Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Ashy Storm-Petrel as Threatened or Endangered, 41832-41860 [E9-19700]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 159 (Wednesday, August 19, 2009)]
[Proposed Rules]
[Pages 41832-41860]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-19700]


=======================================================================
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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2008-0049;1111 FY08 MO-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Ashy Storm-Petrel as Threatened or Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the ashy storm-petrel 
(Oceanodroma homochroa) as threatened or endangered, under the 
Endangered Species Act of 1973, as amended (Act). After a thorough 
review of all available scientific and commercial information, we find 
that listing the ashy storm-petrel is not warranted. We ask the public 
to continue to submit to us any new information concerning the status 
of, and threats to, this species. This information will help us to 
monitor and encourage the conservation of this species.

DATES: The finding announced in the document was made on August 19, 
2009.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov and https://www.fws.gov/arcata/. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Arcata Fish and Wildlife Office, 1655 
Heindon Road, Arcata, CA 95521; telephone 707-822-7201; facsimile 707-
822-8411. Please submit any new information, materials, comments, or 
questions concerning this finding to the above address.

FOR FURTHER INFORMATION CONTACT: Randy Brown, (Acting) Field

[[Page 41833]]

Supervisor, U.S. Fish and Wildlife Service, Arcata Fish and Wildlife 
Office (see ADDRESSES section). If you use a telecommunications device 
for the deaf (TDD), call the Federal Information Relay Service (FIRS) 
at 1-800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition to revise the Lists of Endangered and Threatened 
Wildlife and Plants that contains substantial scientific and commercial 
information that listing may be warranted, we make a finding within 12 
months of the date of our receipt of the petition on whether the 
petitioned action is: (a) Not warranted, (b) warranted, or (c) 
warranted, but the immediate proposal of a regulation implementing the 
petitioned action is precluded by other pending proposals to determine 
whether any species is threatened or endangered, and expeditious 
progress is being made to add or remove qualified species from the 
Lists of Endangered and Threatened Wildlife and Plants. Such 12-month 
findings are to be published promptly in the Federal Register. Section 
4(b)(3)(C) of the Act requires that we treat a petition for which the 
requested action is found to be warranted but precluded as though 
resubmitted on the date of such finding, and we must make a subsequent 
finding within 12 months.

Previous Federal Actions

    On October 16, 2007, we received a petition, dated October 15, 
2007, from the Center for Biological Diversity (CBD or petitioner), 
requesting that we list the ashy storm-petrel as a threatened or 
endangered species throughout its range and that we concurrently 
designate critical habitat (CBD 2007, pp. 1-51). In response to the 
petition, we sent a letter to the petitioner dated January 11, 2008, 
stating that we had secured funding and that we anticipated making an 
initial finding as to whether the petition contained substantial 
information indicating listing the ashy storm-petrel may be warranted 
in Fiscal Year 2008. We also concluded in our January 11, 2008, letter 
that emergency listing of the ashy storm-petrel was not warranted. On 
May 15, 2008, we published a 90-day petition finding (73 FR 28080) in 
which we concluded that the petition provided substantial information 
indicating that listing of the ashy storm-petrel may be warranted, and 
we initiated a status review. This notice constitutes the 12-month 
finding on the petition, dated October 15, 2007, to list the ashy 
storm-petrel as threatened or endangered.

Species Description

    The ashy storm-petrel is a seabird species belonging to the order 
Procellariiformes, family Hydrobatidae. The ashy storm-petrel is one of 
five storm-petrel species (including fork-tailed (Oceanodroma furcata), 
Leach's (O. leucorhoa), black (O. melania), and least (O. microsoma) 
storm-petrels) that nest on islands along the west coast of North 
America (Harrison 1983, pp. 272-278). The ashy storm-petrel is a smoke-
gray, medium-sized bird with long slender wings, a long forked tail, 
and webbed feet (Ainley 1995, p. 2).
    Ashy storm-petrels have been confirmed to breed at 26 locations (on 
islands and offshore rocks) from Mendocino County, California, south to 
Todos Santos Islands, west of Ensenada, Baja California, Mexico (Carter 
et al. 1992, pp. 77-81; Ainley 1995, p. 2; Carter et al. 2006, p. 6; 
Carter et al. 2008a, p. 118). Greater than 95 percent of the species 
breeds in two population centers at the Farallon Islands and in the 
California Channel Islands (Sowls et al. 1980, p. 24; Ainley et al. 
1990, p. 135; Carter et al. 1992, p. 86). Anacapa, San Miguel, Santa 
Cruz, Santa Rosa, San Clemente, San Nicholas, Santa Barbara, and Santa 
Catalina islands comprise the Channel Islands.
    Ashy storm-petrels occur at their breeding colonies nearly year-
round and occur in greater numbers from February through October 
(Ainley 1995, p. 5). Like other procellariids, ashy storm-petrels are 
highly philopatric; that is, birds usually return in consecutive years 
to the same breeding site or colony from which they were raised as 
chicks (James-Veitch 1970, p. 81; Warham 1990, p. 12). Ashy storm-
petrels do not excavate burrows; rather, they nest in crevices of talus 
slopes, rock walls, sea caves, cliffs, and driftwood (James-Veitch 
1970, pp. 87-88; Ainley et al. 1990, p. 147; McIver 2002, p. 1). The 
breeding season is protracted, and breeding activities (courtship, egg-
laying, chick-rearing) at nesting locations occur from February through 
January of the following year (James-Veitch 1970, p. 71, Ainley et al. 
1974, p. 301). During the pre-egg period, adult ashy storm-petrels 
begin to visit nesting sites in February (Ainley et al. 1974, p. 301; 
Ainley 1995, p. 5). Throughout the fledging period, the number of 
visiting adults declines (Ainley et al. 1974, p. 301). At Southeast 
Farallon Island, Ainley et al. (1974, p. 301) reported that immature 
(non-breeding) ashy storm-petrels visited the island from April through 
early July. The egg-laying period extends from late April to October, 
peaking in June and July (James-Veitch 1970, p. 243; Ainley et al. 
1990, p. 148; McIver 2002, p. 17). Clutch size is one egg per year, and 
parents alternate incubation bouts during a 44-day incubation period 
(James-Veitch 1970, p. 244; Ainley 1995, p. 6). Less than about 4 
percent of all eggs laid are replacement (or re-lay) eggs, laid after 
the failure of a first egg (Ainley et al. 1990, p. 148; McIver 2002, p. 
18). Hatchlings are ``semi-precocial'' (James-Veitch 1970, p. 128). The 
term semi-precocial describes young that have characteristics of 
precocial young at hatching (open eyes, downy, capacity to leave the 
nest), but that remain at the nest and are cared for by parents until 
close to adult size (Sibley 2001, p. 573). Once hatched, the nestling 
is brooded for about 5 days, after which it remains alone in the nest 
site for an additional 75 to 85 days (James-Veitch 1970, pp. 141, 212; 
Ainley et al. 1990, p. 152). It is fed irregularly (1 to 3 nights on 
average) during brief, nocturnal visits by its parents from feeding 
areas at sea (James-Veitch 1970, pp. 180-208). Fledging occurs at 
night, from late August to January, and once they leave the nest, 
fledglings are independent of their parents (Ainley et al. 1974, p. 
303; McIver 2002, p. 36). Peak fledging occurs in early to mid-October 
(McIver 2002, p. 18).
    The nocturnal activity (return to and departure from nest) and 
crevice nesting of the ashy storm-petrel are believed to be adaptations 
to avoid predation by diurnal predators, such as western gulls (Larus 
occidentalis), peregrine falcons (Falco peregrinus), and common ravens 
(Corvus corax) (Ainley 1995, p. 5; McIver and Carter 2006, p. 3). Ashy 
storm-petrels are susceptible to predation at night by burrowing owls 
(Athene cunicularia) and barn owls (Tyto alba) (Ainley 1995, p. 5; 
McIver 2002, p. 30). Nesting in crevices and burrows on remote 
headlands, offshore rocks, and islands generally reduces predation of 
storm-petrels by mammalian predators (Warham 1990, p. 13). Known 
mammalian predators of ashy storm-petrels and their eggs include house 
mice (Mus musculus), deer mice (Peromyscus maniculatus), and island 
spotted skunks (Spilogale gracilis amphiala) (Ainley et al. 1990, p. 
146; McIver 2002, pp. 40-41; McIver and Carter 2006, p. 3).
    Obtaining direct population counts of ashy storm-petrels is 
difficult because the species often nests in deep, inaccessible 
crevices (Carter et al. 1992, p. 77; Sydeman et al. 1998a, p. 438). 
Techniques for estimating population size at breeding locations have 
included counting crevices and applying correction factors to account 
for burrow

