Endangered and Threatened Wildlife and Plants; Final Rule To List Six Foreign Birds as Endangered, 3146-3179 [E8-492]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 11 (Wednesday, January 16, 2008)]
[Rules and Regulations]
[Pages 3146-3179]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-492]



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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Final Rule To List Six 
Foreign Birds as Endangered; Final Rule

Federal Register / Vol. 73, No. 11 / Wednesday, January 16, 2008 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R1-JA-2008-007; 96100-1671-000; 1018-AT62]


Endangered and Threatened Wildlife and Plants; Final Rule To List 
Six Foreign Birds as Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
endangered status for six avian species--black stilt (Himantopus 
novaezelandiae), caerulean paradise-flycatcher (Eutrichomyias rowleyi), 
giant ibis (Pseudibis gigantea), Gurney's pitta (Pitta gurneyi), long-
legged thicketbird (Trichocichla rufa), and Socorro mockingbird (Mimus 
graysoni)--under the Endangered Species Act of 1973, as amended (Act). 
This rule implements the protection of the Act for these six species.

EFFECTIVE DATE: This final rule is effective February 15, 2008.

ADDRESSES: The supporting file for this rule is available for public 
inspection, by appointment, during normal business hours, Monday 
through Friday, in Suite 110, 4401 N. Fairfax Drive, Arlington, 
Virginia 22203.

FOR FURTHER INFORMATION CONTACT: Dr. Patricia De Angelis, at the above 
address; by fax to 703-358-2276; by e-mail to 
ScientificAuthority@fws.gov; or by telephone, 703-358-1708.

SUPPLEMENTARY INFORMATION:

Background

    In this final rule, we determine endangered status for six foreign 
bird species under the Act (16 U.S.C. 1531 et seq.): Black stilt 
(Himantopus novaezelandiae), caerulean paradise-flycatcher 
(Eutrichomyias rowleyi), giant ibis (Pseudibis gigantea), Gurney's 
pitta (Pitta gurneyi), long-legged thicketbird (Trichocichla rufa), and 
Socorro mockingbird (Mimus graysoni).

Previous Federal Action

    Section 4(b)(3)(A) of the Act requires us to make a finding (known 
as a ``90-day finding'') on whether a petition to add, remove, or 
reclassify a species from the list of endangered or threatened species 
has presented substantial information indicating that the requested 
action may be warranted. To the maximum extent practicable, the finding 
shall be made within 90 days following receipt of the petition and 
published promptly in the Federal Register. If we find that the 
petition has presented substantial information indicating that the 
requested action may be warranted (a positive finding), section 
4(b)(3)(A) of the Act requires us to commence a status review of the 
species if one has not already been initiated under our internal 
candidate assessment process. In addition, section 4(b)(3)(B) of the 
Act requires us to make a finding within 12 months following receipt of 
the petition on whether the requested action is warranted, not 
warranted, or warranted but precluded by higher-priority listing 
actions (this finding is referred to as the ``12-month finding''). 
Section 4(b)(3)(C) of the Act requires that a finding of warranted but 
precluded for petitioned species should be treated as having been 
resubmitted on the date of the warranted but precluded finding, and is 
therefore subject to a new finding within 1 year and subsequently 
thereafter until we take action on a proposal to list or withdraw our 
original finding. The Service publishes an annual notice of resubmitted 
petition findings (annual notice) for all foreign species for which 
listings were previously found to be warranted but precluded.
    On November 24, 1980, we received a petition (1980 petition) from 
Dr. Warren B. King, Chairman, United States Section of the 
International Council for Bird Preservation (ICBP), to add 79 bird 
species (19 native and 60 foreign) to the List of Endangered and 
Threatened Wildlife (50 CFR 17.11(h)), including the black stilt and 
the long-legged thicket bird (or, long-legged warbler, which was the 
common name used in the petition). In response to the 1980 petition, we 
published a positive 90-day finding on May 12, 1981 (46 FR 26464), for 
77 of the species (19 domestic and 58 foreign), noting that 2 of the 
foreign species identified in the petition were already listed under 
the Act, and initiated a status review. On January 20, 1984, we 
published an annual review on pending petitions and description of 
progress on all petition findings addressed therein (49 FR 2485). In 
that notice, we found that listing all 58 foreign bird species from the 
1980 petition, including the black stilt and the long-legged 
thicketbird, was warranted but precluded by higher-priority listing 
actions. On May 10, 1985, we published the first annual notice (50 FR 
19761) in which we continued to find that listing all 58 foreign bird 
species from the 1980 petition was warranted but precluded. In our next 
annual notice, published on January 9, 1986 (51 FR 996), we found that 
listing 54 species from the 1980 petition, including the black stilt 
and the long-legged thicketbird, continued to be warranted but 
precluded, whereas new information caused us to find that listing four 
other species in the 1980 petition was no longer warranted. We 
published additional annual notices on the species included in the 1980 
petition on July 7, 1988 (53 FR 25511); December 29, 1988 (53 FR 
52746); April 25, 1990 (55 FR 17475); and November 21, 1991 (56 FR 
58664), in which we indicated that the black stilt and the long-legged 
thicketbird continued to be warranted but precluded.
    On May 6, 1991 (1991 petition), we received a petition from Alison 
Stattersfield, of ICBP, to list 53 additional foreign birds under the 
Act. The caerulean paradise-flycatcher, giant ibis, Gurney's pitta, and 
Socorro mockingbird were included in the 1991 petition. On December 16, 
1991, we published a positive 90-day finding and announced the 
initiation of a status review of the 53 foreign birds listed in the 
1991 petition (56 FR 65207). The 1991 petition included the giant ibis, 
Gurney's pitta, Socorro mockingbird, and caerulean paradise-flycatcher 
among the 53 foreign birds that the petitioner requested be listed 
under the Act. On March 28, 1994 (59 FR 14496), we published a proposed 
rule to list 30 African bird species from both the 1980 and 1991 
petitions. In the same Federal Register document, we included a notice 
of findings in which we announced our determination that listing the 38 
remaining species from the 1991 petition was warranted but precluded; 
this group included the giant ibis, Gurney's pitta, Socorro 
mockingbird, and caerulean paradise-flycatcher. On May 21, 2004 (69 FR 
29354), we published an annual notice of findings on resubmitted 
petitions for foreign species and annual description of progress on 
listing actions (2004 annual notice) within which we ranked species for 
listing by assigning them a Listing Priority Number per the Service's 
listing priority guidelines, published on September 21, 1983 (48 FR 
43098). Based on this ranking and priorities, we determined that 
listing five of the previously petitioned species--the black stilt, 
caerulean paradise-flycatcher, giant ibis, Gurney's pitta, and Socorro 
mockingbird--was warranted. In the same 2004 annual notice, we 
determined that the long-legged thicketbird and 16 other species no 
longer warranted listing on the basis that those species were likely 
extinct. In response to the 2004 annual notice, we

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received information indicating that the long-legged thicketbird had 
been rediscovered, in small numbers, in 2002. The magnitude of the 
threat to the species was perceived as high and the immediacy of threat 
imminent. Therefore, we assigned this species a listing priority 
ranking of 1, which ranking is reserved specifically for a monospecific 
genus, and determined that listing the species was warranted at that 
time.
    On November 22, 2006 (71 FR 67530), we published a Federal Register 
notice to list black stilt, caerulean paradise-flycatcher, giant ibis, 
Gurney's pitta, long-legged thicketbird, and Socorro mockingbird as 
endangered. We implemented the Service's peer review process and opened 
a 60-day comment period to solicit scientific and commercial 
information on the species from all interested parties following 
publication of the proposed rule.

