united states cheyenne canyon tussock moth control project...

UNITED STATES

DEPARTMENT OF

AGRICULTURE

FOREST

SERVICE

May 3, 2016

Biological Assessment for Mexican Spotted Owl

Cheyenne Canyon Tussock Moth Control Project

PIKE and SAN ISABEL NATIONAL FORESTS and COMANCHE and

CIMARRON NATIONAL GRASSLANDS

PIKES PEAK RANGER DISTRICT

EL PASO COUNTY, COLORADO

Prepared by:

/s/ Stephanie Shively

Reviewed by:

/s/ Mike Welker

Any questions concerning this Biological Assessment and the analysis should be

directed to Mike Welker, Forest Biologist and Interdisciplinary Team Leader.

Purpose and Need: The purpose of this project is to minimize the spread and intensity of the Douglas-fir

Tussock Moth outbreak in the Colorado Springs area. The project is needed to complement state and

local agency and landowner efforts to control the moth. The greater Colorado Springs area is mosaic of

private, city, state, and federal lands. The juxtaposition of different landownership, as well as divergent

management objectives among local, state, and federal agencies, requires a high level of collaboration and

communication to control the current outbreak. The Tussock Moth causes defoliation and kills Douglas-

fir and other coniferous trees. These trees are a valued component of the scenic backdrop for the

communities, enhance recreation values, and provide watershed protection and wildlife habitat.

On National Forest lands, the Tussock Moth outbreak is immediately adjacent to private, municipal, and

state lands; lies within the Wildland Urban Interface; and is occurring within a heavily-used recreation

area. There are concerns that the outbreak may continue to spread on National Forest lands and onto

adjacent private, city, and state lands. The project is intended to minimize additional Douglas-fir

mortality on the Pike National Forest adjacent to current infestations.

The Tussock Moth is a native defoliator with well documented outbreaks occurring in Colorado since at

least the 1930’s. These outbreaks typically last for two to four years. On the Pike National Forest, the

1993 to 1996 outbreak resulted in 30 to 40 percent Douglas-fir mortality, affecting 18,000 acres. Other

outbreaks have been smaller and more isolated. The current outbreak was first noticed in 2014 on

Cheyenne Mountain State Park and Cheyenne Mountain Air Force Station land.

The current Cheyenne Canyon Tussock Moth infestation covers approximately 1,000 acres across private,

city, state, and federal land ownership. In the Cheyenne Canyon area, there are approximately 50 acres of

infestation on National Forest lands. There are mixed stands of ponderosa pine, Douglas-fir, and white fir

adjacent to existing infestations that could potentially be affected by spread of the Tussock Moth. Within

the project area there are old growth Douglas-fir and Douglas-fir plantations that are now 80 to 110 years

old. Treatments within the project area would maintain desired forest structure by protecting high-value

trees, including old growth and large diameter Douglas-fir adjacent to current infestations, and

complement moth control actions on nearby lands under state, local and private ownership.

Proposed Action: The Pike & San Isabel National Forests and Cimarron & Comanche National

Grasslands propose to implement control measures to minimize the spread and intensity of the Douglas-

fir Tussock Moth outbreak on National Forest System Lands within the Wildland Urban Interface near

Colorado Springs. This initial proposed action will be refined through an open and transparent process

that utilizes public involvement, collaboration, and notification, culminating in a final proposed action

and implementation.

The Project Area encompasses 411 acres near Cheyenne Canyon in El Paso County, Colorado. The

affected areas are in portions of T14S, R67W, Sections 28, 29, 32, and 33; and T15S, R67W, Sections 4,

5, 9, and 10. The attached map shows the current outbreak and the areas on National Forest System Land

that are proposed for treatment. The treatment areas comprise a ¼ mile buffer around the current

infestations.

Cheyenne Canyon Tussock Moth Control Project Biological Assessment Page 2

In separate actions, treatments are scheduled to occur on private, city, and state lands adjacent to the

National Forest. Those treatments are separate from this proposal and are not part of the Forest Service

proposed action.

Control of the moth would be accomplished using Foray 48B Biological Insecticide, which contains

spores and endotoxin crystals of Bacillus thuringiensis kurstaki. The insecticide would be applied from

the air by helicopter. A single treatment would occur during the period of moth larvae emergence, which

is most likely to happen between June 15 and July 1. No application would occur in areas where surface

water is present, including ponds, lakes, and wetlands and perennial, intermittent, and ephemeral streams.

To prevent drift and non-target applications, all label directions will be strictly followed.

