Download Mitigation Recommendations for March Point

PACIFIC INTERNATIONAL ENGINEERING PLLC
TECHNICAL MEMORANDUM
DATE: July 12, 2002
TO: Gene Tanaka, T.Bailey Inc.
FROM: Matthew Boyle, Pacific International Engineering, PLLC
Don Norman, Norman Wildlife Consulting
PROJECT: March Point Fabrication Plant
SUBJECT: March Point Heronry
Introduction
T. Bailey Inc, is proposing to develop a fabrication facility on property leased from the Port of
Anacortes located at South March's Point Road in Anacortes, Washington. Public comment on
the proposed project has identified concerns regarding the effects of facility construction and
operations on the success of a bald eagle nest and great blue heronry occupying the adjacent
property. The Skagit Valley Land Trust owns the adjacent property.
This memorandum was prepared by Pacific International Engineering ad Norman Wildlife
Consulting to address SEPA concerns about the proposed development of the March Point site as
an industrial fabrication facility and the potential impact of noise and development on the heron
colony adjacent to the abandoned gravel pit. Background information on the eagle nest and other
species using the forested area to the south of the proposed site are also addressed.
The purpose of this memorandum is to identify potential effects of the fabrication facility on the
adjacent heronry, and provide mitigation recommendations for facility planning, construction
and operations.
Mitigation and Recommendations
Development of the site should not impact the heronry if performed with the appropriate timing
constraints. Once the herons have initiated incubation, disturbance from construction at the site
is unlikely to cause abandonment, as there is strong site fidelity at the colony. No earth moving
activities on the slope adjacent to the colony should be allowed in February, March and April
when the colony is initiating nesting. Construction of the main building after June 1st should not
interfere with the herons. Construction of the smaller buildings closer to the colony on the
southeast corner and upon the hillside to the west, since they are closer and more visible to the
colony, should be delayed until July 1st.
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July 16, 2002
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Another concern is the noise that will be generated during the fabrication process. The herons
are already significantly adapted to noise from the sawmill adjacent to the colony. Noise
measurements indicate that the average operations noise levels from the new T.Bailey facility
will be below the noise levels from the sawmill.
Lighting is a concern and covered lights pointing away from the forested area to the south should
be installed. Because the forest is well above the ground level, directional lighting should be an
effective mitigation measure.
Design of the building should not allow unmitigated noise escapement towards the forest and
heron colony and eagle nest. Sound dampening insulation and placement of loading facilities
and doorway away from the hillside can effectively dampen loud and abrupt noises.
A 200-ft forested buffer should be retained to between the site and the forest. If the existing
hillside is graded, adequate engineering should be maintained to prevent any slumping accidents.
Skagit County Growth Management Act Critical Area Ordinances
As part of the SEPA review for the proposed T. Bailey project, there are concerns about great
blue herons and bald eagles as Priority Species under the Growth Management Act. Guidelines
were developed by WDFW (1997) to address impacts upon Priority Species. The County and
City of Anacortes have guidelines to address impacts of development on these species and this
report compiles information relation to the heron colony and also relating to potential impacts of
the development upon the colony.
Background Information on the March Point Heron Colony.
The earliest documented visits to the March Point colony were in 1984 (Speich 1992). Eggs
were collected from the colony and some field notes estimated the colony to have 42 nests (S.
Speich, unpublished field notes). Visits from 1992 to 1194 resulted in the tagging of over 100
trees and the documentation of over 192 nests in 1994. The forest containing the eagle nest and
heron colony is a mixed hardwood second growth grand fir forest with a relatively open
understory dominated by nettles, elderberry, and sword fern. The forest also has a large number
of snags and downed trees, providing cavities for wildlife. More detailed monitoring of the
nesting trees was initiated by Skagit Land Trust when they were given a portion of the forest,
approximately 3 acres to help protect the heron colony. The distribution of nesting trees has not
changed in percentage of alder, the dominant nesting tree, but other species vary over time
(Table 1).
