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Title
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Surveying Suburban Barred Owls in Olympia, Washington
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Creator
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Seebeck, Alex
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Identifier
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Thesis_MES_2022_SeebeckA
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extracted text
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Surveying Suburban Barred Owls in Olympia, Washington
By
Alex Seebeck
A Thesis
Submitted in partial fulfillment
of the requirements for the degree
Master of Environmental Studies
The Evergreen State College
December 2022
©2022 by Alex Seebeck. All rights reserved
This Thesis for the Master of Environmental Studies Degree
by
Alex Seebeck
has been approved for
The Evergreen State College
by
________________________
John C. Withey, Ph.D.
Member of Faculty
Abstract
Surveying Suburban Barred Owls in Olympia, Washington
Alex Seebeck
Barred Owls (Strix varia) are a common medium sized owl on the east coast of the U.S. into
Canada. Occupying forestes, this generalist can also be found in suburban areas. Over the past 50
years the Barred Owl has expanded its range west into the Pacific Northwest (PNW). The
endangered Spotted Owl (Strix occidentalis caurina) is an old growth obligate that was severely
impacted by commercial logging. The competition between these two species has led researchers
to lethally remove Barred Owls. However, Barred Owls often reoccupied locations where they
had been removed. This study aims to better understand the distribution of Barred Owls in the
Pacific Northwest. The West peninsula of Olympia, Washington is a mix of dense urban areas,
suburban areas, and fragmented forest. An audio-broadcast survey was conducted for two
months during the summer of 2022 to locate Barred Owls. Responses were classified, based on
the maximum number of owls recorded in a single survey, into Single, Pair, and (if young were
located) Family. Forty-two individual Barred Owls were located in 15.77 km2. Eleven young
Barred Owls were confirmed at six locations. A 500m radius buffer was created around all result
locations to characterize the habitat. One family was in a neighborhood that contained more
developed areas than forest cover. Barred Owls were found on the west Olympia peninsula in
densities similar to those on the east coast. The suburban populations of Barred Owls need
further study to detail territories, numbers, and potential impacts on the Spotted Owls.
Table of Contents
List of Figures……………………………………………………………………..……………....v
List of Tables……………………………………………………………………..………………vi
Acknowledgements……………………………………………………………….….…………..vii
Introduction………………………………………………………………………….…………….1
Literature Review………………………………………………………………….………………4
Owls……………………………………………………………………………………….4
Range Expansion & Implications…………………………………………………………7
Urbanization…………………………………………………………………………...…11
Methods…………………………………………………………………………………………..14
Survey Sites……………………………………………………………………………...14
Calling……………………………………………………………………………………15
Responses………………………………………………………………….……………..16
Mapping………………………………………………………………………………….17
Results……………………………………………………………………………………………19
Survey……………………………………………………………………………………20
Influencing Factors………………………………………………………………………24
Discussion………………………………………………………………………………………..25
Conclusion……………………………………………………………………………………….36
Bibliography……………………………………………………………………………………..38
Appendix…………………………………………………………………………………………46
iv
List of Figures
Figure 1. A satellite image of the West Olympia Peninsula with the extent of the survey area…..3
Figure 2. Screenshots of the Field Maps Phone App used to collect data during the survey……15
Figure 3. Map showing Survey Locations and the number of times surveyed…………………..20
Figure 4. Map of Barred Owls classified by Individual, Pair, or Family based on the survey
results…………………………………………………………………………………………….23
Figure 5. Response Location 18 Land Class Buffer with satellite image and overall location
inset………………………………………………………………………………………………27
Figure 6. Response Location 10 Land Class Buffer with satellite image and overall location
inset………………………………………………………………………………………………28
Figure 7. Response Location 24 Land Class Buffer with satellite image and overall location
inset……………………………………………………………………………………………....29
Figure 8. Map of survey results around Clemson, South Carolina. From Clement, M. A. (2020).
Habitat Features and Behavioral Plasticity Promote Barred Owl Presence in Developed
Landscapes [Diss., UNC Charlotte]. https://tigerprints.clemson.edu/all_theses ..........................32
Figure 9. Juvenile Barred Owl photographed by Alex Seebeck in Olympia, Washington
7/1/20…………………………………………………………………………………………….33
Figure 10. Potential 25, 50, & 75 km Dispersal Rings based on Watson (2021) Characterizing
Barred Owl Dispersal at the Leading Edge of their Range Expansion. Line indicates farthest
recorded dispersal………………………………………………………………………………..35
v
List of Tables
Table 1. Response Table……………………………………………………………………….56
Table 2. Table of Habitat Percentages Within 500m Radius…………………………………..59
vi
Acknowledgments
I would like to thank Evergreen State College and the professors that have encouraged
and supported this journey. A special thank you to my reader John Withey who allowed me the
freedom to explore this topic and provide critical advice and support. Thank you to Mike Ruth
for the amazing GIS classes that helped achieve the mapping goals of this study.
This would not have been possible without the support and encouragement from both my
parents. Thank you, mom, for always providing uplifting enthusiasm and to my father for our
heated debates and deep conversations about the suburban Barred Owls. A special thank you to
my partner Nichole for helping me throughout the entire process. It was amazing to share the
passion I have with my loved ones and I look forward to continuing my understanding of
suburban Barred Owls.
vii
Introduction
Barred Owls (Strix varia) are medium-sized owls common throughout eastern North
America. Barred Owls are identified by the brown bars that run horizontally along its chest and
vertically on its stomach. Their wings and tail also have brown stripes which, combined with its
front, give this owl a dark brown and gray/white appearance. Their calls range from the common
“who cooks for you, who cooks for you all” to sounds similar to monkeys or laughing. Barred
Owls begin breeding in late winter to early spring when calling increases as pairs select, prepare,
and defend the nest. Nesting in cavities, they have adapted to environments such as forests,
fragmented farmlands, and even swamps (Clement et al., 2019; Dykstra et al., 2012; Gagné et al.,
2015; Hindmarch & Elliott, 2015).
Barred Owls have been able to expand their range through Canada and into the Pacific
Northwest (PNW) (Livezey, 2009a). The Barred Owls now overlap the historic range of the
Northern Spotted Owls (Strix occidentalis caurina) (Wood et al., 2020). Conservationists have
been working to understand the relationship between the Barred and Spotted Owls (Buchanan et
al., 2004; Diller et al., 2016; Jenkins et al., 2019; van Lanen et al., 2011; Wiens et al., 2021a).
