HomeMy WebLinkAbout3184; CANNON ROAD WEST; LIGHT-FOOTED CLAPPER RAIL ISSUES; 1999-09-20I
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!EEE\ Merkel &, Associates, In c.
3944 Murphy Canyon Road Suite 006 • San Diego CA 92123
Ph (619) 560 5465 • Fax (619)-560o7779.-
E-mail Merkel1ncaol corn
September 20,-.1999
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Ms Julie Vandeweir
U. S. Fish and Wildlife Service -'Carlsbad Fish and Wildlife Office . . . . .. . . .
2730 Loker. Avenue West
Carlsbad, California 92008
Re Light-footed Clapper Rail Issues at the Cannon Road / Kelly Ranch Site
Dear Julie,
The following Letter is a summary, of observations and relevant information on the light-footed
clapper rail as it relates to proposed construction activities at the Cannon Road/Kelly Ranch site in
Carlsbad Based on a review of the information available regarding the clapper rail occurrence and
the project construction activities, we believe that the proposed continuation of construction of
Cannon Road, as designed and proposed for implementation, would not result in:a significant adverse
effect on this species The following portions of this letter summarize what is known about clapper
rail bolcigy and occurrence within Agua Hedionda Lagoon, as well as the pertinent elements we
believe support our best professional judgement on this issue
CLAPPER RAIL BACKGROUND INFORMATION
Biology
The light-footed clapper rail (Rallus longirostris levipes) is predominantly it. resident of coastal salt
marshes in southern California and Baja California Norte It is the only clapper rail in southern
California Historically, the range of the light-footed clapper rail extended from Carpinteria Marsh in
Santa Barbara County, California, south to San Quentin, Baja California Norte Many marshes,
including the Carpinteria Marsh, have ceased to suppo rail populations, and the species' current
distribution is restricted to small, isolated sub-population
. s (Zembal 1992) The spnng counts in'! 997
revealed 307 pairs of rails in 16 marshes in California Of this total, 49'.5% were in one marsh,
Upper Newport Bay, Orange County, California (Zembal, unpublished data, 1997) In San Diego
County, Tijuaria Marsh National Wildlife Refuge has usually had the greatest numbers of mated pairs
since censuses began in 1980 (Zembal and Massey 1988)
The light-footed clapper rail has been listed as an endangered subspecies since 1973 Its population
decline is mostly due to a dramatic loss of coastal wetland habitat in southern California over the last
few decades Of an estimated 26,000 acres of coastal wetlands once present in southern California,
fewer than 8,500 acres remains (Speth 1971, from Zembal 1992) Recently, rails have been found in
less than half othis potential, habitat.. Marshes that are occupied by rails generally ha low
population densities (Zembal 192)
The defining feature of good clapper rail habitat Is the presence of dense cord grass (Spartinafoliosa)
(Unitt 1984) This salt-tolerant grass grows 60-150 cm tall, in salt marshes, mudflats and along
shorelines This cordgrass is tolerant of regular saltwater inundation, and occurs most often below
Biological Consulting • Environmental Permitting • Habitat Restoration • Ecological Management
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Light-footed'Clapper Rail Issues at cannon Road/Kelly Ranch Site September 20,1999
the mean higher high water line (Merkel 1997).. Rails observed in- the Tijuana Marsh spent most'of
their time in lower salt marsh habitat, particularly in cordgrass if it was available When water
covered the tower marsh, rails foraged on higher ground in low to mid-marsh habitats of pickleweed
Salicorniá virginica, saitwort, (Batis maritima), and jaumea Vaumea' carnosal, and on floating mats
of reeds.: Reed,patches including cattails and buliush,were also extensively used for roosting and
sunning during high tides. When' these were not available, most rails roosted in the upland fringe of
the marsh during the highest.tides (Zembal et. a!: 1989).. .. . '
Rails nest preferentially in•• cordgrass in 'the lower salt marsh. Where or when cordgrass is not
available, the birds still nest preferentially in low marsh, using tide-deposited materials as nesting
cover. Nests"are also built in -common pickleweed and other upper salt marsh plants on hummocks of
high ground 'surrounded. by low marsh (Massey et.. a!'. 1984). Clapper rails are also 'observçdin'
freshwater and brackish marsh habitat. 'Examples of freshwater marsh known to support clapper rails
include the lower Sweetwiter. River (just east'of south San Diego Bay), at GuajOme Regional Park.
