Breeding Dispersal In the California Spotted Owl

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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Habitat Selection in a Changing Environment: The Relationship Between Habitat Alteration and Spotted Owl Territory Occupancy and Breeding Dispersal

The Condor ◽

10.1093/condor/109.3.566 ◽

2007 ◽

Vol 109 (3) ◽

pp. 566-576 ◽

Cited By ~ 6

Author(s):

Mark E. Seamans ◽

R.J. Gutiérrez

Keyword(s):

Habitat Selection ◽

Sierra Nevada ◽

Coniferous Forest ◽

Canopy Cover ◽

Habitat Alteration ◽

Breeding Dispersal ◽

Conifer Forest ◽

Avian Behavior ◽

Spotted Owl ◽

The Relationship

Abstract Abstract. Understanding the effect of habitat alteration on avian behavior is important for understanding a species' ecology and ensuring its conservation. Therefore, we examined the relationship between Spotted Owl habitat selection and variation in habitat in the Sierra Nevada. We estimated habitat selection by modeling the probability of territory colonization (γ), territory extinction (ε), and breeding dispersal in relation to the amount of mature conifer forest within and among territories. Alteration of ≥20 ha of mature conifer forest (coniferous forest with >70% canopy cover dominated by medium [30.4–60.9 cm dbh] and large [>60.9 cm dbh] trees) within individual territories (n = 66) was negatively related to territory colonization and positively related to breeding dispersal probability. Although territory extinction was negatively related to the amount of mature conifer forest, it was not clear whether this relationship was due to variation of mature conifer forest within or among territories. Although modeling results for territory colonization and extinction generally supported the hypothesis that individuals are “ideal” when selecting a habitat in the sense that they settle in the highest-quality site available, we did not find a clear benefit in terms of habitat quality for Spotted Owls that exhibited breeding dispersal.

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California spotted owl habitat selection in a fire-managed landscape suggests conservation benefit of restoring historical fire regimes

Forest Ecology and Management ◽

10.1016/j.foreco.2020.118576 ◽

2021 ◽

Vol 479 ◽

pp. 118576

Author(s):

Anu Kramer ◽

Gavin M. Jones ◽

Sheila A. Whitmore ◽

John J. Keane ◽

Fidelis A. Atuo ◽

...

Keyword(s):

Habitat Selection ◽

Fire Regimes ◽

Spotted Owl ◽

California Spotted Owl

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Estimating the Effects of Map Error on Habitat Delineation for the California Spotted Owl in Southern California

Transactions in GIS ◽

10.1111/j.1467-9671.2005.00234.x ◽

2005 ◽

Vol 9 (4) ◽

pp. 541-559 ◽

Cited By ~ 7

Author(s):

Ellen M. Hines ◽

Janet Franklin ◽

John R. Stephenson

Keyword(s):

Southern California ◽

Spotted Owl ◽

California Spotted Owl

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California Spotted Owl Habitat Selection in the Central Sierra Nevada

Journal of Wildlife Management ◽

10.2307/3802127 ◽

1997 ◽

Vol 61 (4) ◽

pp. 1281 ◽

Cited By ~ 32

Author(s):

Christine A. Moen ◽

R. J. Gutierrez

Keyword(s):

Habitat Selection ◽

Sierra Nevada ◽

Spotted Owl ◽

California Spotted Owl

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Cover of tall trees best predicts California spotted owl habitat

Forest Ecology and Management ◽

10.1016/j.foreco.2017.09.019 ◽

2017 ◽

Vol 405 ◽

pp. 166-178 ◽

Cited By ~ 41

Author(s):

Malcolm P. North ◽

Jonathan T. Kane ◽

Van R. Kane ◽

Gregory P. Asner ◽

William Berigan ◽

...

Keyword(s):

Spotted Owl ◽

California Spotted Owl

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Effects of post-fire logging on California spotted owl occupancy

Nature Conservation ◽

10.3897/natureconservation.24.20538 ◽

2018 ◽

Vol 24 ◽

pp. 93-105 ◽

Cited By ~ 8

Author(s):

Chad T. Hanson ◽

Monica L. Bond ◽

Derek E. Lee

Keyword(s):

Spotted Owl ◽

California Spotted Owl

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Is “Fuel Reduction” Justified as Fire Management in Spotted Owl Habitat?

Birds ◽

10.3390/birds2040029 ◽

2021 ◽

Vol 2 (4) ◽

pp. 395-403

Author(s):

Chad T. Hanson

Keyword(s):

Forest Management ◽

Sierra Nevada ◽

Tree Mortality ◽

Habitat Degradation ◽

Fire Suppression ◽

Fire Severity ◽

Indirect Evidence ◽

Fuel Reduction ◽

Spotted Owl ◽

California Spotted Owl

The California spotted owl is an imperiled species that selects mature conifer forests for nesting and roosting while actively foraging in the “snag forest habitat” created when fire or drought kills most of the trees in patches. Federal agencies believe there are excess surface fuels in both of these habitat conditions in many of California’s forests due to fuel accumulation from decades of fire suppression and recent drought-related tree mortality. Accordingly, agencies such as the U.S. Forest Service are implementing widespread logging in spotted owl territories. While they acknowledge habitat degradation from such logging, and risks to the conservation of declining spotted owl populations, agencies hypothesize that such active forest management equates to effective fuel reduction that is needed to curb fire severity for the overall benefit of this at-risk species. In an initial investigation, I analyzed this issue in a large 2020 fire, the Creek Fire (153,738 ha), in the southern Sierra Nevada mountains of California. I found that pre-fire snag density was not correlated with burn severity. I also found that more intensive forest management was correlated to higher fire severity. My results suggest the fuel reduction approach is not justified and provide indirect evidence that such management represents a threat to spotted owls.

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