[Federal Register: April 14, 2006 (Volume 71, Number 72)]
[Rules and Regulations]
[Page 19452-19458]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14ap06-10]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AU22; 1018-AI48
Endangered and Threatened Wildlife and Plants; Final Rule To
Remove the Arizona Distinct Population Segment of the Cactus
Ferruginous Pygmy-owl (Glaucidium brasilianum cactorum) From the
Federal List of Endangered and Threatened Wildlife; Withdrawal of the
Proposed Rule To Designate Critical Habitat; Removal of Federally
Designated Critical Habitat
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule; withdrawal of proposed rule; removal of critical
habitat designation.
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SUMMARY: We, the Fish and Wildlife Service (Service), under the
authority of the Endangered Species Act of 1973 (Act), as amended, have
determined that it is appropriate to remove the Arizona distinct
population segment (DPS) of the cactus ferruginous pygmy-owl
(Glaucidium brasilianum cactorum) (pygmy-owl) from the Federal List of
Endangered and Threatened Wildlife and, accordingly, also remove
designated critical habitat for this DPS found in the Code of Federal
Regulations (CFR) at 50 CFR 17.95. Additionally, we are withdrawing the
proposed rule to designate new critical habitat for the Arizona DPS of
the pygmy-owl (67 FR 7103, November 27, 2002). The Arizona DPS of the
pygmy-owl was listed as endangered on March 10, 1997 (62 FR 10730), and
critical habitat was designated on July 12, 1999 (64 FR 37419). On
January 9, 2001, a coalition of plaintiffs filed a lawsuit with the
District Court of Arizona challenging the validity of our listing of
the pygmy-owl as a DPS and the designation of its critical habitat.
After the District Court remanded the designation of critical habitat
(National Association of Home Builders et al. v. Norton, Civ.-00-0903-
PHX-SRB), we proposed a new critical habitat designation on November
27, 2002 (67 FR 7103). Ultimately, as a result of this lawsuit, the
United States Court of Appeals for the Ninth Circuit issued an opinion
on August 19, 2003, stating that ``the FWS acted arbitrarily and
capriciously in designating the Arizona pygmy-owl population as a DPS
under the DPS Policy'' (National Association of Homebuilders v. Norton,
340 F.3d 835, 852 (9th Cir. 2003)). In light of the Ninth Circuit's
opinion, we have reassessed the application of the DPS significance
criteria to the Arizona population of the pygmy-owl. Based on a review
of the available information and science, the public comments received
during the public comment period, and our DPS policy, we do not believe
that the Arizona DPS of the pygmy-owl qualifies as an entity that can
be listed under the Act.
DATES: This rule is effective May 15, 2006.
ADDRESSES: The administrative record for these actions is available for
inspection, by appointment, during normal business hours at the Arizona
Ecological Services Office, 2321 West Royal Palm Road, Suite 103,
Phoenix, Arizona 85021-4951.
FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor (see
ADDRESSES) (telephone 602/242-0210; facsimile 602/242-2513).
SUPPLEMENTARY INFORMATION:
Background
The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum)
(pygmy-owl) is in the order Strigiformes and the family Strigidae. It
is a small bird, approximately 17 centimeters (cm) (6.75 inches (in))
long. Males average 62 grams (g) (2.2 ounces (oz)), and females average
75 g (2.6 oz). The pygmy-owl is reddish brown overall, with a cream-
colored belly streaked with reddish brown. Color may vary, with some
individuals being more grayish brown. The crown is lightly streaked,
and a pair of black/dark brown spots, outlined in white, occurs on the
nape suggesting ``eyes.'' This species lacks ear tufts, and the eyes
are yellow. The tail is relatively long for an owl and is colored
reddish brown with darker brown bars (Proudfoot and Johnson 2000). The
pygmy-owl is primarily diurnal (active during daylight) with
crepuscular (active at dawn and dusk) tendencies. These owls can be
heard making a long, monotonous series of short, repetitive notes,
mostly during the breeding season (Proudfoot and Johnson 2000).
The pygmy-owl is one of four subspecies of the ferruginous pygmy-
owl. It occurs from lowland central Arizona south through western
Mexico to the States of Colima and Michoacan, and from southern Texas
south through the Mexican States of Tamaulipas and Nuevo Leon. Only the
Arizona population of the pygmy-owl was listed as an endangered species
(62 FR 10730; March 10, 1997).
Historically, pygmy-owls were recorded in association with riparian
woodlands in central and southern Arizona (Bendire 1892; Gilman 1909;
Johnson et al. 1987). Plants present in these riparian communities
included cottonwood (Populus fremontii), willow (Salix spp.), ash
(Fraxinus velutina), and hackberry (Celtis spp.). However, recent
records have documented pygmy-owls in a variety of vegetation
communities such as riparian woodlands, mesquite (Prosopis velutina and
P. glandulosa) bosques (woodlands), Sonoran desertscrub, semidesert
grassland, and Sonoran savanna grassland communities (Monson and
Phillips 1981; Johnson and Haight 1985; Proudfoot and Johnson 2000)
(see Brown 1994 for a description of these vegetation communities).