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Table 1. March Point Heron Rookery Survey Data
Tag #
201
202
R376
471
472
474
475
476
178
179
414
415
481
457
480
180
486
459
232
181
182
327
326
273
271
214
274
275
482
276
278
279
280
442
443
444
302
183
495
263
200
#Nests
2
2
1
3
2
2
1
1
1
1
2
0
2
1
1
01
1
1
1
1
Species
AlRu
AcMa
AlRu
AlRu
AlRu
AlRu
AlRu
AlRu
Salix
AlRu
AlRu
PsMe
AcMa
AbGr
AbGr
fir
AlRu
AlRu
AlRu
AlRu
DBH(cm)
54
174
Condition
live
live
dGPS pos
02
02
47
live
live
live
live
live
live
live
live
03
28
55
36
26
33.5
65
162
41.5
65
26
39
45
eggshells
2 unhatched
1 unhatched
Notes
GPS at 20ft N, nest on ground, dbl trunk
5 trunks
lots of chick noise
04
05
06
06
07
active
active
Scouler's(?), new tag
2 unhatched
not in colony?
08
live
live
live
live
live
live
09
10
1 unhatched
11
4 hatched
12
13
eggshell fresh
edge, new tag
leaning into another tree
2 fresh eggshells
new tag
gen. bound. shot ~45ft NE of nests
very high density of nests
1
AlRu
33
live
5
AlRu
2
AlRu
1
AlRu
2
AlRu
live
open area on ground
1
PsMe
68
live
14
1
PsMe
nest high up
2
AlRu
40
live
15
nest leaning in tree
1
ThPl
64
live
15
3 hatched
1
PsMe
30
live
16
possible 4th eggshell
1
PsMe
live
4
PsMe
92
live
17
1
PsMe
live
25ft SW of dGPS shot
1
AlRu
live
18
nest on very top of snag
1
PsMe
27
dead
19
1
PsMe
1
Salix
live
5
AcMa
1 nest not active
2
AcMa
76
live
20
1 hatched
eggshell down slope
3
AcMa
125
live
1
AcMa
73
live
21
2
AlRu
41
live
22
AlRu = red alder, PsMe = Douglas fir, ThPl = western red cedar, Salix = willow, AcMa = bigleaf maple, AbGr = grand fir
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The heron colony is unusual because it has a large percentage of its nest in trees other than alder.
While alder (Alnus rubra) is still the dominant nesting tree, a large percentage of the nests
occurred in grand fir (Abies grandis) and big-leaf maple (Acer macrophyllum), with as many
nests as Douglas fir (Pseudotsuga menziesii), western red cedar (Thuja plicata), willow
(probably Scouler's willow, Salix scouleriana), bitter cherry (Prunus emarginata), and a few in
hemlock (Tsuga heterophylla). The distribution of nests in trees is typical with most trees
having 1 or 2 nests: a few trees have a large number of nest As the colony has grown, to its
current 410" nests in over 200 trees, the nesting has not concentrated in the same number of trees
but spread over a larger area. The colony was delineated with dGPS on 23 May 2002 (Figure 1).
There has been a fourfold increase in the number of heron nests at March Point from 1992 to
2001. This increase is one of the largest in the Pacific Northwest, and may be due to the
decrease of the nearby Samish Island colony, 8 miles to the north. Th number of heron nests at
Samish Island in 1998 was 355; while the most recent census indicates less than 150 active nests
remain. This is not an unusual situation, as the primary forage area, Padilla Bay is between the
two colonies and accessible from both colonies. It is possible that there has not been a change in
the foraging areas during the minus tide in early June when both adults are foraging found that
the number of herons parallel the number of active nests (Norman 2001). If this foraging survey
represents the number of herons in the area, the addition of the nesting numbers from both
colonies in 1988 are similar to those for 2001. Productivity measurements that have been
collected at the Samish Island and March Point colonies since 1988 indicate a growing
population, yet there is no indication of an overall nest increase. There has been some evidence
that eagles are affecting the productivity at some heron colonies (Norman et al 1989) but the
more likely cause is increased juvenile mortality after fledging and over winter. This points
more to the lack of upland foraging areas for juveniles (Butler 1995, Norman 1995). The colony
at March Point is growing and using many, if not all, suitable sized trees for nesting. An
assessment of the future available trees in the vicinity has not been conducted.