Summary of Comments and Recommendations

    In the proposed rule of November 22, 2006 (71 FR 67530), we 
requested that all interested parties submit information that might 
contribute to development of a final rule. We received five comments: 
two from members of the public and one each from the governments of 
Cambodia, Fiji, and Mexico. In accordance with our policy, ``Notice of 
Interagency Cooperative Policy for Peer Review in Endangered Species 
Act Activities,'' published on July 1, 1994 (59 FR 34270), we also 
sought the expert opinion of at least three appropriate independent 
specialists regarding the proposed rule.
    Comment 1: Four commenters supported the proposed listings, 
including the governments of Cambodia, Fiji, and Mexico. The government 
of Cambodia ``strongly endorsed[d] the proposal of giant ibis to be 
listed in [the] U.S. Endangered Species Act. The Fijian government 
noted that the benefits of listing the long-legged thicketbird under 
the Act are ``perhaps marginal'' but that a listing could help where 
species, such as the thicketbird, are not listed in the Appendices of 
the Convention on International Trade in Endangered Species of Wild 
Fauna and Flora (CITES) because trade in the wild bird is not a concern 
at this time. The potential funding and technical support (see 
Available Conservation Measures) for the development of management 
programs for the conservation of species in foreign countries could be 
beneficial to the thicketbird in Fiji. Similarly, the government of 
Mexico commented that listing the Socorro mockingbird under the Act 
would support its ongoing efforts and additional actions to be 
undertaken by the Mexican government, including scientific 
investigations, in order to protect the species.
    Our Response: While general support of a listing is not, in itself, 
a substantive comment that we take into consideration as part of our 
five-factor analysis, we appreciate the support of these range 
countries. Cooperation is important to the conservation of foreign 
species.
    Comment 2: One researcher opposed the listing of the long-legged 
thicketbird on the basis that the species is not endangered, but merely 
elusive to the inexperienced or to those with an uneducated eye.
    Our Response: We have taken into account in our review of the long-
legged thicketbird the bird's elusive behavior. However, we believe 
that we have used the best available scientific information in our 
status review and have accurately determined the appropriate threat 
status for this species.
    Comment 3: One commenter recommended that the term kak[iuml] be 
used to refer to the black stilt throughout the rule, as it is the 
preferred name in New Zealand.
    Our Response: We have added this common name in the species 
description for the black stilt, but have chosen to use the common name 
``black stilt'' throughout the rule and in the list because the federal 
listing will be categorized under the species grouping ``stilt.''
    Several commenters provided additional information on the species. 
This information has been considered and incorporated into the 
rulemaking as appropriate (as indicated in the citations by ``in 
litt.'').

Species Information and Factors Affecting the Species

    Under section 4(a) of the Act (16 U.S.C. 1533(a)(1)) and 
regulations promulgated to implement the listing provisions of the Act 
(50 CFR part 424.11), we may list a species as threatened and 
endangered on the basis of five threat factors: (A) Present or 
threatened destruction, modification, or curtailment of its habitat or 
range; (B) overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. Listing may be warranted based on 
any of the above threat factors, either singly or in combination.
    Under the Act, we may determine a species to be endangered or 
threatened. An endangered species is defined as a species which is in 
danger of extinction throughout all or a significant portion of its 
range. A threatened species is defined as a species which is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. Therefore, we evaluated the 
best available scientific and commercial information on each species 
under the five listing factors to determine whether they met the 
definition of endangered or threatened.
    Following is a species-by-species analysis of these five factors. 
The species are considered in alphabetical order: Black stilt, 
caerulean paradise-flycatcher, giant ibis, Gurney's pitta, long-legged 
thicketbird, and Socorro mockingbird.

I. Black stilt (Himantopus novaezelandiae)

Species Description

    The black stilt is a wading bird in the family Recurvirostridae. It 
is native to New Zealand and is locally known there by its Maori name 
``kaki.'' Adults are characterized by long red legs, a slender bill and 
black plumage (BirdLife International (BLI) 2007a; New Zealand 
Conservation Management Group (NZ CMaG 2007). Adult males and females 
are generally regarded as having identical plumage (BLI 2007e); 
however, Elkington and Maloney (2000) determined that white flecking 
around their eyes and crown is generally indicative of older males. 
Juveniles have a white-plumed breast, neck, and head (BLI 2007e). Black 
and pied stilt (Himantopus himantopus) hybridize (see Taxonomy, below), 
and hybrids are more varied in color, with varying gradations of white 
and black plumage, and varying body characteristics, such as shorter 
legs and longer bills (BLI 2007e; Department of Conservation (DOC) 
2007a; Maloney & Murray 2002; Reed et al. 2007).
    The species can reach 16 inches (in) (40 centimeters (cm)) (BLI 
2007e) in height, with a wingspan of 23 in (58 cm). The average age of 
birds in the current population is 6 years (BLI 2007e; Maloney & Murray 
2002). The potential lifespan of the species is unknown, but the oldest 
recorded specimen, a banded female relocated in 1983, was estimated to 
be at least 12 years old (Pierce 1986b).

Taxonomy

    The black stilt was first taxonomically described by Gould in 1841 
and placed in the family Recurvirostridae. It is one of two stilt 
species in New Zealand, the other being the pied stilt (Pierce 1984a;

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Reed et al. 1993a). Where their ranges overlap, the black stilt may 
interbreed with its close relative, the pied stilt (Reed et al. 1993a). 
It is generally accepted that hybridization between these two species 
has been occurring only in the last two centuries, as the pied stilt 
expanded its range from Australia to New Zealand in the early 19th 
century (Greene 1999; Pierce 1984a; Reed et al. 1993a). During the late 
19th century, the frequency of hybrid sightings increased (Pierce 
1984b) but observers of the time did not realize that the two species 
were hybridizing, and the taxonomy of Himantopus species of New Zealand 
was the subject of much debate (Buller 1874; Potts 1872; Travers 1871). 
In 1984, Pierce (1984b) concluded on the basis of morphological, 
ecological, and behavioral differences that the two species remained 
distinct. Genetic analysis in the 20th century confirmed that the two 
species were undergoing introgressive hybridization, wherein viable 
offspring produced from the successful mating of two distinct species 
were subsequently capable of mating with parental species (Greene 
1999). From these studies, despite the genetic similarity between the 
two species, Greene (1999) concluded that the species remain distinct.

