Cougars not needed for deer management TOM VENESKY OUTDOORS
Deer are overabundant, and the reason why is because the eastern cougar is extinct.That's the position that one group has taken after the U.S. Fish and Wildlife Service declared the cougar as extinct in the eastern and southern United States. The move, according to the Cougar Rewilding Foundation, is a "death-knell" for eastern ecosystems because "superabundant" deer will continue to overbrowse. This will deplete the habitat of several endangered and declining species, the group claims.
In many parts of the state, deer aren't overabundant. This is proven by the annual population assessments and antlerless license allocation recommendations conducted for each Wildlife Management Unit by the Pennsylvania Game Commission. According to the 2010-11 report, the PGC recommended antlerless license allocations that would stabilize deer populations in 18 of the 22 WMUs. Surely the agency wouldn't intend to stabilize an overabundant deer population.(overabundant by what measure,,,,,,should be about the overall carrying capacity of the land, not just from a hunters perspective that it should be a "deer shooting galley" every Fall--blogger Rick
According to a release from the Cougar Rewilding Foundation, the browsing from an overabundant deer population could result in the collapse of deciduous forests, and declaring the eastern cougar as extinct only makes the situation worse.
Foundation vice-president Dr. John Laundre stated in the release that predators such as cougars help forest regeneration by moving prey species such as deer. "Cougar presence moves browsing deer around, which allows seedlings and saplings to mature and the forest to regenerate. Without predators, deer act like pastured cattle, eating everything to the ground," Laundre stated.
As far as Pennsylvania is concerned, cougars haven't been a part of the ecosystem for more than a century, dating back to 1874 when the last known one in the state was killed in Berks County. Since then there have been plenty of reported sightings and even a few releases of domestic cougars, but nothing close to a self-sustaining population that would have any impact on the deer herd in the state.--a mistake on our part to eliminate them--blogger Rick
Also, deer don't need to be pushed from one area to another by predators. They move quite well on their own. Young bucks typically disperse three to six miles. According to findings yielded by a current PGC study, bucks outfitted with radio collars have moved as much as 20 miles from where they were trapped. One buck traveled more than 40 miles.--yes, but they move on their own volition, eating casually and as long as they desire.....predators cause deer to be vigilant and not eat to their hearts content--blogger Rick
I'm sure if a cougar moved into an area the deer would respond by moving.
Initially.But over time, the threat of a predator is something that deer would adapt to. They would become more wary, but I doubt they would permanently leave an area.--but their impact on the land and regeneration of forest seedlinegs would be greatly reduced by the fear that the cougars(and one day wolves)would induce--blogger Rick
The Cougar Rewilding Foundation is wrong to imply that restoration of the eastern cougar is critical to controlling deer numbers. It's a far-fetched notion. Deer numbers are controlled just fine by lawful hunting.--hunters do not reduce the herds in the same fashion that cougars and wolves do..........fish and wildlife have to keep amending the "shooting rules" to keep does in check whereas cougars and wolves are equal opportunity clean up hitters taking animals of all classifications on an on-going basis--for millenia the ebb and flow of predator and prey worked quite well.............blogger Rick
But if somehow the eastern cougar could return, I wouldn't oppose that.. They are, after all, a native species of Pennsylvania.They were here before we were, and if by chance a truly wild cougar naturally makes its way back into the state, it's something we should protect. But we should only protect such a comeback because the cougar belongs here, not because it's needed to control deer.--deer and cougars, wolves and bears have been dancing partners for thousands of years...........Deer were extirpated from Pennsylvania and restored by us..................so should cougars and wolves be on the ground again...............restored by us as natural occurring populations are just too far from the keystone State at this point in time--blogger Rick
Tom Venesky covers the outdoors for The Times Leader. Reach him at tvenesky@timesleader.com
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Deer, Ecosystem Damage, and Sustaining Forest Resources
by David S. deCalesta*
Prior to colonization of North America by European settlers, deer density in eastern deciduous forests, including Pennsylvania, was approximately 7 to 10 deer per square mile, and was affected by forage availability, weather, and predation (Witmer and deCalesta 1992, deCalesta 1997).