While native and nonnative plant species composition differs among
these communities, there are certain unifying characteristics such as
(1) the presence of vegetation in fairly dense thickets or woodlands,
(2) the presence of trees, saguaros (Carnegiea giganteus), or other
columnar cacti large enough to support cavities for nesting, and (3)
elevations below 1,200 meters (m) (4,000 feet (ft)) (Swarth 1914;
Karalus and Eckert 1974; Monson and Phillips 1981; Johnsgard 1988;
Enriquez-Rocha et al. 1993; Proudfoot and Johnson 2000). Large trees
provide canopy cover and cavities used for nesting, while the density
of mid- and lower-story vegetation provides foraging habitat and
protection from predators and contributes to the occurrence of prey
items (Wilcox et al. 2000).
Distinct Vertebrate Population Segment
We must consider a species for listing under the Act if available
information indicates that such an action might be warranted.
``Species'' is defined by the Act as including any subspecies of fish
and wildlife or plants, and any distinct vertebrate population segment
of fish or wildlife that interbreeds when mature (16 U.S.C. 1532(16)).
We, along with the National Marine Fisheries Service (National Oceanic
and Atmospheric Administration--Fisheries), developed the Policy
Regarding the Recognition of Distinct Vertebrate Population Segments
under the Endangered Species Act (DPS Policy) (61 FR 4722, February 7,
1996) to help us in determining what constitutes a DPS. Under this
policy, we use three elements to assess whether a population under
consideration for listing may be recognized as a DPS: (1)
[[Page 19453]]
Discreteness of the population in relation to the remainder of the
species to which it belongs; (2) the significance of the population
segment to the species to which it belongs; and (3) the population
segment's conservation status in relation to the Act's standards for
listing.
A population segment may be considered discrete if it satisfies
either one of the following conditions: (1) Marked separation from
other populations of the same taxon resulting from physical,
physiological, ecological, or behavioral factors, including genetic
discontinuity; or (2) populations delimited by international boundaries
within which differences in control of exploitation, management of
habitat, conservation status, or regulatory mechanisms exist that are
significant in light of 4(a)(1)(D) of the Act. If a population is
considered discrete under one or more of the above conditions, its
biological and ecological significance is assessed. Measures of
significance may include, but are not limited to, the following: (1)
Persistence of the discrete population segment in an ecological setting
unusual or unique for the taxon; (2) evidence that loss of the discrete
population segment would result in a significant gap in the range of
the taxon; (3) evidence that the discrete population segment represents
the only surviving natural occurrence of the taxon that may be more
abundant elsewhere as an introduced population outside its historical
range; and (4) evidence the discrete population segment differs
markedly from other populations of the taxon in its genetic
characteristics.
If a population segment is discrete and significant, its evaluation
for endangered or threatened status will be based on the Act's
definitions of those terms and a review of the factors enumerated in
section 4(a). ``Endangered'' means the species is in danger of
extinction throughout all or a significant portion of its range.
``Threatened'' means the species is likely to become endangered within
the foreseeable future throughout all or a significant portion of its
range.
The Ninth Circuit's opinion held that we did not arbitrarily find
the Arizona pygmy-owl to be discrete because differences in
conservation status exist across the international boundary between the
United States and Mexico. We argued that in this case the term
``conservation status'' means ``the number of individuals left in the
population.'' We found that conservation status differs because there
are differences in the number of owls on either side of the border. The
court deferred to our interpretation of the term ``conservation
status'' and stated, ``We conclude that `conservation status,' as used
in the discreteness test, is a term of art that lends itself to
interpretation by the FWS'' (CV 00-0903 SRB). The Ninth Circuit's
opinion stated that we did not articulate a rational basis for finding
that the discrete population is significant to the taxon, but did not
actually rule on whether the DPS is significant. Instead the 9th
Circuit remanded the decision of significance, and that is the issue
which is addressed in this finding.
Previous Federal Action
Previous Federal actions for the Arizona pygmy-owl DPS can be found
in our proposed delisting rule that published in the Federal Register
on August 3, 2005 (70 FR 44547). That information is incorporated by
reference into this final rule.
Summary of Comments and Recommendations
In the August 3, 2005, proposed delisting rule (70 FR 44547) and
associated notifications, we invited interested parties to submit
comments or information that might contribute to the final delisting
determination for this species. The public comment period closed
October 3, 2005. We contacted and sent announcements of the proposed
delisting rule to appropriate Federal and State agencies, county
governments, scientific organizations, and other interested parties. We
established an Internet email address for electronic submittal of
comments and hearing requests by any party. We received three requests
to hold a public hearing, and we held a public hearing on September 20,
2005, in Tucson, Arizona. We received a total of 578 written and oral
comments from interested parties. Of this total, 540 of the comments
expressed either support or opposition to the proposed delisting
without providing any substantial information that would contribute to
the final determination. Of these, 16 parties expressed support for the
proposed delisting, while 523 parties indicated their opposition to the
proposed rule. Thirty-eight commenters provided substantial comments
related to our determination, which are either incorporated or
addressed in the following summary.
General Comments Issue 1: Basing the Determination on Science
(1) Comment: Several commenters stated that the proposal to delist
the pygmy-owl is being driven by politics, not by science.