Habitat and Life History

    Black stilt habitat includes riverbanks, lakeshores, swamps, and 
shallow ponds (Maloney & Murray 2002; Pierce 1982; Potts 1872; Reed et 
al. 1993a). The species' habitat preferences shift slightly depending 
on the seasons, which are: Breeding (braided rivers, side streams, and 
swamps), post-breeding (riverbeds and shallow tarns), and wintering 
(inland waters or river deltas) (Maloney & Murray 2002). However, these 
habitats are often located within the same watershed, and the species 
is considered a primarily sedentary, nonmigrating species (Maloney & 
Murray 2002; Pierce 1986b). About 90 percent of the black stilt 
population overwinters in the Upper Waitaki Basin (UWB; in the central 
region of the South Island) by moving to inland areas to continue 
feeding on aquatic insects, including larvae of mayfly (Deleatidium 
sp.) and caddisfly (Olinga sp.), and, to a lesser extent, on mollusks 
and fish (DOC 2007a; Reed et al. 1993a). Researchers believe that the 
black stilt's long legs allow them to wade out into the deeper, 
unfrozen sections of rivers where they can continue foraging throughout 
the winter (DOC 2007a; Reed et al. 1993a).
    A small percentage (about 10 percent) of the population migrates to 
coastal Canterbury on South Island or Northern Island coastal areas in 
the winter, from February to June, before returning to the UWB to breed 
in July and August (BLI 2007e; Maloney & Murray 2002: NZ CMaG 2007; 
Pierce 1984a; Pierce 1996; Reed et al. 1993a). Reed et al. (1993a) 
believe that this migratory behavior has resulted from hybridization 
with the pied stilt (which migrates to coastal waters in the winter) 
(Dowding & Moore 2006). In the absence of a suitable mate of the same 
species, black stilts will mate and produce hybrid offspring with the 
pied stilt (BLI 2007e; DOC 2007a; Maloney & Murray 2002; Reed et al. 
1993a). Mixed pairs (a black stilt paired with a pied stilt) and their 
offspring are more likely to participate in migratory behavior (Dowding 
& Moore 2006; Reed et al. 1993a). Hybridization is discussed further 
under Factor E.
    Black stilts reach adulthood around 18 months of age, attaining 
sexual maturity between 2 and 3 years of age. They mate for life, nest 
in solitary pairs (often miles (kilometers) from another pair), and 
exhibit high nesting fidelity (returning to the same location to nest 
each year) (BLI 2007e; DOC 2007a; Maloney & Murray 2002; Pierce 1984a; 
Reed et al. 1993a). The breeding season begins in July or August and 
egg-laying occurs from September to December (BLI 2007e; Maloney & 
Murray 2002; NZ CMaG 2007). Ground-nesting birds, black stilts prefer 
open nesting sites, such as dry, stable riverbanks (Maloney & Murray 
2002; Pierce 1982; Pierce 1986b; Reed et al. 1993a). They lay a typical 
clutch size of four eggs and have a lengthy fledging period of 40 to 55 
days (the amount of time it takes birds to hatch and leave the nest) 
(Maloney & Murray 2002). Both sexes share the nesting responsibility 
(Maloney & Murray 2002; Pierce 1986b; Pierce 1996; Sanders & Maloney 
2002). Eggs are incubated by both sexes for 25 days, and pairs will 
often re-nest if the first clutch is lost early in the season (BLI 
2007e; Reed et al. 1993a; Maloney & Murray 2002; NZ CMaG 2007). Chicks 
are precocial (the young are relatively mature and mobile from the 
moment of hatching) and capable of feeding themselves within hours of 
hatching (DOC 2007a; Reed et al. 1993a). After fledging, chicks stay 
with parents until the beginning of the following breeding season 
(Maloney & Murray 2002).
    The black stilt's breeding success in the wild is very low. For 
example, according to Maloney and Murray (2002), from 1977 to 1979, of 
33 chicks that hatched in unmanaged nests, only 2 individuals (or 6.1 
percent) survived to fledge (i.e., lived long enough to leave the 
nest). Overall breeding success (nesting success plus fledging success) 
for the same period was 0.9 percent. Recruitment, defined by Maloney 
and Murray (2002) as the number of chicks attaining 2 years of age, is 
only about 4 percent.
    Reproductive potential does not appear to be the primary limiting 
factor to the black stilt's breeding success and recruitment rates. The 
black stilt has high reproductive capability, first reproducing at age 
2 and continuing to produce multiple clutches in captivity to at least 
age 13 plus (Maloney & Murray 2002; Reed 1998). The species has high 
fecundity, producing clutches of one to four eggs every breeding 
season, and will re-nest if clutches are lost early in the season (BLI 
2007e; Reed et al. 1993a; Maloney & Murray 2002). Moreover, a review of 
captive breeding records from two breeding seasons (1981 to 1982 and 
2001 to 2002) found that the survival rate of captive-bred stilts 
reintroduced to the wild at 2 months and 10 months increased to 88 
percent and 82 percent, respectively (Van Heezik et al. 2005).

Historical Range and Distribution

    When it was described in 1841, the species' range included both the 
North and South Islands of New Zealand (Pierce 1984a). Its range has 
contracted twice in the 20th century: Once in the 1940s, when the 
breeding range became restricted to the South Island, and again in the 
1960s, when the UWB became their only breeding area (Maloney & Murray 
2002; Pierce 1984a; Reed et al. 1993a).
    As the black stilt's range contracted, researchers noticed that the 
pied stilt's range had increased (Pierce 1984a). In the last quarter of 
the 19th century, both black and pied stilts were considered common 
across South Island (Buller 1874, 1878; Travers 1871). By the 1980-1981 
breeding season, the estimated number of pied stilts in the UWB was 
between 1,500 and 2,000 (Pierce 1984a). At the same time, only 23 black 
stilt adults were known in the wild (Maloney & Murray 2002; Van Heezik 
et al. 2005). Experts considered whether the black stilts were being 
competitively excluded by the pied stilt and found that this was not 
the case. Black stilts and pied stilts prefer slightly different 
feeding areas (black stilts forage in riffles and pied stilts at pools) 
(Pierce 1986a); black stilts are better foragers than pied stilts 
(employing a greater variety of foraging techniques that allow them to 
obtain more food) (DOC 2007a; Pierce 1986a; Reed et al. 1993a); also, 
black stilts are territorially dominant over pied stilts when breeding 
areas overlap (Maloney & Murray 2002). From

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this work, researchers concluded that the decreasing range and numbers 
of black stilts in the face of the increasing pied stilt population 
reflected the black stilt's inability to adapt as readily to man-
induced changes, namely, the introduction of predators and habitat 
modification (Pierce 1986a, 1986b; Maloney & Murray 2002: Reed et al. 
1993a). Historical declines were attributed primarily to predation by 
mammals introduced in the 19th century and secondarily to habitat loss 
and hybridization with the pied stilt (Pierce 1984b; Reed et al. 1993a, 
1993b).
    For a primarily sedentary species, the black stilt requires a 
fairly large area for feeding and nesting. In counts conducted between 
1991 and 1994, Maloney (1999) found less than one black stilt for every 
3 mi (5 km) of river surveyed. The species' tendency to overwinter 
inland requires sufficiently large areas of river habitat to allow for 
continuous year-round feeding (DOC 2007a; Reed et al. 1993a). Life 
history traits, such as lifelong pair-bonding combined with high 
nesting fidelity (returning to the same location to nest each year) and 
solitary nesting combined with their preference for open nesting sites 
(often miles from another pair), contribute to the highly dispersed 
nature of the population and their resultant large habitat requirement 
(Maloney & Murray 2002; Pierce 1982, 1986b; Reed et al. 1993a).