However, by the end of the nineteenth century much of Pennsylvania's forests had been completely cut over, and the deer herd was nearly eliminated by unregulated deer harvest (Redding 1995). Vast amounts of deer forage were produced by this extensive timber harvest, deer hunting was heavily limited to allow the population to rebuild, and major deer predators were extirpated from Pennsylvania.
The result was an explosion of the deer population in the first quarter of the twentieth century, with deer density exceeding 50 deer per square mile in northwestern Pennsylvania (Clepper 1931, Redding 1995).
The expanding deer herd then eliminated its food supply, and during a series of hard winters in the late 1930s declined to around 10 to 15 deer per square mile.--even during harsh conditions, no where near the the 7 to 10 per square mile that existed in colonial times--blogger Rick
Coincidentally, timber harvest began anew in the 1950s, as forests harvested fifty to eighty years earlier approached commercial maturity. In the ensuing 40 years the deer population again increased, averaging over 30 deer per square mile, even while sustaining a population decline following a series of harsh winters in 1978- 79 (Figure 1).
Whitney (1984) and Hough (1965) documented the loss since the 1930s of herbaceous and shrub species from unmanaged mature forests in northwestern Pennsylvania, and attributed the declines to herbivory by deer. Composition of understory vegetation shifted from shrubs and herbs to grasses and ferns in this period (Marquis and Grisez 1978, Horsley and Marquis 1983), with reductions in species richness and abundance of seedlings of woody plants that jeopardized development of future forests.
In the late 1970s a study was designed in northwestern Pennsylvania to provide quantitative evaluation of the impact of deer on forest resources. The effect of varying white-tailed deer densities on regeneration of woody vegetation and on songbird and herbaceous communities was evaluated during 1980-1991 (Tilghman 1989, deCalesta 1994, Jones et al. 1993). In this study species richness and height of saplings declined once deer density exceeded 20 deer per square mile (Tilghman 1989, deCalesta 1992) (Figure 2). At deer densities greater than 20 per square mile, seedlings of six woody tree species were missing or prevented by deer browsing from becoming incorporated into the overstory (deCalesta 1992), and clearcut sites approached monocultures of black cherry (Prunus serotina). Thus, when deer abundance exceeded estimated pre-European settlement density, deer impact truncated species richness and vertical structure of understory vegetation, thereby influencing the regeneration process and future overstory tree composition.
Deer browsing can affect vegetation that songbirds use for foraging surfaces, for cover for escape/hiding from predators, and for nesting. By significantly reducing the height of woody vegetation, white-tailed deer affected habitat for songbirds that feed, nest, and seek cover in the 0-7.6 m height interval (deCalesta 1994). Birds that utilize this intermediate foliage canopy exhibited significant reductions in species richness and abundance when deer density exceeded 20 per square mile (Figure 3).
Once deer density exceeded 10 per square mile, five songbird species were no longer observed on study sites. Abundance of songbirds declined when deer density exceeded 10 per square mile. As with regeneration of woody tree species, deer impact significantly affected songbirds when deer population density exceeded estimated pre-settlement density.
Species richness and abundance (expressed as percent ground cover) of shrubs and herbaceous plants were significantly impacted when deer density exceeded 10 per square mile (deCalesta 1992) (Figure 4). Two shrub species and one herbaceous species disappeared when deer density exceeded 20 deer per square mile.
Species richness and abundance of plants in the herb/shrub layer shifted significantly when deer densities exceeded 20 per square mile: percent ground cover of ferns, grasses, and mosses increased, while that of shrubs and other herbs decreased (deCalesta 1992).
Many herb and shrub species noted in earlier (pre-1950) surveys (Jennings 1953) were not found, presumably having been eliminated by 70 years of browsing pressure by deer populations exceeding 20 per square mile. Species richness and abundance of plants in the herb and shrub communities, like that of songbirds, were significantly reduced when deer population density exceeded estimated pre-European settlement density.
Thus, sustainability of woody regeneration, songbirds and songbird habitat, and herbs and shrubs is affected once white-tailed deer density exceeds that of pre-European settlement: species richness and abundance of all these resources decline.
