstract We estimated concentrations of fecal reproductive steroid metabolites in free-ranging California Spotted Owls (Strix occidentalis occidentalis) during the breeding season. We collected fresh fecal samples (n = 142) from 65 individual owls in the Sierra Nevada during April–August of 2001. We developed and validated radioimmunoassay procedures to quantify fecal estrogen metabolites and fecal testosterone metabolites. We used an information-theoretic approach to identify factors that might influence fecal estrogen (E), fecal testosterone (T), and fecal estrogen:testosterone ratio (E:T ratio) levels during the owl's breeding season. We hypothesized that factors related to sampling procedures, owl characteristics (sex, reproductive status), and habitat might influence fecal reproductive steroid levels. Our analyses suggested that sampling factors and owl characteristics, but not habitat variables, were related to fecal reproductive steroid levels in Spotted Owls. Our most supported models explained <30% of the observed variation. Fecal testosterone levels were higher in male Spotted Owls than females, whereas E:T ratios were higher in females compared to males. High fecal estrogens were correlated with high fecal glucocorticoids in nonbreeding Spotted Owls, whereas fecal estrogens and fecal glucocorticoids were not related in breeding birds. Sampling influenced fecal reproductive steroid measures, and bias from small-mass fecal samples might partially explain these relationships. Noninvasive measurements of fecal reproductive steroids might be useful for sex determination and reproductive assessment of free-ranging Spotted Owls. However, more research is needed to understand the variability we observed in sex steroids before this technique can be effective in conservation studies. Factores Asociados con los Estrógenos Fecales y la Testosterona Fecal en Strix occidentalis occidentalis Resumen. Estimamos las concentraciones de metabolitos esteroides reproductivos en individuos silvestres de la especie Strix occidentalis occidentalis durante la época reproductiva. Colectamos muestras fecales frescas (n = 142) pertenecientes a 65 lechuzas en la Sierra Nevada entre abril y agosto de 2001. Desarrollamos y validamos un procedimiento de radioinmunoensayo para cuantificar metabolitos de estrógeno fecales y metabolitos de testosterona fecales. Utilizamos un enfoque informativo-teórico para identificar los factores que podrían influenciar los niveles de estrógenos fecales (E), testosterona fecal (T) y el cociente entre estrógenos y testosterona (cociente E:T) durante la época reproductiva de las lechuzas. Hipotetizamos que factores relacionados con los procedimientos de muestreo, características de la lechuza (sexo, estado reproductivo) y el hábitat podrían influenciar los niveles de esteroides reproductivos en las fecas. Nuestros análisis sugieren que los factores asociados al muestreo y las características de la lechuza se correlacionaron con los niveles de esteroides reproductivos en las fecas, pero éstos no se relacionaron con las variables de hábitat. Nuestro modelo más robusto explicó <30% de la variación observada. Los niveles de testosterona fecal fueron mayores en los machos que en las hembras, mientras que el cuociente E:T fue mayor en las hembras que en los machos. En lechuzas no reproductivas, los niveles altos de estrógenos fecales se correlacionaron con niveles altos de glucocorticoides fecales, mientras que en individuos reproductivos los estrógenos fecales y los glucorticoides fecales no se correlacionaron. Estas relaciones pueden ser explicadas en parte por la influencia del muestreo sobre las medidas de esteroides reproductivos fecales y por el sesgo causado por muestras fecales muy livianas. Los niveles de esteroides reproductivos fecales medidos con técnicas no invasivas pueden ser útiles para la determinación de sexos y la evaluación del estado reproductivo de individuos silvestres de la especie S. occidentalis occidentalis. Sin embargo, antes de que esta técnica pueda ser efectiva en estudios de conservación, se requiere de más investigación para entender la variabilidad que observamos en los niveles de esteroides sexuales.

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Long, Linda L., and Jared D. Wolfe. "Review of the effects of barred owls on spotted owls." Journal of Wildlife Management 83, no. 6 (July 17, 2019): 1281–96. http://dx.doi.org/10.1002/jwmg.21715.

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Hamer, Thomas E., and Eric D. Forsman. "Hybridization between Barred and Spotted Owls." Auk 111, no. 2 (April 1994): 487–92. http://dx.doi.org/10.2307/4088616.

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Wan, Ho Yi, Joseph L. Ganey, Christina D. Vojta, and Samuel A. Cushman. "Managing emerging threats to spotted owls." Journal of Wildlife Management 82, no. 4 (February 1, 2018): 682–97. http://dx.doi.org/10.1002/jwmg.21423.