Current Range and Distribution

    The current range of the black stilt is estimated to be an 821 
square mile (mi\2\) (2,830 square kilometer (km\2\)) area in the 
``braided-river'' habitat of the UWB (BLI 2007e). Located on the 
eastern side of the Southern Alps, in central South Island, New 
Zealand, the following rivers and lakes comprise the braided river 
habitat: Tasman, Godley, Hopkins, Ahuriri, Tekapo, Cass, Dobson, 
Macaulay, Lower Ohau, Pukaki and Upper Ohau, as well as Lakes Ohau and 
Pukaki (Maloney et al. 1997). The UWB population is sometimes referred 
to in the literature as the Mackenzie Basin population (for example, in 
Reed et al. 1993a). According to Dr. Richard Maloney of the Department 
of Conservation, Twizel, New Zealand (in litt. November 2007), although 
the two areas represent slightly different geographical boundaries, the 
black stilt population being referred to is the same in either 
instance. Because habitat quality in the species' present range is 
considered to be higher than in other former localities, the species is 
managed in situ (Maloney & Murray 2002).
    The black stilt is considered locally extinct in 9 of the 13 
Department of Conservation Conservancy Districts, occurring only in 2 
districts (Canterbury and Otaga) on the South Island and 2 (Waikata and 
Bay of Plenty) on the North Island (Hitchmough 2002). The majority of 
the population remains in the UWB, on the South Island, year round (BLI 
2007e; Maloney & Murray 2002: Pierce 1984a; Reed et al. 1993a; NZ CMaG 
2007), and their breeding range is now entirely confined to the 
wetlands and rivers of the UWB (Maloney & Murray 2002; Pierce 1984a).

Population Estimates

    The wild black stilt population has undergone severe reductions in 
numbers concomitant with the reduction in range area. In the 1950s, the 
total population was estimated at 500 to 1,000 birds; however, within 
one decade the population decreased to between 50 to 100 birds (Pierce 
1996).
    Since 1981, the New Zealand Department of Conservation has 
intensively managed the wild black stilt population, including the 
establishment of a captive population (Maloney & Murray 2002; Reed 
1998; Reed et al. 1993a, 1993b). The captive breeding program entails 
the transfer of ``eggs, chicks, juveniles and sub-adults from one part 
of the range to any other part of the range'' (R. Maloney in litt. 
October 2007). For further discussion on the captive breeding program, 
see ``Management Plans,'' under Factor D.
    Since the establishment of the captive breeding program, the 
Department of Conservation has managed the global population of black 
stilts, including captive-held and wild birds, as a single breeding 
population (R. Maloney in litt. November 2007). Wild and reintroduced 
birds are free to move across the full geographical range of the 
species. Thus, the number of adults in the wild should be considered in 
conjunction with the number of breeding pairs held in captivity. 
According to Dr. Maloney (in litt. October 2007), a total wild 
population number, including immature individuals, ``is not 
informative'' because the total wild population is dependent on how 
many young the breeding program produces and releases each year. The 
number of breeding pairs is more informative as an indicator of the 
status of the population (R. Maloney in litt. November 2007). The 
number of available females is particularly important because of the 
species' tendency to hybridize with pied stilt when male black stilts 
are unable to find suitable mates (see Factor E) (Maloney & Murray 
2002).
    Wild population estimates: From 1975 to 1979, there were an 
estimated 50 to 60 adults in the wild (Pierce 1984a); by 1981, only 23 
adults remained in the wild (Maloney & Murray 2002; Van Heezik et al. 
2005). In August 2000, there were 48 adults in the wild, of which 15 to 
18 were females. As of February 2007, the wild adult population 
consisted of 87 adults, including 17 productive pairs and a total of 41 
females (DOC 2007b).
    Captive-held population numbers: Throughout the 1980s, an average 
of 15 birds was managed in captivity (Reed et al. 1993a). In 1998, the 
number of managed birds reached 48 individuals. At that time, it was 
decided that the captive-held population should be maintained at 
approximately 6 breeding pairs. It was further determined that, in 
order to maintain a genetic diversity among the breeding stock, a base 
population of at least 18 breeding adults and juveniles would be 
maintained as replacement stock and, barring a catastrophic loss of the 
wild population, only first-generation captive stock would be used for 
breeding (Reed 1998). As of 2007, the captive breeding program 
consisted of 15 adults, including 6 productive pairs (DOC 2007b).
    The black stilt is considered to be one of the rarest wading birds 
in the world (BLI 2007e; Caruso 2006; Reed et al. 1993a). Since 1994, 
the species has been categorized by the World Conservation Union (IUCN) 
as ``Critically Endangered'' (BLI 2007a). The species' continued 
existence in the wild today is considered a direct result of the 
captive breeding program (Maloney & Murray 2002; Reed et al. 1993a; Van 
Heezik et al. 2005). According to the priority management ranking 
system devised by Molloy and Davis (1992) for the New Zealand 
Department of Conservation, the species was ranked as a Category ``A'' 
species, which includes the ``highest priority threatened species'' 
(Hitchmough et al. 2005; Reed et al. 1993a). Under New Zealand 
Department of Conservation's management system devised in 2002, the 
black stilt is classified as ``Nationally Critical'' (Hitchmough et al. 
2005). In the 2004 to 2005 breeding season, 7 pairs of captive-held 
black stilt and 12 pairs in the wild produced ``up to 100 birds per 
year for release into the wild'' (NZ CMaG 2007).

Summary of Factors Affecting the Black Stilt

A. The Present or Threatened Destruction, Modification, or Curtailment 
of the Black Stilt's Habitat or Range

    Today, it is estimated that only 10 percent of New Zealand's 
wetlands remain intact (Caruso 2006). The