Currently, Barred Owls are viewed as an aggressive and invasive detriment to the federally
endangered Spotted Owl (Livezey, 2010). Researchers have attempted to remove Barred Owls to
benefit the Spotted Owl, but other Barred Owls tend to reoccupy such sites (Diller et al., 2014).
Habitat characteristics are important factors influencing the interactions between Barred Owls
and Spotted Owls. In areas of co-inhabitation Spotted Owls more often utilize steep slopes and
higher elevations, while Barred Owls primarily occupy the lower elevations regardless of cover
1
type (Hamer et al., 2007). As a generalist, Barred Owls can occupy more diverse habitats, even
those not typically associated with large raptors.
Olympia, Washington (Figure 1) is an ideal location to survey for suburban Barred Owls
because it has a mix of residential, fragmented forests, and downtown developed areas. Barred
Owls have been seen and heard in locations around Olympia (personal observations and
Observations · INaturalist, 2022). If Barred Owls can thrive in developed urban areas of
Olympia, they would likely be found in all urban areas in the PNW. If areas similar to Olympia,
Washington and Portland, Oregon have thriving Barred Owl populations, the forests surrounding
those areas could be populated by their young. Management practices must acknowledge
suburban source populations and adapt conservation toward old-growth preservation.
The goal of this study was to survey the West Olympia Peninsula and identify and
quantify the suburban Barred Owl population living there. The importance of this study is that
suburban Barred Owls may be the source population that is recolonizing the forests and
outcompeting the Spotted Owls. Conservationists cannot address this problem unless the size and
range of the Barred Owl population is identified across the entire landscape, including urban
areas. Therefore, adequate, and effective population surveys of PNW Barred Owls are rare but
are necessary as sources of information about their impact on the success of Spotted Owl
conservation. Audio broadcasts surveys were conducted for two months during the summer of
2022 to locate, not only individual Barred Owls, but also families and young. Results have been
summarized and mapped using ArcGIS Pro and ArcGIS Online to provide detailed records of
Barred Owls in Olympia, Washington.
2
Figure 1. A satellite image of the West Olympia Peninsula with the extent of the survey area.
3
Literature Review
The important goal of this project is to identify and better understand Barred Owl
presence in suburban areas in the PNW. Since 2014, researchers have attempted to determine the
relationship between the Barred and Spotted Owls (Diller et al., 2014; Hamer et al., 2007;
Jenkins et al., 2019), including removal experiments with Barred Owls being killed by the
thousands (Wiens et al., 2021a). Although similar in size and appearance, Barred Owls are far
more adaptable to various habitats and prey than the Spotted Owls. In the PNW only one report
details Barred Owls found along a suburban gradient (Rullman & Marzluff, 2014). However, on
the East Coast Barred Owls have been studied in detail in suburban environments of Charlotte,
NC (Gagné et al., 2015; JS Mason, 2004) as well as in Clemson, SC (Clement, 2020).
Owls
Barred Owls are a member of the Genus Strix which include two other North American
species; Great Grey Owls (S. nebulosa), and Spotted Owls. The Great Grey Owl’s range is in the
northern forests of the United States and Canada. The Spotted Owl is a resident of the Old
Growth forests of the PNW. On the east coast, Barred Owls are considered a keystone or
indicator species that signify forest health and diversity (McGarigal & Fraser, 1985).
Management utilizes this species to conserve productive forests and environments.
Barred Owls are characterized as a generalist species that consume a wide variety of prey
and utilize a broad range of habitats. Mating occurs during early spring and successful pairs can
4
raise 2-4 young per year. Nesting primarily in cavities the Barred Owl was classified as a forest
dependent species that requires large tracts of contiguous forest to find suitable habitat
(Bosakowski & Smith, 1997). Recent studies and accounts indicate that the Barred Owl is more
adaptable than once thought (Bierregaard, 2018; Clement, 2020; Rullman & Marzluff, 2014).
Taking advantage of a wide variety of prey options has enabled Barred Owl success in the
swamps of the south, cities on the east coast, and the forests of the north.
Barred Owl diets consist primarily of small mammals (mice, rats, voles, shrews,
squirrels, and rabbits), birds, reptiles, amphibians, crustaceans, fish and more. A study in the
PNW (Wiens et al., 2014) found ninety-five prey species ranging from the more common
mammals, insects and amphibians to fish, snails, and birds. Barred Owl presence can be used to
understand the abundance and amount of smaller prey species whether in the forest or urban
environments. Any prey small enough to swallow whole is digested while the hair and bones are
regurgitated out in the form of a pellet. These pellets can be studied to give a detailed record of
their diet. Urban Barred Owls, in a study in British Columbia, primarily consumed rats (54.5%)
as well as field voles (19.3%) (Hindmarch & Elliott, 2015). They found sixteen different prey
species (Orders Rodentia, Lagomorpha, Soricomorpha, Passeriformes, Anura, and Coleoptera)
being utilized by Barred Owls. Barred Owls are resourceful and opportunistic, often consuming a
resource when it is more readily available. Livezey et al. (2008) recorded Barred Owls feeding
on earthworms and slugs. Although they tend to rely on a few abundant species, their wide
variety in diet has allowed them to find sufficient food across North America and continue to
expand their range.
5
Breeding season begins around January when Barred Owls increase vocalizations which
cement pair bonds and re-establish territory (Johnsgard, 2002). Frequently erupting in raucous
caterwauling, Barred Owls can regularly be heard calling during dusk and into the night. Nesting
begins around March when females lay a clutch of 2-4 eggs. Once the chicks hatch, they spend a
few weeks in the nest then begin to fledge and explore their territory (Johnsgard, 2002). The
young and adults use high pitches EEE-eeee’s to communicate. As the young develop, they learn
to fly and call using the adult vocalizations. Surveying during the breeding season allows
researchers to record not only the territorial owls, but also the young they produce.