[[Page 41834]]

occupancy, mark and recapture using mist nests, and direct observation 
of nest sites. Estimates of breeding ashy storm-petrels for California 
have ranged from 5,187 (Sowls et al. 1980, p. 25) to 7,209 (Carter et 
al. 1992, p. I-87). Additional colony sites and larger ashy storm-
petrel numbers have been found at several locations in the Channel 
Islands and along the mainland coast of California (Carter et al. 
2008a, p. 119). Table 1 provides various estimates of numbers of 
breeding ashy storm-petrels at 26 locations in California and Baja 
California Norte, Mexico.

 Table 1. Estimates of Numbers of Breeding Ashy Storm-Petrels at 26 locations in California (United States) and
                                         Baja California Norte (Mexico).
----------------------------------------------------------------------------------------------------------------
                                                                                                  Source for
                                       Location          Ownership or        Estimated No.      Breeding Birds
                                                         Management\a\      Breeding Birds       Estimates\b\
----------------------------------------------------------------------------------------------------------------
1                                Bird Rock near       BLM                  10                 1,2,3
                                  Greenwood,
                                  Mendocino County
----------------------------------------------------------------------------------------------------------------
2                                Caspar, near Point   BLM                  10                 1,2,3
                                  Cabrillo,
                                  Mendocino County
----------------------------------------------------------------------------------------------------------------
3                                Bird Rock, Marin     NPS                  10                 4
                                  County
----------------------------------------------------------------------------------------------------------------
4                                Stormy Stack, Marin  NPS                  10                 4
                                  County
----------------------------------------------------------------------------------------------------------------
5a                               Southeast Farallon   FWS                 4,000               5
                                  Island
----------------------------------------------------------------------------------------------------------------
5b                               Southeast Farallon   FWS                 3,402               6
                                  Island
----------------------------------------------------------------------------------------------------------------
5c                               Southeast Farallon   FWS                 1,990               6
                                  Island
----------------------------------------------------------------------------------------------------------------
6                                Castle/Hurricane     BLM                  60                 7
                                  Colony Complex,
                                  Monterey County
----------------------------------------------------------------------------------------------------------------
7                                Castle Rock, Santa   USN/NPS              200                8
                                  Barbara County
----------------------------------------------------------------------------------------------------------------
8                                Prince Island        USN/NPS             1,154               1
----------------------------------------------------------------------------------------------------------------
9                                Shipwreck Cave,      TNC/NPS              20                 9
                                  Santa Cruz Island
----------------------------------------------------------------------------------------------------------------
10                               Dry Sandy Beach      TNC/NPS              80                 10,11,12,13
                                  Cave, Santa Cruz
                                  Island
----------------------------------------------------------------------------------------------------------------
11                               Del Mar Rock, Santa  NPS                  10                 1
                                  Cruz Island
----------------------------------------------------------------------------------------------------------------
12                               Cave of the Bird's   TNC/NPS              52                 10,11,12,13
                                  Eggs, Santa Cruz
                                  Island
----------------------------------------------------------------------------------------------------------------
13                               Diablo Rocks, Santa  NPS                  20                 8
                                  Cruz Island
----------------------------------------------------------------------------------------------------------------
14                               Orizaba (``Sppit'')  NPS                  40                 10,11,12,13
                                  Rock, Santa Cruz
                                  Island
----------------------------------------------------------------------------------------------------------------
15                               Bat Cave, Santa      NPS                  48                 10,11,12,13
                                  Cruz Island
----------------------------------------------------------------------------------------------------------------
16                               Cavern Point Cove    NPS                  0                  10,11,12,13
                                  Caves, Santa Cruz
                                  Island
----------------------------------------------------------------------------------------------------------------
17                               Scorpion Rocks,      NPS                  140                1
                                  Santa Cruz Island
----------------------------------------------------------------------------------------------------------------
18                               Willows Anchorage    NPS                  111                1
                                  Rocks, Santa Cruz
                                  Island
----------------------------------------------------------------------------------------------------------------
19                               Gull Island          NPS                  2                  8
----------------------------------------------------------------------------------------------------------------
20                               Santa Barbara        NPS                  874                1
                                  Island
----------------------------------------------------------------------------------------------------------------
21                               Sutil Island         NPS                  586                1
----------------------------------------------------------------------------------------------------------------
22                               Shag Rock            NPS                  10                 13
----------------------------------------------------------------------------------------------------------------
23                               Ship Rock, Santa     BLM                  2                  14
                                  Catalina Island
----------------------------------------------------------------------------------------------------------------
24                               Seal Cove Area, San  BLM                  10                 15
                                  Clemente Island
----------------------------------------------------------------------------------------------------------------
25                               Islas Los            MX                   100                16
                                  Coronados, Mexico
----------------------------------------------------------------------------------------------------------------
26                               Islas Todos Santos,  MX                   10                 17
                                  Mexico
----------------------------------------------------------------------------------------------------------------
                                 Total, if using                          7,569               ..................
                                  line 5a
----------------------------------------------------------------------------------------------------------------
                                 Total, if using                          6,971               ..................
                                  line 5b
----------------------------------------------------------------------------------------------------------------
                                 Total, if using                          5,559               ..................
                                  line 5c
----------------------------------------------------------------------------------------------------------------
\a\Entity listed once if same for both ownership and management, as follows: Bureau of Land Management (BLM);
  Mexican Government (MX); National Park Service (NPS); The Nature Conservancy (TNC); U.S. Fish and Wildlife
  Service (FWS); and U.S. Navy (USN).