Disturbance at Colonial Water bird Colonies; Literature Review
The primary focus of this report is the issue of disturbance, the concern that the herons can be
disturbed and abandon their nesting sites. There are differences in sensitivity between herons at
different colonies, as well as differences within a colony over the nesting period. The most
sensitive period during nesting is the early portion of the season, prior to incubation.. Some
colonies associate with fresh water sites may return early in January, others on saltwater may not
return to the colony site until April (Norm 1989). Colonies are typically empty by late summer,
though some locations may have late nesting chicks in the nest until September. There is
evidence that most late nests are less productive (Stabins 2001) and that successfully late-fledged
herons do not have enough time to learn to forage by winter (Butler 1995). The March Point
colony was typical this year in that most of the nests were not incubating until late April.
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Guidelines for the protection of herons from disturbance focus upon the nesting colonies and are
regulated by local Critical Area Ordinances and the Forest Practices Act. The typical reasons for
colony abandonment include excessive and sudden disturbances close to the colony, loss of
buffer, and entrance into the colony especially early in the nesting season.
In the proposed development at March Point, the primary concern is noise. The distance that
heron colonies may be protected vary from 50 to 250 meters (Carney and Sydeman 1999),
though WDFW guidelines recommend between 100 and 300 meters (WDFW 1997). At March
Point, there is already disturbance from the road and industrial noise within this range of
distance. It is important to note that the road and sawmill do not appear to have any effect on
colony success. Additional development should be addressed, however, because of the size and
importance of this heron colony.
A review of disturbance in colonial water bird colonies was recently discussed and rebutted in
published literature (Carney and Sydeman 199, Nisbet 200, Carney and Sydeman 2000). Of
concern in the proposed in the proposed industrial development is the effect of sporadic noise
related to metals fabrication. The articles referring to noise were related to helicopter and
aircraft noise, which tended to be sporadic and unlikely to cause disturbance if the birds were not
directly threatened by close passes. These papers also did not typically determine the level of
the noise . Nisbet did not address the issues of adjacent site disturbances and no papers were
found that addressed the cumulative impact of noise. E-mail was sent to Ian Nisbet and Bill
Sydeman at Point Reyes Bird Observatory, among others, to see if they were aware of any noise
was specifically measured. No one was aware of any specific studies.
One of the most controversial aspects of disturbance is measuring the actual outcome of the
disturbance. Nisbet (2000) criticized earlier literature reviews because they did not address
different levels of responses of disturbance. Nisbet proposed an increasing scale of effects.
1.
2.
3.
4.
5.
6.
7.
8.
Physiological effects without any visible impacts in behavior.
Moving or flying off the nest but returning after the disturbance ended.
Desertion of the nest.
Abandonment of the colony site by some or all of the birds.
Reduction in hatching success, death of individual chicks
Reduction in breeding success (requires measurement of productivity and statistical documentation of reduction),
typically with a reference colony
Death of adults as a result of disturbance
Reduction in populations (local, regional, or local).
Few studies have addressed any of the values above #4, and Nisbet provided cases where
alternative nesting did not result in any loss of lifetime reproductive success, as many colonial
water birds typically face disturbance that causes relocation of nesting area. Two factors in the
Pacific Northwest appear to have differing impacts on disturbance. These are bald eagle
predation and acclimation to human disturbance. Bald eagles appear to have increased their
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predation at heron colonies over the past 20 years, and may be a factor in colony abandonment.
Brood reduction in herons may allow from as many as 2 chicks to be removed by eagles without
affecting the regional fledging average. The increase in the bald eagle population has also
increased heron predation and a recent assessment has also show that incursions into colonies are
occurring earlier in the year with eagles eating eggs.