Barred Owls utilize an incredible diversity of habitats across North America. Researchers
find Barred Owls in deep forests with large territories, urban areas nesting in backyard trees, and
swamp/marsh land in the south. Allen (1987) stated that Barred Owls prefer expansive
woodlands and claimed that tens of hectares of forest would not be enough to sustain them. This
opinion has changed, and studies now find Barred Owls in urban areas with very little forest
cover (Bosakowski & Smith, 1997; Clement et al., 2019; Dykstra et al., 2012; Rullman &
Marzluff, 2014). As their environment changes, species adapt and evolve, and different
geographical regions will have different habitat suitability. Barred Owls have been able to, in
less than a century, expand north, adapt to urban areas, and continue to find new suitable habitat
in western North America (Livezey, 2009a). Spotted Owls are considered a species dependent on
old growth and require contiguous, higher elevation, forests to maintain their population (Hamer
et al., 2007; Jones et al., 2018; Spies et al., 2018). Conversely, Barred Owls use habitats
according to their availability, indicating their generalist nature (Hamer et al., 2007).
6
Owl habitat and territory size is very different across North America. The Barred Owl
was described as a species that “requires an expansive forested area that contains large mature
and decadent trees that provide cavities suitable for security and reproduction” (Allen, 1987).
However, Barred Owls can also inhabit urban areas like the suburbs of Charlotte, North Carolina
(Bierregaard et al., 2008) and here in Olympia, Washington (Observations · INaturalist, 2022).
These urban areas provide insight about the minimum requirements of Barred Owls. One study
of urban Barred Owls in Clemson, South Carolina found that Barred Owl home ranges were an
average of only 0.5 km2 (Clement et al., 2019). Habitat requirements vary widely based on
geography and availability of resources. Barred Owls have adapted to a wide variety of forest
stand sizes, compositions, canopy closures, and more. Urban areas can provide all these needs if
development has left patches of forest and fields, or if neighborhoods contain old trees for
nesting (Bierregaard, 2018).
Range Expansion & ImplicationsCurrently, most species are impacted directly or indirectly by anthropogenic climate
change. While some species, such as the Spotted Owl, have been declining as human disturbance
affects their habitats; others, such as the Barred Owl, have been expanding their range (Boal et
al., 2018). Barred Owls are not the only species that have taken advantage of the changes in
climate and habitat. Avian species have expanded their ranges to utilize regions where climatic
patterns are “typical of pre-expansion distribution” (Johnson, 1994). Blue Jays have expanded
their range west and have benefited from urbanization and increased food supplies (K. G. Smith,
1978). Eastern Screech Owls have also been observed benefiting from increased temperatures
due to the earlier availability of food sources (Gehlbach, 2012).
7
Barred Owls have been common throughout Eastern North America for centuries.
Scientists began to record Barred Owls moving north into Canada, eventually making their way
into the PNW. The first account of a Barred Owl in the PNW was around 1965 (Livezey, 2009a).
Possibly utilizing areas of human disturbance and fragmentation, these adaptable owls found
large tracks of forest as well as mixed urban areas (Livezey, 2009b). Barred Owls have since
completely overlapped the historic range of the Northern Spotted Owls (Livezey, 2009a). Also,
studies of displacement tend to exclude habitat change and focus only on detection to indicate
competition (Kelly et al., 2003). Considered an aggressive invasive species, Barred Owls have
entered the territory of resident Spotted Owls (Dugger et al., 2011). Studies that measure
territory attributes find there is very little overlap of home ranges between barred and spotted
owls (Hamer et al., 2007). Also, studies of displacement tend to exclude habitat change and
focus only on detection to indicate competition (Kelly et al., 2003).
Researchers are interested in the relationship between the two species (Baumbusch, 2016;
Hamer et al., 1994; Long & Wolfe, 2019; Sovern et al., 2014; Wiens et al., 2021a). Barred Owls
are being removed from areas near Spotted Owl territories to test their impact on Spotted Owls
(Diller et al., 2016). These studies have difficulty completely removing the Barred Owls. The
Spotted Owls must have old growth forest to survive, but the Barred Owl is more generalized
(Buchanan et al., 2004). Research in the Pacific Northwest is focused on the areas where Barred
Owls have replaced or compete with Spotted Owls in the forests. Diller (2014) spent seven years
trying to completely remove Barred Owls from areas with Spotted Owls. He mentions that
recolonization by Barred Owls allows for easier removal, however, does not indicate where the
owls came from. Recolonization is viewed by Diller (2014) as a minor consideration although he
8
admits “Reoccupation of sites by Barred Owls will likely vary based on proximity to and size of
a source population and the presence of non-territorial owls, variation in annual reproductive
success, availability of habitat, and size of the area from which Barred Owls have been
removed.” Recolonization may come from urban and suburban areas where Barred Owls occur at
higher densities (Rullman & Marzluff, 2014). In California, research aims to better understand
the dispersal of juvenile Barred Owls to determine where removal efforts would be most
effective at minimizing immigration from source populations (Peery et al., 2018).
A recent paper focused on removal of Barred Owls in California, Oregon and
Washington found that the impact of Barred Owls on Spotted Owls could only be detected using
meta-analysis (Wiens et al., 2021a). Their results show an increase in estimated mean annual rate
of population change from -12.1% in control areas to -0.2% in areas with removals. However,
this study found it difficult “detecting a strong effect of Barred Owl removal for some individual
study areas” (Wiens et al., 2021a). In fact, the individual study areas often showed no changes
between control and treatment areas. For example, mean change in apparent survival contained
confidence intervals that were below zero for three out of the five study locations. They assert
that removal of Barred Owls alone is not sufficient to stabilize Spotted Owl populations because
the lack of recruitment and older forests are key factors limiting Spotted Owls. They also claim
that any lapse in management would allow barred owls to rapidly recolonize and “erode
conservation gains” (Wiens et al., 2021a). However, the supplemental information they provide
shows that the total number of Barred owls removed increased in three of the five locations
during the experiment (Wiens et al., 2021b). The success and total distribution of Barred Owls
has been under-acknowledged and their removal only temporary. Removal of Barred Owls is the
latest step in Spotted Owl management that started with the Northwest Forest Plan.
9
The Northwest Forest Plan (U.S. Department of Agriculture Forest Service, 1994) was
created in 1994 to guide forest management toward the conservation of threatened species.
Unfortunately, after two decades of management suitable habitat decreased on both federal and
private lands (Spies et al., 2018). The fragmentation of the PNW has negatively affected spotted
owls while simultaneously increasing Barred Owl habitat. The historic changes of the PNW may
have created an “extinction debt” where long-lived species decline or become extinct from prior
habitat change (Jones et al., 2018). This may be a factor in the spotted owl decline over the entire
population. Jones et al. (2018) only found reduction in Spotted Owl populations resulting from
extinction debt and not from severe wildfires or Barred Owls. The type and extent of habitat
determines the species, and the northwest has been transformed into a patchwork of various aged
stands, separated by clear cuts, waterways, and high elevation habitats. Some studies have found
Barred Owls at lower elevation with more gentle slopes, while Spotted Owls tend to rely on the
higher elevation slopes (Singleton et al., 2010). The high elevations remain the last stronghold of
the Spotted Owl perhaps because of the lack of profitable timber or the difficulty to harvest it.