[[Page 41835]]

 
\b\Sources are as follows: 1-Carter et al. 1992; 2-Carter et al. 2008a; 3-Carter et al. unpublished notes; 4-
  Whitworth et al. 2002; 5-Ainley and Lewis 1974; 6-Sydeman et al. 1998a; 7-McChesney et al. 2000; 8-Hunt et al.
  1979; 9-H. Carter, unpublished data; 10-McIver 2002; 11-McIver and Carter 2006; 12-Carter et al. 2007; 13-
  McIver et al. 2008; 14-FWS estimate, based on Carter et al. 2008a; 15-H. Carter and D. Whitworth, unpublished
  data; 16-Carter et al. 2006a; and 17-Carter et al 2006b.

    Four thousand to six thousand ashy storm-petrels are usually 
observed in the fall in Monterey Bay, approximately 3 to 10 miles (mi) 
(5 to 16 kilometers (km)) offshore from the town of Moss Landing, 
California. As many as 10,000 ashy storm-petrels were estimated to be 
present in Monterey Bay in October 1977 and in September 2008 (Roberson 
1985, p. 42; Shearwater Journeys 2008). However, both of these 
estimates were from non-standardized visual estimates.
    Spear and Ainley (2007, p. 27) examined the seasonal at-sea 
distributions and abundance of storm-petrel species (including ashy 
storm-petrels) with generalized additive models, and estimated 4,207 
and 7,287 birds during autumn and spring, respectively (95 percent 
confidence interval: 2,700 to 6,400 in autumn and 4,500 to 9,070 in 
spring) off of Sonoma to Monterey counties. Spear and Ainley (2007, p. 
7) suggested that higher numbers of ashy storm-petrels may occur at 
Southeast Farallon Island, and other of the Farallon Islands, than have 
previously been reported. The total population of ashy storm-petrels 
(including breeders and non-breeders) has been estimated to be 
approximately 10,000 birds (Sowls et al. 1980, p. 24; Ainley 1995, 
p.1). Based on estimates at breeding locations and at-sea observations 
in Monterey Bay and off Sonoma to Monterey counties, we consider 7,000 
to 10,000 birds to be a reasonable estimate of the total population 
size of ashy storm-petrels. However, based on other visual estimates 
mentioned above, the total population could be as high as 13,000 birds.
    More ashy storm-petrels breed at Southeast Farallon Island than at 
any other single location (Sowls et al. 1980, p. 24; Carter et al. 
1992, p. I-78). Assessing population size and trends has been done 
through capture-recapture techniques using audio playback and mist nets 
(see Ainley and Lewis 1974, p. 435; Sydeman et al. 1998a, p. 438). 
Ainley and Lewis (1974, pp. 432-435) estimated 4,000 breeding ashy 
storm-petrels at Southeast Farallon Island in years 1971 to 1972, from 
birds captured and recaptured in mist nets at night. Sydeman et al. 
(1998a, p. 438-442) re-analyzed data from Southeast Farallon Island for 
years 1971 and 1972 (Ainley and Lewis 1974) and included data from year 
1992 to estimate 6,461 total ashy storm-petrels and 3,402 breeding ashy 
storm-petrels in 1971 to 1972, and 4,284 total ashy storm-petrels and 
1,990 breeding ashy storm-petrels in 1992. Based on comparison of these 
data sets, Sydeman et al. (1998a, p. 442) suggested declines of 34 
percent and 42 percent in the total population and breeding population 
of ashy storm-petrels, respectively, at Southeast Farallon Island. 
Sydeman et al. (1998a, pp. 445-446) reported that this decline occurred 
in prime storm-petrel nesting habitat, and suggested that this decline 
in population size at Southeast Farallon Island was due to, in part, an 
increase in the predation rate on ashy storm-petrel adults and sub-
adults by western gulls and burrowing owls. We interpret these results 
cautiously because they are based on two data points: one from 1972 and 
one 20 years later from 1992. Sydeman et al. (1998b, pp. 1-74) 
conducted a population viability assessment of ashy storm-petrels at 
Southeast Farallon Island, quantitatively examining the effects of 
predation on population decrease of ashy storm-petrels. Sydeman et al. 
(1998b, pp. 1-2) estimated a 2.87 percent decline in the population of 
ashy storm-petrels from 1972 to 1992 and hypothesized that removal of 
western gull predation would produce a stable population. They also 
stated, given current population parameters and predation rates, the 
population of ashy storm-petrels faces a high probability of quasi-
extinction within 50 years (Sydeman et al. 1998b, p. 2). Since 1992, 
capture-recapture of ashy storm-petrels at Southeast Farallon Island 
has continued and techniques have been further standardized (McChesney 
2008, p. 4). Using data from 1999 to 2007, Warzybok and Bradley (2007, 
p. 17) describe analysis of capture-recapture data that shows 
increasing capture rates and increasing survival of ashy storm-petrels. 
Specifically, they report the mean standardized capture rate (number of 
birds caught per hour of effort) increased from approximately 13 birds 
per hour to 38 birds per hour between 1999 and 2005 but declined 
slightly in 2006. The mean capture rate for 2007 was 39 birds per hour 
(Warzybok and Bradley 2007, p. 17). The authors also note that there 
were a greater number of occupied nesting sites than in previous years. 
Although there are caveats associated with Warzybok and Bradley's 
(2007) analysis (See Factor C: Disease and Predation section below), 
their report represents the best available information to date and 
suggests an increasing population of ashy storm-petrels.
    Research on reproductive success (or productivity, defined as 
number of fledged chicks per adult pair) of the ashy storm-petrel has 
been conducted only at Southeast Farallon Island (James-Veitch 1970, 
pp. 1-366; Ainley et al. 1990, pp. 128-162; Sydeman et al. 1998a, pp. 
1-74; PRBO Conservation Science,) and Santa Cruz Island (McIver 2002, 
pp. 1-70; McIver and Carter 2006, pp. 1-6; Carter et al. 2007, pp. 1-
32; McIver et al. 2008, pp. 1-23; McIver et al. 2009, pp. 1-30; McIver 
et al., in preparation, pp. 1-23). Reported productivity values are 
presented in Table 2.