Our Response: Our reevaluation of the pygmy-owl listing focuses on
compliance with our DPS policy and the court's order. We considered and
used the best available scientific and commercial information that
existed at the time of and since the listing. Public comments were
considered and used to the extent that they fell within the scope of
our reevaluation. The available scientific information related to the
pygmy-owl was considered. However, we were unable to determine that any
of this information substantiated a finding that the Arizona DPS of the
pygmy-owl is significant to the taxon as a whole (see analysis below).
Therefore, we are unable to conclude that the pygmy-owl is an entity
that qualifies for listing under our DPS policy.
(2) Comment: The proposed rule ignores the best available science,
as well as the recommendation of the Service's own biologists as found
in a white paper prepared in December 2003.
Our Response: As indicated in our previous response, we used all
available scientific information related to the pygmy-owl during our
reevaluation of the significance criteria. This included information we
had at the time of listing, as well as all information generated since
then. A substantial amount of information was also provided to us
during the public comment period. Not all of the information submitted
was pertinent to our reevaluation of the significance of the Arizona
DPS of the pygmy-owl to the taxon as a whole, but we evaluated and used
where appropriate all of the information that was pertinent to this
issue. The white paper prepared by Service biologists in December 2003
was developed to synthesize all available information that related to
determining whether the Arizona DPS of the pygmy-owl satisfied the
significance criteria outlined in our DPS policy. This information was
considered during our reevaluation of the significance issue. The white
paper made no determination of the significance of the Arizona
population to the rest of the taxon as a whole. A good deal of the
information we reviewed, including the white paper, included
discussions related to pygmy-owl issues of a broader context than the
Arizona DPS and were not pertinent to our consideration of the
significance of the Arizona DPS.
General Comments Issue 2: Unique Ecological Setting
(3) Comment: We received comments both supporting and opposing the
notion that pygmy-owls occupy a
[[Page 19454]]
unique ecological setting in the Sonoran Desert.
Our Response: Following our reevaluation of all the available
information pertinent to this issue, we were unable to conclude that
the Arizona DPS of the pygmy-owl occurs in a unique ecological setting.
While the Sonoran Desert may make up a relatively small portion of the
overall range of the pygmy-owl, the Arizona DPS does not occupy the
only area of Sonoran Desert within the range of the taxon.
General Comments Issue 3: Gap in the Range of the Species
(4) Comment: Some parties indicated that they felt the loss of the
Arizona DPS of pygmy-owls would create both a genetic gap and a
geographic gap in the range of the species. They felt that the loss of
the Arizona DPS would result in the loss of genetic variability in the
taxon. Other commenters argued that no such gap would be created by the
loss of the Arizona DPS of the pygmy-owl. Some commenters indicated
that we should consider the percentage of Sonoran Desert occupied by
the Arizona DPS versus the total area of Sonoran Desert occupied by the
pygmy-owl, including Mexico, when determining if a gap would occur in
the range of the taxon.
Our Response: Based on our review of the available information on
the genetics of the pygmy-owl, we concluded that the loss of the
Arizona DPS would not result in a genetic gap within the taxon (see
analysis below). We conducted a refined analysis of the current and
historical range of the pygmy-owl and concluded that the contribution
of the Arizona DPS to the current (approximately 5 percent) and
historical (approximately 12 percent) range of the taxon was not
significant. The issue regarding the contribution of the Arizona DPS to
the range of the pygmy-owl within Sonoran Desert areas is not pertinent
to the question at hand. Per our DPS policy and the 9th Circuit's
opinion, we must consider the contribution of the Arizona DPS to the
entire range of the taxon.
General Comments Issue 4: Significance of the Arizona DPS as a
Peripheral Population
(5) Comment: We received comments both supporting and opposing the
significance of the Arizona DPS as a peripheral population, occurring
at the northern extent of its range.
Our Response: It is well documented that species at the periphery
of their range are less common and more irregular in their occurrence
than at the core of their range. However, the mere occurrence of a
population at the edge of its range does not, in itself, reduce the
significance of that population. Significance does not rely simply on
the numerical contribution of a peripheral population. Peripheral
populations, even those with reduced numbers, may be significant to the
taxon as a whole through contributions to genetic variability,
environmental adaptation, and supplying emigrants to other populations.
The Arizona DPS of the pygmy-owl may well contribute to the taxon as a
whole in these ways, but our review of the available information does
not adequately support a determination that this contribution is
significant (see ``Delisting Analysis'' below).
General Comments Issue 5: Genetics of the Pygmy-Owl in Arizona, Texas,
and Mexico
(6) Comment: An extension or reopening of the comment period was
requested so that genetic information about to be published by Dr.
Glenn Proudfoot could be considered in our determination.
Our Response: Our review of Dr. Proudfoot's work indicates that the
information that he will soon publish is related more to the broad
issue of pygmy-owl genetics across the entire range of the taxon and
does not provide any additional information that shows a marked genetic
difference between the Arizona DPS and other portions of the pygmy-owl
range. No new information related to the Arizona DPS is presented that
is not already found in Proudfoot and Slack 2001, which is available to
the public and cited in our proposed rule. We did not rely on any of
the work within Dr. Proudfoot's unpublished papers in making our
determination. Therefore, we do not believe that reopening the public
comment period after Dr. Proudfoot's work is published will provide any
new information that would contribute to our determination.