Although many researchers focus on the relationship between the two owl species, others call for
the conservation of old growth trees and to restore the habitat of degraded forest ecosystems
(Jones et al., 2018; McMullin & Wiersma, 2019; Strittholt et al., 2006).
One complicated aspect of the range expansion of Barred Owls is their ability to
hybridize with the Spotted Owl creating so-called “Sparred Owls”. Studies of these hybrids have
found that they are most often between a female Barred Owl and a male Spotted Owl (Haig et
al., 2004). The viability of the hybrids indicates that the two species are very close genetically
(Hamer et al., 1994), but they are still considered two distinct species that had no previous gene
flow between them (Haig et al., 2004). As the Barred Owl becomes more common in the PNW
10
the hybridization of the two species has increased (Spies et al., 2018). Other species also
experience hybridization when range expansion occurs. Blue Jays (Cyanocitta cristata) have
expanded westward, and records indicate they have hybridized with the resident Stellar’s Jay
(Cyanocitta stelleri) (K. G. Smith, 1978). Smith (1978) found that similar to the Barred Owl,
Blue Jays are utilizing habitats that native corvids do not use. Other studies on captive falcons
have observed that morphological differences alone (phenotype) cannot be relied on for species
identification, with the implication that genetic testing will be the main driving force to conserve
species (Eastham & Nicholls, 2005). Current literature acknowledges that Barred Owls are
interacting with Spotted Owls in more ways than previously thought. Hybridization complicates
the legislation of conservation (Spies et al., 2018).
UrbanizationUrban and suburban environments have long been associated with a small variety of
songbirds and small mammals (Boal et al., 2018). In recent decades researchers have begun
describing larger raptors, including Barred Owls, utilizing suburban environments (Bosakowski
& Smith, 1997; Clément et al., 2021; Gagné et al., 2015; Rullman & Marzluff, 2014; Tilghman,
2015). Sharp-Shinned Hawks (Accipiter striatus) studied in the Montreal area of Canada were
not negatively affected when nesting in urban areas (Coleman et al., 2002). In fact, some species
like the Cooper’s Hawk (Accipiter cooperii) have been found in higher densities when nesting in
suburban and urban environments (Stout et al., 2007). Dykstra et. al. (2012) found that suburban
Red-Shouldered Hawks (Buteo lineatus) and Barred Owls nested in locations that were virtually
identical. Some owls, like the Great Horned Owl (Bubo virginianus), have been shown to
actively select habitat that is urbanized and fragmented (D. G. Smith et al., 1999). Barred Owls
11
in Charlotte, North Carolina and Clemson, South Carolina have been found and studied utilizing
urban and suburban environments (Clément et al., 2021; Gagné et al., 2015).
The population of Barred Owls in the northwest occurs in the forests as well as in urban
areas. Most of the parks around the city of Portland, Oregon have Barred Owls (Natural Areas |
Portland.Gov, 2022). By having reduced forested habitats, urban areas allow us to understand
the minimum requirements of Barred Owls (Clement et al., 2019). These urban areas may
continue to supply the surrounding forests with Barred Owls for years to come. Understanding
this source population could help inform further decisions about owl conservation in the PNW.
The full extent of the Barred Owl expansion has not been acknowledged in the literature.
Rullman and Marzluff (2014) found Barred Owls near Seattle, Washington at 76.2% of their
survey sites, and suggest that suburban Barred Owls may be the source population that is
recolonizing nearby forests (Rullman & Marzluff, 2014). Barred Owls are spread throughout the
PNW from the forests to suburban areas (Livezey, 2007, 2009a; Rullman & Marzluff, 2014).
Barred Owls have been able to adapt to human disturbance and benefit from less
destructive developmental practices (Clément et al., 2021). In stark contrast, Spotted Owls have
been unable to successfully adapt to human interference and their populations continue to decline
(Long & Wolfe, 2019). The Spotted Owls cannot find enough arboreal prey outside large tracks
of old-growth forests to sustain their population (Wiens et al., 2014). The habitat of the PNW
forests has been changing since the first people settled in the area thousands of years ago
(Livezey, 2009b). In recent decades industrial logging has vastly changed the forests. These
changes decrease total forested habitat which reduces arboreal prey species, increases edge
effects and predation risks, as well as alters territory suitability due to buffer zones or decreased
water quality (U.S. Department of Agriculture Forest Service, 1994). Barred Owls utilize fields
12
for hunting and the increase of terrestrial prey in open spaces creates more suitable habitat for the
Barred Owls. The adaptability of Barred Owls, compared to the restricted requirements of
Spotted Owls, will continue to favor the Barred Owls in the PNW.
Until the suburban Barred Owl population is studied further, we will not know the full
extent of the Barred Owl expansion. If the suburban Barred Owls are finding suitable habitat and
reproducing, they will continue to thrive outside of Spotted Owl conservation efforts. This
project will help to understand the extent of suburban Barred Owls and how successful they are
in Olympia, Washington. The importance of this study is that suburban Barred Owls may be the
source population that is recolonizing the forests and outcompeting the Spotted Owls.
Acknowledging the existence of the suburban Barred Owl populations will help better inform
Spotted Owl conservation in the PNW.
13
Methods
To locate Barred Owls on the West Olympia Peninsula in Washington State, potential
habitats were surveyed using audio broadcasts to call the owls and elicit a response. Surveys
were conducted from June 15th to August 15th, 2022, the approximate period when the young
have left the nest but before they have left the territory (Bierregaard, 2018; Leder & Walters,
1980). Calling was conducted for two months to find Barred Owls while reducing the
disturbance to the success of the owls. Surveys were spaced by at least a week before the
location was surveyed again. Surveying methods were similar to other suburban owl studies
(Clement, 2020; McGarigal & Fraser, 1985). The data was collected using ArcGIS Field Maps
and analyzed using ArcGIS Pro.