   Table 2. Average values for productivity (fledged chicks per adult pair) of ashy storm-petrels at Southeast
  Farallon Island and Santa Cruz Island, California, for several studies during 1964-1966 and 1971-2008. Sample
                                         sizes are shown in parentheses.
----------------------------------------------------------------------------------------------------------------
              Location                      Productivity                Years                    Source
----------------------------------------------------------------------------------------------------------------
Southeast Farallon Island             0.42\a\(n = 184)         1964-1966                James-Veitch (1970)
----------------------------------------------------------------------------------------------------------------
Southeast Farallon Island             0.69(n = 356)            1972-1983\b\             Ainley and Boekelheide
                                                                                         (1990)
----------------------------------------------------------------------------------------------------------------
Southeast Farallon Island             0.74\d\(n = 540)         1971-1992\b\             Sydeman et al. (1998b)
----------------------------------------------------------------------------------------------------------------
Southeast Farallon Island             0.54\c\(n = 283)         1996-2007\e\             PRBO Conservation
                                                                                         Science unpublished
                                                                                         data; Warzybok and
                                                                                         Bradley (2007)
----------------------------------------------------------------------------------------------------------------

[[Page 41836]]

 
Santa Cruz Island                     0.55(n = 477)            1995-1998                McIver et al. in
                                                                                         preparation, Table 4
----------------------------------------------------------------------------------------------------------------
Santa Cruz Island                     0.65(n = 293)            2005-2008                McIver et al. in
                                                                                         preparation, Table 4;
                                                                                         McIver et al. (2009)
----------------------------------------------------------------------------------------------------------------
\a\Researcher disturbance (daily nest checks) negatively affected productivity.
\b\Excludes year 1977, when researcher disturbance negatively affected productivity.
\c\Sample sizes not provided for year 1996-2005, so annual sample size during this time period. assumed at 22
  nests, based on average sample size in Sydeman et al. (1998b).
\d\Based on two data points.
\e\Based on yearly date.

    No data are currently available regarding adult life span, 
survivorship, and age at first breeding for ashy storm-petrels (Ainley 
1995, p. 8). However, like other procellariids, storm-petrels are long-
lived (Warham 1996, p. 20). Some ashy storm-petrels reach 25 years old 
(Sydeman et al. 1998b, p. 7), and breeding adults over 20 years in age 
have been reported in the closely related Leach's storm-petrel (Morse 
and Bucheister 1977, p. 344). Mean age of first breeding in the Leach's 
storm-petrel has been reported at 5.9 years  1.3 years 
(Huntington et al. 1996, p. 19). Sydeman et al. (1998b, p. 7) concluded 
that 90 percent of adult ashy storm-petrels were capable of breeding at 
6 years of age.

Marine Environment

    Ashy storm-petrels are not as migratory as other storm-petrel 
species, foraging primarily in the California Current, from northern 
California to central Baja California, Mexico; the birds forage in 
areas of upwelling, seaward of the continental shelf, near islands and 
the coast (Ainley et al. 1974, p. 300; Briggs et al. 1987, p. 23; Mason 
et al. 2007, p. 60). The California Current flows along the west coast 
of North America, and like three other major, global, eastern boundary 
(along the eastern edges of oceanic gyres and the western edges of 
continents) currents, is characterized by the upwelling of cool, 
nutrient-rich waters, which results in increased productivity of the 
ocean (i.e., production of phytoplankton and zooplankton) in the region 
(Hickey 1993, pp. 19-70). The California Current extends about 190 mi 
(300 km) offshore from southern British Columbia, Canada, to Baja 
California, Mexico, and is comprised of a southward surface current, 
and a northward (poleward) undercurrent and surface countercurrents 
(Miller et al. 1999, p. 1; Dailey et al. 1993, pp. 8-10). Upwelling is 
an oceanographic phenomenon that involves wind-driven motion of dense, 
cooler, and usually nutrient-rich water towards the ocean surface, 
which replaces the warmer and usually nutrient-depleted surface water 
(Smith 1983, pp. 1-2). Coastal upwelling replenishes nutrients in the 
euphotic zone (zone of water where photosynthesis occurs), resulting in 
increased productivity in higher trophic levels (position within the 
food chain) (Batchelder et al. 2002, p. 37).
    Crossin (1974, p. 176) observed ashy storm-petrels as far north as 
latitude 49[deg] N, as far south as latitude 7[deg] S, and 
approximately 300 mi (480 km) from shore near latitude 14[deg] N. 
However, Spear and Ainley (2007, p. 7) disputed these observations and 
state that these observations likely represented misidentified dark-
rumped Leach's storm-petrels. At-sea observations of ashy storm-petrels 
south of Islas San Benitos, Mexico (latitude 28[deg] N) are unusual, 
and most observations of the species are off the coasts of California 
and Baja California Norte, Mexico (Briggs et al. 1987, p. 23; Ainley 
1995, p. 2). Aerial and boat observations at-sea confirm that the 
species is associated with pelagic (offshore) waters along the slope of 
and just seaward of the Continental Shelf and the Monterey Submarine 
Canyon, and less often in neritic (nearshore) waters (Briggs et al. 
1987, p. 23; Mason et al. 2007, pp. 56-60; Adams and Takekawa 2008, pp. 
12-13). Ashy storm-petrels are not known to be associated with the 
deeper and warmer oceanic waters west of the California Current, unlike 
the closely-related Leach's storm-petrel (Ainley et al. 1974, pp. 299-
300). Thus, the Service considers the at-sea geographic distribution 
(i.e., marine range) of the ashy storm-petrel to include waters off the 
western coast of North America, from latitude 42[deg] N (approximately 
the California-Oregon State line) south to latitude 28[deg] N 
(approximately Islas San Benitos, Mexico), and approximately 75 mi (120 
km) out to sea from mainland and island coasts. The diet of ashy storm-
petrels has not been extensively studied, but likely includes 
euphausiids (Euphausia spp., Thysanoessa), other crustaceans, larval 
lanternfish, unidentified fish, fish eggs, and squid (Warham 1990, p. 
186; McChesney 1999, pers. com.; Adams and Takekawa 2008, p. 14).

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
at 50 CFR part 424 set forth procedures for adding species to the 
Federal List of Endangered and Threatened Wildlife. In making this 
finding, we summarize below information regarding the status and 
threats to this species in relation to the five factors in section 
4(a)(1) of the Act. In our 90-day finding for this petition (73 FR 
28080), we organized potential threats under the five factors according 
to how they were organized and described in the petition. In this 12-
month finding, we analyze all of the potential threats described in the 
petition, but have reorganized them slightly under the factors that 
more appropriately categorize them. In making our 12-month finding, we 
considered and evaluated all scientific and commercial information 
available, including information received during and after the public 
comment period that ended July 14, 2008.