EXPECTATIONS FOR SUSTAINED HARVESTS OF DEER AND TIMBER
Deer are valued positively as an economic and recreational resource. Over 400,000 deer were harvested annually in Pennsylvania over the 1988-1993 span, which was associated with an average post-hunt density of 28 deer per square mile and a harvest level of 15 deer per square mile (W. Palmer, Pennsylvania Game Commission, personal communication). Post-hunt deer density has exceeded 31 per square mile in northwestern Pennsylvania since the late 1920s (excepting two notable crashes) (Figure 1), and the last three generations of deer hunters have come to expect these deer densities and associated harvests as normal and sustainable. Hunters have numbered over 1 million in Pennsylvania for the last three decades (Witmer and deCalesta 1992) and represent a significant lobbying force for maintaining these high deer densities and harvests.
Income generated by deer-hunting activities in Pennsylvania amounts to at least 1 billion dollars annually (Kosack 1991). Both business and hunting interests have benefited under the high deer densities and harvests experienced over the last 60 years; these interests exert considerable pressure to maintain post-hunt deer densities in excess of 11 per square kilometer.
Since the second-growth forest in Pennsylvania became commercially mature in the late '50s, there has been an increasing amount of timber harvested (Figure 1). Expectations of the timber industry are that timber harvest could be sustained at a level comparable to that of the past few decades. However, timber stands cannot be harvested if advance regeneration (tree seedlings) is inadequate to produce replacement trees. McWilliams et al. (1993) reported that only 4- 20 percent of forested lands surveyed across Pennsylvania in 1990 had advance regeneration sufficient to provide adequate regeneration of diverse woody species under conditions ranging from unfavorable to favorable. Overabundant white-tailed deer populations were hypothesized as the primary cause for failure of advance regeneration. DeMarco (1994, Allegheny National Forest, Warren, PA, personal communication) noted that only 33 percent of maturing forestland within the Allegheny National Forest carried sufficient advance regeneration to permit removal of overstory timber with reasonable expectation of successful regeneration.
Six decades of high deer densities and harvests developed expectations of and demands for continuance of a perceived sustainable deer harvest. However, deer density required to maintain this level of harvest affects sustainabilities of other forest resources.
INTEGRATING AND SUSTAINING FOREST RESOURCES
Woodland and Daly (1996) added social/political factors to economic development and environmental protection as components of sustainability. They suggested that these three components be addressed and defined separately by experts in those disciplines. They suggested integrating these components in their discussion of environmental sustainability and argued against managing for sustainable yields of single resources at the expense of others. Without such integration, the component with the most political/societal/economic clout may well predominate, at the expense of sustainability of the others. In Pennsylvania this has occurred with sustainability of high deer harvests overriding sustainability of other forest resources.
Management of deer is based on sustaining harvestable yields such that post-hunt populations are stable through time (Caughley 1976). McCullough (1979) added the refinement of "optimum sustained yield," which is the greatest number of animals that can be harvested, year after year, from a deer population such that human benefits (e.g., economic return or hunter satisfaction) can be optimized. However, all forest resources should be managed to produce "the simultaneous sustained yield of many interrelated populations in an ecosystem" (Goodland and Daly 1996).
Forest management has yet to produce integrated management plans for all forest resources. Such integrated management may require the rescaling of optimum sustained yields of some resources to achieve sustainability of others. For example, harvest of buck white-tailed deer within the Allegheny National Forest in northwestern Pennsylvania has averaged about 6,400 for the last 60 years (Figure 5). At first glance, this seems like a sustained yield, perhaps even an optimum sustained yield. Data collected by the Pennsylvania Game Commission over this period reveals a maintained overwinter deer density averaging 29 per square mile for the Allegheny National Forest.
But research conducted within the same forest over the same period suggests that when deer density exceeds 20 per square mile, sustainability of other forest resources, including hardwood regeneration, wildlife habitat, songbirds, and herbs and shrubs will decline. Thus, sustaining all forest resources may require scaling back sustained yields of buck deer to a level supported by 20 deer per square mile over winter.
Finally, according to Goodland and Daly (1996), the optimal sustained yield of a single resource, such as deer harvest, eventually results in the declining utility or declining natural capital of that same resource sometime in the future. In the experiment to determine the impact of deer on multiple forest resources, simulated densities of 10, 20, 38, and 64 deer per square mile were to be maintained in large (at least 32 acres) enclosures for ten years. After five years, deer in the 38- and 64-deer density enclosures began to starve to death, having exhausted natural forage resources (deCalesta 1994). In this experiment, deer densities greater than 40 per square mile were not sustainable. Thus, what originally might seem as a sustainable harvest yield of white-tailed deer cannot be maintained if other resources such as timber production, populations of other wildlife species, and even deer themselves, are to be integrated and sustained within the same landscape. To sustain multiple forest resources, including deer, requires that management for each individual resource be compatible with that of others.