The treatment area would be closed to the public during the period of aerial application and would reopen

after the treatment is completed.

Habitat Description: The proposed project area is within the ecotone of the Pikes Peak-Rampart

Range and the Northern Arkansas Granitics ecological subsections as defined by McNab, et al. (2007).

The area lies within the Cheyenne Creek and City of Colorado Springs-Fountain Creek sixth level

watersheds.

The project area is in a montane climate zone at elevation between 7,000 and 8,500 feet. All aspects are

present in the vicinity, and slopes may be over 60 percent. Vegetation is described as mixed conifer,

Ponderosa Pine-Douglas-fir, Ponderosa Pine/Gambel Oak, and Ponderosa Pine/grass dominated. There

are plantations of Douglas-fir intermixed with Ponderosa Pine and White Fir.


Threatened Species: Based on habitat type and records from the Pikes Peak Ranger District, the

project area could provide suitable habitat for the Mexican spotted owl.

Consultation History: In April 2016, several conversations between Leslie Ellwood (U.S. Fish and

Wildlife Service, Ecological Services, Colorado Field Office) and Stephanie Shively (USDA Forest

Service, Salida Ranger District) took place and it was recommended Mexican spotted owl habitat


modeled as potential nesting/roosting site be field verified to determine whether surveys would be

needed. Photos of modeled habitat existing on National Forest System Lands were taken on April 20 and

sent to Leslie for confirmation. On April 28, it was determined and agreed upon that no surveys were

needed, but habitat for nesting could exist on surrounding private lands and a Biological Assessment

would be necessary to address cumulative effects.

Species Federally Listed as Threatened

MEXICAN SPOTTED OWL (Strix occidentalis lucida)

Status and Distribution

The Mexican spotted owl (MSO or spotted owl) is one of three subspecies of spotted owl that includes the

California and northern spotted owl subspecies (USDI FWS 2012). The Mexican spotted owl occurs in

areas that correspond with isolated mountain ranges and canyon systems over a broad geographic area

that includes Utah, Colorado, Arizona, New Mexico, and the western portions of Texas south into several

States of Mexico (USDI FWS 2012).

Mexican spotted owls nest, roost, forage, and disperse in a diverse array of biotic communities. Spotted

owl can be found in heavily forested areas as well as in rocky canyons with sparse or no forest cover

(Ganey and Dick 1995, Ward et al. 1995, in USDI FWS 2012). In both forest and canyon environments,

spotted owls tend to select roosting and nesting sites that provide thermal protection. In the case of

forested sites, large trees, dense canopy cover, and first or second order tributaries all act to create a

cooler microclimate during warm ambient temperatures of the breeding season (USDI FWS 2012).

Mexican spotted owls consume a variety of prey throughout their range. Spotted owls commonly eat

small- and medium-sized rodents such as woodrats, mice, and voles, but they also consume bats, birds,

reptiles, and arthropods (Ward and Block 1995 in USDI FWS 2012). Spotted owls utilize a wider variety

of cover types for foraging than for roosting or nesting, including: managed and unmanaged forests,

piñon-juniper woodlands, mixed-conifer and ponderosa pine forests, on cliff faces and terraces between

cliffs, and along riparian zones (multiple sources in USDI FWS 2012).

Habitat Assessment

About 8.6 million acres of critical habitat (i.e., habitat that is essential for the conservation of this species)

is designated for the Mexican spotted owl on Federal lands in Arizona, Colorado, New Mexico, and Utah.

The northwest and southeast portions of the Pikes Peak Ranger District occur within two critical habitat

units that encompass about 54,365 acres of the district. The critical habitat designation includes areas

within these mapped units that are protected or restricted habitat as defined in the original Recovery Plan

(USDI FWS 1995). The proposed project area is located approximately two miles north of these critical

habitat units (MSO Protected Activity Centers [PAC]).

Within the project area, forested stands with the vegetative type and structural features that may support

this species encompass about 96 acres of the project area (USDA FS 2014). According to the MSO

Model for the Pike/San Isabel National Forest (USDA FS 2014) about 3.24 acres of the project area

contain potential nest/roost habitat. In addition, the project area contains 68.4 acres of stands lacking the

habitat complexity or structure to support the nesting or roosting habitat required by this species.

However, these stands are suitable as foraging habitat for the spotted owl and are considered forested

recovery habitat (i.e., replacement nest/roost habitat). The project area also contains 24.7 acres of rocky

canyon habitat on National Forest System Lands.