Factor A: The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

    Like most other procellariids, ashy storm-petrels feed mostly 
offshore or pelagically (Warham 1990, p. 10; Ainley 1995, p. 2) and 
return to land to breed at locations on islands and offshore rocks 
protected from mammalian predators (Warham 1990, p. 13; Ainley 1995, p. 
3). Consequently, in this section, we describe various threats that may 
destroy, modify, or curtail the ashy storm-petrel's marine and 
terrestrial habitats and range. The petitioner asserts that the ashy 
storm-petrel is

[[Page 41837]]

being or will be negatively affected by current and future climate 
change (specific effects: reduction in ocean productivity; ocean 
acidification; and sea level rise), tourism (specific effects: 
disturbance of habitats and nesting birds), and introduced grasses (CBD 
2007, p. 15). The petitioner further asserts that the ashy storm-
petrel's at-sea foraging habitat is being degraded by artificial 
(human-caused) light pollution, chemical and plastics pollution, and 
current and future oceanic changes related to climate change resulting 
from greenhouse gas emissions (CBD, p. 15); We addresspotential threats 
posed by artificial light pollution and chemical and plastics pollution 
under Factor E below. In this 12-month finding, we discuss under Factor 
A the following potential threats: (1) Climate change and associated 
effects--specifically, reduced productivity, ocean acidification, and 
sea-level rise; (2) introduced grasses; and (3) degradation of nesting 
habitats from tourism and military operations. The petitioner states 
that global warming will likely affect the ashy storm-petrel by causing 
warmer water and reduced upwelling, which reduces primary productivity 
in the California current system that would in turn decrease ashy 
storm-petrel breeding success and perhaps survival; global warming is 
leading to more intense El Ni[ntilde]o events that could lead to ashy 
storm-petrel breeding failures; sea-level rise will eliminate important 
ashy storm-petrel breeding habitat in sea caves and off-shore rocks in 
the Channel Islands; and ocean acidification may lead to declines in 
the prey species upon which petrels depend (CBD 2007, p 2). We discuss 
first below the various climate-related factors affecting ashy storm-
petrels.

El Ni[ntilde]o and Reduced Productivity

    The term El Ni[ntilde]o-Southern Oscillation (hereafter, El 
Ni[ntilde]o) is used to describe periodic basin-wide changes in air-sea 
interaction in the equatorial Pacific Ocean region, which result in 
increased sea-surface temperatures, reduced flow of eastern boundary 
currents, and reduced coastal upwelling (Norton and McLain 1994, pp. 
16,019-16,030; Schwing et al. 2002, p. 461). La Ni[ntilde]a events 
(sometimes called anti-El Ni[ntilde]o or cold-water events) produce 
effects in the northeast Pacific Ocean that tend to be the reverse of 
those that occur during El Ni[ntilde]o events; during La Ni[ntilde]a 
events, strong upwelling-favorable winds and a shallow thermocline 
(zone of rapid temperature change with increased depth that typically 
separates warm and cold water) result in colder, more nutrient-rich 
waters than usual (Murphree and Reynolds 1995, p. 52; Oedekoven et al. 
2001, p. 266). In addition to inter-annual climate events such as El 
Ni[ntilde]o and La Ni[ntilde]a, the mid-latitude Pacific Ocean 
experiences warm and cool phases that occur on decadal time scales 
(Mantua 2000, p. 2). The term ``Pacific Decadal Oscillation'' was 
coined to describe long-term climate variability in the Pacific Ocean, 
in which there are observed warm and cool phases, or ``regime shifts'' 
(Mantua et al. 1997, pp. 1069-1079).
    The California Current system is affected by inter-annual (ENSO-
related (El Ni[ntilde]o/La Ni[ntilde]a)) and inter-decadal (Pacific 
Decadal Oscillation) climatic processes. The petitioner cites 
Behrenfeld et al. (2006, pp. 752-755) to describe significant global 
declines in net primary production between years 1997 and 2005, 
attributed to reduced nutrient enhancement due to ocean surface warming 
(CBD 2007, p. 25). Specific to the marine range of the ashy storm-
petrel, the petitioner states that the California Current System has 
experienced some of the most well-documented changes in ocean climate 
due to global warming (CBD 2007, p. 25). The petition cites several 
examples of changes in the California Current System, which it 
attributes to climate change, that all relate to reduced ocean 
productivity, including: reduction in zooplankton biomass and increased 
sea surface temperatures (Roemmich and McGowan 1995, pp. 1324-1326; 
Lynn et al. 1998, pp. 25-49); upwelling of warmer, nutrient-depleted 
waters, which leads to breeding failures, mortality, and population 
declines across trophic levels (Barber and Chavez 1983, pp. 1203-1210); 
delay in the onset of spring upwelling (Schwing et al. 2006, pp. 1-5); 
anomalously warm water, low nutrient levels, and low primary production 
(Thomas and Brickley 2006, pp. 1-5); reduced zooplankton biomass 
(Mackas et al. 2006, pp. 1-7); unprecedented seabird breeding failures 
(Sydeman et al. 2006, pp. 1-5); and anomalously low recruitment of 
rocky intertidal organisms (Barth et al. 2007, pp. 3719-3724). Specific 
changes in the California Current that may negatively affect the ashy 
storm-petrel are discussed below.
    Roemmich and McGowan (1995, pp. 1324-1326) described 43 years (from 
1951 to 1993) of observations off the southern California coast. They 
reported that zooplankton had decreased by 80 percent, and that surface 
temperatures taken during transects off Point Conception and Orange 
County (approximately) warmed by an average of 2.2 [deg]F (1.2 [deg]C) 
and 2.3 [deg]F (1.6 [deg]C), respectively, during this period. They 
suggested that the zooplankton decline was directly related to and 
caused by the observed warming (Roemmich and McGowan 1995, p. 1325). 
The petitioner cited Schwing et al. (2006, pp. 1-5), Barth et al. 
(2007, pp. 3719-3724), and Sydeman et al. (2006, pp. 1-5) to describe a 
delay in the onset of spring upwelling in the northern California 
Current that resulted in breeding failures of Cassin's auklets 
(Ptychoramphus aleuticus) at Southeast Farallon Island, and at Triangle 
Island, British Columbia, in 2005 (CBD 2007, p. 25). At Southeast 
Farallon Island, Cassin's auklets also failed to breed in 2006 as well, 
likely as a result of warm-water conditions, reduced upwelling, and 
reduced availability of krill (Warzybok et al. 2006, pp. 12-14).
    At Southeast Farallon Island, productivity (chicks fledged per 
breeding pair) of ashy storm-petrels was 0.56 in 2005, and 0.48 in 2006 
(Warzybok et al. 2006, p. 7). At Santa Cruz Island, productivity of 
ashy storm-petrels was 0.58 in 2005, and 0.68 in 2006 (McIver et al. in 
preparation, tables 2-4). Sydeman et al. (2006, p. 1) reported that 
euphausiid crustacean (krill) biomass in the Gulf of the Farallones was 
reduced in 2005, but remained high south of Point Conception. To 
successfully raise a chick, an adult storm-petrel must obtain enough 
food for itself, plus one-half the food requirements of the chick, plus 
food to fuel the metabolic costs of transporting food to the nesting 
location (Quinlan 1979, p. 103). Thus, if food was less available to 
ashy storm-petrels foraging north of Point Conception (presumably, 
Southeast Farallon Island breeders) in 2005 and 2006, adverse affects 
may have appeared during the chick stage, and this could explain (in 
part) reduced breeding success at Southeast Farallon Island in 2006.
    Like Cassin's auklets, ashy storm-petrels feed on krill. However, 
unlike Cassin's auklets, ashy storm-petrels have more extended 
incubation and chick-rearing periods (per egg-laying effort), and feed 
over a wider geographic area; thus, they are likely more able to 
exploit similar food resources when these resources are reduced or more 
patchily distributed. As stated earlier, Cassin's auklets failed to 
breed in 2005 and 2006, in contrast to ashy storm-petrels, which did 
breed. Additionally, Ainley (1990b, pp. 357-359) reported that ashy 
storm-petrels showed the lowest inter-annual variability in 
productivity of any species breeding at Southeast Farallon Island, for 
the years 1971 to 1983. Ashy storm-petrel productivity was 0.64 and 
0.69 in 1972