CONCLUSION
Studies in northwestern Pennsylvania provide evidence of the pervasive impact of deer on sustainability of forest. This paper demonstrates how management to sustain an optimum harvest of deer can affect sustainability of other forest resources. Managing deer density to optimize recreational and economic benefits may result in continued reductions in species richness, abundance, and shifts in composition of plant and animal communities, effectively thwarting the main goal of EM (preservation of ecosystem integrity). Future conduct of EM must incorporate proactive management activities that produce benign rather than negative deer impact by reducing deer density. Practitioners of EM, where it requires reducing deer density, must be prepared to address and counter political and social pressures that will resist such action.
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By Bob Frye
TRIBUNE-REVIEW
Monday, March 29, 2010
There's been a lot of talk about how much coyotes are impacting the state's deer herd. One researcher believes it's much ado about nothing.
Duane Diefenbach, adjunct professor of wildlife ecology and leader of the Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State's school of forest resources, said coyotes do prey on fawns, here as well as elsewhere. But there's no evidence they're depressing the state's deer population, he said. That's true even though coyote numbers have grown over the years, he said.
"But our data tell us that coyote predation is not an issue in Pennsylvania," he said.
For the past decade, he and his students have been monitoring thousands of deer -- 3,000 overall -- that they captured and fitted with radio collars. "Significantly, very, very few adult deer in our studies have succumbed to predation from coyotes, bears or anything else," he said. "We now know that in this state, once a deer reaches about 12 months of age, the only significant mortal dangers it faces are getting hit by a car or being harvested by a hunter.
Fawns fare pretty well in a world with coyotes, too, he added. A fawn study done in the state a decade ago found predation rates similar to what exists elsewhere, like in Maine, Illinois, Minnesota, Iowa and New Brunswick, Canada. "Our research has shown that overall mortality here is not extraordinary," he said.
Deer, Ecosystem Damage, and Sustaining Forest Resources
by David S. deCalesta*
Prior to colonization of North America by European settlers, deer density in eastern deciduous forests, including Pennsylvania, was approximately 7 to 10 deer per square mile, and was affected by forage availability, weather, and predation (Witmer and deCalesta 1992, deCalesta 1997).
However, by the end of the nineteenth century much of Pennsylvania's forests had been completely cut over, and the deer herd was nearly eliminated by unregulated deer harvest (Redding 1995). Vast amounts of deer forage were produced by this extensive timber harvest, deer hunting was heavily limited to allow the population to rebuild, and major deer predators were extirpated from Pennsylvania.
The result was an explosion of the deer population in the first quarter of the twentieth century, with deer density exceeding 50 deer per square mile in northwestern Pennsylvania (Clepper 1931, Redding 1995).
The expanding deer herd then eliminated its food supply, and during a series of hard winters in the late 1930s declined to around 10 to 15 deer per square mile.--even during harsh conditions, no where near the the 7 to 10 per square mile that existed in colonial times--blogger Rick
Coincidentally, timber harvest began anew in the 1950s, as forests harvested fifty to eighty years earlier approached commercial maturity. In the ensuing 40 years the deer population again increased, averaging over 30 deer per square mile, even while sustaining a population decline following a series of harsh winters in 1978- 79 (Figure 1).
Whitney (1984) and Hough (1965) documented the loss since the 1930s of herbaceous and shrub species from unmanaged mature forests in northwestern Pennsylvania, and attributed the declines to herbivory by deer. Composition of understory vegetation shifted from shrubs and herbs to grasses and ferns in this period (Marquis and Grisez 1978, Horsley and Marquis 1983), with reductions in species richness and abundance of seedlings of woody plants that jeopardized development of future forests.