(7) Comment: Another party indicated that work by Dr. Proudfoot
could not legally be considered in our determination until it had been
made available to the public.
Our Response: For the reasons described in our previous response,
we did not rely on Dr. Proudfoot's unpublished work to make our
determination.
(8) Comment: Dr. Proudfoot provided comments recommending that the
Service should recognize current biological information and ascertain
the distribution of what seems to be a genetically fragmented
population in Arizona and Sonora prior to delisting the pygmy-owl.
Our Response: Dr. Proudfoot's comments indicated some genetic
differentiation is occurring in south central Sonora, Mexico. As a
result, he recommends that pygmy-owls in Sonora and Arizona be
considered a separate conservation unit from pygmy-owls throughout the
remainder of the western population. However, Dr. Proudfoot's comments
included no additional information showing that the genetic makeup of
the Arizona DPS differs markedly from other pygmy-owls within the
western population.
(9) Comment: We should only be considering the significance of the
Arizona DPS in relation to the western population because it has been
shown that the eastern and western pygmy-owl populations are
genetically different.
Our Response: Information found in Proudfoot and Slack (2001) does
indicate that there is a marked genetic difference between the eastern
and western populations of the pygmy-owl. However, we have not
determined that these two populations are separate listable entities
under the Act (species, subspecies, or DPS), and therefore, separate
taxons. Accordingly, as required by our DPS policy, we evaluated
whether the Arizona DPS is significant in relation to the taxon as a
whole.
(10) Comment: There is not a marked genetic difference between
pygmy-owls in Mexico and Arizona, and the loss of the Arizona DPS would
not result in a decrease in genetic variability.
Our Response: Following a review of all the available information
related to pygmy-owl genetics, we determined that the Arizona DPS of
the pygmy-owl does not differ markedly in its genetic makeup from other
pygmy-owls within the western population. Current information indicates
some genetic differentiation occurring within Arizona and within the
state of Sonora in Mexico. However, none of this information indicates
that this differentiation is a marked genetic difference. Nonetheless,
the Arizona DPS of the pygmy-owl does contribute to the genetic
variability within the taxon and the loss of the Arizona DPS would
result in the loss of some genetic variability within the species.
However, we have determined that, because there is not a marked genetic
difference, the contribution of the Arizona DPS is not significant to
the taxon as a whole.
[[Page 19455]]
General Comments Issue 6: Additional Threats to the Pygmy-Owl in
Arizona and Mexico, Including Drug Smuggling, Illegal Immigration, Law
Enforcement Activities, Urban Development, Invasive Non-Native Species,
and Fire
(11) Comment: A number of commenters provided information showing
that pygmy-owls and pygmy-owl habitat in Arizona are being affected by
drug smuggling, illegal immigration, law enforcement activities, urban
development, and fire.
Our Response: These comments are related to threats and impacts to
the pygmy-owl that would be appropriate for an analysis of the five
factors outlined in the Act's standard for listing and which are
considered in determining whether a listable entity is endangered or
threatened. These comments do not inform our determination of the
significance of the Arizona DPS of the pygmy-owl. We have determined
that the Arizona DPS of the pygmy-owl is not a listable entity and,
therefore, the five-factor analysis related to the Act's standard for
listing is not relevant.
(12) Comment: The introduction of invasive, non-native grass
species and a changing fire regime is resulting in the conversion of
native vegetation communities in both Sonora, Mexico, and Arizona to
habitats that are not suitable for the pygmy-owl.
Our Response: As we indicated in our response to the previous
comment, these are issues that are related to the five factors we
consider in determining if a listable entity is endangered or
threatened and not in determining the significance of the Arizona DPS.
General Comments Issue 7: Application of the Service's DPS Policy
(13) Comment: Commenters indicated that our evaluation of the
significance of the Arizona DPS of the pygmy-owl is not restricted to
the factors listed in the proposed rule. They argue that the
significance of the Arizona DPS to the population of pygmy-owls in the
United States should be considered.
Our Response: While our DPS policy does indicate that factors
related to significance other that those discussed in the proposed rule
can be considered, the 9th Circuit's opinion clearly stated that
considering the significance of the Arizona DPS of the pygmy-owl to
just the United States was not appropriate.
(14) Comment: The Service's DPS policy needs to be revised to
conform to the intent of the Act and the DPS policy.
Our Response: As indicated in the 9th Circuit's opinion, the
revision of the Service's DPS policy is not the issue at hand.
(15) Comment: Commenters indicated that the Act cannot control the
management or protection of the pygmy-owl in Mexico and that we should
not have to rely on Mexico for protection of this species. Rather, we
should protect it in the United States, where the Act has authority.
Our Response: Under the Act, it is possible to list and afford the
protections of the Act to species that occur outside of the boundaries
of the United States. However, we also acknowledge our limitations in
prescribing and implementing conservation actions in other countries.
