HomeMy WebLinkAboutHANSEN FARM - PDP - PDP170036 - SUBMITTAL DOCUMENTS - ROUND 2 - ENVIRONMENTAL REPORTFebruary 12, 2018
Jeff Mark
President
The Landhuis Company
212 N. Wahsatch Ave., Suite 301
Colorado Springs, CO 80903
RE: Revised and Updated Ecological Characterization Study (ECS) Letter Report for the Proposed Hansen
Property Development, Fort Collins, Colorado
Jeff:
This letter report has been revised from the original ECS report submitted on June 1, 2017 to incorporate
additional data requested by the City of Fort Collins Planning Department’s October 2017 review comments on
the original PDP submittal for the Hansen Property development. The report is submitted to satisfy the
requirements of Section 3.4.1 of the Land Use Code of the City of Fort Collins regarding the submittal of an ECS
report for proposed development projects. The Hansen Property project site is an approximate 70-acre parcel
located west of Timberline Road, South of Kechter Road, and north of Trilby Road in the northeast ¼ of Section
7 (Township 6 North, Range 68 West) in Fort Collins, Colorado. Ecological characteristics of the property were
previously reviewed on December 6, 2012 for McWhinney, and site conditions were again evaluated on May 15,
2017 for this report. In addition, an updated wetland survey was completed on November 15, 2017 and raptor
night roost surveys were completed in January 2018.
The May 17, 2017 field survey was conducted to characterize existing wildlife habitats, as well as identify any
unique or sensitive natural resource features. Prior to the initiation of the field survey, Natural Resources
Conservation Service (NRCS) soils mapping (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx) was
reviewed to determine if any known hydric (wetland) or highly erosive soil mapping units are located on the
property. Observations recorded during the field evaluation included: major vegetation communities / wildlife
habitats present within the property; dominant vegetation associated with each community / habitat; unique
habitat features; and observations of wildlife species and/or definitive sign. Photographs showing representative
views of existing habitats were also taken to document site conditions. Wildlife presence and habitat use was
based on on-site observations and habitat presence in conjunction with the known habitat requirements of
potential wildlife species. Existing habitats were also evaluated regarding their ability to support populations of
threatened, endangered, and other sensitive plant and wildlife species.
The following provides a summary of information required by Fort Collins Land Use Code under 3.4.1 (D) (1)
items (a) through (k).
ECOLOGICAL STUDY CHARACTERIZATION CHECKLIST
(a & j) Existing habitats on the property consist almost entirely of grass/alfalfa hayfield with a few exceptions.
Aside from grass/alfalfa hayfield there is a small strip of nearly pure grass hayfield along the southern property
boundary (see attached Figure 1). The majority of the property’s surface has been planted to alfalfa (Medicago
sativa1) and non-native grass, primarily smooth brome (Bromus inermis), for hay production (see attached
Figure 1). Less dominant vegetation species recorded in grass/alfalfa hayfield included tall fescue (Festuca
1 Scientific nomenclature follows USDA, NRCS Plants Database. Available online at: http://plants.usda.gov/java/
J. Mark
2/12/2018
Page 2 of 6
arundinacea), cheatgrass (Bromus tectorum), field bindweed (Convolvulus arvensis), common dandelion
(Taraxacum officinale), and Canada thistle (Cirsium arvense). The grass hayfield strip is dominated by smooth
brome. Attached Photo 1 provides a representative view of grass/alfalfa hayfield.
There are three other habitats or habitat features on the property. These are irrigation ditches, mature trees,
and wetlands. Irrigation ditches run along the south, north, and west edges of the property. These ditches
support pockets of wetland vegetation as well as several large, mature eastern cottonwood trees (Populus
deltoides), small multi-trunked peachleaf willows (Salix amygdaloides), one green ash tree (Fraxinus
pennsylvanicus), and one dead Siberian elm (Ulmus pumila) (see attached Figure 1). Wetland vegetation,
within the irrigation ditches banks, consists of non-continuous pockets of reed canarygrass (Phalaris
arundinacea), Emory sedge (Carex emoryi), showy milkweed (Asclepias speciosa), and sandbar willow (Salix
exigua). One other small, isolated wetland is present on the property (see following Section b).