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Weathers, Wesley W., Peter J. Hodum, and Jennifer A. Blakesley. "Thermal Ecology and Ecological Energetics of California Spotted Owls." Condor 103, no. 4 (November 1, 2001): 678–90. http://dx.doi.org/10.1093/condor/103.4.678.

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Abstract In this study, we used open-circuit respirometry and the doubly labeled water technique (DLW) to examine the thermal ecology and ecological energetics of California Spotted Owls (Strix occidentalis occidentalis). Our physiological and behavioral observations indicated that Spotted Owls are less heat tolerant than typical birds. At temperatures above the thermoneutral zone (18.2–35.2°C), resting metabolic rate increased 1.48 times faster than predicted allometrically, and behavioral responses to heat stress (increased breathing rate, ptiloerection, gaping, and wing drooping) occurred at relatively modest temperatures, 30–34°C. Our data support the hypothesis that Spotted Owls prefer old-growth and late seral stage forests because they provide favorable microclimates. Our metabolic measurements reveal that Spotted Owls have exceptionally low energy requirements. Their basal metabolic rate, 10.13 ± 0.46 J g−1 hr−1, is only 82% of that predicted allometrically for owls. Field metabolic rate (FMR) of five adults provisioning dependent young averaged 249 ± 60 kJ day−1, only 34% of that predicted for comparably sized non-passerine birds. We calculated Spotted Owl prey requirements from our FMR data, laboratory determinations of assimilation efficiency (77%), and the body composition of representative prey types. On average, Spotted Owls feeding young can meet their own energy needs by consuming one northern flying squirrel (Glaucomys sabrinus) every 1.8 days or one woodrat (Neotoma fuscipes) every 3.7 days. Ecología Térmica y la Energética Ecológica de Strix occidentalis occidentalis Resumen. En este estudio usamos respirometría de circuito abierto y la técnica de agua doble-marcada (DLW) para examinar la ecología térmica y la energética ecológica de la lechuza moteada californiana (Strix occidentalis occidentalis). Nuestras observaciones fisiologicas y comportamentales indican que las lechuzas moteadas son menos tolerantes a temperaturas elevadas que las aves en general. A temperaturas sobre de la zona de neutralidad térmica (18.2–35.2°C), la tasa metabólica basal se incrementó 1.48 veces más rápido que la predicha alométricamente, y la respuesta en el comportamiento a la tensión térmica (incremento en la tasa respiratoria, erección de las plumas, jadeo y el reposo de las alas) ocurrió a temperaturas relativamente bajas (30–34°C). Nuestros datos son consistentes con la hipótesis que las lechuzas moteadas prefieren bosques maduros y en etapas avanzadas de suseción debido a su microclima favorable. Nuestras medidas metabólicas indican que las lechuzas moteadas tienen requerimientos energéticos excepcionalmente bajos. Su tasa metabólica basal, 10.13 ± 0.46 J g−1 hr−1, representa solo el 82% del valor predicho para lechuzas. La tasa metabólica de campo (TMC) de cinco adultos que se encuentraban criando polluelos promedió 249 ± 60 kJ day−1, solamente un 34% del valor predicho para aves no-paserinas de tamaño comparable. Calculamos los requisitos de alimentación para lechuzas moteadas usando nuestros datos de TMC, las determinaciones en el laboratorio de la eficiencia de la asimilación (77%), y la composición corporal de varios tipos de alimentos. En promedio, las lechuzas moteadas criando polluelos pueden mantenerse alimentandose de una ardilla (Glaucomys sabrinus) cada 1.8 días o una rata (Neotoma fuscipes) cada 3.7 días.

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Diller, Lowell V., Keith A. Hamm, Desiree A. Early, David W. Lamphear, Katie M. Dugger, Charles B. Yackulic, Carl J. Schwarz, Peter C. Carlson, and Trent L. McDonald. "Demographic response of northern spotted owls to barred owl removal." Journal of Wildlife Management 80, no. 4 (February 17, 2016): 691–707. http://dx.doi.org/10.1002/jwmg.1046.

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30

Gutierrez, R., and Sarah Rinkevich. "Distribution and Abundance of Spotted Owls in Zion Natioinal Park." UW National Parks Service Research Station Annual Reports 14 (January 1, 1990): 193–98. http://dx.doi.org/10.13001/uwnpsrc.1990.2941.