Cooperative management of endangered species in coordination with other
countries is a high priority within our agency. However, as discussed
in our previous response, the 9th Circuit's opinion clearly stated that
we cannot narrow our analysis of significance to just the United
States. We must consider whether the Arizona DPS of the pygmy-owl is
significant to the taxon as a whole.
General Comments Issue 8: Relationship of the Proposed Delisting to the
9th Circuit's Opinion and Other Court Cases
(16) Comment: The courts did not strip the Arizona DPS of its
endangered status; therefore the Service should not be proposing
delisting. The courts upheld the Service's determination of
discreteness and did not find that the Arizona DPS was not significant.
Our Response: The courts have upheld our determination of the
discreteness of the Arizona DPS. However, the 9th Circuit's opinion
clearly stated that our determination of the Arizona DPS of the pygmy-
owl was arbitrary and capricious because we were unable to articulate
the significance of this DPS to the taxon as a whole. The District
Court of Arizona remanded the listing of this DPS to us for
reconsideration in light of the 9th Circuit's opinion. We have
reconsidered our determination using the information available at the
time of the listing, information related to pygmy-owls that has been
generated since the listing, and public comments received during the
public comment period. We have determined that the Arizona DPS of the
pygmy-owls does not meet the criteria for significance as contained in
our DPS policy (see ``Delisting Analysis'' below).
(17) Comment: The proposed delisting appears to be contrary to
court rulings related to the tiger salamander in California, the gray
wolf in Vermont and Oregon, and the green sturgeon in California.
Our Response: The cases mentioned have no bearing on determining
the significance of a DPS and set no precedent that is pertinent to our
determination.
(18) Comment: It is illegal to consider new information in making
our determination. If new information is considered, the issue of
discreteness should be revisited by the Service.
Our Response: The Arizona District Court order specifically
indicated that we could consider information related to the pygmy-owl
that has been generated since the listing in 1997. The courts upheld
our determination of the discreteness of the Arizona DPS. No
information was presented during the public comment period that
compelled us to reconsider our determination of discreteness.
General Comments Issue 9: Effect of the Delisting on Local Conservation
Planning Efforts
(19) Comment: A number of commenters were concerned that if the
pygmy-owl is delisted, the work of local communities will be undermined
with regard to ongoing conservation planning efforts.
Our Response: To the contrary, absent the protections of the Act,
we believe that these local conservation efforts are even more
important and can make significant contributions to the conservation of
the pygmy-owl in Arizona. This final rule in no way diminishes the
Service's mission to conserve fish and wildlife resources for the
benefit of the American people. Our determination is the result of
further analyses concerning our DPS policy and the direction of the
courts. We continue to support the conservation of the pygmy-owl using
all available conservation tools. We will continue to work in
coordination with local entities to complete the ongoing conservation
planning efforts. In addition, we will look for opportunities to use
other tools, such as candidate conservation agreements, to further the
conservation of the pygmy-owl. We will continue to coordinate with the
Arizona Game and Fish Department and other pygmy-owl researchers in
implementing conservation activities for this species.
General Comments Issue 10: Information on the Historical Distribution,
Current Numbers, Habitat Preferences, Population Trends, etc., as Basis
for a ``Not Significant'' Determination
(20) Comment: Some parties provided extensive information on the
historical distribution, current numbers, habitat preferences,
population trends, etc., in support of a ``not significant''
[[Page 19456]]
determination and the delisting the Arizona DPS of the pygmy-owl.
Our Response: The information provided (some of which are documents
not previously in the Service's record on this action) does not
constitute significant new information relevant to our determination.
Much of the content involves issues, data, analyses, and discussions
that have been debated since the listing of the Arizona DPS during
recovery planning and other processes associated with the pygmy-owl.
For example, the issues of historical occurrence of the pygmy-owl in
riparian vs. desert scrub communities, the interpretation of historical
data, current vs. historical range and associated population numbers,
the contribution to the overall population of pygmy-owls in Tucson and
northward as compared to those closer to Mexico have all been debated
during the development of the draft recovery plan, as well as critical
habitat proposals. There has been a history of scientific disagreement
regarding the interpretation of this information. Since our rationale
for a ``not significant'' determination is provided elsewhere in this
final rule, and because we do not believe this information is pertinent
to our determination, we do not address these comments here.
General Comments Issue 11: Numbers of Pygmy-Owls Outside of Arizona
(21) Comment: Some parties indicated that the additional pygmy-owls
located in Mexico since the listing in 1997 support the idea that the
Arizona DPS is not significant.
Our Response: As stated in a previous response, the significance of
a population is not solely related to the numbers of individuals within
that population. Populations may be significant to the taxon as a whole
through contributions to genetic variability, environmental adaptation,
and supplying emigrants to other populations. The Arizona DPS of the
pygmy-owl may well contribute to the taxon as a whole in these ways,
but our review of the available information did not indicate that this
contribution is significant (see ``Delisting Analysis'' below).
(22) Comment: The numbers of pygmy-owls in Mexico are also
declining, making the pygmy-owls in Arizona more significant to the
taxon.