There are also a number of large deciduous and evergreen trees supported in the residence/farmstead area at
the southeast property corner and a cluster of 21 blue spruce (Picea pungens) trees in the southeast portion of
the hayfield (see attached Figure 1). A number of large cottonwoods also grow along the north irrigation ditch
(Mail Creek Ditch). These trees are outside the Hansen Property north boundary. Most trees on the property
are over 6 inches in diameter and may be classified by the City Forester as significant based on the Fort Collins
Land Use Code. The City Forester will need to evaluate the health of these trees in order for their significance
status to be determined.
Aside from potentially significant trees, irrigation ditches, and small wetland areas, the property does not support
any native vegetation or other unique habitat features, and no features of ecological value exist within 500 feet
of the development site. Grass/alfalfa and grass hayfields are non-native habitats that have been planted after
clearing native vegetation and woody species, and as a result, support no natural habitat features and have
minimal ecological and wildlife habitat value. There are a few abandoned black-tailed prairie dog burrows in
grass/alfalfa hayfield in the northwest portion of the property. These burrows have not been occupied for
several years since all of the burrow openings have collapsed and the burrow mounds are relatively indistinct.
Trees on the property may be used for perching, nesting, and foraging by raptors and urban-adapted songbirds,
and Canada geese grass may occasionally graze the hayfield areas. Two groups of approximately 40 and 150
Canada geese were observed grazing in grass/alfalfa hayfield during the January 2018 raptor roost surveys
(see Section g). Raptor nests located in trees along the south irrigation ditch during the December 2012 survey
were no longer present at the time of the May 15, 2017 survey. The only larger stick nest found during the May
2017 survey was an abandoned black-billed magpie nest in a dead Siberian elm along the south irrigation ditch
(see Figure 1).
(b) Wetlands within the Mail Creek Ditch and other unnamed irrigation ditches have not been delineated since
the only project-related impacts to the ditches would be pedestrian and street crossings, whose locations have
not been finalized. Once the locations of these ditch crossings are determined, ditch wetlands at these crossing
will be delineated and mapped so wetland impacts can be determined. The ditch crossing wetland report and
mapping will be provided to the City as an addendum to this report.
One other isolated wetland area, not associated with the ditches, exists on the property in a depression that
appears to collect excess irrigation water (see attached Figure 1 and Photo 2). The central and wettest portion
of this wetland is typically saturated or holds shallow standing water during the growing season and after
precipitation events and is dominated by smartweed (Perisicaria sp. - FACW) and broadleaved pepperweed
(Lepidium latifolium - FACW). The outer perimeter portion of this wetland is dominated by reed canarygrass
J. Mark
2/12/2018
Page 3 of 6
(Phalaris arundinacea - FACW). Several young (< 6-inch) eastern cottonwoods and peachleaf willows grow
around the edge of the depression.
The wetland in this depression was initially delineated on December 6, 2012 using the methods and techniques
specified for "routine on-site delineations" in the publication, Corps of Engineers Wetlands Delineation Manual
(USACOE 1987), and supplemented by the document, Interim Regional Supplement to the Corps of Engineers
Wetland Delineation Manual: Great Plains Region (USACOE 2008). Northern Engineering of Fort Collins
surveyed the wetland boundaries after the delineation was completed and determined the wetland area to be
0.29 acre in size. The wetland report and a request for a jurisdictional determination were submitted to the U.S.
Army Corps of Engineers (Littleton District Office) on January 2, 2013. The U.S. Army Corps of Engineers
determined the wetland survey and report as accurate and acceptable and that the wetland was non-
jurisdictional since it had no connection to Waters of the United States (see attached Corps letter). (The date on
the Corps letter is incorrect and should be January 16, 2013, not January 16, 2012.)
City Environmental Planning staff requested an updated delineation of this wetland in their October 2017 review
comments on the Hansen property PDP submittal, and the wetland was re-surveyed on November 15, 2017.
Because of relatively mild fall weather, the soil surface was not frozen and conditions were suitable for wetland
delineation using Corps of Engineers approved delineation methods, described previously in this section. A new
delineation report was not submitted to the Corps of Engineers since the wetland area was previously
determined to be non-jurisdictional. A summary of the survey results is provided in the following paragraph.