[[Page 41838]]

(n = 36) and 1973 (n = 35), respectively; 0.81 in 1976 (n = 37); and 
0.75 and 0.67 in 1982 (n = 28) and 1983 (n = 18), respectively (Ainley 
and Boekelheide 1990, p. 392). This is of importance because during 
this time period, El Ni[ntilde]o events occurred in 1972-73, 1976, and 
1982-83 (Ainley 1990a, p. 36). Ainley (1990b, p. 371) reported that 
breeding by other seabirds at Southeast Farallon Island was poor to 
nonexistent in 1973, 1976, 1978, 1982, and 1983. As noted above, ashy 
storm-petrels were the exception to this observation; they bred in all 
years of the study, and no clear correlation between warm-water years 
and reduced reproductive success (productivity) was evident for this 
species (Ainley and Boekelheide 1990, p. 392). The only response to El 
Ni[ntilde]o conditions that may be evident are smaller numbers of ashy 
storm-petrels breeding and delayed egglaying (later in the season than 
in other years) (Ainley and Boekelheide 1990, p. 392; Ainley et al 
1990, pp. 149-150). However, since regular annual monitoring of nesting 
activities began at Southeast Farallon Island (in 1971) and at Santa 
Cruz Island (in 1994), researchers have observed ashy storm-petrels (on 
a population level) breeding each year. In research conducted in 1995-
97 and 2005-07, McIver et al. (in preparation, p. 10) report that 
reproductive success (productivity) of ashy storm-petrels at Santa Cruz 
Island did not appear to be negatively affected by El Ni[ntilde]o 
conditions (although timing of breeding was later in 1998, an El 
Ni[ntilde]o year), and no clear relationship between oceanographic 
conditions in southern California and reproductive success of ashy 
storm-petrels was observed. As presented above, this is supported by 
data from research at Southeast Farallon Island. Productivity of ashy 
storm-petrels at Southeast Farallon Island declined from the late 1980s 
to the mid-1990s (Sydeman et al. 2001, p. 315; CBD 2007, p. 8; Warzybok 
and Bradley 2007, p. 7). However, more recent data indicate that this 
decline in productivity has not continued. Warzybok and Bradley (2007, 
p. 17) describe an analysis of capture-recapture data that shows 
increasing capture rates and increasing survival of ashy storm-petrels 
on Southeast Farallon Island. Based on observed annual breeding and 
reproductive success values of ashy storm-petrels during El Ni[ntilde]o 
events, and the low inter-annual variability in reproductive success as 
reported by Ainley and Boekelheide (1990, p. 392) and McIver (2002, p. 
29), we conclude there is no clear relationship between reduced 
productivity of phytoplankton and zooplankton in the California Current 
due to El Ni[ntilde]o events and reproductive success of ashy storm-
petrels.
    As enumerated above, the petition cited several examples of changes 
in the California Current System, revolving around ocean productivity, 
which the petition claims has had an adverse effect on ashy storm-
petrels. Based on our review of the available information, we found 
that some species of seabirds have experienced breeding failures in 
certain years, which can be linked to El Ni[ntilde]o events, warmer 
water, or lower primary productivity. However, productivity of the ashy 
storm-petrel over approximately the past 40 years does not show 
breeding failures in those same years. This is likely due to the 
species' ability to exploit a wider range of resources than other 
seabirds. Based on the species' response to El Ni[ntilde]o events, we 
conclude the ashy storm-petrel is not likely to be adversely affected 
by potentially lower ocean productivity due to long-term ocean warming. 
In 2006, when Cassin's auklets failed to breed at Southeast Farallon 
Island likely as a result of warm-water conditions, reduced upwelling, 
and reduced availability of krill or a delay in the onset of spring 
upwelling, ashy storm-petrels did breed but had slightly lower 
productivity. Based on this information, we do not consider the delay 
in the onset of spring upwelling to be a threat to the species. 
Therefore, based on the best scientific information available to the 
Service regarding the effects of climate change, including the effects 
of El Ni[ntilde]o and changes in the California Current on ocean 
productivity, we do not consider this to be a significant threat to the 
ashy storm-petrel at Southeast Farallon Island, at the Channel Islands, 
or rangewide.

Climate Change - Ocean Acidification

    The petitioner claims that ocean acidification may eventually have 
detrimental impacts on the ashy storm-petrel's crustacean prey species 
(e.g., Euphausia pacifica, Thysannoessa spinifera) that may be impaired 
in building their exoskeletons in the coming decades (CBD 2007, p. 29). 
The petitioner cites Orr et al. (2005, p. 682) that mid-latitude 
waters, where the California Current Ecosystem is located, are 
experiencing the largest decreases in surface carbonate ion 
concentrations.
    The chemical processes behind ocean acidification are well known. 
The presence of inorganic carbon in the ocean is largely responsible 
for controlling the pH (the measure of acidity) of seawater, and 
dissolved inorganic carbon in seawater exists in three major forms, 
including a bicarbonate ion, carbonate ion, and aqueous carbon dioxide 
(Fabry et al. 2008, pp. 414-415). Human industrial and land use 
activities are resulting in increased atmospheric concentrations of 
carbon dioxide (Feely et al. 2004, p. 362); much carbon dioxide is 
absorbed by the oceans (Caldiera and Wickett 2003, p. 365; Sabine et 
al. 2004, p. 370). When carbon dioxide dissolves in water, carbonic 
acid is formed, most of which quickly dissociates into a hydrogen ion 
and a bicarbonate ion; the hydrogen ion can further react with a 
carbonate ion to form bicarbonate (Fabry et al. 2008, p. 415). The 
effects of increased absorption of carbon dioxide by the oceans have 
been given the term ``ocean acidification'' and include an increase in 
concentrations of carbonic acid, bicarbonate, and hydrogen ions; a 
decrease in concentration of carbonate; and a reduction in the pH level 
in seawater (Caldiera and Wickett 2003, p. 365; Royal Society et al. 
2005, p.16; Fabry et al. 2008, p. 415). Pure water has a pH of 7; 
solutions below pH 7 are acidic, and solutions above pH 7 are alkaline, 
or basic (summarized in Hardt and Safina 2008, p. 1). Oceans are 
slightly alkaline, with a pH of 8.1 (at latitude 30[deg]N, 
approximately; Caldiera and Wickett 2005, p. 5). Measurements of 
surface ocean pH in 2005 were 0.1 unit lower than preindustrial values 
(prior to the 1850s) and could become 0.3 to 0.4 units lower by the end 
of the 21st century (Caldiera and Wickett 2005, p. 5). Marine organisms 
that produce shells, such as corals, mollusks, echinoderms, and 
crustaceans, require carbonate ions to produce their calcium carbonate 
shells and skeletons (Orr et al. 2005, p. 681; Fabry et al. 2008, p. 
415). There are three mineral forms of calcium carbonate (magnesium-
calcite, aragonite, and calcite), and each has different tendencies to 
dissolve (solubility) in seawater (summarized in Hardt and Safina 2008, 
p. 2). The reaction of excess carbon dioxide with seawater reduces the 
availability of carbonate ions necessary for shell and skeleton 
formation for these organisms (Fabry et al. 2008, p. 415). Generally, 
oceanic surface waters are saturated with calcium carbonate, deeper 
waters are under-saturated, and the depth where waters transition from 
saturated to unsaturated is called the saturation horizon (summarized 
in Hardt and Safina 2008, p. 2). A reduction in carbonate ions causes 
all forms of calcium carbonate to dissolve at shallower depths, and 
causes a reduction in the rate at which marine