Our Response: Information submitted during the public comment
period included one study that showed a short-term decline in the
number of pygmy-owl responses along the U.S./Mexico border. We
considered this study in determining whether loss of pygmy-owls in
northern Sonora, Mexico, would result in Arizona pygmy-owls occupying a
unique ecological setting (i.e., a desert habitat); however, we did not
find this to be the case (see ``Delisting Analysis'' below). This
information is more relevant to a discussion concerning the status of
an entity, in other words, whether the entity is threatened or
endangered under the definitions in the Act. The question at issue for
us was whether the Arizona population of pygmy owl is a valid listable
entity under the DPS policy. Since we determined that the discrete
population was not significant to the taxon as a whole, we are not
required to evaluate the status and therefore this information is
irrelevant to our determination.
(23) Comment: Other commenters stated that, even though the pygmy-
owl appears to be more common in Mexico than in Arizona, this does not
reduce the significance of the Arizona population because of ongoing
issues in Mexico, including the invasion of natural vegetation
communities by non-native species; the loss of soil organic carbon,
soil litter and vegetative cover; more intense drought effects,
including higher nighttime minimum temperature increasing
evapotranspiration; and increased fire.
Our Response: As stated in previous responses, these threats would
be considered in an evaluation of threatened or endangered status if we
had determined that the Arizona DPS was a listable entity under the DPS
policy.
General Comments Issue 12: Other DPS Configurations
(24) Comment: The Service should consider a DPS configuration for
all Sonoran Desert areas, including Sonora, Mexico.
Our Response: While we have initiated some work to evaluate the
potential of other DPS configurations through the development of the
December 2003 white paper, we note that we did not receive any new
information during the open comment period. Additional biological
research and evaluation of existing data are needed to determine
whether a different DPS configuration could be delineated consistent
with our DPS policy and whether such an entity would merit
consideration for listing.
Delisting Analysis
Application of the Significance Criteria to the Pygmy-Owl in Arizona
In the discussion below we evaluate the significance of the Arizona
DPS in light of our DPS policy and the Ninth Circuit's ruling in this
case. We considered the best available scientific information and
public comments in this analysis. Thus, information known at the time
of the listing of the pygmy-owl, as well as information obtained
subsequently, was considered.
(1) Persistence of the discrete population segment in an ecological
setting unusual or unique for the taxon.
Approximately 80 percent of the historical distribution of the
pygmy-owl falls within biotic communities classified as Forest,
Woodland, or Scrubland communities. This includes pygmy-owls of
southern Texas south through the Mexican states of Tamaulipas and Nuevo
Leon, which occupy mesquite forest, riparian forest, thorn forest,
tropical deciduous forest, heavy riparian forest, and areas more
tropical in nature, including cypress groves (Cartron et al. 2000;
Proudfoot and Johnson 2000; Leopold 1950). It also includes areas in
southern Sonora, Sinaloa, and Nayarit where pygmy-owls occur within the
tropical Sinaloan thornscrub and Sinaloan deciduous forest community
types and associated riparian communities (Leopold 1950; Brown 1994;
Phillips and Comus 2000).
Approximately 20 percent of the historical distribution, including
pygmy-owls in Arizona, south through western Mexico and into the state
of Sonora, falls within drier, desert-like communities, including
Desertlands and Grasslands. In Arizona, the pygmy-owl is found within
Sonoran Desert scrub or Semidesert Grassland biotic communities and
associated riparian and xeroriparian (dry washes) communities (Cartron
et al. 2000; Proudfoot and Johnson 2000). In northern Sonora, Mexico,
the ecological setting in which the pygmy-owl is found exhibits similar
ecological conditions to the range of the Arizona pygmy-owl with regard
to vegetation, climate, soils, etc. (Leopold 1950; Brown 1994; Phillips
and Comus 2000; http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://mexicochannel.net/maps/vegetation.gif; http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://mexicochannel.net/maps/fauna.gif; http://mexicochannel.net/maps/
icochannel.net/maps/
soils.gif; http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://mexicochannel.net/maps/temperatures.gif; http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://mexicochannel
.net/maps/climates.gif).
Approximately 45 percent of the pygmy-owl range supporting these
desert-like communities occurs in Arizona, with the remainder occurring
in Sonora, Mexico. These numbers indicate that, while the area of
Desertland and Grassland communities occupied by pygmy-owls within
their overall range is considerably less than the wetter, more tropical
vegetation
[[Page 19457]]
communities, Arizona does not support the only, or even a majority, of
these biotic communities within the historical range of the pygmy-owl.
In northern Sonora, Mexico, millions of acres of Sonoran Desert and
thornscrub are being converted to buffelgrass (Pennisetum ciliaris)
which represents both a direct and an indirect loss of habitat because
of invasion into adjacent areas and increased fire frequency and
intensity (Burquez-Montijo et al. 2002). This conversion of habitat may
ultimately result in the creation of an ecological setting in northern
Mexico that is very different than the Sonoran desert scrub currently
found in Mexico and Arizona. However, in determining the significance
of the Arizona DPS, we must consider the current conditions occupied by
the species. The direct and indirect threats associated with the
conversion of Sonoran desert scrub to exotic grasslands is more
appropriately considered under the determination of endangered or
threatened status rather than the significance of the DPS. We find that
there is not adequate information to indicate that Arizona pygmy-owls
occupy an ecological setting differing enough from pygmy-owls in
northern Sonora, Mexico, to be considered unique for the taxon.
