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Northern goshawk
Accipiter
gentilis
Photo © Steve Garvie
The northern goshawk is found
across Eurasia and North America, and is the largest of all
goshawk species. In California, the northern goshawk only breeds
in the northern mountain ranges and in the southern portion of
the Los Padres National Forest around Mt. Abel, Mt. Pinos,
Frazier Mountain, and the Tecuya Range in northern Ventura
County. Well-distributed across their core breeding range in the
north, the birds are quite rare in southern California.
| Goshawks build their nests in mature and old-growth forest stands, preferring
trees like ponderosa pine, Jeffrey pine,
white fir, and lodgepole pine. Northern goshawks are
monogamous (and solitary outside of the breeding season) with
pairs typically meeting at nesting territories by February each
year. They sometimes migrate in the winter if food is scarce,
but often will remain near nests year-round in the warmer
southern climates. Breeding typically begins in April and lasts
into August, but can begin as early as February and extend
through September. |
A northern
goshawk nest. |
Northern goshawks prey on a variety of animals including squirrels, hares, grouse, woodpeckers, and other raptors. They
are considered sit-and-wait predators, perched on branches
scoping the landscape for food, often switching perches numerous
times during the hunt. Large snags and downed logs are important
because they support prey species like small mammals and
cavity-nesting birds upon which goshawks depend for food.
Northern goshawks are
wide-ranging birds, with a breeding pair defending a territory
ranging from 1,500 to 8,500 acres. Their large home-range,
combined with their relatively low reproductive rate, make
northern goshawks particularly vulnerable.
Threats
Northern goshawk populations in California are poorly
understood, and comprehensive surveys have not been completed. A
recent estimate for goshawks statewide was only 1,000 breeding
territories (approximately 2,000 birds). Active nest
sites were last recorded on Mt. Abel and Mt. Pinos in the late
1980s, but these areas have not been surveyed recently. A goshawk family was
recently observed on Frazier Mountain in July
2011, indicating that goshawks are nesting on Frazier
Mountain as well.
A young northern goshawk on
Frazier Mountain in 2011. Photo © John Vanderpoel
The primary threats facing northern goshawks are habitat
degradation and loss from wildfires, fire suppression and
vegetation treatment projects,
and timber harvest, which removes nesting trees and the downed
logs on which goshawks rely for foraging. This makes projects on
forest land that remove large old-growth timber
particularly harmful to goshawk populations.
Small numbers of goshawks are allowed to be collected for
falconry in California, but biologists believe that the current
collection levels do not affect statewide population numbers.
Conservation
The
best way to ensure that goshawks continue to survive in the Los
Padres National Forest is to protect and restore the mature
conifer forest habitats on which the birds depend.
According to the Forest Service, the greatest concern for
goshawks is the prevention of large-scale wildfire plus the
restoration of forested vegetation types. To accomplish these
goals, the Forest Service has imposed several Best
Management Practices including retaining large trees and
down logs for prey species, and limiting harmful
activities within 1/4 mile of nest sites during the
breeding season. |
Photo © Sarah
Parker |
No comprehensive goshawk surveys have been conducted in the Los Padres National Forest, so while these
practices are a good first step towards protecting the birds, a more
solid understanding of goshawk distribution and habitat use in
southern California is still needed. The Forest Service has
recognized this point, stating:
More information is needed on
where goshawks may nest in the mountains of southern California.
The breeding population is clearly small. It's not known why
goshawks numbers are so low in southern California. Efforts to
maintain the integrity of breeding territories of northern
goshawks cannot be made until their locations are known. To
ensure the goshawk's existence will require the restoration of
these degraded habitats and the protection of native processes.
Additionally, from 2005 to 2011, the Forest Service
proposed several commercial timber sales in northern goshawk
habitat in the Los Padres National Forest. ForestWatch has worked
to stop these projects, encouraging forest officials to focus
instead on
non-commercial forest thinning, targeting small-diameter trees
while leaving large trees, snags, and downed logs in place for
the benefits they provide to goshawks and their prey. In 2012, the Forest Service agreed to incorporate
ForestWatch recommendations to protect northern goshawks on Frazier Mountain.
ForestWatch will continue to work with forest officials to ensure that
the goshawks in the Los Padres National Forest receive the
highest level of protection, and that surveys are conducted to better understand
where goshawks are nesting so that their habitat can be
protected.
Photo © Tom Munson
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