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braided river habitat of UWB is a globally rare ecosystem. With an 
estimated area of 3,664 mi\2\ (9,490 km\2\), the UWB may account for 50 
to 60 percent of the remaining suitable braided river habitat in New 
Zealand (Caruso 2006; Maloney et al. 1997). The UWB is the only 
breeding ground for the black stilt and most of the population remains 
in the UWB year-round (Maloney & Murray 2002; Pierce 1984a; Reed et al. 
1993a).
    Several factors affect the quality of black stilt breeding and 
nesting grounds. Among the most significant impacts to the UWB has been 
the diversion of rivers for hydroelectric power (HEP) development 
(Caruso 2006; Collar et al. 1994a; Maloney 1999). Since 1935, eight HEP 
plants have been built on rivers, floodplains, and wetlands associated 
with the UWB (Caruso 2006). The damming of rivers for HEP and flood 
control projects has reduced river flows and interrupted the natural 
flooding cycles vital to the creation and maintenance of the open 
gravel braided river system of the UWB. It is estimated that 
floodplains have been reduced by 17 percent in the 11 major rivers of 
the UWB (Caruso 2006; Maloney & Murray 2002).
    Disturbance by recreational users of riverbeds and riversides also 
affects black stilt habitat within the UWB (Maloney & Murray 2002). The 
riverine habitat where black stilts live and nest is a prime outdoor 
recreation area. According to the New Zealand Ministry for the 
environment (NZ MFE 2007), recreational activities include water sport 
fishing, mountain biking, four-wheel driving, and jet skiing. Central 
South Island Fish and Game New Zealand manages the Waitaki Catchment 
(which includes rivers of the UWB and associated wetlands) and 
considers the Catchment to be ``outstanding publicly accessible game 
bird hunting and waterfowl habitat'' (NZ MFE 2007). According to the 
New Zealand Ministry for the Environment (NZ MFE 2007), recreational 
use and impacts on the areas of the Waitaki Catchment are predicted to 
increase. The New Zealand Ministry for the Environment (2007) does not 
address the effect that increased recreational activities will have on 
the black stilt or other native species (See also Factor D). Maloney 
and Murray (2002) indicate that the species does not tolerate human 
disturbance. Recreational activities that are disruptive to the black 
stilt's life cycle are considered to be a potentially serious threat to 
the species (R. Maloney in litt. February 2007). Indiscriminate use of 
off-road vehicles and jet-boats, disturbance by hikers and dogs, and 
fishing and camping activities are disruptive to black stilts (Maloney 
& Murray 2002). Recreational use of riverbed sites disturbs nesting 
birds and prevents successful rearing of offspring (BLI 2007e).
    Additional impacts on black stilt habitat include drainage for 
fields or irrigation, overgrazing of wetlands, and water extraction for 
agricultural irrigation (Caruso 2006; Collar et al. 1994a; Maloney & 
Murray 2002). Since 1850, 40 percent of UWB wetlands have been drained 
for farming (Caruso 2006). Proliferation of introduced weeds is a 
problem (Maloney & Murray 2002). Invasive plants, especially the crack 
willow (Salix fragilis), introduced by settlers as windbreaks, degrade 
black stilt habitat by contributing to an overgrowth in formerly open 
areas (Caruso 2006; Collar et al. 1994a; Maloney & Murray 2002: Pierce 
1996; Reed et al. 1993).

Summary of Factor A

    The black stilt's primary habitat and only known nesting ground 
within the UWB is a globally rare ecosystem that is being altered by 
water diversion, wetland conversion, invasive species, and recreation. 
Lack of suitable habitat for feeding and nesting increases the species' 
risk of extinction. The species does not tolerate human disturbance, 
and recreational activities within the species' riverside nesting 
grounds has the potential to disrupt the species' breeding success. 
Reduction in habitat quality is likely to increase the vulnerability of 
black stilt to predation (see Factor C). We find that the black stilt 
population is at significant risk throughout all of its range by the 
present or threatened destruction, modification, or curtailment of its 
habitat.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes et al.here is no known threat to the species from 
use for commercial, recreational, scientific, or educational purposes. 
The species has not been formally considered for listing in the 
Appendices of CITES (https://www.cites.org).

C. Disease or Predation

    There are currently no known diseases affecting the black stilt in 
the wild. Jakob-Hoff (2001) of the Auckland Zoo Wildlife Health and 
Research Centre, New Zealand, conducted a risk assessment for disease 
transmission caused by the translocation of captive black stilt to the 
wild population. The assessment considered a number of ``diseases of 
concern'' that may potentially threaten the wild population, including 
salmonellosis, yersiniosis, campylobacteriosis, pasteurellosis (fowl 
cholera), capillariasis, cestodiasis, trematodiasis, avian malaria, and 
coccidiosis. The assessment found no reported major die-offs of wild 
black stilts resulting from infectious diseases carried by birds 
translocated from captivity to the wild. Most of the illnesses and 
deaths that occurred among captive-reared birds were related to 
husbandry and could be controlled with improved husbandry methods, such 
as improved diet and parasite screening. Finally, the assessment 
suggested the establishment of a surveillance program to determine the 
prevalence of significant disease outbreaks in wild black stilts and 
facilitate development of pre-release quarantine and health-screening 
protocols regarding captive-reared birds (Jakob-Hoff 2001). A screening 
program for potential pathogens and improved husbandry methods specific 
to the black stilt captive population were outlined in the 1998 
management plan for captive black stilts (Reed 1998). In 2005, a review 
of the records since 1995 for captive-held birds showed that infection, 
along with trauma, was a major cause of death among all age classes in 
captivity, especially chicks within the first two weeks after hatching 
(Van Heezik et al. 2005). Van Heezik et al. (2005) reported that 
protocols that monitor birds, intervene at the first signs of illness, 
and minimize the introduction of pathogens into the breeding unit were 
strictly adhered to. This has prevented the spread of these infectious 
diseases among captive-held birds or transmission into the wild 
populations (Van Heezik et al. 2005).
    Predation by introduced mammalian predators and by unnaturally high 
numbers of avian predators is a primary threat to the black stilt (R. 
Maloney in litt. February 2007). Non-native predators introduced since 
the late 19th century include feral cats (Felis catus), ferrets 
(Mustela furo), stoats (M. erminea), hedgehogs (Erinaceus europaeus), 
and brown rats (Rattus norvegicus) (Maloney & Murray 2002; R. Maloney 
in litt. February 2007; Pierce 1996; Sanders & Maloney 2002). In 
addition, population numbers of avian predators, such as the non-native 
Australian harrier (Circus approximans) and the native kelp gull (Larus 
dominicanus), are unnaturally high because of human-induced changes, 
such as the introduction of rabbits, agricultural development, and the 
presence of rubbish dumps (Dowding & Murphy 2001; Maloney & Murray 
2002). New Zealand is home to only one native