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The recent listing of the Northern spotted owl (Strix occidentalis caurina) by the U.S. Fish and Wildlife Service as a threatened species (Federal Register 1990) raises heated debate concerning the long-term survival of the species and perceived economic cost to timber industry (Thomas et al. 1988). Long term studies of the owls's ecology are necessary to provide information needed for ecologically based management plans (Dawson et al. 1987). Much is already known about the natural and life history of the Northern spotted owl (Forsman et al. 1984, Gutierrez et al. 1984, Gutierrez 1985, Franklin et al. 1990) as well as the California subspecies (S. o. occidentalis) (Gutierrez and Pritchard 1990). In contrast, the Mexican spotted owl (S. o. Iucida) is the least studied of the three subspecies (Ganey and Balda 1989). It is known that this latter subspecies inhabits rocky canyonlands and coniferous forests in the southwestern United States and Mexico (Kertell1977, Wagner et al. 1982, Webb 1983, Johnson and Johnson 1985, Ganey 1988, and Skaggs 1988) but there are few published studies on its ecology and habitat needs (Ganey 1988). Also, the effects of human activities, such as recreation, on the Mexican subspecies are unclear, particularly in isolated habitats (Gutierrez 1985). Therefore, in 1989, we initiated a two year investigation of abundance and distribution of Mexican spotted owls in Zion National Park. This report summarizes our 1990 survey effort and research findings.

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31

Livezey, Kent B. "Killing Barred Owls to Help Spotted Owls I: A Global Perspective." Northwestern Naturalist 91, no. 2 (September 2010): 107–33. http://dx.doi.org/10.1898/nwn09-37.1.

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32

Bodine, Erin N., and Alex Capaldi. "Can culling Barred Owls save a declining Northern Spotted Owl population?" Natural Resource Modeling 30, no. 3 (July 11, 2017): e12131. http://dx.doi.org/10.1111/nrm.12131.

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33

IRWIN, LARRY L., LAURIE A. CLARK, DENNIS C. ROCK, and SUZANNE L. ROCK. "Modeling Foraging Habitat of California Spotted Owls." Journal of Wildlife Management 71, no. 4 (June 2007): 1183–91. http://dx.doi.org/10.2193/2006-122.

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34

Paton, Peter W. C., Cynthia J. Zabel, Donald L. Neal, George N. Steger, Nancy G. Tilghman, and Barry R. Noon. "Effects of Radio Tags on Spotted Owls." Journal of Wildlife Management 55, no. 4 (October 1991): 617. http://dx.doi.org/10.2307/3809508.

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Delaney, David K., Teryl G. Grubb, and Paul Beier. "Activity Patterns of Nesting Mexican Spotted Owls." Condor 101, no. 1 (February 1999): 42–49. http://dx.doi.org/10.2307/1370444.

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36

Sovern, Stan G., Damon B. Lesmeister, Katie M. Dugger, M. Shane Pruett, Raymond J. Davis, and Julianna M. Jenkins. "Activity center selection by northern spotted owls." Journal of Wildlife Management 83, no. 3 (January 10, 2019): 714–27. http://dx.doi.org/10.1002/jwmg.21632.

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37

Irwin, Larry L., Dennis F. Rock, and Suzanne C. Rock. "Do northern spotted owls use harvested areas?" Forest Ecology and Management 310 (December 2013): 1029–35. http://dx.doi.org/10.1016/j.foreco.2013.04.001.

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38

Sovern, Stan G., Eric D. Forsman, Gail S. Olson, Brian L. Biswell, Margaret Taylor, and Robert G. Anthony. "Barred owls and landscape attributes influence territory occupancy of northern spotted owls." Journal of Wildlife Management 78, no. 8 (October 9, 2014): 1436–43. http://dx.doi.org/10.1002/jwmg.793.

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39

Freudenburg, William R., Lisa J. Wilson, and Daniel J. O'Leary. "Forty Years of Spotted Owls? A Longitudinal Analysis of Logging Industry Job Losses." Sociological Perspectives 41, no. 1 (March 1998): 1–26. http://dx.doi.org/10.2307/1389351.