(2) Evidence that loss of the discrete population segment would
result in a significant gap in the range of the taxon.
In the listing rule (March 10, 1997; 62 FR 10730), we found that
the gap in the range of the taxon through loss of the Arizona pygmy-
owls would be significant because it would (a) decrease the genetic
variability of the taxon; (b) reduce the current range of the taxon;
(c) reduce the historical range of the taxon; and (d) extirpate the
western pygmy-owls from the United States.
With regard to genetic variability, factor (a) above, in our
listing rule we were able to determine genetic distinctness between
western and eastern pygmy-owls; however, we did not have evidence of
genetic differences between pygmy-owls in Arizona and northwestern
Mexico. Proudfoot and Slack (2001) found that there were distinct
differences between pygmy-owls in Arizona and Texas. Their work also
showed genetic differences between pygmy-owls in eastern and western
Mexico. Dr. Proudfoot has conducted considerable work on pygmy-owl
genetics since the 2001 report. However, he has presented no new
information that would indicate that pygmy-owls in Arizona differ
markedly in their genetic makeup from other pygmy-owls within the
western population.
Genetic divergence tends to occur at the periphery of a species'
range (Lesica and Allendorf 1995). The peripheral nature of the Arizona
pygmy-owls may increase the potential for the population to diverge
from populations in Sonora and Sinaloa, Mexico at some point in the
future. However, significance must be judged based on the current facts
regarding the species, not on future possibilities. Because there is
currently no indication that pygmy-owls in Arizona are genetically
distinct from those in northern Sonora, we have no evidence to suggest
that the contribution of the Arizona DPS to the genetic diversity of
this species as a whole is significant.
With regard to factor (b), a reduction in current range, the court
looked to other DPS rules and findings published by the Service. In
particular, the court looked at the Service's DPS listing of the
northern bog turtle (November 4, 1997, 62 FR 59605) and the 12-month
finding for the yellow-billed cuckoo in the western continental United
States (July 25, 2001, 66 FR 38611). In summary, the court found that
determining a gap to be significant based on the curtailment of a
taxon's current range requires the loss of a geographic area that
amounts to a substantial reduction of a taxon's range. In this case,
the taxon's (Glaucidium brasilianum cactorum) range includes both the
western and eastern pygmy-owl populations, occurring from lowland
central Arizona south through western Mexico to the States of Colima
and Michoacan, and from southern Texas south through the Mexican states
of Tamaulipas and Nuevo Leon. As stated in the 1997 listing rule,
Arizona pygmy-owls would only represent a small percentage of the total
range of the taxon. Our reevaluation of the current distribution of the
pygmy-owl indicates that Arizona makes up approximately 5 percent of
the entire range. We do not believe that this is sufficient evidence to
support a determination that loss of Arizona pygmy-owls represents a
substantial reduction in the taxon's range based on the geographic area
which would be lost. Therefore we find that the geographic area of the
current range that would be lost, in and of itself, is not significant.
The current range of the pygmy-owl in Arizona could also be
significant if the population in Arizona is numerous or constitutes a
significant percentage of the total number of pygmy-owls within the
taxon, the loss of which would be a significant gap in the population.
However, pygmy-owls in Arizona are not numerous, nor do we believe that
they represent a significant percentage of the pygmy-owls within the
taxon. We do not find that the numbers of pygmy-owls in Arizona, both
currently and historically, represent a basis for determining that the
loss of the Arizona DPS would result in a significant gap in the
population numbers of the taxon as a whole.
With regard to factor (c) above, we found in our listing rule that
the gap would be significant because the loss of the Arizona pygmy-owls
would reduce the historical range of the taxon. We found this to be
true because the Arizona population is at the periphery of the western
pygmy-owls' historical range, and that this peripheral population was
always a stable portion of that range. We do believe that protection
and management of peripheral populations may be important to the
survival and evolution of species. Maintaining genetic diversity within
the western population and the taxon as a whole is even more important
in the face of documented land use changes, primarily effects from
converting native vegetation to agricultural crops and buffelgrass
pastures for livestock grazing, in Mexico (Burquez and Martinez-Yrizar
1997). Peripheral populations often persist when core populations are
extirpated (Channell and Lomolino 2000a, 2000b; Lomolino and Channell
1995). In the face of changing environmental conditions, what
constitutes a peripheral population today could be the center of the
species' range in the future (Nielsen et al. 2001). Peripheral
populations survive more frequently than do core populations when
species undergo dramatic reductions in their range (>75 percent;
Channell and Lomolino 2000a). However, the court found that this factor
alone does not make Arizona a ``major geographical area'' in the
western pygmy-owl's historical range.