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mammal, a species of bat, and introduced mammalian predators pose a 
great risk to native bird species of New Zealand, including the black 
stilt, because these species evolved in the absence of these predators 
(Caruso 2006).
    Several aspects of the black stilt's life history and nesting 
behavior contribute to heavy predation losses (Dowding & Murphy 2001). 
Solitary ground-nesting birds, the black stilt's preference for open 
nesting sites and feeding areas, such as dry, stable riverbanks, may 
increase their susceptibility to predation by mammalian predators, such 
as feral cats and ferrets, which use the banks as pathways (Maloney & 
Murray 2002; Pierce 1982; Pierce 1986b; Reed et al. 1993a). Nesting as 
early as August, when other prey sources are less available, adds to 
the black stilts' vulnerability (Reed et al. 1993a). Both sexes share 
nesting responsibility during the lengthy fledging period and are 
equally vulnerable to predation during the breeding season (Maloney & 
Murray 2002; Pierce 1986b; Pierce 1996; Sanders & Maloney 2002). Black 
stilts exhibit ineffective anti-predator behavior, contributing to 
significant mortality of nestlings and fledglings (Maloney & Murray 
2002). For instance, black stilts do not perform distraction displays 
until late in incubation (Reed et al. 1993a). They will also re-nest in 
the same site if a clutch is lost to predation (Pierce 1986b; Sanders & 
Maloney 2002).
    To test the effects of predation on the black stilt, Pierce (1986a) 
undertook a predator control study in a portion of the species' range 
during three breeding seasons, from 1977 to 1979, monitoring a total of 
50 nests. Traps were placed around 23 randomly selected nests; these 
nests were ``protected.'' These and the remaining 27 nests, designated 
as ``unprotected,'' were monitored. Pierce (1986a) determined that 64 
percent of black stilt breeding failures were attributed to predation 
and found that success in fledging and breeding increased at protected 
nests to 32.5 percent and 10.8 percent, respectively (R. Maloney in 
litt. February 2007). Most predation was caused by brown rats (14 
nests), ferrets (13 nests), and cats (11 nests).
    In a review of 499 eggs placed in the wild from 1979 to 1999, 
mortality was attributed to predation (45 percent); unknown causes (43 
percent); flooding (10 percent); and human disturbance, disease, cold 
weather, poor parenting, and starvation (2 percent) (Maloney and Murray 
2002). However, direct observation of predation events is difficult (R. 
Maloney in litt. February 2007), and, of all these deaths, only 11 were 
known conclusively (5 of which were directly observed predation 
events).
    In an unpublished report by Saunders et al. (1996, as cited in 
Dowding & Murphy 2001), predation may have accounted for nearly 77 
percent of black stilt chick losses between 1982 and 1995. Using video 
cameras, Sanders and Maloney (2002) studied the causes of mortality on 
ground-nesting birds in the UWB. The study monitored 23 black stilt 
nests and recorded 5 lethal events attributed primarily to cats and 
harriers. Cats were observed eating eggs, killing an adult nesting 
bird, and stalking nests. One black stilt nest containing ceramic eggs 
was visited by cats nine times over a 32-day period. A harrier ate a 
chick and a hatching egg in another nest. Unlike other bird species 
being observed in the same study, black stilts continued to nest upon 
dummy eggs even after being visited by cats, revealing that the use of 
dummy eggs increased their risk of mortality and further confirming 
that the species is ill-adapted to this predation pressure (Sanders & 
Maloney 2002).
    Despite 20 years of predator trapping undertaken by the New Zealand 
Department of Conservation to protect black stilt nesting and fledging 
attempts, predator control efforts have met with mixed success. 
Fledging success (the number of chicks fledged versus the number of 
chicks hatched) was increased in some but not all years (Keedwell et 
al. 2002). In a review of predator trapping activities conducted 
between 1981 and 2000, Keedwell et al. (2002) found that efforts were 
inconsistent, resulting in highly variable results each season. For 
instance, predator control was sometimes undertaken for the entire 
breeding season but other times began well after the start of the 
breeding season. Keedwell et al. (2002) calculated that over the 20-
year management period, the effort expended in predator control was 
equivalent to roughly 9.8 ``person years.'' According to Dr. Maloney 
(in litt. March 2007), the intensity and scale of control need to be 
significantly expanded to be effective in increasing fledgling survival 
and recruitment.

Summary of Factor C

    For the reasons outlined above, we believe that disease is not 
currently a contributory threat factor for the black stilt. Predation 
by introduced mammalian and avian predators causes black stilt 
mortality at all life stages. Despite evidence that predator control 
significantly increased the species' breeding success, predator control 
efforts have been limited and inconsistent. We consider predation to be 
a significant contributory factor currently threatening this species 
and one that is projected to continue in the future.

D. The Inadequacy of Existing Regulatory Mechanisms

    Four aspects are considered under this factor: National protection, 
habitat protection, the black stilt's status as a culturally 
significant species, and the species' management plans.
    National protection: The black stilt is an ``absolutely protected'' 
species under the New Zealand's Wildlife Act of 1953 (1953 Act No. 31 
1953). Under this Act, it is illegal to (a) hunt or kill; (b) buy, 
sell, or otherwise dispose of, or have possession of any absolutely 
protected wildlife or any skin, feathers, or other portion, or any egg 
of any absolutely protected wildlife; or (c) rob, disturb, or destroy, 
or have possession of the nest of any absolutely protected species 
(Part 5, 63(1)). Violations of this law by individuals can result in 
imprisonment for a term not exceeding 6 months; or a fine not exceeding 
$100,000 plus a further fine not exceeding $5,000 for each head of 
wildlife and egg of wildlife in respect of which the offence is 
committed (Part 5, 67(A)(1)(a)). Violations by corporations can result 
in a fine not exceeding $200,000 plus a further fine not exceeding 
$10,000 for each head of wildlife and egg of wildlife in respect of 
which the offence is committed (Part 5, 67(A)(1)(a)). Given that take 
by humans is not a threat to the black stilt, this law does not reduce 
any threats to the species.
    Habitat protection: New Zealand protects more than 30 percent of 
its total land area as reserve land (Craig et al. 2000; Green & 
Clarkson 2006). However, except for a few small and scattered wetland 
reserves, most black stilt habitat is unprotected by the government 
(Maloney & Murray 2002). Habitat modification, including diversion or 
use of water for electrical generation, agriculture, and recreational 
activities (as discussed under Factor A), is a primary threat to this 
species.
    The Waitaki Catchment Water Allocation Plan addresses water 
allocation for activities that involve the take, use, damming, and 
diversion of water in relation to the Waitaki Catchment. The most 
recent plan was approved in 2004 by the New Zealand Ministry for the 
Environment, in accordance with the Resource Management Act of 1991 and 
the Resource Management (Waitaki Catchment) Amendment Act of 2004 (NZ 
MFE 2005). The objectives of the