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The protection of habitat for an officially designated “threatened” species, the Northern Spotted Owl, is widely seen as having endangered the survival of a very different “species,” namely the rural American logger. In spite of the widespread agreement on this point, however, it is not clear just how many jobs have been endangered, over just how long a period, due to the protection of spotted-owl habitat and of the environment more broadly. In the present paper, we analyze longer term employment trends in logging and milling, both nationally and in the two states of the Pacific Northwest where the spotted-owl debate has been most intense, to determine the length of time over which such environmental protection efforts have been creating the loss of logging and milling jobs. There are three potential key “turning points” since the start of high-quality employment data in 1947—the 1989 controversy over the federal “listing” of the Northern Spotted Owl under the Endangered Species Act, the earlier increase in environmental regulations accompanying the first Earth Day in 1970, and the still-earlier “locking up” of timber after the passage of the Wilderness Protection Act in 1964. We also examine the effects of two other variables that have received considerable attention in the ongoing debates—levels of U.S. Forest Service timber harvests and the exporting of raw logs. We find that the 1989 listing of the spotted owl has no significant effect on employment—not even in the two states where the debate has been most intense. Instead, the only statistically significant turning point came with the passage of the Wilderness Act in 1964. The direction of the change, however, was precisely the opposite of what is generally expected. Both nationally and in the Pacific Northwest, the greatest decline in timber employment occurred from 1947 until 1964—a time of great economic growth, a general absence of “unreasonable environmental regulations,” and growing timber harvests. The period since the passage of the Wilderness Act has been one of increased complaints about environmental constraints, but much less decline in U.S. logging employment. If logging jobs have indeed been endangered by efforts to protect the environment in general and spotted-owl habitat in particular, what is needed is a plausible explanation of how the influence of the owls could have begun more than forty years before the species came under the protection of the Endangered Species Act.

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Gutiérrez, R. J., and George F. Barrowclough. "Redefining the Distributional Boundaries of the Northern and California Spotted Owls: Implications for Conservation." Condor 107, no. 1 (February 1, 2005): 182–87. http://dx.doi.org/10.1093/condor/107.1.182.

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Abstract The Northern Spotted Owl (Strix occidentalis caurina) is listed as a threatened species. However, the range description given at the time of listing is inconsistent with the range delineation given by the American Ornithologists' Union checklist of North American birds. Despite the quandary that this inconsistency represents regarding the area of protection afforded the Northern Spotted Owl, the range used in listing is consistent with the actual range suggested by mtDNA haplotypes diagnostic for the subspecies. The range description used in the listing decision of the Northern Spotted Owl and in many conservation plans have been repeated through time without a formal revision or basis for support. Based on current knowledge of Spotted Owl locations we revise the range limits for both Northern and California (S. o. occidentalis) Spotted Owls. Redefinición de los Límites de las Distribuciones de Strix occidentalis caurina y S. o. occidentalis: Implicaciones para Conservación Resumen. La lechuza Strix occidentalis caurina se considera amenazada. Sin embargo, la descripción de su rango de distribución hecha al momento en que fue incluida en la lista de especies amenazadas es inconsistente con la delimitación de su rango hecha por la lista de chequeo de aves de Norte América de la American Ornithologists' Union. A pesar de la incertidumbre que esta inconsistencia representa con respecto al área de protección con que cuenta S. o. caurina, el rango empleado al incluirla en la lista es consistente con el rango real sugerido por haplotipos de ADN mitocondrial diagnósticos para esta subespecie. La descripción del rango de distribución empleada para tomar la decisión de incluir a S. o. caurina en la lista de aves amenazadas y para muchos planes de conservación ha sido repetida a través del tiempo sin una revisión formal fundamentada. Con base en el conocimiento actual, en este estudio revisamos los límites de los rangos de S. o. caurina y de la subespecie de California, S. o. occidentalis.

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41

Kristan, Deborah M., R. J. Gutiérrez, and Alan B. Franklin. "Adaptive significance of growth patterns in juvenile spotted owls." Canadian Journal of Zoology 74, no. 10 (October 1, 1996): 1882–86. http://dx.doi.org/10.1139/z96-212.

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We examined relative growth patterns of six morphological features of fledgling spotted owls (Strix occidentalis). Juvenile spotted owls exhibit early nest desertion, possibly to avoid parasitism or detection by predators or to reduce thermal stress. Because juveniles leave the nest before they are capable fliers, they primarily use morphological features other than their wings and tail to move among roost locations. When juveniles fledged, mass, wing chord, and tail length were still increasing, whereas tarsus length and bill depth were near adult size. Moreover, juvenile bill length was greater than mean adult bill length for nearly all time periods. Early growth in tarsi and bills may increase juveniles' ability to effectively locomote after they have fledged but before they can adequately fly.

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Crozier, Michelle L., Mark E. Seamans, R. J. GutiÉRrez, Peter J. Loschl, Robert B. Horn, Stan G. Sovern, and Eric D. Forsman. "DOES THE PRESENCE OF BARRED OWLS SUPPRESS THE CALLING BEHAVIOR OF SPOTTED OWLS?" Condor 108, no. 4 (2006): 760. http://dx.doi.org/10.1650/0010-5422(2006)108[760:dtpobo]2.0.co;2.