as well 'as a clapper rail pair consistently, found at Agua Hedionda,- at a 'location to the northwest
(along Park Drive) and well, distanced from the construction activities of Cannon Road. In these
instances where clapper rails are known to occupy dense (cattail/bulrush) freshwater marsh, these
habitats are typically quite extensive. " ' •,' ' ' . ,'.' S . ,
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Uritt' (1984) reports egg dates from March 6 to May 23; hOwever, Jorgenson obseved active-pests
with eggs as late as July 15 in the Tijuana River estuary (in Unitt 1984) Zeiner et a! (1990) report
thatciappér rails in San,Francisco ,Bay breed from mid-March through July, with peaks observed in
early May and late June.. Incubation* is reported 'tO be 20-23 'days in Ehrlich et a! (1988) and from 18-
29 days in Zeiner et a! (1990)..Hatchlrng rails are covered in black down and are able to follow
along after the adults in the marsh within a 'few hours' Of hathing. The young rails are dependent on
the adults for several weeks and are still being fed occasionally up to at least 6 weeks of age (Zembal
1989).
Inter-marsh movements by adult rails are rare. Within-marsh movements are small., usually of, no
greater distance than 400 m. Mature rails with established 'territories have very small home ranges.
Two banded adults, one male and one female, were observed no more than 70 in from their capture
site over a period of a year and a half. This female's home range was approximatOly 0.5 hi (1.2
acres), and she maintained this home range with three different 'mates Young rails trayel larger
distances, sometimes- leaving the marsh'of their birth when chased away by mature,. established 'rails,
The longest movements by immature rails are 'in late' summer and fall, and 'the longest 'of these ever
recorded 'was 21.7' km. However, if there is room, 'there is a strong. tendency for young rails to
establish home ranges near their natal territories, and to'remain.there once.established (Zembal 'etal.
1989; Zembal and Massey 1988).
clapper Rail Status at Agua Hedionda Lagoon ' ' .' ' .• . '
One pair of light-footed clapper rail's occupied the cattail marsh east of the open water of the lagoon
in 1997 (Zembal '1997, unpublished data). Since censusing of rail' p9pulations began in 1980, the
Agua Hedionda Lagoon rail population peaked at 7 pairs in'1983, but- dropped off to 'zero pairs in the
late 1980s and early 1990s (Zembal 1992, Zembal etal. 1.996). The reoccupation' of this marsh by
one pair may 'result in the re-expansion of this subpopulatiOn; The Agua Hedionda raila were
detected in the cattail 'marsh, which currently covers 24, acres' in' the area 'east of the 'lagoon..
Assuming the home ranges reported by Zembal (1989) to be comparablefor the habitat available
within Agua' Hedionda Lagoon, and an equal suitability of 'all cat-tail habitat at the lagOon,, an
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Light-footed Clapper Rail Issues at Cannon Road/Kelly Ranch Site. . S September'20, 1999
estimated carrying capacity of the, system would be approximateLy 20 pairs of rails. This capacity
has not ever been approached' in the 17 years of monitoring this species.. The highest reported
'density 'for Agua HediOnda Lagoon was during' 1983 and 1984.when 7 and 6 pairs, respectively, were
recorded. While it is not believed-that the cattail marsh'within Agua HediOnda LagOon serves as
optimal nesting habitat,' this assessment would suggest that available cattail marsh habitat is not
presently. limiting rail populations in this system.
The single pair of light-footed clapper rails (Rallus longirostri.s levipe.$) present within the lagoon
during the 1997 survey (Zèrnbal, unpublished data) occupies 'cattail'habitát located at the' ouffall of an
urban drain on the north side of .the lagoon. Whi1e recent pros surveys have not, detected' pair.s in
Agua Hedionda Lagoon Since 1985, clapper rails' were present 'at, this location' during the late 198OS'
and early 1990s and were' detected intermittently from approximately 1988 through 1992 (K; Merkel,
pers. obs;).
1999 Clapper Rail Status At Cannon Road
Habitat occupied by light-footed clapper rails at the Cannon Road site consists of dense freshwater
marsh comprised of cattails (Typha spp.) and bulrush (Scirpi&s spp.). Habitat quality may. be
somewhat reduced by its particularly narrow configuration supported in part by an artificial berm on
the south side of the drainage On the north side, the marsh habitat is bordered by high quality
willow riparian woodland To the south, it is flanked by disturbed, ruderal fields and non-native
grasslands.
Light-footed clapper rails have had an inconsistent record of occurrence, or at least detection, at the
Cannon Road location. The -species- was initially identified in May 1999. Several 'sightings and/or
vocalizations were recorded over the* course of the next several weeks. The clapper rail, was then -not
detected for 2-3 months, until it was again sighted on August 21,1999. It has not been detected since
the August21 date. During recent surveys'and a prior survey' in this area by M&A biologist, David.