Survey Sites
Potential survey locations were identified using ArcGIS Pro and Field Maps to find
forested areas with vehicle access. The size or composition of the forested area was not as
important as proximity and/or access to the patch. Some potential habitats were surveyed from a
variety of locations to ensure maximum coverage. While surveying, those responses that could
not be confirmed were called closer to the possible location of the source to validate the
response. Some locations with no further potential responses were only called once. As the
survey progressed, locations were selected that expanded the total area covered until the entire
West Olympia Peninsula was surveyed.
The survey form was created using ArcGIS Pro and Field Maps (Figure 2). A point was
created in Field Maps for each location data was collected. The data recorded was surveyor
14
name, date, weather, wind, start time, owl species, sex, response time, response type, call type,
notes, end time and pictures/video taken during the survey (See Appendix - Weekly Results).
The results were stored into an ArcGIS Online Map that could be accessed and adjusted during
the survey.
Figure 2. Screenshots of the Field Maps Phone App used to collect data during the survey.
Calling
Audio playback surveys use recorded conspecific calls to attract or elicit a response from
a target species. Barred Owls are often successfully surveyed using this technique (McGarigal &
15
Fraser, 1985). Starting half an hour before sunset each station was surveyed until owls were
detected. The standard procedure was to play a call, then allow a two-minute listening period
before continuing the survey. The order of the owl call recordings progressed in complexity and
territorial status. The calls began with an individual male and female calling and at the end of the
audio the owls were duetting and caterwauling together. The survey lasted 14 minutes to ensure
the owls have time to respond and to help overcome any suburban noises that make surveying
difficult. All owl species that responded during the survey were recorded. However, if a GreatHorned Owl responded, the survey was stopped to minimize predation risk to any Barred Owls.
The volume of the survey was also adjusted to minimize disturbing residents. Surveying was
adjusted to later start times to reduce urban noises such as traffic, people, and pets. To maximize
effectiveness, surveys were not conducted on Friday or Saturday nights when more traffic and
urban noises were present. Near Highway 101 the noise of cars was a constant disturbance and
only the early hours of the morning had the least amount of traffic. Wind and weather were
factors that could impact audio broadcast surveying. When there is wind and rain, surveying is
difficult because it is harder to hear responses. Surveying during the summer months minimizes
the chances of rain during the survey period. The northern point of the west Olympia Peninsula
can be impacted by ocean breezes because it narrows to less than a mile. This and other coastal
areas tended to have higher winds, potentially impacting the ability to hear owls calling.
Responses
Surveys produce a variety of common Barred Owl response types including calling from
a distance, flying in and calling loudly, flying in and not calling, as well as young begging. If a
Barred Owl flies in but does not call it is impossible to determine the sex of the owl. Male and
16
female Barred Owls can be identified by the octave of their calls (Odom & Mennill, 2010).
Males tend to be lower and end their 8-note calls abruptly. The female Barred Owls are higher
pitched and often elongate the final notes more than the males. Young can be identified by the
high pitch begging call they repeat. A location was considered completed when young were
detected and to prevent further impacts on the family it was not surveyed again. The weekly
result maps are found in the Appendix. After the first week it became clear that surveys would
need to start later at night to reduce the urban background noise. The third week expanded the
survey areas as well as rechecking locations. Week 4 was the first time young Barred Owls were
calling with the adults. During week 5 the surveying expanded and resulted in more young owls
being discovered. Surveying during week 6 expanded into the northern peninsula and continued
into the urban gradient to the south. Weeks 7 and 8 were spent expanding the survey locations
and coverage. Weeks 9 and 10 repeated the survey at as many locations as possible as well as
surveys at locations that produced single or pair responses in a final attempt to find young owls
Mapping
Field Maps was used on my cell phone to record the results of each survey. The data was
stored and could be accessed in ArcGIS Online. This data was divided into increments of one
week and is displayed in the Appendix. When the survey was completed, the data was imported
into ArcGIS Pro. The data was summarized into results and locations layers. The total dataset
had overlapping information that needed to be summarized. The owl responses were classified as
Single, Pair, or Family based on the maximum number of owls detected (Figure 4). Survey
Locations were also summarized into single spots because some of the calling was adjusted to
improve the chances of detection (Figure 3). Land classification data (USANLCD) was imported
17
from ArcGIS Portal and used to compile habitat information. A circular buffer with a radius of
500m was created surrounding the location point of owls on the Results Map. These buffers were
combined with the land classification data to characterize and analyze the habitat. The total area
for each classification found within the buffer was divided by the total area to create Land Class
percentages (See Figures 5,6,7, and Appendix: Table of Habitat Percentages Within 500m
Radius) These percentages are not without bias, since individual owls may have traveled in
towards the recorded calls before responding.
18
Results
Barred Owls were successfully located throughout the West Olympia Peninsula during
the eight-week survey period. Surveying a total of 170 times at 91 locations (Figure 3), 38
detections of owls were recorded. A total of 31 adults and 11 young Barred Owls were found
(Figure 4). Owl families were located in neighborhoods, next to shopping centers, as well as in
forested areas of the northern peninsula. Survey results were summarized based on the maximum
number of owls recorded in one visit. All the results from the survey are mapped and available in
a Web map using ArcGIS Online (https://arcg.is/1PPHaG).
19
Figure 3. Map showing Survey Locations and the number of times surveyed.
Survey
Figure 3 shows the summarized survey locations and the number of times that each was
surveyed. A major goal of this study was to survey as many locations as possible to maximize
the Barred Owls recorded on the West Olympia Peninsula. Of the 91 total locations 55 were
surveyed at least twice. Of the 36 locations that were surveyed once, 3 locations had families
responding and were therefore considered completed. Other locations were not repeated due to
traffic/urban noise, proximity to Barred Owl family response, and proximity to Great Horned
20
Owl presence. Locations were summarized into points based on distance to other surveys, size of
the stand or area, and environmental impacts such as traffic noise or ocean winds. At locations
where Barred Owl individuals or pairs responded the survey was repeated to confirm the
occupancy and attempt to find young. The results of each survey, divided into 7-day increments,
can be found in the Appendix.
In total, 42 individual Barred Owls were detected during the survey period (Figure 4). Of
the total number found, 11 young were recorded. Six places were classified as having a family
because of the presence of young at those locations. There were three places where a pair of
Barred Owls was responding but no young ever recorded. At the remaining 19 locations a Barred
Owl was recorded but only one individual at a time. The west Olympia Peninsula, 15.77 mi2,
contained on average 2.66 Barred Owls per square mile. While Barred Owls were the target
species for the survey any owl that responded was recorded as a response. Great Horned Owls
were recorded at three locations and one Barn Owl was observed. Great Horned Owls negatively
impact Barred Owl responses and have been known to kill Barred Owls so when a Great Horned
Owl was found that location and surrounding areas were not surveyed further to reduce the
potential negative impacts on Barred Owls.