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Waitaki Catchment Regional Plan were to balance electrical generation 
with conservation and other human uses of the Catchment, including an 
evaluation of minimum lake levels required to achieve these objectives. 
The evaluation gave specific consideration to the effect of water flow 
changes on the feeding, roosting, and breeding habitat of the black 
stilt (and other wetland birds), and it was determined that the 
established water levels were suitable for these wetland species (NZ 
MFE 2005). However, the Waitaki Catchment Regional Plan provided 
exemptions for other activities that also adversely affect black stilt 
and its habitat, including certain agricultural uses and recreational 
activities (See Factor A). Policy 35 of the Waitaki Catchment Water 
Allocation Plan exempts certain activities from allocation limits, 
including ``tourism and recreational facilities from the lakes [Tekapo, 
Pukaki and Ohau] and from the canals leading from them'' (NZ MFE 2004). 
Rule 2(2) of the Waitaki Catchment Water Allocation Plan exempts 
``stock drinking-water * * * and processing and storage of perishable 
produce'' from consideration under the allocation limits (NZ MFE 2005). 
Thus, while the Waitaki Catchment Water Allocation Plan addresses 
regulation on water levels associated with hydroelectric power 
generation, it did not address or reduce threats to black stilt habitat 
from water diversion for certain agricultural and recreational 
activities, which is adversely affecting the black stilt (Factor A).
    Status as a culturally significant species: The UWB is considered a 
``taonga,'' and the black stilt a ``taonga'' species for the Ngai tahu, 
the native tribal population inhabiting most of the South Island, New 
Zealand (Schedule 97 1998; NZ MFE 2005). ``Taonga'' is a Maori word for 
any item, object or thing that has special significance to the culture, 
including birds and plants (Auckland Museum 1997). Under the Ngai 
tah[umacr] Claims Settlement Act of 1998, the New Zealand Department of 
Conservation must consult with, and have particular regard to, the 
views of the Ngai tah[umacr] when making management decisions 
concerning ``taonga'' species (1998 Act No. 97. 1998; Maloney & Murray 
2002). An Ngai tah[umacr] representative is a member of the Kak[iuml] 
Recovery Group (Maloney in litt. February 2007), which implements the 
management plan for the black stilt (Maloney & Murray 2002). Including 
the tribes in resource decision-making is an important conservation 
strategy undertaken by the New Zealand government (NZ MFE 2001). New 
Zealand's Resource Management Act of 1991 is based on sustainably 
managing resources, while encouraging community and individual 
involvement in the planning for conservation (NZ MFE 1991). We believe 
that local involvement is important for resource conservation and may 
help to reduce threats to the species by increasing awareness of the 
conservation risks.
    Management plans: According to the New Zealand Ministry of 
Environment, high priority is afforded to the black stilt recovery plan 
(NZ MFE 1997). Beginning in 1981, the New Zealand Department of 
Conservation undertook management of the wild black stilt population to 
increase fledging success and recruitment of juveniles in the declining 
populations in Mackenzie basin (R. Maloney in litt. March 2007; Reed et 
al. 1993b). Since 1993, black stilt management has been guided by two 
consecutive recovery plans, the first published in 1993 (Reed et al. 
1993a) and a second, updated plan approved in 2002 (Maloney & Murray 
2002), that covers the period 2001-2011.
    The goals of the current recovery plan (effective from 2001 to 
2011) are to increase the black stilt population within the next 10 
years to more than 250 breeding individuals, with a mean annual 
recruitment rate that exceeds the mean annual adult mortality rate 
(Maloney & Murray 2002). There are two overlapping phases. Phase 1 of 
the program involves a series of objectives aimed at increasing the 
number of black stilts in the wild by maximizing recruitment rate both 
in the wild (for instance, by ensuring that all female black stilts are 
mated with a male each season) and by captive-rearing black stilts and 
releasing large numbers of captive-born young to the wild. A review of 
captive breeding records from two breeding seasons (1981 to 1982 and 
2001 to 2002) found that the survival rate of captive-bred stilts that 
were reintroduced to the wild was 88 percent at 2 months and 82 percent 
at 10 months (Van Heezik et al. 2005). Between 1992 and 1999, 
researchers determined that the recruitment rate of chicks that had 
been artificially incubated in captivity and then hatched and raised in 
the wild was only 4 percent, with only 8 of the 189 chicks surviving to 
2 years of age. However, birds that were hatched and raised in 
captivity and then released into the wild achieved a minimum 
recruitment rate of 22 percent (Maloney & Murray 2002). Thus, wild 
losses of eggs, chicks, and fledglings are largely avoided by 
artificially incubating and captive-rearing young to 3 or 9 months of 
age before releasing them back to the wild. This technique has been 
used for most eggs since 1998, and has resulted in approximately 30 
percent recruitment rate (Van Heezik et al. 2005).
    A second concurrent phase seeks to increase black stilt breeding 
success and adult survival in the wild by continuing research on the 
primary causes of mortality and developing mitigation measures to 
prevent excess mortality. Attempts to monitor all forms of mortality 
via direct observation began in 1998 and are ongoing. Goals under this 
phase include obtaining a better understanding of the causes of chick 
and adult mortality, developing multi-species predator control methods, 
and understanding mate choice decisions at different population 
densities. As an example, because monitoring birds between post-flight 
to adulthood is difficult, researchers are monitoring adults using 
transmitters (Maloney & Murray 2002). In September 2007, researchers 
released 38 adult black stilts fitted with transmitters (Timaru Herald 
2007). These transmitters help researchers locate wild birds that have 
died (Maloney & Murray 2002).
    The management of the captive black stilt population is addressed 
in both recovery plans (Reed et al. 1993; Maloney & Murray 2002), and 
also in a separate Department of Conservation management plan published 
in 1998 (Reed 1998). According to Reed (1998), the goals of the captive 
management plan are to provide young birds for release into the wild 
and develop a self-sustaining captive population. Five objectives were 
established to achieve these goals: (1) Establish a captive population 
capable of being self-sustaining, (2) provide juveniles for release and 
eggs for fostering to the wild, (3) undertake research to increase 
productivity and survival, (4) establish health monitoring of the 
captive population, and (5) advocate conservation of black stilts to 
the general public. This management plan outlines the expansion of the 
captive breeding program and formalizes the protocols for captive 
release, health screening, and monitoring.
    Experts consider that, despite only incremental success in 
increasing wild population numbers, the captive-breeding program, along 
with predator control, have prevented the species from going extinct in 
the wild (BLI 2007e; Maloney & Murray 2002: Reed et al. 1993; Van 
Heezik et al. 2005). The management plans are addressing several 
aspects to facilitate the species' recovery, including research into 
survival, production of offspring for release into the wild, and 
continued

[[Page 3153]]

research into the causes of mortality in the wild, including predation. 
However, the relative success of the captive breeding program is 
hindered by the inadequacy of regulatory mechanisms, combined with 
limited or inconsistent efforts to control predators (Factor C) and 
conserve and provide suitable habitat for the species (Factor A).

Summary of Factor D

    Regulatory mechanisms exist to protect the black stilt from take. 
However, take is not a primary threat to the species. Government-
sponsored measures are in place to facilitate the species' recovery (as 
discussed under this factor), including mitigating threats from 
predation (as discussed under Factor C). However, the inadequacy of 
regulatory mechanisms to protect or curb habitat destruction in the 
species' only known breeding ground (Factor A), combined with 
inconsistent predator control (Factor C), results in failure to reduce 
or remove threats from the species' habitat. As such, we believe that 
the inadequacy of regulatory mechanisms is a contributory risk factor 
currently and in the future for this species.