[[Page 41839]]

organisms can produce calcium carbonate (summarized in Hardt and Safina 
2008, p. 2). In other words, once formed, calcium carbonate will 
dissolve back into the water unless the surrounding seawater contains 
sufficiently high concentrations of carbonate ions (Royal Society et 
al. 2005, p. 10).
    The major planktonic calcium carbonate producers in the ocean are 
coccolithophores (single-celled phytoplankton), foraminifera (amoeboid 
protists), and pteropods (marine mollusks) (Fabry et al. 2008, p. 417). 
Marine organisms act as a ``biological pump,'' removing carbon dioxide 
and nutrients from the surface ocean and transferring these elements 
into the deeper ocean and ocean bottom (Zondervan et al. 2001, p. 507; 
Chen et al. 2004, p.18).
    Feely et al. (2008, pp. 1490-1492) conducted hydrographic surveys 
along the continental shelf of North America, and found evidence for 
undersaturated (with respect to aragonite) and low pH (less than 7.75) 
waters at mid-shelf depths of approximately 131 to 394 feet (ft) (40 to 
120 meters (m)) from about middle California (latitude 37[deg] N, 
approximately) to Baja California Sur, Mexico (latitude 26[deg] N, 
approximately). Feely et al. (2008, p. 1492) reported that much of the 
corrosive character of these waters is natural as the result of 
respiration processes at intermediate depths below the euphotic zone. 
Feely et al. (2008, p. 1492) cautioned that the California coastal 
region continues to accumulate anthropogenic carbon dioxide, and 
concluded that seasonal upwelling processes enhance the advancement of 
the corrosive deep water into wide regions of the North American 
continental shelf. Feely et al. (2008, p. 1492) further reported that 
little was known about how intermittent exposure to acidified water 
might affect the development of calcifying, or shell building, 
organisms in this region.
    The ecological effects of changing ocean carbonate chemistry are 
uncertain due to complexities of marine ecosystems, and research to 
date has focused on the impact of acidification on calcifying organisms 
(Antarctic Climate & Ecosystems Cooperative Research Centre 2008, p. 
7). Although the chemical processes associated with ocean acidification 
and the biological processes involving the transport of carbon in the 
oceans have been studied and described in detail, little research has 
been conducted to assess the response of many zooplankton populations, 
including euphausiids (upon which ashy storm-petrels likely feed), to 
ocean acidification (Fabry et al. 2008, p. 426). However, the Service 
is aware of one study (Yamada and Ikeda 1999, pp. 62-67) that 
experimentally tested the acute (lethal) effects of lowered pH levels 
upon Euphausia pacifica, a species of krill that occurs in the northern 
Pacific Ocean and is a known prey item of ashy storm-petrels. Observing 
5 juveniles and 20 nauplii (the free-swimming first stage of the larva) 
of Euphausia pacifica, Yamada and Ikeda (1999, pp. 65) found increased 
mortality with increased exposure time and decreased pH (less than 
6.9). Based on their data, Yamada and Ikeda (1999, p. 66) also 
suggested that the ability to tolerate lowered pH may be highly 
variable between and possibly within species, as in the case of nauplii 
and juveniles of Euphausia pacifica. Yamada and Ikeda (1999, p. 66) 
suggested that information about pH levels that induce chronic 
(sublethal) effects would be more appropriate to estimate the long-term 
consequences for a given zooplankton population, in that zooplankton 
may survive exposure to lower pH levels but may be unable to produce 
normal offspring. The Service is also aware of research currently being 
conducted to study the possible effects of ocean acidification on 
euphausiids in waters near Antarctica (see Rowbotham 2008, p. 1), but 
this research has just begun and data are currently not available (T. 
Berli, personal communication 2008).
    As stated in the Species Description section, the diet of ashy 
storm-petrels has not been extensively studied; however, like other 
species of storm-petrels, ashy storm-petrels likely feed on 
euphausiids, juvenile lanternfish, fish eggs, and other small fish that 
occur at the surface of the ocean. Our review of the available 
information did not reveal any information regarding diet studies or 
measurements of chick growth and weight that indicate that ashy storm-
petrels are eating fewer euphausiids or are providing less food to 
their chicks. Additionally, our review of the available information did 
not find any research indicating that ocean acidification is causing 
acute or chronic effects to euphausiid populations that occur in the 
California Current, or any other species of krill that occur in the 
California Current, on which ashy storm-petrels feed. Although the 
processes and potential effects of ocean acidification on biological 
food webs have been described, and experimental research on Euphausia 
pacifica has tested lethal effects of exposure to low pH, our review of 
the available information did not reveal any evidence that demonstrates 
a direct link between ocean acidification and reduced abundance and 
survival of prey items on which ashy storm-petrels depend. 
Additionally, Ainley (1990b, p. 371) reported that breeding by other 
seabirds at Southeast Farallon Island was poor to nonexistent during 
warm-water years (El Ni[ntilde]o events). However, ashy storm-petrels 
bred in years that other seabird species did not (Ainley and 
Boekelheide 1990, p. 392), which is an indication that the ashy storm-
petrel is less affected by changes in ocean productivity than other 
species. Therefore, based on our review of the available information, 
we conclude that the potential effects of ocean acidification are not 
currently a significant threat to ashy storm-petrels based on the 
uncertainty of the ecological effects of changing ocean carbonate 
chemistry.
    Published research and oceanographic modeling does show that oceans 
are acidifying, and we recognize that ashy storm-petrels may be 
susceptible to changes in the oceans' chemistry in the future. However, 
based on the best scientific information available to the Service 
regarding ocean acidification, at this time we do not consider ocean 
acidification to be a significant threat to the ashy storm-petrel at 
Southeast Farallon Island, at the Channel Islands, or rangewide.