Numerous check holes were dug and three formal sample points were established by the November 2017
survey to define the wetland boundary. A summary of the three formal sample points is provided in Table 1.
Copies of field data sheets are provided as an attachment to this report.
TABLE 1
Summary of Hansen Property Wetland and Upland Sample Point Characteristics
Sample
Point Dominant Species
Hydric Soil
Indicator(s)
Primary &
Secondary
Hydrology
Indicator(s)
COE
Wetland
H-1
(Wetland) Phalaris arundinacea - FACW A4, F3 A2, A3, C9, D2 PEM1
H-2
(Upland) Chenopodium album - FACU none D2 No
H-3
(Upland) Bromus inermis - UPL none none No
The November 2017 wetland survey confirmed that wetland and adjacent upland vegetation characteristics have
remained similar to those described by the 2012 wetland survey with one exception. The central and lowest
elevation portion of the wetland held standing surface water at the time of the November 2017 survey, and this
area is still dominated by smartweed and broadleaved pepperweed. No sample point was established in this
inundated and obvious wetland area. Reed canarygrass still dominates most of the outer, less-saturated
perimeter of the wetland area, and this perimeter area is represented by Sample Point H-1 confirming its status
as wetland (see Table 1). The one change was at the east end of the 2012 wetland area where the wetland
boundary had withdrawn. This end of the former wetland is represented by Sample Point H-2 (see Table 1) and
is now dominated by lambsquarters (Chenopodium album) and did not exhibit any hydric soil characteristics so
it was classified as upland. A final sample point H-3) was established at a slightly elevated location above H-2
and outside of the edge of the wetland depression area. As indicated in Table 1, this sample point is dominated
by smooth brome and exhibited no hydric soil or wetland hydrology characteristics so it was also classified as
upland. Based on these three sample points the wetland/upland boundary was determined to be defined by a
J. Mark
2/12/2018
Page 4 of 6
transition in dominance from reed canarygrass to smooth brome or lambsquarters. This boundary was flagged
in the field and Northern Engineering surveyed the boundary for portrayal on project development maps. A copy
of the surveyed wetland map showing the wetland boundary and formal sample points is provided as an
attachment to this report. Northern Engineering’s survey of the wetland determined the wetland to be 0.23 acre
in size confirming that the wetland was reduced in size by 0.06 acre from the 2012 survey.
(c) The Hansen Property provides relatively unobstructed views of the Front Range foothills.
(d & e) As indicated in Section a & j the Hansen Property supports little native vegetation, and significant trees
and other woody vegetation are restricted to the irrigation ditches and the residential/farmstead area (see Figure
1). Trees on the property will need to be inventoried by the City Forester to determine significance potential and
possible need for mitigation, if trees need to be removed for development. Russian olive (Elaeagnus
angustifolia) trees are considered undesirable, invasive species, but even non-significant or undesirable, non-
native tree species provide some wildlife habitat, and mitigation may be required for those trees lost to
development.
(f) There are no natural drainages on or near the Hansen Property. Mail Creek Ditch and the unnamed irrigation
ditches on or adjacent to the property are constructed water conveyance features for irrigation water distribution.
The 50-foot buffer zone to be established for these ditches would be sufficient to protect water quality in the
ditches and maintain possible wildlife use of the ditches as movement corridors.
(g) There is no suitable habitat for any threatened, endangered, or other sensitive species on or adjacent to the
Hansen Property. As indicated under Section a & i there has been past raptor nesting in trees along the
irrigation ditches, but no evidence of these nests was found by the May 15, 2017 survey. Historical observations
have indicated some bald eagle winter perching use of large cottonwood trees along the south boundary
irrigation ditch. The property owner (Doug Hansen) retained Cedar Creek Associates, Inc. in the late winter
(early February-early March) of 2004 to determine if these perch sites represented important winter roosting
sites or simply occasional daytime perching use. Based on the survey completed (see attached report), it was
determined that none of the large trees on the property were used as important night roost sites by bald eagles
or other raptor species. No bald eagle winter perching use of these trees was noted during the December 6,
2012 survey.