This study located Barred Owls in a wide variety of areas in and around Olympia,
Washington. The habitats where they were found varied from larger tracts of Douglas Fir to
small stands of hardwoods around drainages. These variations highlight the adaptability of
Barred Owls. The Table of Habitat Percentages Within 500m Radius found in the Appendix
details the habitats where responses were recorded. It is important to note that these points and
the surrounding buffer area are inherently biased because surveying can result in owls traveling
outside of their core habitat areas to respond. The descriptive data of habitat percentages can still
21
provide important information about the areas Barred Owls are occupying in Olympia. Every
buffer area contained at least Low Intensity Development and Developed Open Space while 10
contained some High Intensity Development (maximum of 1.85%). All buffer areas also
contained Deciduous Forest (min .74%, max 34.32%, Evergreen Forest (min 1.77%, max
40.79%), and Mixed Forest (min .03%, max 39.20%).
Based on the results, Barred Owls have found ample habitat options in Olympia.
However, the presence of many single responses indicates that there may be more Barred Owls
than were located. These individuals may be part of a pair or family that was not found during
the surveys. Further study of the suburban resident Barred Owls is necessary to better understand
the total population, territory sizes, and impacts they may be having on surrounding areas.
22
Figure 4. Map of Barred Owls classified by Individual, Pair, or Family based on the survey
results.
23
Influencing Factors
Surveying in suburban environments is very different than surveying in the forested
mountains. Initially, surveys were conducted following protocols similar to those conducted in
the forest. However, within a week it became clear that I would not be able to start the surveys
until much later in the evening after most people were asleep. The traffic noise along major roads
and in the South and SE near Highway 101 resulted in calling from multiple locations searching
for potential responses. Along with traffic noise, people influenced the survey in a variety of
ways. Some locations were only called one time due to the presence of people either in the
forested patches or in nearby houses and businesses. At three survey locations campus security
or Olympia Police stopped to check on me. One OPD officer even admitted to hitting an owl
with his car. Highway records confirm that Barred Owls are being killed along major roadways
throughout the state and in other areas where they inhabit suburban areas (Croston, 2021; Gagné
et al., 2015). People and traffic were considerations throughout the survey. While surveying in
the SE and central suburban areas the goal was to find locations close to forested patches but not
close to houses. While in neighborhoods calling volume was reduced to balance surveying the
patch while minimizing impact on residents. Where possible, locations were chosen to maximize
distance to surrounding houses. However, many times houses were very close to survey
locations. Another aspect of suburban surveying were the dogs that would respond to the calls.
Some locations were more difficult than others to hear owls because the dogs were so far away
that they sounded very similar to a responding owl. Many times, when there was a suspicious
response, it was a distant dog rather than an owl.
24
Discussion
This survey found that Barred Owls, located on the western peninsula of Olympia,
Washington, are successfully reproducing. Within the two months of surveying eleven young
were confirmed at six locations. The young indicate that a pair of Barred Owls have an
established and suitable territory (Doyon et al., 2000). The suburban areas of western Olympia
are a patchwork of developments, forest stands and open fields and grass. In fact, Barred Owls
are known to thrive in mixed land class areas throughout their Eastern range (Clement et al.,
2019). While surveying an area of 15.77 mi2 (40.84 km2) a total of 42 Barred Owls were located.
This results in a density of 2.66 owls/mi2 on the West Olympia Peninsula.
To better understand the areas where Barred Owls were found a buffer of 500m radius
was created around the response locations. Figure 5 is an example of an individual owl response.
This location had responses on multiple surveys however, because only one owl was located
during each survey this location was designated as a single owl point. This area is a good
example of the more forested residential neighborhoods on the west Olympia Peninsula. Figure 6
highlights a pair designation where two adults were calling together on multiple occasions.
Located very close to Evergreen State College, this pair occupied territory that was more
forested. However, where these owls responded from was closer to the developments and
campus recreational fields than the more heavily forested areas to the east. These owls were
surveyed repeatedly to try to locate any young they may have produced. Unfortunately, no young
were confirmed, so this location was recorded as a pair. The presence of a pair could indicate
young not surveyed and at least increases the potential for young in the future.
25
The final example of response type and land class, Figure 7, shows a family response
near the more-urban part of the peninsula (ID 24). This location was interesting because it was
surveyed prior to finding the young. Those initial surveys were unable to locate any Barred Owls
nearby. However, while driving I saw an adult fly over the road and so I stopped and surveyed. It
was during this final survey the young were heard calling from the forest patch on the eastern
side of Grass Lake Nature Reserve. This was one of the two families located within the
neighborhoods of high and medium development. This location exemplifies the suburban
environment: forest patch, surrounded by shopping centers, houses, a school, and busy roads.
Response location 23 also contained a family of Barred Owls within a neighborhood. At the
corner of Muirhead Ave. NW and Division St. NW the adults were frantically searching for the
intruding owl while the young called from the backyards SE of the intersection. Locations 23 and
24 indicate that Barred Owls can successfully nest and reproduce within suburban environments
of the PNW.
26
Figure 5. Response Location 18 Land Class Buffer with satellite image and overall location inset.
27
Figure 6. Response Location 10 Land Class Buffer with satellite image and overall location inset.
28
Figure 7. Response Location 24 Land Class Buffer with satellite image and overall location inset.
29
Until the individual owls and their territories are studied in more detail all land cover
descriptions are based on the buffer around the approximate location of the recorded owls. The
composition of the environment in each response buffer is found in the Appendix. It is important
to note that the buffers are influenced by the survey locations because roads and driveways were
used to survey. Despite roads increasing developed open spaces amounts (max 38.04%, min
7.02%) there were only 3 buffers that did not contain at least some medium intensity
development. High intensity development was at most 1.85% (ID 9) and found in ten buffers.
The primary cover type of the PNW is evergreen forests which had a maximum of 40.79% (ID 7)
and a minimum of 1.77% (ID 23). Interestingly response location 23 only had 11.26% evergreen
forest and 22.92% mixed forest. With a total tree cover at 35.95% this location had 43.61% low
intensity development. What makes this location interesting is that it was a family response and
had two young. In fact, the young were in someone’s backyard responding while the adults flew
around in defense. However, until the suburban Barred Owls are radio-tracked the exact
composition and size of these suburban territories are unknown. These area values should not be
interpreted to represent, average or calculate habitat utilized by Barred Owls but rather only that
these are places where owls have been found.