In the late 1970s a study was designed in northwestern Pennsylvania to provide quantitative evaluation of the impact of deer on forest resources. The effect of varying white-tailed deer densities on regeneration of woody vegetation and on songbird and herbaceous communities was evaluated during 1980-1991 (Tilghman 1989, deCalesta 1994, Jones et al. 1993). In this study species richness and height of saplings declined once deer density exceeded 20 deer per square mile (Tilghman 1989, deCalesta 1992) (Figure 2). At deer densities greater than 20 per square mile, seedlings of six woody tree species were missing or prevented by deer browsing from becoming incorporated into the overstory (deCalesta 1992), and clearcut sites approached monocultures of black cherry (Prunus serotina). Thus, when deer abundance exceeded estimated pre-European settlement density, deer impact truncated species richness and vertical structure of understory vegetation, thereby influencing the regeneration process and future overstory tree composition.
Deer browsing can affect vegetation that songbirds use for foraging surfaces, for cover for escape/hiding from predators, and for nesting. By significantly reducing the height of woody vegetation, white-tailed deer affected habitat for songbirds that feed, nest, and seek cover in the 0-7.6 m height interval (deCalesta 1994). Birds that utilize this intermediate foliage canopy exhibited significant reductions in species richness and abundance when deer density exceeded 20 per square mile (Figure 3).
Once deer density exceeded 10 per square mile, five songbird species were no longer observed on study sites. Abundance of songbirds declined when deer density exceeded 10 per square mile. As with regeneration of woody tree species, deer impact significantly affected songbirds when deer population density exceeded estimated pre-settlement density.
Species richness and abundance (expressed as percent ground cover) of shrubs and herbaceous plants were significantly impacted when deer density exceeded 10 per square mile (deCalesta 1992) (Figure 4). Two shrub species and one herbaceous species disappeared when deer density exceeded 20 deer per square mile.
Species richness and abundance of plants in the herb/shrub layer shifted significantly when deer densities exceeded 20 per square mile: percent ground cover of ferns, grasses, and mosses increased, while that of shrubs and other herbs decreased (deCalesta 1992).
Many herb and shrub species noted in earlier (pre-1950) surveys (Jennings 1953) were not found, presumably having been eliminated by 70 years of browsing pressure by deer populations exceeding 20 per square mile. Species richness and abundance of plants in the herb and shrub communities, like that of songbirds, were significantly reduced when deer population density exceeded estimated pre-European settlement density.
Thus, sustainability of woody regeneration, songbirds and songbird habitat, and herbs and shrubs is affected once white-tailed deer density exceeds that of pre-European settlement: species richness and abundance of all these resources decline.
EXPECTATIONS FOR SUSTAINED HARVESTS OF DEER AND TIMBER
Income generated by deer-hunting activities in Pennsylvania amounts to at least 1 billion dollars annually (Kosack 1991). Both business and hunting interests have benefited under the high deer densities and harvests experienced over the last 60 years; these interests exert considerable pressure to maintain post-hunt deer densities in excess of 11 per square kilometer.
Since the second-growth forest in Pennsylvania became commercially mature in the late '50s, there has been an increasing amount of timber harvested (Figure 1). Expectations of the timber industry are that timber harvest could be sustained at a level comparable to that of the past few decades. However, timber stands cannot be harvested if advance regeneration (tree seedlings) is inadequate to produce replacement trees. McWilliams et al. (1993) reported that only 4- 20 percent of forested lands surveyed across Pennsylvania in 1990 had advance regeneration sufficient to provide adequate regeneration of diverse woody species under conditions ranging from unfavorable to favorable. Overabundant white-tailed deer populations were hypothesized as the primary cause for failure of advance regeneration. DeMarco (1994, Allegheny National Forest, Warren, PA, personal communication) noted that only 33 percent of maturing forestland within the Allegheny National Forest carried sufficient advance regeneration to permit removal of overstory timber with reasonable expectation of successful regeneration.
Six decades of high deer densities and harvests developed expectations of and demands for continuance of a perceived sustainable deer harvest. However, deer density required to maintain this level of harvest affects sustainabilities of other forest resources.
INTEGRATING AND SUSTAINING FOREST RESOURCES
Woodland and Daly (1996) added social/political factors to economic development and environmental protection as components of sustainability. They suggested that these three components be addressed and defined separately by experts in those disciplines. They suggested integrating these components in their discussion of environmental sustainability and argued against managing for sustainable yields of single resources at the expense of others. Without such integration, the component with the most political/societal/economic clout may well predominate, at the expense of sustainability of the others. In Pennsylvania this has occurred with sustainability of high deer harvests overriding sustainability of other forest resources.