E. Other Natural or Manmade Factors Affecting the Continued Existence 
of the Species

    Three additional factors are considered herein: Genetic risks 
associated with small population sizes, hybridization, and threats from 
stochastic events (random natural occurrences).
    Genetic risks associated with small population sizes: The small 
size of the black stilt population, estimated in 2007 as 87 adults 
consisting of 17 breeding pairs (DOC 2007b), makes this species 
vulnerable to any of several risks, including inbreeding depression, 
loss of genetic variation, and accumulation of new mutations. 
Inbreeding can have individual or population-level consequences either 
by increasing the phenotypic expression (the outward appearance or 
observable structure, function or behavior of a living organism) of 
recessive, deleterious alleles or by reducing the overall fitness of 
individuals in the population (Charlesworth & Charlesworth 1987; 
Shaffer 1981). Small, isolated populations of wildlife species are also 
susceptible to demographic problems (Shaffer 1981), which may include 
reduced reproductive success of individuals and chance disequilibrium 
of sex ratios. Research has shown that the long-term survival of the 
black stilt as a species requires gene flow to be at least 5 percent, 
and that the present gene flow is approximately 15 percent (Maloney & 
Murray 2002). However, the relatedness of the entire black stilt 
population has not been determined, and inbreeding depression is a 
possible threat (Maloney & Murray 2002).
    A general approximation of minimum viable population size is the 50 
/ 500 rule (Soul[eacute] 1980; Hunter 1996). This rule states that an 
effective population (Ne) of 50 individuals is the minimum 
size required to avoid imminent risks from inbreeding. Ne 
represents the number of animals in a population that actually 
contribute to reproduction, and is often much smaller than the census, 
or total number of individuals in the population (N). Furthermore, the 
rule states that the long-term fitness of a population requires an 
Ne of at least 500 individuals, so that it will not lose its 
genetic diversity over time and will maintain an enhanced capacity to 
adapt to changing conditions.
    The available information for 2007 indicates that the breeding 
population of the black stilt (based on the number of wild and captive-
held breeding pairs) is 46 individuals (DOC 2007b); 46 is just below 
the minimum effective population size required to avoid risks from 
inbreeding (Ne = 50 individuals). Moreover, the upper limit 
of the population is 102 adults (DOC 2007b). This represents the 
maximum potential number of reproducing members in the wild black stilt 
population and is less than one-fifth of the upper threshold 
(Ne = 500 individuals) required for long-term fitness of a 
population that will not lose its genetic diversity over time and will 
maintain an enhanced capacity to adapt to changing conditions. As such, 
we currently consider the species to be at risk due to lack of near- 
and long-term viability.
    Hybridization: Black stilt males and pied stilt females can produce 
fertile offspring (BLI 2007e; DOC 2007a; Maloney & Murray 2002; Reed et 
al. 1993a). However, hybrid offspring exhibit distinct differences in 
survival rate and behavior that may be deleterious to the species' 
long-term survival (Reed et al. 1993a). Hybrid survival to adulthood is 
about 50 percent that of the offspring of pure black stilt pairs. In 
addition, researchers noted changes in behavioral patterns in chicks 
fostered to pied stilt parents between 1981 and 1987. Due to the 
limited number of wild black stilt breeding pairs, part of the species' 
management plan at that time was to cross-foster black stilt eggs to 
pied stilt parents. Cross-fostered black stilts were half as likely to 
be re-sighted in the UWB and mixed pairs were more likely to 
participate in migratory behavior with the pied stilt population rather 
than remain in their natal range, as pure black stilts would. As a 
result, cross-fostering of black stilt eggs with pied stilt parents was 
discontinued. More importantly, this research revealed that 
hybridization was detrimental to the long-term survival of the black 
stilt, as mixed pairs were effectively ``lost'' from the population 
(Reed et al. 1993b).
    Hybrid management (such as breaking up mixed-pair bonds prior to 
mating) is part of the conservation strategy identified in the black 
stilt recovery plan, and researchers believe black stilts possess 
several inherent qualities that reduce gene flow, such as the black 
stilt's strong positive assortative mating (selecting black stilt over 
pied stilt when given the choice) and the low fitness of hybrid 
offspring (Maloney & Murray 2002). However, black stilts live in 
relative isolation from each other, and nesting pairs are often located 
miles (kilometers) apart (BLI 2007e; DOC 2007a; Pierce 1984a; Reed et 
al. 1993a). Sex ratios are an important indicator of the species' 
tendency to pair with pied stilts (Maloney & Murray 2002), and experts 
note that black stilts pair with the pied stilt when ``suitable'' mates 
within the species are not available (DOC 2007a; Greene 1999; NZ CMaG 
2007; Reed et al. 1993a). Given the species' dispersed nature, the 
likelihood for hybridization with the growing population of pied stilts 
increases as black stilt population numbers decrease and black stilt 
males are less able to find females (Greene 1999; Pierce 1996).
    Threats from stochastic events: With a wild adult population of 87 
adults (DOC 2007b), experts consider the risk of a single catastrophic 
event to be a serious threat that could destroy most of the population 
(Maloney & Murray 2002). New Zealand's South Island is subject to 
tsunamis and earthquakes. According to the New Zealand Institute of 
Geological and Nuclear Sciences (NZ GNS) (2007), since 1840, when 
tsunami recordkeeping began, 10 tsunamis measuring 16.4 ft (5 m) or 
higher have hit New Zealand. New Zealand is vulnerable to tsunamis 
because of the high amount of seismic activity in the region. 
Approximately 10,000 to 15,000 earthquakes occur in New Zealand 
annually, most of low magnitude (Quake Trackers 2007). New Zealand is 
expected to experience earthquakes of magnitude of 7 on the Richter 
scale only about once a decade (Walsh 2003). However, since 2003, the 
southern region of the South Island has been rocked by at least three 
earthquakes near or above that magnitude. Centered in or near 
Fiordland, 266 mi (429 km) south of the heart of black stilt territory 
(The

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New Zealand (NZ) Herald 2004, 2007; Walsh 2003), the years and 
magnitudes of each of these high-magnitude earthquakes were: 2003, 7.2 
magnitude; 2004: 7.2 magnitude; 2007: 6.7 magnitude (NZ Herald 2004, 
2007; Walsh 2003). The 2003 earthquake was the first on-land earthquake 
of this magnitude since 1968 (Walsh 2003). The main quake triggered a 
small tsunami that brought flooding as far north as Haast (Jackson 
Bay), less than 100 mi (161 km) from the UWB, where the majority of the 
black stilt population lives year-round and the only known breeding 
ground for the species (McGinty & Hancox 2004; Walsh 2003). At least 
5,000 aftershocks were recorded from the 2003 earthquake, one 
registering 6.1 on the Richter scale (McGinty & Hancox 2004; NZ Herald 
2007). More than 400 landslides were triggered, the largest of which 
sent 262,000 cubic yards (yd\3\) (200,000 cubic meters (m\3\)) of soil 
crashing down the fiord at Charles Sound, triggering a 3 to 6 ft (1 to 
2 m) high tsunami that inundated surrounding vegetation 13 to 16 ft (4 
to 5 m) above sea level (McGinty & Hancox 2004). According to Maloney 
and Murray (2002), flooding was the second leading cause of egg 
mortality in a study conducted between 1977 and 1979. Stochastic 
events, such as earthquakes and tsunamis, could result in extensive 
mortalities from which the population may be unable to recover, leading 
to extinction (Caughley 1994; Charlesworth & Charlesworth 1987; Maloney 
& Murray 2002).

Summary of Factor E

    The black stilt is subject to genetic dilution, including changes 
in survival and behavior, due to demographic problems and hybridization 
with the pied stilt, and is also susceptible to other genetic risks, 
such as inbreeding, due to its small population size. The species is 
vulnerable due to stochastic event, such as a tsunamis or earthquakes, 
which are known to occur in the region. We consider the species' 
extremely small population size, along with the associated risks of 
genetic dilution, demographic shifts, and vulnerability to stochastic 
events, to be significant risks factors throughout the black stilt's 
range currently and in the future.

Conclusion and Determination for the Black Stilt

    We have carefully assessed the best available scientific and 
commercial information regarding the past, present, and potential 
future threats faced by the black stilt. We have determined that the 
species is in danger of extinction throughout all of its known range 
primarily due to ongoing threats to its habitat (Factor A); predation 
(Factor C); and genetic dilution from hybridization, lack of near- and 
long-term genetic viability, and susceptibility to stochastic events 
due to risks associated small population sizes (Factor E). Furthermore, 
we have determined that the inadequacy of existing regulatory 
mechanisms is a contributory risk factor that endangers the species' 
continued existence (Factor D). Therefore, we are determining 
endangered status for the black stilt under the Act. Because we find 
that the black stilt is endangered throughout all of its range, there 
is no reason to consider its status in any significant portion of its 
range.

II. Caerulean Paradise-Flycatcher (Eutrichomyias Rowleyi)

Species Description

    The caerulean paradise-flycatcher is a member of the Monarchidiae 
family, locally known as ``burung niu'' (Whitten 2006). It is native to 
Indonesia, and adults are about 5 in (18 cm) in height, with a long 
tail and long rictal bristles (stiff hairs around the base of the bill