Mayer, a Virginia rail (Rallus.lirnicola'limicolq was identified in the same location as 'that where the
clapper rail has been' previously. identified. The Virginia rail, which emerged from the vegetation,
was noted. by Leo Todd, Shea Homes, constuction representative, tube significantly smaller than the
rail 'which has been observed in this area in the past. Furthermore, clapper rails were clearly detected
by qualified biologists earlier in the season (.LFancher, USFWS',.pers. comm.).
The breeding status of the detected rail is uncertain. No more than one rail has been detected. at any
given time, 'and there have been no recorded incidence of courtship vocalizations throughout 1999,
(i.e., 'duet calls'); hOwever, the aggressive behavior observed in* May 1999, during which periods, a,
rail emerged from'the vegetation in response to calls, was believed to be indicative of potential
nesting (Doug Gettiriger, 'Ogden, personal. communication). 'Conversely, although rails would. be
expected to be less vocal, during periods of incubatiOn, the comp1ete'.absnce of detection between
late June through August seems unusual if a pair was in fact,resident at -this 'location. Additionally,
there were no 'observations of adult rails being followed by 'either young fledglings or dependent
'juveniles at any period during the past several months. ' '. . • : '
No nest searches were made of the cattail marsh in which a rail has been observed. While this can be
done in some habitats, searching for a nçst in dense freshwater marsh vegetation would be' difficult
and destructive to this limited habitat. Moreover, because of the low potential for observing .a nest
and high' potential for an adverse impact in the event that. an active nest occurs, such a nest search is
not advisable. ' ' S ' 'S • '
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Light-footed Clapper Rail issues at Cannon Road / Kelly Ranch Site ', '.September 20, 1999
While, it is not possible to determine with certainty whether a breeding pair exists at this site, or
whether nesting was performed during 1999;. it is likely that either no nest was ever constructed and
the bird was an individual attempting to establish a territory and attract a mate, or a nest was
established and failed and renesting was not attempted Either of these circumstances could explain
the intermittent survey findings and long period of non-detectkin. Based on conversations regarding
the circumstances at this site, Jack Fancher has suggested that it would not be surprising to make
intermittent observations of an individual at this site if regular censusing was performed. He'pqints
out that the narrow fringing marsh serves .as a connector that links habitats' in this extensive wetland.
The area in which the rail has been observed is an ideal travel corridor, albeit not ideal breeding
habitat.
PROJECT CONSTRUCTION STATUS '1 ''. ': •. . .
At present, no additional direct impact is' 'expected to 'occur to marsh 'habitat at thó location of the
previous clapper rail sightings. 'The remaining construction activities to' be completed in proximity to
the locatiOn in which the rail was observed involve sewer and roadway improvements located
approximately 50 feet, or greater frOm the, edge of the marsh. No direct impacts, 'are anticipaied to
wetlands in this vicinity.
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DIscussioN.
The primary issue of concern' is that of a potential for..indirect effects in the form of noise and
proximity disturbance on breeding activities of clapper rails. The clapper rail's inconsistent detection
in the late spring and- summer is puzzling. While. the aggressive behavior exhibited 'by,a bird earlier
in the year maybe indicative 'of breeding, there have' not been any. indications of two birds being
present and the limited late season occurrences have not been suggçstive of breeding activities.' In
light of the very narrow nature of the freshwater marsh, the habitat is believed to be of relatively'
marginal suitability :for nesting by' this species; however, it is reasonable to expect 'that any clapper.
'rails that occur at the 'lagoon, even on a temporary basis (including periods of dispersal), 'would
occasionally utilize the habitat at the Cannon Road site.
The potential for clapper rails to be incubating'a: nest, at this time (late-September).is believed to. be
very low.. Even assuming' the latest recorded egg dates were early in the incubation period, any
nesting activity would. be expected to, be completed' by early. September. While an active nest would
be very unexpected, it is possible that any adult rails, if pTesent, could still be caring for dependent
young. However, clapper rail young are extremely precocious and may follow adults within ,a few
hours' of hatching 'While. observations in,other systems indicate that 'adults. may" feed dependent
young for .at least six weeks, ,the 'young are mobile and follow the adults through the marshes. and
may move to alternative day nests away from the natal' nesta.