Management of deer is based on sustaining harvestable yields such that post-hunt populations are stable through time (Caughley 1976). McCullough (1979) added the refinement of "optimum sustained yield," which is the greatest number of animals that can be harvested, year after year, from a deer population such that human benefits (e.g., economic return or hunter satisfaction) can be optimized. However, all forest resources should be managed to produce "the simultaneous sustained yield of many interrelated populations in an ecosystem" (Goodland and Daly 1996).
Forest management has yet to produce integrated management plans for all forest resources. Such integrated management may require the rescaling of optimum sustained yields of some resources to achieve sustainability of others. For example, harvest of buck white-tailed deer within the Allegheny National Forest in northwestern Pennsylvania has averaged about 6,400 for the last 60 years (Figure 5). At first glance, this seems like a sustained yield, perhaps even an optimum sustained yield. Data collected by the Pennsylvania Game Commission over this period reveals a maintained overwinter deer density averaging 29 per square mile for the Allegheny National Forest.
But research conducted within the same forest over the same period suggests that when deer density exceeds 20 per square mile, sustainability of other forest resources, including hardwood regeneration, wildlife habitat, songbirds, and herbs and shrubs will decline. Thus, sustaining all forest resources may require scaling back sustained yields of buck deer to a level supported by 20 deer per square mile over winter.
Finally, according to Goodland and Daly (1996), the optimal sustained yield of a single resource, such as deer harvest, eventually results in the declining utility or declining natural capital of that same resource sometime in the future. In the experiment to determine the impact of deer on multiple forest resources, simulated densities of 10, 20, 38, and 64 deer per square mile were to be maintained in large (at least 32 acres) enclosures for ten years. After five years, deer in the 38- and 64-deer density enclosures began to starve to death, having exhausted natural forage resources (deCalesta 1994). In this experiment, deer densities greater than 40 per square mile were not sustainable. Thus, what originally might seem as a sustainable harvest yield of white-tailed deer cannot be maintained if other resources such as timber production, populations of other wildlife species, and even deer themselves, are to be integrated and sustained within the same landscape. To sustain multiple forest resources, including deer, requires that management for each individual resource be compatible with that of others.
CONCLUSION
Studies in northwestern Pennsylvania provide evidence of the pervasive impact of deer on sustainability of forest. This paper demonstrates how management to sustain an optimum harvest of deer can affect sustainability of other forest resources. Managing deer density to optimize recreational and economic benefits may result in continued reductions in species richness, abundance, and shifts in composition of plant and animal communities, effectively thwarting the main goal of EM (preservation of ecosystem integrity). Future conduct of EM must incorporate proactive management activities that produce benign rather than negative deer impact by reducing deer density. Practitioners of EM, where it requires reducing deer density, must be prepared to address and counter political and social pressures that will resist such action.
______________________________________________________________________
By Bob Frye
TRIBUNE-REVIEW
Monday, March 29, 2010
There's been a lot of talk about how much coyotes are impacting the state's deer herd. One researcher believes it's much ado about nothing.
Duane Diefenbach, adjunct professor of wildlife ecology and leader of the Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State's school of forest resources, said coyotes do prey on fawns, here as well as elsewhere. But there's no evidence they're depressing the state's deer population, he said. That's true even though coyote numbers have grown over the years, he said.
"But our data tell us that coyote predation is not an issue in Pennsylvania," he said.
For the past decade, he and his students have been monitoring thousands of deer -- 3,000 overall -- that they captured and fitted with radio collars. "Significantly, very, very few adult deer in our studies have succumbed to predation from coyotes, bears or anything else," he said. "We now know that in this state, once a deer reaches about 12 months of age, the only significant mortal dangers it faces are getting hit by a car or being harvested by a hunter.
Fawns fare pretty well in a world with coyotes, too, he added. A fawn study done in the state a decade ago found predation rates similar to what exists elsewhere, like in Maine, Illinois, Minnesota, Iowa and New Brunswick, Canada. "Our research has shown that overall mortality here is not extraordinary," he said.
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