Herons have also moved closed to human activities, typically where there are barriers to prevent
access to the nesting trees, i.e. swamps, ravines, or fences. A recent survey of heron nests in
King County found many colonies with human activity within 50 feet of the nesting trees
(Stabins 2001). Herons nest near the runway at Ault Field at Whidbey Naval Air Station, and
are able to tolerate excessive noise. Though no detailed productivity measurements have been
made or compared to other locations, as Nisbet requires, that colony appears to be growing.
Types of Disturbance at the Proposed Facility
Disturbance is an important concern at the proposed site. While herons appear to be acclimated
to the sawmill at March Point, site development will produce additional noise close to the
colony. This noise may be sporadic in nature. The increase in traffic may create additional
disturbance in the colony, as more individuals maybe be interested in entering the colony.
Previous surveys in the colony were conducted in 1993 and 1994. In review of field notes
(DMN Unpublished Field Notes), there was an indication of disturbance, typically flush and
return, but in may instances adults remained in the nest in incubation posture as long as no
snapping noises were produced by branches breaking.
In 1993, a study was conducted to determine if the sawmill east of the proposed site was causing
some disturbance at the March Point colony (Norman 2001b). Specific observations of herons
just prior and after the starting up of the mill in the morning and after shut down in the early
evening were made to see of herons moved away from the noise during their flights to and from
Padilla Bay. The observations, which totaled 18 hours, found no difference in the percentage of
flyovers between periods when the mill was in operation and when it was closed.
More important than the accumulated observations were the direct individual observations of
herons that occurred just before or after the mill started up or shut down. These observations
showed no sudden veering away or move off the arrival or departure line. Since it was often
possible to view a heron arriving from a great distance, it was also clearly observed that herons
did not alter their course to the nest unless there were strong winds. While this information does
not rule out impacts of the noise, it does indicate that there is no visible change in behavior
(Norman 2001b).
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Assessment of Noise Measurements at the March Point Heron Colony.
In early April 2002, a noise study was conducted to measure background noise levels at the
current T. Bailey facility as well as at the northern end of the heron colony. The average sound
at the T. Bailey facility was 62 decibels (dBA) over a 20-hour period, (range 44.2 - 94.3). The
mean ambient noise measurement of 56 dBA was given for a three-hour daytime measurement at
the edge of the heron colony, when the sawmill was in operation (range 45.2 - 84.2). The
conclusions of the Prezant study were that the diminution of the average level of T. Bailey plant
noise over the space from the proposed plant site to the edge of the heron colony would be well
below the existing ambient noise from the sawmill. The reduction in noise is due to the distance
of the proposed facility, which is approximately 700 feet from the northern edge of the colony.
A heron colony at the Whidbey Island Naval Air Station (Ault Field) has been located there for
15 years, growing from a small colony to one well over 1000 nests (Matt Klope, NAS, personal
communication, 2001). The colony is well located within the 75dBA modeled noise contours of
the noise from Navy fighter-bombers landing within 4000 feet of the colony. It is apparent the
herons can withstand sudden noise without affect on productivity. Assuming that the average
peak noises at the T. Bailey site and at the sawmill are also under 75 dBA, it is unlikely that the
noise will affect the colony.
The site proposed for development has been largely unused for the past 10 years. During the
summer and fall of 2001, it was used as a staging yard for sewer line construction beneath South
March's Point Road, but was otherwise been abandoned. A red alder forest has grown on the
upper portions of the sited adjacent to the heron colony and grasses are thick on the slope. Field
notes from 1993 indicate that rough-wing swallows were observed at the site, potentially nesting
on the sandy banks, but these banks are not available now.
In addition to great blue herons and eagle, it is likely that band-tailed pigeons and pileated
woodpeckers, two additional Washington State Priority species, use the forest adjacent to the
proposed gravel pit site. Though no band-tailed pigeons have been observed at the site, they use
mixed coniferous forest and also eat elderberries, which are common on the site (Jarvis and
Passmore 1992). Evidence of pileated woodpecker drill holes on trees was observed on several
field trips into the heron colony but no sightings were made indicating nesting (Don Norman,
unpublished field notes). A compilation of upland species likely to be using the site was
compiled using information from the Breeding Bird Atlas and habitat assessment (see Norman
2001a). It is unlikely that these species will be affected by the site development.