Noise .and diturbance are known to adversely affect some species' breeding behavior by causing site'
abandonment. There is also some si:ggestion that.noise may adversely impact some communication'
between birds or 'impact a bird's ability to detect predators' or prey. However, there are no relevant
observations or published literature identified for this species, thus a definitive statement regarding
the clapper' rail's relative tolerance or intolerance to noise is not possible. "However, assuming
observations from other species' are applicable, 'it has been noted that noise impacts are much more
likely to be, detrimental in the 'initial stages of breeding, such as territory' establishment, nest,
construction, or immediately following egg' laying. Adult birds are much less likely .to abandon
nestlings or dependent flOdges when significant investment has been made in the offspring.. . In
addition, the opportunity 'to relocate with young further reduces the potential for adverse noise
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Light-footed Clapper Rail Issues.at Cannon Road/ Kelly Ranch Site . September 20. 1999
impacts in the event that a pair of rails does occur adjacent to Cannon Road and did successfully nest
in. 1999, and. still, maintains dependent young. . . . . .
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CONCLUSIONS . .. '. . . . .. . . . :.. . :
If a take were to occur to clapper rails as. a' result of continuing construction of Cannon Road at the
present time, the w take ould be in the form of "harassment". Under the Endangered Species Act,
harass means an.-intentional or negligent act or-omission which creates the likelihood of injury .to
wildlife by annoying It to such an extent as to significantly disrupt normal behavior patterns which
include, but are not limited to, breeding, feeding, or sheltering (50CFR 17.3). In..the current
circumstances, the principal concern is that construction in areas near • clapper rail habitat and
associated noise and activities may harass clapper rails to the extent that significant disruption of
normal breeding behavior occurs. . . . . . . . . . . . . . .
Despite relatively frequent observations, of the habitat being made by a qualified biological.observer,.
it is still unknown if: 1) apair of rails exists at the subject site; 2)if a pair does exist, that breeding
activities were ever initiated, 3) if breeding activities were successful in hatching eggs and if
hatching occurred at the latest possible time of the breeding season, 4) if viable young were produced
and 'Continue-to persist under the dependence of adult birds, 5) if adults and young remain at or near
the natal nest; and 6) if noise at late stages of breeding,.-.or any stage. of breeding. activity, has an.
adverse effect on clapper rails For harassment under the ESA to occur, all of these outstanding
questions must be answered affirmatively Absent any supporting evidence that a pair of birds exists
or that y outig 'Were produced, there is. little to support a reasoned determination that nesting activities
occur at: the Cannon Road site at the present time, 'although one cannot rule-Out the potential that.
early nesting did occur. As a result, it is out judgement that the proposed construction at this time
would not result in a significant adverse affect on the clapper rail
Please review this letter. and let me know what your thoughts are on the subjecL I understand that the
City and developer for Cannon 'Road 'are anxious to completethe work as soon as possible to avoid
significant prOblems during the rainy season. If you have .an' additional'.questions regarding-'this
letter, please call ma. '
1•1
Cc Jack Fancher, USFWS
Sherri Howard, City of Carlsbad
Russ Haley,' Shea Homes
Greg Poñce, Shea Homes
Dale Greenhaigh, Consultant to 'Shea Homes
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Light-footed Clapper Rail Issues at Cannon Road / Kelly.Ranch Site September 20, 1999 ..
LITERATURE CITED
Ehrlich, P.R.; D.S. Dbbkin, and D. Wheye. 1988. A Field Guide to the Naturüi History of North
American Birds.. Simon and Schuster, Inc. ...
Massey et a! 1984 Referenced in letter to Keith Takata
Merkel, K. 1997. Predicted Habitat Effects of Tidal Prism Enhancement Within the Inner Agua
Hedionda Lagoon..
Speth, J.W. .1971:. The status.of coastal wetlands in southern California. Cal-Neva Wildlife, Western
Section Wildlife Society Transactions: 51-59. • . .
Unitt, P 1984 The Birds of San Diego County. San Diego Society of Natural History, Memoir 13
276 pp
Zerner, D C, W F Laudenslayer, K E Mayer, and M White, 1990 California's Wildlife, Volume
Birds California Department of Fish & Game November 1990
Zembal, R 1989 Referenced in letter to Keith Takata
Zembat, R 1992 Status and management of light-footed clapper rails in coastal southern
California. . Transactions-of the Western Section of the. Wildlife S66ety28:1-5. .. .• . :•;, . Zembal R and B W Massey. 1988 Light-footed clapper rail census and study 1988
UnpubLshed Report.
Zembal, R, B W Massey, and J. M Fancher. 1989 Movements and activity patterns of the light-
footid clapper rail. Journal of Wildlife Management 53(1);3942. 0 ••
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