Although the target species for this survey was Barred Owls, three owl species were
recorded during the two months. Great Horned Owls were recorded at multiple locations in West
Olympia. If a Great Horned Owl was heard before the survey the location was not called to
prevent threats to the Barred Owls. During one survey, what was later identified as a juvenile
Great Horned Owl was located and the point surveyed because the species was not known at the
time. The other nontarget owl that responded was a Barn Owl heard calling around the golf
30
course. The other owls recorded are common owls that thrive in suburban environments
(Johnsgard, 2002).
Despite the limited amount of time Barred Owls have been present in the PNW their
numbers in suburban areas are comparative to other suburban studies. Bierregaard (2018) found
1.1 pair/km2 in the suburbs of Charlotte, North Carolina. Clement (2020) found 1.1 pairs of
Barred Owls in adjacent territories per square kilometer in Clemson, South Carolina suburbs
(Figure 8). They assumed, based on Johnsgard (2002), that each response represented a territory
and indicated a pair. The adjacent territories they measured covered 27.27 km2 of the Clemson
suburbs. The Olympia Peninsula is 15.77 mi2 or 40.84 km2 and was found to contain 42 total
owls resulting in 1.03 Barred Owls per square kilometer. This survey recorded the exact number
of owls that responded and did not assume that a response indicated a pair. Also, locations with
young recorded only the adult owls that responded and the number of young that could be
individually identified (primarily by strength of calls and location). By only recording the owls
that responded this survey most likely did not record every owl on the Olympia Peninsula. In
fact, one location was found to have young in 2020 (personal observation, Figure 9) but only
responded as a single owl during the survey. If each response was counted as a pair, there would
have been approximately 54 adult owls. However, because Barred Owls exist as roaming single
owls as well as territorial pairs a response was not assumed to be a pair. Further studies of the
suburban Barred Owl populations are needed to fully understand their numbers, habitat usage
and potential impacts.
31
Figure 8. Map of survey results around Clemson, South Carolina. From Clement, M. A. (2020).
Habitat Features and Behavioral Plasticity Promote Barred Owl Presence in Developed
Landscapes [Diss., UNC Charlotte]. https://tigerprints.clemson.edu/all_theses
32
Figure 9. Juvenile Barred Owl photographed by Alex Seebeck in Olympia, Washington 7/1/20
One of the potential impacts of the residential suburban owl population is the dispersal of
young into surrounding areas. Juvenile and non-territorial adults occupy less-desirable habitats
until they can find their own territories (Johnsgard, 2002). Although the dispersal of suburban
Barred Owls in the PNW has not been studied, other suburban owls have been found to travel
2.7km (Bierregaard, 2018). They also found that rural Barred Owls dispersed further than
suburban residents at 4.2km. However, studies that track dispersal of Barred Owls on the
California coast have recorded owls traveling up to 146km and almost 60% traveling over 50km
(Watson, 2021). If the eleven young Olympia Barred Owls dispersed 50km they could reach
Tacoma and at 75km the southeast corner of the Olympic National Forest. To better visualize
these distances Figure 10 shows 25, 50 and 75 km dispersal rings as well as the maximum
straight-line recorded dispersal. Until suburban juvenile Barred Owls in the PNW are tracked,
33
there is no way to determine how far or exactly where the young are dispersing. Further study is
needed to fully understand how they are impacting the surrounding areas.
Suburban areas, like Olympia, Washington, can be found throughout the PNW. Further
studies in suburban areas are likely to find more resident Barred Owls. IF the results of this
survey are typical of other suburban Barred Owl's reproduction, they will continue to thrive even
in areas where they were lethally removed. Initial results indicate that Barred Owls have found
successful territories that are independent from the old-growth forests. More detailed study of the
suburban Barred Owls in the PNW will help to better understand the full range and extent of this
controversial owl.
34
Figure 10. Potential 25, 50, & 75 km Dispersal Rings based on Watson (2021) Characterizing
Barred Owl Dispersal at the Leading Edge of their Range Expansion. Line indicates farthest
recorded dispersal distance.
35
Conclusion
This study has found that Barred Owls occupy a wide variety of habitats beyond large,
forested tracts. Barred Owls have established themselves in suburban areas including Olympia,
Washington. This population has found suitable habitats and is reproducing, creating juveniles to
occupy more territories. Further study of the suburban owl population in the PNW is necessary to
better understand the full coverage of Barred Owls. Spotted owl conservation must focus on the
Spotted Owls and their preferred habitats rather than managing/removing Barred Owls. The
Barred Owls have found ample habitats in the PNW including the backyards and fragmented
forest patches of suburban areas.
Surveying in Olympia shows that Barred Owls are reproductive residents in suburban
areas of Washington State. The focus of conservation in the NW has been how the Barred Owls
impact the Spotted Owls. Unfortunately, the Barred Owls occupy more than just the forests of
the PNW. Studies have attempted to remove Barred Owls to reduce competition for Spotted
owls. However, they were unable to fully eradicate the Barred Owls. Barred Owls successfully
reproducing in residential areas in Olympia indicates that no amount of removal in the forests
can fully eradicate the Barred Owls from the PNW. The suburban owls have formed a stable
population and thus any removal from the forests will only temporarily hinder Barred Owls but
never eradicate them fully.
Despite extensive studies involving Barred Owls in the PNW, researchers are primarily
focused on the relationship between the Barred and Spotted Owls. The endangered Spotted Owl
has been drastically impacted by industrial logging and in recent decades competition with
36
Barred Owls. This project located reproducing Barred Owl in suburban areas of the PNW in
densities comparable to studies in the SE. Until Barred Owls are recognized as both forest AND
suburban species the total population in the PNW cannot be measured. As a prolific generalist
Barred Owls are now permanent residents where they have expanded their range. Spotted Owl
conservation will not be able to remove all Barred Owls in the PNW and must instead focus on
habitat preservation as some researchers have suggested (Jones et al., 2018).