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43

Ganey, Joseph L. "Calling Behavior of Spotted Owls in Northern Arizona." Condor 92, no. 2 (May 1990): 485. http://dx.doi.org/10.2307/1368245.

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44

Salwasser, Hal. "Spotted Owls: Turning a Battleground into a Blueprint." Ecology 68, no. 4 (August 1987): 776–79. http://dx.doi.org/10.2307/1938348.

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45

Pater, Larry L., David K. Delaney, Teryl G. Grubb, Paul Beier, and M. Hildegard Reiser. "Effects of helicopter noise on spotted owls: Methodology." Journal of the Acoustical Society of America 98, no. 5 (November 1995): 2940. http://dx.doi.org/10.1121/1.414113.

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Delaney, David K., Teryl G. Grubb, Paul Beier, Larry L. Pater, and M. Hildegard Reiser. "Effects of Helicopter Noise on Mexican Spotted Owls." Journal of Wildlife Management 63, no. 1 (January 1999): 60. http://dx.doi.org/10.2307/3802487.

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47

Swarthout, Elliott C. H., and Robert J. Steidl. "Flush Responses of Mexican Spotted Owls to Recreationists." Journal of Wildlife Management 65, no. 2 (April 2001): 312. http://dx.doi.org/10.2307/3802910.

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48

Franklin, Alan B., James P. Ward, R. J. Gutierrez, and Gordon I. Gould. "Density of Northern Spotted Owls in Northwest California." Journal of Wildlife Management 54, no. 1 (January 1990): 1. http://dx.doi.org/10.2307/3808893.

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49

LaHaye, William S., Guthrie S. Zimmerman, and R. J. Gutiérrez. "Temporal Variation in the Vital Rates of an Insular Population of Spotted Owls (Strix Occidentalis Occidentalis): Contrasting Effects of Weather." Auk 121, no. 4 (October 1, 2004): 1056–69. http://dx.doi.org/10.1093/auk/121.4.1056.

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Abstract We studied the demography of an insular California Spotted Owl (Strix occidentalis occidentalis) population in southern California for 12 years. We used model selection based on information theory to examine the relationship between weather and reproduction and survival. Mean annual fecundity was 0.139 (SE = 0.050) for subadult females and 0.345 (SE = 0.028) for adult females. Adult females had higher fecundity than subadult females during all years, and fecundity in both age classes was higher when a wet year preceded a dry spring (i.e. breeding season). A model incorporating these factors explained 100% of the estimated temporal process variation in fecundity. Mean apparent survival was 0.796 (SE = 0.012), 0.880 (SE = 0.041), 0.692 (SE = 0.062), and 0.368 (SE = 0.038) for adult, second-year subadult, first-year subadult, and juvenile (first-year) owls, respectively. We found no temporal process variation in survival. Using a Leslie projection matrix, we estimated the finite rate of population change to be 0.906 (SE = 0.018) over the entire period of study (1987–1998), which indicated that the population declined ≈9% per year during the study. That rate of decline was higher than a rate (λ1991–1998 = 0.921, SE = 0.020) we estimated for a shorter period (1991–1998) that matched the time interval used in a recent meta-analysis of Spotted Owl population dynamics. We believe that both the present estimates and those of the meta-analysis are valid, given their respective goals. The study population was characterized by relatively high, constant survival of territorial birds, low and variable annual reproduction, and relatively low juvenile survival. Because weather was strongly correlated with reproduction, fecundity rates for the species may decline during short-term droughts and when storms occur during the breeding season. Weather extremes may not, however, be sufficient to affect temporal variation in survival of Spotted Owls in this part of their range.

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50

Thompson, Ian D. "Could marten become the spotted owl of eastern Canada?" Forestry Chronicle 67, no. 2 (April 1, 1991): 136–40. http://dx.doi.org/10.5558/tfc67136-2.

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Conservation of spotted owl habitat in western North America illustrates the difficult decisions that must be taken and the conflicts that can arise in land-use planning. In eastern North America, spotted owls are absent but marten, an animal species which prefers old-growth forest, has become rare in some areas as a result of habitat loss. The marten is a threatened species in Newfoundland, exists in small numbers in Nova Scotia, and has been extirpated in Prince Edward Island. Lack of long-term integrated forest resource planning, short rotations, and silvicultural practices that produce sub-optimal habitat may eliminate the species in Atlantic Canada. Two cases are discussed from Newfoundland and New Brunswick where unbalanced forest age structures suggest a bleak future for the marten. Other larger jurisdictions in Canada should closely examine their forest land management plans in view of the Atlantic experience.

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