City Environmental Planning staff requested a more recent assessment of possible raptor roosting of trees on
and adjacent to the project area in their October 2017 review comments on the Hansen property PDP submittal.
The property was surveyed for raptor presence on a once weekly basis for four weeks in January 2018 (1/4/18-
1/23/18) in response to this request. The surveys were conducted from approximately 0.5 hour before to 0.5
hour after sunset. Each survey consisted of viewing all the larger trees on the property, or next to the property
boundary, to search for perching raptors located on the property. Emphasis was placed on searching the large
cottonwood trees for possible raptor night-roosting use. The January 2018 survey confirmed the findings of the
previous 2004 and 2012 surveys that trees on or near the Hansen property do not serve as important or
consistently used raptor night roost sites. The January 2018 surveys recorded only one raptor observation, and
this was of an American kestrel, which perched briefly near sundown in one of the large cottonwoods on the
south boundary irrigation ditch. Based on the fact that all trees growing along the irrigation ditches are
deciduous and do not provide suitable cover for shielding raptors from winter winds and inclement weather, it is
unlikely these trees would ever be used by raptors for winter night-roosting. Observed past use of these trees
by bald eagles and red-tailed hawks was likely related more to their use as suitable daytime hunting perch sites
when the abandoned prairie dog town in the northwest portion of the property was active. Prairie dogs are a
preferred prey item for bald eagles and red-tailed hawks, but since the prairie dog town has been abandoned
since at least 2012, the suitability of the Hansen property for raptor hunting use has been diminished
considerably.
J. Mark
2/12/2018
Page 5 of 6
(h) Past agricultural and residential conversion of the lands on the Hansen Property has eliminated the potential
for any special habitat features on the property, aside from the large trees and small wetland areas.
(i) The Mail Creek Ditch along the north property edge represents the only possible wildlife movement corridor
on the Hansen property. This ditch connects open space at the west end of the Hansen Property with open
space, agricultural land, and eventually Fossil Creek Reservoir east of the Hansen Property. However
Timberline Road and Ziegler Road interrupt the continuity of this corridor. The irrigation ditches along the west
and south property boundaries does not represent a potential wildlife movement corridor since their continuity
ends at Timberline Road.
(k) Because of the lack of natural habitat features on the Hansen Property there is only one issue regarding the
timing of property development and ecological features or wildlife use of the project area. If development
includes removal of any trees on the property or if construction occurs near an occupied bird nest during the
songbird nesting season (March through July), these activities could result in the loss or abandonment of a nest
and may be in violation of the federal Migratory Bird Treaty Act.
(l) Since the entire project area has been converted to agricultural or residential land use, project development
would have no impact on natural habitats or important habitat features, other than existing trees on the property.
The 50-foot buffer established for the Mail Creek Ditch in the current development plans would protect the
current condition of project area portions of the Mail Creek Ditch as a wildlife movement corridor. This buffer
would also meet the City buffer standard for wetlands less than 0.3 acres in size since the canal wetlands are
confined entirely with the canal embankments. It is recommended that existing native and non-native trees and
shrubs adjacent to canals be preserved to the extent possible, unless they are in poor condition. Removal of
any trees classified as significant would need to be mitigated with replacement trees, as determined by the City
Forester based on the Land Use Code. Mitigation plantings of trees and shrubs would also be appropriate
within the ditch buffer zones as long as plantings are in compliance with ditch operation and maintenance
activities.
Supplemental irrigation may be required for initial establishment of shrubs, trees, and herbaceous species in the
buffer zone. A weed management plan should be developed in concert with habitat enhancement plantings to
minimize the development of non-desirable, invasive species in the buffer zone enhancement area.
The Land Use Code wetland buffer requirement of 50 feet would apply the small wetland located on the project
area since it is less than 0.3 acre in size. The most current concept plan for the proposed development
indicates planned housing lots would encroach into the 50-foot buffer and a small portion of the southwest
corner of the wetland. Any wetland loss would need to be mitigated on a one-to-one basis with an established
50-foot buffer. Reconfiguration of the existing wetland with the stormwater detention area planned for the
project site may be the most appropriate means of mitigating wetland loss with a buffer zone as long as
sufficient soil moisture conditions can be created to sustain a created wetland area.
