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, 19452-19458 [06-3470]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 71, Number 72 (Friday, April 14, 2006)]
[Rules and Regulations]
[Pages 19452-19458]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3470]


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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; https://mexicochannel.net/maps/vegetation.gif; https://
mexicochannel.net/maps/fauna.gif; https://mexicochannel.net/maps/
soils.gif; https://mexicochannel.net/maps/temperatures.gif; https://
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