37
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45
Appendix
46
47
48
49
50
51
52
53
54
55
Tables
Indicates Family
Response Table
OBJECTID *
Response Type
# of Responses
Surveys
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Single
Family
Family
Single
Pair
Single
Single
Pair
Single
Pair
Single
Single
Single
Family
Single
Single
Single
Single
Single
Family
Single
Single
Family
Family
Single
Single
Single
1
1
1
1
2
2
2
2
2
4
1
1
4
1
1
1
1
2
1
1
1
1
1
1
1
3
1
2
2
2
2
2
2
2
5
4
5
2
3
3
1
3
4
4
4
2
1
3
2
1
2
2
3
1
56
Number of
Young
0
1
2
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
2
0
0
2
3
0
0
0
Total Owls
1
2
2
1
2
1
1
2
1
2
1
1
1
3
1
1
1
1
1
3
1
1
4
4
1
1
1
Survey Location Table
Survey Point
Surveys
Success
Adults
Young
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
3
2
5
4
4
3
1
3
4
2
3
4
4
2
2
1
2
3
2
3
2
2
2
2
1
4
2
2
2
2
2
1
4
2
1
1
2
1
1
1
1
1
1
2
1
0
0
2
2
3
1
0
1
3
0
1
1
4
0
1
0
1
1
0
0
0
0
0
0
0
3
0
0
0
0
1
0
4
0
0
0
0
0
0
0
0
0
0
0
1
0
0
3
2
4
1
0
1
3
0
1
1
4
0
1
0
2
1
0
0
0
0
0
0
0
3
0
0
0
0
1
0
5
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
57
Survey Point
Surveys
Success
Adults
Young
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
1
1
1
2
1
2
2
1
2
2
1
1
2
2
3
1
1
2
1
1
1
1
2
2
2
2
2
2
2
2
1
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
0
1
0
0
1
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
2
0
2
0
0
1
0
0
0
0
0
0
0
0
0
2
0
1
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
1
0
2
0
0
2
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
58
Table of Habitat Percentages Within 500m Radius
ORIG_FID
Barren Land
Deciduous Forest
Developed High
Intensity
Developed Medium
Intensity
Developed Low
Intensity
Developed Open
Space
Emergent Herbaceous
Wetlands
Evergreen Forest
Grassland/Herbaceous
Mixed Forest
Open Water
Pasture/Hay
Shrub/Scrub
Woody Wetlands
1
2
3
4
5
6
7
8
9
10
18.27%
10.62%
8.41%
8.73%
4.99%
3.75%
2.41%
7%
34.32%
0.87%
1.85%
0.83%
6.53%
19.91%
0.74%
1.72%
1.20%
3.48%
0.45%
0.20%
9.31%
3.69%
24.01%
26.64%
9.03%
13.58%
6.25%
0.82%
9.43%
16.25%
11.45%
26.37%
23.43%
38.04%
21.70%
27.91%
33.95%
18.95%
18.51%
21.80%
2.02%
1.54%
7.68%
6.98%
1.05%
21.24%
1.80%
20.52%
21.40%
40.79%
34.54%
17.60%
27.72%
13.44%
38.69%
11.77%
9.62%
21.04%
21.71%
0.74%
39.20%
32.78%
18.27%
0.98%
19.33%
25.80%
18.23%
0.16%
1.71%
0.74%
1.39%
4.31%
3.11%
1.32%
59
2.47%
2.13%
0.51%
4.60%
1.39%
2.26%
ORIG_FID
11
8.87%
Deciduous Forest
2.06%
1.03%
1.66%
6.33%
6.66%
17.03%
15.30
%
21.02%
17
18
19
20
2.86%
1.23%
28.54
%
20.07
%
0.56%
0.25%
7.28%
2.08%
4.80%
0.45%
0.60%
14.45
%
22.42
%
4.90%
17.64
%
14.12
%
23.16
%
0.81%
11.47
%
38.51
%
24.95
%
35.22
%
22.02
%
19.45
%
21.04
%
30.48
%
10.01
%
21.25
%
3.71%
0.65%
0.89%
15.76
%
2.45%
3.45%
7.13%
12.47
%
11.69
%
5.31%
6.34%
23.64
%
28.77
%
35.47
%
25.74
%
0.53%
0.99%
10.06%
7.87%
18.08
%
0.02%
13.35
%
0.80%
Open Water
14.12
%
1.31%
13.69
%
6.64%
10%
5.11%
20.41
%
18.05
%
0.05%
1.07%
0.01%
0.25%
0.25%
0.17%
1.42%
6.08%
4.07%
21.37
%
0.13%
0.53%
0.74%
18.67%
Woody Wetlands
2.60%
16
1.24%
Mixed Forest
Shrub/Scrub
2.62%
15
4.27%
Evergreen Forest
Pasture/Hay
14
0.53%
10.83%
Developed Open Space
Grassland/Herbaceous
18.39
%
0.09%
Developed Low Intensity
Emergent Herbaceous
Wetlands
13
2.46%
Barren Land
Developed High Intensity
Developed Medium
Intensity
12
0.49%
1.48%
32.05
%
0.74%
60
29.68
%
30.25
%
2.39%
ORIG_FID
21
22
23
24
25
26
27
0.17%
Barren Land
Deciduous Forest
Developed High
Intensity
West
Oly.
4.54%
0.84%
3.13%
11.26
%
0.49%
0.74%
2.36%
0.25%
0.82%
2.56%
8.59%
0.26%
Developed Medium
Intensity
12.85%
11.21
%
3.45%
9%
9.95%
1.88%
2.80%
4.67%
Developed Low
Intensity
53.72%
43.02
%
43.61
%
21.11
%
7.29%
23.92
%
33.59
%
18.15%
24.55%
27.66
%
16.99
%
7.02%
8.63%
22.57
%
27.18
%
22.77%
3.66%
0.74%
0.34%
1.61%
26.68
%
24.05
%
21.46
%
19.37%
0.20%
0.74%
0.62%
0.19%
26.43
%
17.25
%
4.99%
16.70%
0.29%
1.73%
0.05%
0.17%
1.34%
1.04%
0.12%
1.42%
0.20%
0.97%
12.23
%
2.12%
8.78%
5.91%
Developed Open
Space
Emergent Herbaceous
Wetlands
Evergreen Forest
Grassland/Herbaceou
s
Mixed Forest
1.82%
0.03%
7.34%
6.86%
1.77%
22.92
%
29.42
%
13.89
%
Open Water
Pasture/Hay
0.01%
Shrub/Scrub
Woody Wetlands
1.65%
18.58
%
0.28%
61
0.47%