Because tree removal or construction near trees during the nesting season could result in the loss or
abandonment of a nest, it is recommended that tree removal or construction near trees occur outside of the
nesting season (February – July 31), or trees be surveyed to ensure lack of nesting prior to removal or
construction activities during the nesting season. This mitigation recommendation would preclude the possible
incidental take or disturbance of active songbird or raptor nests.
Another raptor use consideration for the Hansen property is the historic bald eagle winter perching use of two of
the large cottonwood trees along southern property boundary. Previous habitat assessment surveys completed
by Cedar Creek in January 2004 for the Hansen property, as well as casual observations made by the property
owner (Doug Hansen, pers. comm.), indicate bald eagles have occasionally perched in the large cottonwood
trees along the Hansen property southern boundary. The trees are apparently used as a daytime foraging perch
J. Mark
2/12/2018
Page 6 of 6
sites during the winter season. What was not known, at the time, was whether or not any of the larger trees
surrounding the property were used as a communal night roost. Night roost sites are typically communal (used
by more than one eagle) and usually provide some level of protection from winter wind and precipitation events.
Cedar Creek completed surveys from early February through early March 2004 to determine if bald eagles use
any of the trees near on or near the Hansen property as communal roost sites. The property was again
surveyed for possible raptor night roosting use in January 2018. The results of these surveys indicated that bald
eagles occasionally use these trees for daytime and early evening perch sites, but the trees were not used as
communal night roosts. It is unlikely these trees would ever be used as communal winter night roost since they
are relatively exposed and would provide little protection from inclement winter weather. No bald eagle or other
large raptor perching use of these trees was documented by the May 2017 or January 2018 surveys. It is
possible that occasional bald eagle perching use of these trees continues. However, as indicated in Section g,
past use of these trees by bald eagles and red-tailed hawks was likely related more to their use as suitable
daytime hunting perch sites when the abandoned prairie dog town in the northwest portion of the property was
active. Prairie dogs are a preferred prey item for bald eagles and red-tailed hawks, but since the prairie dog
town has been abandoned since at least 2012, the suitability of the Hansen property for raptor hunting use has
been diminished considerably.
One final mitigation recommendation is based on Article 3.2.4(D)(6) in the City of Fort Collins Land Use Code,
which requires protection of natural areas and natural features from light spillage from off site sources.
Therefore, the intensity of night lighting from the areas of development facing the ditch buffer zones should be
shielded or directed to minimize the intrusion of artificial nighttime light into these areas.
This concludes my evaluation of the Hansen Property. If you have any questions or require additional
information regarding my evaluation, please give me a call.
Sincerely,
T. Michael Phelan
Wildlife and Wetland Consulting
attachments: Figure 1, Habitat Mapping for the Hansen Property; Photos 1 and 2; 2013; Surveyed Wetland Map
and November 2017 Wetland Data Sheets; Army Corps of Engineers determination letter; and Night Roosting
Raptor Report for the Hansen Property, 2004
pc: K. Turner, The Birdsall Group
November 2017 Wetland Survey Map
(Created by Northern Engineering)
&
Wetland Data Sheets
NIGHT ROOSTING RAPTOR SURVEY REPORT
FOR THE
HANSEN PROPERTY
Prepared
by
Cedar Creek Associates, Inc.
Fort Collins, Colorado
Prepared
for
Doug Hansen
Lafayette, Colorado
March 16, 2004
1
NIGHT ROOSTING RAPTOR SURVEY REPORT
FOR THE
HANSEN PROPERTY
1.0 BACKGROUND AND LOCATION
Bald eagles in the Fort Collins area occur primarily as wintering birds from late November through early
March. Although its dietary staple is fish, wintering bald eagles also consume waterfowl, shorebirds,
prairie dogs, and carrion. Wintering birds are attracted to the area to feed on dead and crippled geese or
ducks on open or frozen reservoirs, prairie dogs in open rangeland, deer carcasses, or road kills in some
areas. They also occasionally perch and forage along the major river corridors in the region. Bald eagles
typically prefer foraging in areas where large trees provide suitable perch sites overlooking hunting sites.