Map 2: Mexican Spotted Owl Habitat Types Modeled within the Project Area on National Forest Service


Survey Results & Field Reconnaissance

Several Mexican spotted owl surveys were conducted at 16 sites across the Pikes Peak Ranger District

during the early 1990’s. As a result of these early survey efforts, two Protected Activity Centers (i.e.,

known or historical nest and/or roost sites) were established at Rock Creek and Little Fountain Creek,

located about 2 miles south of the project area. The Forest Service conducted four MSO surveys each in

South Cheyenne Creek in 1990 and in North Cheyenne in 1992 and had negative results. The species has

not been documented in the project area.

Further analysis of the modeled MSO habitat in the field occurred on April 20, 2016 by Stephanie

Shively, Ed Biery and Steve Olson from the Pike and San Isabel National Forests, Cimarron and

Comanche National Grasslands (PSICC). Reclassification of the modeled habitat was conducted during

field reconnaissance. The 3.24 acres of nest/roosting habitat located on National Forest is showing

tussock moth infestation and is of poor quality for nesting MSO (Photo 1).

Photo 1 - Nest/Roost Habitat Modeled on National Forest Lands along Gold Camp Road

In addition, several of the polygons identified as MSO forested nest/roost habitat were actually poor

quality sites of Douglas-fir plantations approximately 100 years in age. It is difficult to pull some of these

characteristics out of a habitat model covering an entire forest. An example of one site is shown in Photo

2. The trees are evening spaced in rows, all the same species and less than 15 inches in diameter. These

units are neighboring treatment units on National Forest. In general, the mixed conifer forest on the

National Forest within the project area was of poor quality for Mexican spotted owls due to a lack of the

following: dense forest canopy, large diameter trees, rocky canyons and riparian zones.


Photo 2 – Example of the Douglas-fir stands planted in the early 1900's.

All photos were shared with the USFWS Biologist, Leslie Ellwood, who agreed that the nesting/roosting

habitat modeled for MSO would not need further survey work and is not likely to contain nesting birds

(USFWS April 28, 2016).

Direct and Indirect Effects

The proposed tussock moth control management actions will avoid all the MSO Protected Activity

Centers at Rock Creek and Little Fountain Creek located approximately two miles to the south from the

project. If an active MSO nest is present in the project area, disturbance from helicopters flying during

implementation could cause adult birds to flush from the nest during fledgling periods, but research has

shown they will not, or are less likely, to flush during incubation and nestling periods (Delany et al.

1999). The helicopter activities during one day between June 15 and July 1 are not likely to affect nesting

success or nest abandonment. Mexican spotted owl seem to be more tolerant of human activities than

other raptor species (Delany et al. 1999). No direct mortality or nest failure is likely to be caused by the

project. No direct mortality is likely from the spray itself (Durkin 2004).

Field Reconnaissance of the project area determined the MSO habitat on Forest Service Lands provides

conditions for foraging. The Mexican spotted owl diet relies mainly on small mammals such as woodrats,

mice, and voles. There is no plausible basis for concern regarding adverse effects in birds, plants, soil

microorganisms or invertebrates other than insects after exposure to B.t.k. (Durkin 2004). Small mammal

availability for the MSO is not likely to be reduced by the treatment/spraying for tussock moth. During


implementation, some prey species might be displaced, but likely to return shortly after to their home

ranges, nests, etc. The nocturnal habits of the foraging owl are suspected to remain the same after the

project is completed during daylight hours. Foraging habitat within the mixed conifer forest will remain

the same with the treatment for tussock moth. Without the treatment, prey habitat conditions are likely to

be altered and potentially reduce the quality of foraging habitat for the Mexican spotted owl as fir tree

mortality increases.

Cumulative Effects

The treatment area on National Forest System Lands contains relatively poor Mexican spotted owl habitat

relative to lands along the North and South Cheyenne Canyon bottoms, privately owned by Colorado

Springs, CO and others. These areas contain higher quality habitat due to the presence of rocky-canyons,

riparian corridors and dense canopy cover in mixed-conifer forest (MSO nesting/roosting) but most of

these sites show heavy tussock moth infestation and are likely to be experiencing tree mortality in the

near future, altering the suitability of MSO habitat (Photo 3).

Photo 3 - Colorado Springs Lands along North Cheyenne Canyon

It is possible an active nest could be present within these private lands which could be disturbed during

the application and spraying with a helicopter. There is a risk a nest could be abandoned during the

implementation of the project, resulting in a loss of reproduction, but research of military helicopter

flights and noise on MSO has shown it does not occur with a single, short duration flight (Delaney et al.