Discussion
Concern about the overall development of the site, and a plan to ensure continuing success of the
heron colony will require a coordinated effort by the Land Trust and property owners. Retention
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of the trees on top of the slope at the south end of the T. Bailey property will help buffer the site.
It is not clear how long the eagle nest tree will last, as it is dead and exhibits insect infestation. It
is not clear whether herons are avoiding nesting close to the eagle nest or not. No eagle
predation of herons has been documented in the many hours of observation there. Since herons
are observed to use the windbreak at the top of the forest to the west and north of the colony
especially upon arrival from the foraging areas, protection of the trees above the slope would
retain that windscreen.
Additional types of disturbance at the colony include increased visitation into the colony,
lighting effects and future development closer to the colony. Increased traffic at the site could
result in increased trespass unless signage is posted.. Well publicized activities, including tours
into the colony at the end of the season and outside the nesting season also provide persons
interested in seeing the birds up close an opportunity without increasing random disturbance,
which is more likely to result in disturbance.
The proposed site grading is substantial and should be restricted between February 1 and May 1.
Herons may still be present in the colony after June 1; therefore, construction traffic should be
routed to the west from the site through July. While there is already sawmill related traffic on
South March's Point Rd (below the colony), the large increase in traffic below the site could
disturb feeding juvenile herons.
Lighting is also a concern. Since the site is much lower than the forested area to the south and
west, directional downward lighting with covers will effectively prevent light spread to the
south.
Future buildings on the site, specifically near the top of the hill should be carefully planned with
the same timing restrictions as noted above. Retaining as much of the buffer to the south will
protect herons from seeing movements at these structures. Since the road to the proposed office
is below the grade of the heronry, disturbance from road use should be minimal.
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References
Butler, R. W. 1995. The Patient Predator. Canadian Wildlife Service Monograph.
Carney, K. M. and W. J. Sydeman. 1999. A Review of Human Disturbance Effects on Nesting
Colonial Waterbirds. Waterbirds 22: 68-79.
Carney, K. M. and W. J. Sydeman. 2000. Response: Disturbance, Habituation, and Management
of Waterbirds. Waterbirds 23: 333-334.
Jarvis, R. L. amd M. F. Passmore. 1992. Ecology of band-tailed pigeons in Oregon. US Dept
of the Interior, USFWS Biol. Report 6, Wash, DC.
Nisbet, I. C. T. 2000. Disturbance, habituation, and management of waterbird colonies.
Waterbirds 23. 312-332
Norman, D. 2001b. The Big Sit. Monitoring Great Blue Heron Foraging Sites Everett to Point
Roberts June 2001. A Cooperative Project between WDFW PSAMP and NWC funded by
WDFW ALEA and PSAT. December 2001, Shoreline, WA.
Norman, D. M. 1995. The status of great blue herons in Puget sound: Population Dynamics and
Recruitment Hypotheses. Puget Sound Research 95, Bellevue, WA. pp 638-642.
Norman, D.M. 2001a. Assessment of Proposed Development Impacts upon Wildlife at the
Lockview Nursing Home in North Magnolia, Seattle. Report to Heartland, Seattle, WA.
Norman, D. M., I. Moul, and A. Breault. 1989. Bald eagle incursions and predation in great blue
heron colonies. Colonial Waterbirds. 12: 215-217.
Speich, S.M., J. Calambokidis, D. W. Shea, J. Heard, M. Witter, and M. D. Fry. 1992. Eggshell
thinning and organochloorine contaminants in western Washington waterbirds. Colonial
Waterbirds 15: 103-112.
Stabins, A. 2001. Great Blue Herons in King County, Washington. MS Thesis, University of
Washington, Seattle, WA 76pp.
WDFW. 1997. Priority Habitats and Species. Management Recommendations for
Washington's Priority Species, Volume IV. Great Blue Heron.
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