Climate Change - Sea Level Rise

    The petitioner claims that climate change will cause rises in the 
elevation of the oceans that will have negative consequences for ashy 
storm-petrels by eliminating (presumably, by inundation and submersion 
by seawater) important habitat in sea caves and offshore rocks in the 
California Channel Islands (CBD 2007, p. 28). Sea levels along the 
California coast are projected to rise approximately 1 ft (0.3 m) by 
2050 and approximately 3 ft (0.9 m) by 2100 (California Coastal 
Commission 2001, pp. 14-15; Cayan et al. 2006, p. S71). Future sea 
levels along the coast of California will likely depend upon (in part): 
future changes in global temperatures; lag time between atmospheric 
changes and oceanic reactions; thermal expansion of ocean water; 
effects of atmospheric temperature changes on Antarctica; melting of 
Greenland ice and other glaciers; and local subsidence and uplift of 
coastal areas (California Coastal Commission 2001, p. 12). Gradual sea 
level rises progressively worsen the impacts of high tides (through 
erosion and submersion), surge, and waves resulting from storms (Cayan 
et al. 2008, pp. S57-S58).

[[Page 41840]]

    We reviewed topographic maps and information provided in Sowls et 
al. (1980), Bunnell (1988), and Carter et al. (1992; 2006a; 2006b) to 
estimate the range of elevations above sea level of suitable ashy 
storm-petrel habitat at each of the 26 known breeding locations (Table 
3).

Table 3. Estimated range of elevation above sea level (ASL) in feet (ft)
     and meters (m) of known nesting habitat of ashy storm-petrels.
------------------------------------------------------------------------
       Location  Number         Breeding Location Name    Elevation ASL
------------------------------------------------------------------------
1.............................  Bird Rock near          10-40 ft (3-12
                                 Greenwood, Mendocino    m)
                                 County.
2.............................  Caspar, near Point      10-40 ft (3-12
                                 Cabrillo, Mendocino     m)
                                 County.
3.............................  Bird Rock, Marin        10-40 ft (3-12
                                 County.                 m)
4.............................  Stormy Stack, Marin     10-50 ft (3-15
                                 County.                 m)
5.............................  Southeast Farallon      10-330 ft (3-100
                                 Island.                 m)
6.............................  Castle/Hurricane        10-100 ft (3-30
                                 Colony Complex,         m)
                                 Monterey County.
7.............................  Castle Rock, Santa      20-80 ft (6-24
                                 Barbara County.         m)
8.............................  Prince Island.........  20-300 ft (6-91
                                                         m)
9.............................  Shipwreck Cave, Santa   5-15 ft (1.5-5
                                 Cruz Island.            m)
10............................  Dry Sandy Beach Cave,   5-15 ft (1.5-5
                                 Santa Cruz Island.      m)
11............................  Del Mar Rock, Santa     5-20 ft (1.5-6
                                 Cruz Island.            m)
12............................  Cave of the Birds       5-10 ft (1.5-3
                                 Eggs, Santa Cruz        m)
                                 Island.
13............................  Diablo Rocks, Santa     10-40 ft (3-12
                                 Cruz Island.            m)
14............................  Orizaba Rock, Santa     10-30 ft (3-9 m)
                                 Cruz Island.
15............................  Bat Cave, Santa Cruz    5-20 ft (1.5-6
                                 Island.                 m)
16............................  Cavern Point Cove       0-10 ft (0-3 m)
                                 Caves, Santa Cruz
                                 Island.
17............................  Scorpion Rocks, Santa   10-40 ft (3-12
                                 Cruz Island.            m)
18............................  Willow Anchorage        10-40 ft (3-12
                                 Rocks, Santa Cruz       m)
                                 Island.
19............................  Gull Island, Santa      10-100 ft (3-30
                                 Cruz Island.            m)
20............................  Santa Barbara Island..  10-600 ft (3-183
                                                         m)
21............................  Sutil Island..........  10-250 ft (3-76
                                                         m)
22............................  Shag Rock.............  10-50 ft (3-15
                                                         m)
23............................  Ship Rock, Santa        5-20 ft (1.5-6
                                 Catalina Island.        m)
24............................  Seal Cove Area, San     10-50 ft (3-15
                                 Clemente Island.        m)
25............................  Islas Los Coronados,    10-100 ft (3-30
                                 Mexico.                 m)
26............................  Islas Todos Santos,     10-100 ft (3-30
                                 Mexico.                 m)
------------------------------------------------------------------------

    The nesting habitat at the majority of ashy storm-petrel breeding 
locations will likely not be affected by the sea level rise projected 
for California by 2100 (Table 3). Some nesting habitat at only one 
location at Cavern Point Cove Caves, Santa Cruz Island, would likely be 
submerged if projected sea level rises of 1 ft (0.3 m) by 2050 occur; 
much of the nesting habitat at this location would likely be submerged 
if the sea level rises 3 ft (0.9 m) by year 2100. Prior to the 
mortality event in 2008 at this location (see Factor C), Cavern Point 
Cove Caves had approximately 40 breeding birds annually. Some habitat 
at other cave locations on Santa Cruz Island may be susceptible to 
submersion by seawater. For example, on Santa Cruz Island in November 
2008, McIver et al. (2009, p. 6) reported flooding by ocean water in a 
sea cave that likely killed one storm-petrel chick. Despite this 
unusual event, the majority of the nesting habitat in the sea caves at 
Santa Cruz Island occurs greater than 3 ft (1 m) above current sea 
level, and would not likely be submerged during breeding season months 
(April through November) within the next 40 to 50 years. Winter storm 
surges periodically wash all of the sea caves at Santa Cruz Island, but 
these storm events likely do not negatively affect ashy storm-petrels, 
since most ashy storm-petrels are not attending the colonies during 
winter months (Ainley 1995, p. 5). In fact, past winter storms have 
benefited ashy storm-petrels at Santa Cruz Island by creating nesting 
habitat; approximately 25 percent of ashy storm-petrel nest sites in 
Bat Cave occur among accumulated driftwood debris (both human-made and 
natural) that has washed into the cave during past winter storm events.
    Based on information available to the Service regarding elevations 
(above current sea level) of breeding locations of ashy storm-petrels, 
and projected estimates of sea level rise along the west coast of North 
America during the 21st century, we conclude that a small portion of 
the total population of ashy storm-petrels (approximately 0.8 percent) 
could be negatively affected by rising sea levels by 2050. Therefore, 
based on the best scientific information available to the Service 
regarding climate change-induced sea level rise, at this time we do not 
consider this to be a significant threat to the ashy storm-petrel at 
Southeast Farallon Island, at the Channel Islands, or rangewide.

Changes in Terrestrial Breeding Habitat

Introduced Grasses
    The petitioner asserts that the ashy storm-petrel's island breeding 
habitats are being modified and degraded by introduced species and 
specifically, that introduced grasses have increased at Southeast 
Farallon Island, causing some nesting areas to be unusable for ashy 
storm-petrels (CBD 2007, p. 30). In addition, the petitioner claims 
that introduced grasses are widespread at all ashy storm-petrel 
colonies and that their effects have not been evaluated (CBD 2007, p. 
30). Ainley (1995, p. 9) desc