In the Fort Collins area suitable perch sites are typically large cottonwood trees with dead limbs near the
top that permit unobstructed landing and takeoff as well as providing commanding views of suitable
foraging habitat. Large trees along the southern property boundary of the Hansen property provide views
of golf course greens to the west and ponds to the south that attract Canada geese, which in turn, provide
a potential food source for bald eagles, particularly if geese wounded by hunting land in these areas.
Night roost sites are another winter habitat feature for wintering bald eagles, especially during periods of
inclement weather. Night roost sites are typically communal (used by more than one eagle) and usually
provide some level of protection from winter wind and precipitation events.
Previous habitat assessment surveys completed for the Hansen property, as well as casual observations
made by the property owner (Doug Hansen, pers. comm.), indicate bald eagles occasionally perch in one
large cottonwood tree along the Hansen property southern boundary. This tree is apparently used as a
daytime foraging perch site during the winter season. What is not known is whether or not any of the
larger trees surrounding the property are used as night roost sites as well. The purpose of the surveys
completed for this report was to determine if bald eagles or other raptors use any of the trees near on or
near the Hansen property for night roosting purposes.
The property addressed by this report is located in Fort Collins, Colorado in the northeast 1/4 of Section 7
(T. 6 N. R. 68 W.). The property boundaries are defined by the Mail Creek Ditch and Willow Springs
residential development on the north, Timberline Road on the east, an unnamed irrigation ditch on the
south, and existing fencelines and undeveloped land on the west. Large cottonwood trees are supported
along the ditches along the north and south property boundaries. The location of the Hansen Property is
shown on Figure 1.
2
3
2.0 METHODOLOGY
An initial habitat survey was completed for the property on January 19, 2004. This survey documented
bald eagle perching use of one tree along the southern property edge, and subsequent conversations with
the property owner, Doug Hansen, confirmed that bald eagles occasionally used the same diurnal perch
tree through the winter period, particularly during the waterfowl hunting season. Follow-up surveys to
check for possible night-roosting raptor use were completed on a weekly basis (both in the early morning
and early evening hours) from early February through the first week of March 2004. Timing for the raptor
night roost surveys targeted primarily an hour in the early evening (from before sunset to last light). Two
surveys were also completed for an hour in the early morning (starting at first light before sunrise) to
check the possibility of night roosting use by raptors arriving in the area after complete darkness in the
evening.
Each survey included viewing of all the trees surrounding the property and identifying any raptors located
in these trees. Binoculars and a spotting scope were used to aid species identification. Survey emphasis
was placed on searching the large cottonwood trees along the property boundary ditches for perching or
roosting hawks. Surveys were conducted from a vehicle by slowly driving and stopping along the dirt two-
track road located along the northern property edge. Unobstructed views could be obtained of all trees
along both edges of the property from this dirt road. Much of the survey period utilized a single
observation station that provided excellent views of most of the larger cottonwood trees. Locations of the
survey route and the primary observation point are plotted on Figure 2. Raptor observations made on or
near the property were recorded by species, time, location, and specific activity (perching, hunting,
territorial behavior, flyover, etc.).
3.0 RESULTS
Table 1 provides a compilation of all raptor observations recorded for the property during the survey
period. Bald eagle and red-tailed hawk were the only raptor species observed on site. Bald eagles were
observed on three occasions while red-tailed hawk was only recorded on one occasion. Raptor
observations are recorded graphically for each survey visit on Chart 1. Chart 2 portrays the frequency of
the total number of raptor observations for all survey periods. Observations of bald eagle and red-tailed
hawk consisted entirely of these birds perching in at the beginning of the evening survey period. For the
three bald eagle observations, these birds all left their perch site by the end of the survey period. The
single perching red-tailed hawk remained on the property until viewing was obscured by darkness and a
heavy snowstorm. No raptor observations were recorded during the two early morning surveys. The
March 2 bald eagle observation indicated the bird was feeding on an undetermined prey item. No other
behavioral activity, such as hunting or courtship, was noted during survey period.