Arizona makes up only about 12 percent of the historical range of
the pygmy-owl, and we do not find that the loss of 12 percent of the
historical range represents a significant geographic area. We found no
information indicating that the population of pygmy-owls found in this
12 percent of the historical range made contributions to the entire
taxon that were unique to Arizona. We have not found sufficient
information to indicate that the contribution of this historical
proportion of the range contributes to the long-term survival of the
species. Additionally, as noted above, we also do not have evidence
that the historical range of the pygmy-owl in Arizona supported a
marked genetic difference between Arizona pygmy-owls and pygmy-owls in
western Mexico. Because we found that the 12
[[Page 19458]]
percent of the pygmy-owl's historical range found in Arizona does not
constitute a major geographic area, nor does it, as a peripheral
population, contribute significantly to the overall genetic diversity
of the species, we are unable to determine that the loss of the Arizona
DPS would represent a significant gap in the range of the pygmy-owl
based on the reduction of the historical range.
With regard to (d) above, we determined that a gap would be
significant because it would deprive the United States of its portion
of the western pygmy-owl's range. The Ninth Circuit rejected this
argument as a misconstruction of this criterion. The court found that
in designating a DPS under the DPS policy, we must find that a discrete
population is significant to the taxon as whole, not to the United
States. We determined in our listing rule that Arizona pygmy-owls
represented only ``a small percentage'' of the total range of the
western pygmy-owls. As noted above, the taxon includes both the western
and eastern pygmy-owl populations, occurring from lowland central
Arizona south through western Mexico to the States of Colima and
Michoacan, and from southern Texas south through the Mexican States of
Tamaulipas and Nuevo Leon. We do not believe that we have sufficient
evidence to support a determination that the Arizona pygmy-owls
represent a significant portion of the geographical range of the taxon
in light of the court's finding that we can not rely on the value of
the United States' portion of the range in applying the DPS policy.
(3) Evidence that the discrete population segment represents the
only surviving natural occurrence of the taxon that may be more
abundant elsewhere as an introduced population outside its historical
range.
This criterion does not apply to the pygmy-owl.
(4) Evidence the discrete population segment differs markedly from
other populations of the taxon in its genetic characteristics.
As discussed above, a marked difference between the eastern and
western pygmy-owl population segments has been documented, but no
information exists that provides evidence to support that there is a
marked genetic difference between pygmy-owls in Arizona and the rest of
the western population of pygmy-owls.
Effects of the Final Rule
This action removes the Arizona DPS of the pygmy-owl from the List
of Endangered and Threatened Wildlife. The prohibitions and
conservation measures provided by the Act no longer apply to this
species. Federal agencies are no longer required to consult with us on
their actions that may affect the pygmy-owl and to insure that any
action they authorize, fund, or carry out is not likely to jeopardize
the continued existence of the pygmy-owl. At this time we can't
speculate about the future of lands conserved through previous section
7 consultations. The conservation of those lands will depend upon the
mechanisms by which they were conserved and the purpose of the
conservation. Federal agencies are also relieved of their
responsibilities under section 7(a)(1) of the Act to use their
authorities to further the conservation of the pygmy-owl. Additionally,
we will not finalize the designation of critical habitat nor will we
complete a final recovery plan. The critical habitat designation for
the pygmy-owl, as described in 50 CFR 17.95, is removed.
Currently, we provide technical assistance to the public to
minimize effects from non-Federal projects to the pygmy-owls and their
habitat. We will likely no longer receive these types of requests.
Permitted scientific take as a result of surveys and research will
likely continue to be regulated by the State of Arizona, Arizona Game
and Fish Department, and will be considered in the context of potential
effects to population stability.
Future Conservation Measures
The 1988 amendments to the Act require that all species delisted
due to recovery be monitored for at least five years following
delisting. The pygmy-owl is being delisted because it fails to meet the
criteria outlined in our DPS policy and, therefore, does not qualify as
a listable entity. Therefore, no monitoring period following delisting
is required.
Required Determinations
Paperwork Reduction Act
OMB regulations at 5 CFR 1320, which implement provisions of the
Paperwork Reduction Act, require that Federal agencies obtain approval
from OMB before collecting information from the public. Implementation
of this final rule does not include any collection of information that
requires approval by OMB under the Paperwork Reduction Act.
National Environmental Policy Act (NEPA)
We have determined that Environmental Assessments and Environmental
Impact Statements, as defined under the authority of the National
Environmental Policy Act of 1969, need not be prepared in connection
with regulations adopted pursuant to section 4(a) of the Endangered
Species Act of 1973, as amended. A notice outlining our reasons for
this determination was published in the Federal Register on October 25,
1983 (48 FR 49244).
References Cited
A complete list of references cited in this final rule is available
from the Arizona Ecological Services Field Office (see ADDRESSES).
Authors
The primary authors of this document are staff located at the
Arizona Ecological Services Office (see ADDRESSES).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Regulation Promulgation
0
Accordingly, we hereby amend part 17, subchapter B of Chapter I, title
50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
Sec. 17.11 [Amended]
0
2. Amend Sec. 17.11(h) by removing the entry for ``Pygmy-owl, cactus
ferruginous'' under ``BIRDS'' from the List of Endangered and
Threatened Wildlife.
Sec. 17. 95 [Amended]
0
3. Amend Sec. 17.95(b) by removing designated critical habitat for
``Cactus Ferruginous Pygmy-Owl (Glaucidium brasilianum cactorum)''
under ``BIRDS''.
Dated: April 3, 2006.
H. Dale Hall,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 06-3470 Filed 4-13-06; 8:45 am]
BILLING CODE 4310-55-P