1999) and the birds return to the nest within 10-15 minutes after the disturbance. This research was

specific to site conditions and types of helicopter used, so is possible different results could occur within

the Cheyenne Canyon project area. The process of feeding young on the nest could also be impacted by

the helicopter flights if within close proximity of the nest. The closer the proximity to the nest, the greater

likelihood of flushing the birds (USFWS 2006, Delany et al. 1999).


Cheyenne Canyon is located in the foothills of Colorado Springs and contains several miles of roads and

trails popular with the public. Noise disturbance associated with these human activities is present,

particularly during spring, summer and fall. Military operations (Air force academy and Fort Carson

Army Base) and a local Colorado Springs airport are present nearby. Some wildlife species may have

habituated to these types of human activities.

As the progression of the tussock moth continues, habitat for the Mexican spotted owl may decline in the

project area and birds will be displaced to lands outside the Cheyenne Canyon watershed. The proposed

treatment will reduce the risk of further Douglas-fir, white-fir mortality in the area and will protect what

habitat currently exists.

Determination of Effects

The determination of the effect of the Proposed Action is ‘may affect, not likely to adversely affect’ the

Mexican spotted owl (Strix occidentalis lucida).

Literature Cited/References: CEQ. 1997. Considering Cumulative Effects under the National Environmental Policy Act. Council On

Environmental Quality, Executive Office of the President. 64 pp. + appendices.

Delaney, D.K., T.G. Grubb, P. Beier, L.L. Pater, M.H. Reiser. 1999. Effects of helicopter noise on Mexican spotted

owls. Journal of Wildlife Management 63(1):60-76.

Durkin, P.R. 2004. Control/eradication agents for the gypsy moth – human health and ecological risk assessment

for Bacillus thuringiensis var. kurstaki (B.t.k.) final report. For USDA, Forest Service, Forest Health

Protection. Syracuse Environmental Research Associates, Inc., Fayetteville, New York.

Endangered Species Act of 1973, as amended, 16 U.S.C. 1531 et seq.

Kingery, H.E., ed. 1998. Colorado breeding bird atlas. Colorado Springs, CO: Colorado Bird Atlas Partnership.

Olson, S. 2015. Endangered, threatened, proposed and Regional forester’s sensitive species in the Rocky Mountain

Region (R2). What’s important for the Pike and San Isabel National Forests and the Cimarron and Comanche

National Grasslands (PSICC)? Pueblo, CO. 166 pp.

Quesada, F., D. Bohon. 2015. Bear Creek Watershed Restoration Biological Assessment/Biological Evaluation of

Fisheries and Wildlife Resources. Pikes Peak Ranger District, Pike and San Isabel National Forests and

Cimarron and Comanche National Grasslands. 77pp.

USDA Forest Service. 1984. Land and Resource Management Plan, Pike and San Isabel National Forests;

Comanche and Cimarron National Grasslands, Rocky Mountain Region.

____. 2014. Mexican Spotted Owl (Strix occidentalis lucida) Recovery Habitat Mapping for the

Pike & San Isabel National Forests. C. Beal, Pikes Peak Ranger District, Colorado Springs, CO. 16 pp.

U.S. Fish and Wildlife Service. 1998. Endangered Species Act Consultation Handbook. Procedures for

Conducting Consultation and Conference Activities Under Section 7 of the Endangered Species Act. U.S.

Fish and Wildlife Service and National Marine Fisheries Service. Final, March 1998.

___ .1995. Recovery plan for the Mexican spotted owl: Vol. I. Albuquerque, New Mexico. 347 pp.

___ . 2006. Estimating the Effects of Auditory and Visual Disturbance on the Northern Spotted owl and Marbled

Murrlet in Northwestern California.

___ . 2012. Final Recovery Plan for the Mexican Spotted Owl (Strix occidentalis lucida), First Revision. U.S. Fish

and Wildlife Service. Albuquerque, New Mexico, USA. 413 pp.

____ . 2016. USWFS and USFS Communication Record on MSO with Cheyenne Canyon Tussock Moth Control


Project. Salida, CO. April 16 & 28, 2016.

Wrigley, M.J., M. White, B. Elliott, M. Comer, R.E. Torretta, P. Gaines, S. Olson, K. Meyer, M. Painter,

J. Windorski, F. Quesada, and M. Welker. 2012. Threatened, endangered, and Forest Service sensitive

species on the Pike and San Isabel National Forests (updated June 2012). Unpubl. Rpt. U.S. Department

of Agriculture, Forest Service. Pike and San Isabel National Forests and Comanche and Cimarron National

Grasslands. Salida, Colorado. 115pp + appendices.

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