4
5
Week Date Time Raptors Observed
(# - species) Activity and Comments Weather
2/5/04 4:55-5:50 PM 1-bald eagle
Bald eagle perched in Tree A at start of survey. Remained in
tree until near dark then flew off to southeast. Hundreds of
starlings flocking in and out of perch tree and trees to west.
24° F at start; mostly cloudy; 5-10
mph southeast wind; 4" fresh snow on
ground.
2/6/04 5:00-6:00 PM no observations Hundreds of starlings flocking in and out of perch tree and
trees to west.
28° F at start; clear; 0-3 mph north
wind
2/10/04 5:10-6:05 PM no observations No activity 27° F at start; mostly clear, ~25%
cloud cover; calm
2/12/04 5:15-6:15 PM 1-bald eagle Bald eagle perched in Tree A at start of survey. Remained in
tree until 5:40 PM then flew off to east-southeast.
25° F at start; clear; calm
2/17/04 5:15-6:15 PM no observations Hundreds of starlings flocking in and out of perch tree and
trees to west.
40° F at start; ~25% cloud cover;
calm
2/19/04 6:20-7:20 AM no observations No activity 42° F at start;100% cloud cover; calm
2/24/04 5:15-6:15 PM no observations Hundreds of starlings flocking in and out of perch tree and
trees to west.
45° F at start; ~75% cloud cover;
calm
2/26/04 6:10-7:10 PM no observations No activity 27° F at start; ~75% cloud cover;
calm
3/2/04 5:30-6:30 PM 1-bald eagle
Bald eagle perched in Tree B at start of survey. Eagle
appeared to be feeding on prey item. Remained in tree until
6:10 PM then flew off to the west-northwest.
40° F at start; ~35% cloud cover; 0-3
mph east wind
3/4/04 5:30-6:20 PM 1- red-tailed hawk
Red-tailed hawk perched in Tree A at start of survey.
Snowing heavily with poor visibility. Hawk was likely waiting
out storm and remained in tree for duration of survey.
Survey ended when view of tree was obscured by falling
snow and darkness.
33° F at start; snowing heavily; snow
started ~ 4:30 PM; 1-3 mph northeast
wind
4
5
2
3
1
TABLE 1
Hansen Property Raptor Night Roosting Survey Results - February 5 through March 4, 2004
6
0!
1!
2!
2/5! 2/7! 2/9! 2/11! 2/13! 2/15! 2/17! 2/19! 2/21! 2/23! 2/25! 2/27! 2/29! 3/2! 3/4!
Number of Birds!
Date!
CHART 1!
Number of Raptor Observations Recorded by Survey!
Date on the Hansen Property - February through early March 2004!
Bald eagle!
Red-tailed hawk!
70.0%!
30.0%!
90.0%!
10.0%!
0.0%!
10.0%!
20.0%!
30.0%!
40.0%!
50.0%!
60.0%!
70.0%!
80.0%!
90.0%!
100.0%!
0! 1!
Percent Occurrence!
Number of Individuals!
CHART 2!
Frequency of the Total Number of Individual Raptors!
Observed for All Site Visits - February through Early March 2004!
Bald eagle!
Red-tailed hawk!
7
As indicated in Table 1, all perching birds, except for the March 2 bald eagle observation were in Perch
Tree A (see Figure 2). This tree appears to be the tallest cottonwood on the property, and it has a dead
upper branch that was used consistently for perching. The two bald eagles observed during the initial site
survey on January 19 were also observed in Perch Tree A, and Doug Hansen indicated that the majority
of his incidental observations of bald eagles were located in this tree as well. The March 2 bald eagle
was the only observation recorded in Perch Tree B (see Figure 2). This perch site also appeared to be a
dead limb, but the height of this tree limb is near mid-height of the tree rather than close to the top like the
dead limb used in Perch Tree A.
4.0 CONCLUSIONS
Based on the results of this survey, it does not appear that any of the trees located on or near the Hansen
Property are used as night roost sites by bald eagles or other raptor species. The single observation of a
red-tailed hawk that remained in Perch Tree A until after dark was likely the result of the heavy snowstorm
occurring at the time and did not represent consistent night-roosting use of this tree.