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CFR Citation: 50 CFR Part 17

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

NOTICE: Part III

DOCUMENT ACTION: Final rule.

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

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

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine endangered status for six avian speciesblack stilt (Himantopus novaezelandiae), caerulean paradiseflycatcher (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.

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL INFORMATION

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 paradiseflycatcher
(Eutrichomyias rowleyi), giant ibis (Pseudibis gigantea), Gurney's pitta (Pitta gurneyi), longlegged 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 ``90day 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 higherpriority listing actions (this finding is referred to as the ``12month 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 longlegged thicket bird (or, longlegged warbler, which was the common name used in the petition). In response to the 1980 petition, we published a positive 90day 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 longlegged thicketbird, was warranted but precluded by higherpriority 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 longlegged 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 longlegged 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 paradiseflycatcher, giant ibis, Gurney's pitta, and Socorro mockingbird were included in the 1991 petition. On December 16, 1991, we published a positive 90day 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 paradiseflycatcher 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 paradiseflycatcher. 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 speciesthe black stilt, caerulean paradiseflycatcher, giant ibis, Gurney's pitta, and Socorro mockingbirdwas warranted. In the same 2004 annual notice, we determined that the longlegged 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 longlegged 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 paradiseflycatcher, giant ibis, Gurney's pitta, longlegged thicketbird, and Socorro mockingbird as endangered. We implemented the Service's peer review process and opened a 60day 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 longlegged 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 fivefactor 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 longlegged 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 speciesbyspecies analysis of these five factors. The species are considered in alphabetical order: Black stilt, caerulean paradiseflycatcher, giant ibis, Gurney's pitta, longlegged 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 whiteplumed 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; [[Page 3148]]
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), postbreeding (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 egglaying occurs from September to December (BLI 2007e; Maloney & Murray 2002; NZ CMaG 2007). Groundnesting 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 renest 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 renest 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 captivebred 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 19801981 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 yearround feeding (DOC 2007a; Reed et al. 1993a). Life history traits, such as lifelong pairbonding 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 ``braidedriver'' 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 subadults 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 captiveheld 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).

Captiveheld 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 captiveheld 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 firstgeneration 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 captiveheld 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 yearround (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, fourwheel 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 offroad vehicles and jetboats, 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 (http://www.cites.org). C. Disease or Predation

There are currently no known diseases affecting the black stilt in the wild. JakobHoff (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 dieoffs 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 captivereared 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 prerelease quarantine and healthscreening protocols regarding captivereared birds (JakobHoff 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 captiveheld 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 captiveheld 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). Nonnative 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 nonnative Australian harrier (Circus approximans) and the native kelp gull (Larus dominicanus), are unnaturally high because of humaninduced 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 groundnesting 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 antipredator 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 renest 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 groundnesting 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 32day 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 illadapted 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 drinkingwater * * * 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 decisionmaking 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 20012011.

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 captiverearing black stilts and releasing large numbers of captiveborn 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 captivebred 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 captiverearing 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 multispecies predator control methods, and understanding mate choice decisions at different population densities. As an example, because monitoring birds between postflight 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 selfsustaining captive population. Five objectives were established to achieve these goals: (1) Establish a captive population capable of being selfsustaining, (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 captivebreeding 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
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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 populationlevel 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 longterm 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 longterm 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 onefifth of the upper threshold (Ne = 500 individuals) required for longterm 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 longterm 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' longterm 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 crossfoster black stilt eggs to pied stilt parents. Crossfostered black stilts were half as likely to be resighted 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, crossfostering of black stilt eggs with pied stilt parents was discontinued. More importantly, this research revealed that hybridization was detrimental to the longterm survival of the black stilt, as mixed pairs were effectively ``lost'' from the population (Reed et al. 1993b).

Hybrid management (such as breaking up mixedpair 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 highmagnitude 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 onland 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 yearround 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 longterm 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 ParadiseFlycatcher (Eutrichomyias Rowleyi)

Species Description

The caerulean paradiseflycatcher 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) (Riley & Wardill 2001; Whitten et al. 1987). There is scant biometric data for this species, because, other than the type specimen, only one additional specimen was captured, measured, and released in 1998 (Riley & Wardill 2001). The species is described as a bright cerulean blue (which can be likened to a deep blue sky) with gray undertones on the belly, legs, upper wing coverts (feathers) and down the sides of the neck to the breast (BLI 2007d; Riley & Wardill 2001; Whitten et al. 1987). The type specimen, which was described as a male, is slightly larger and duskier in appearance than the specimen measured in 1998, leading researchers to believe that the former specimen was a juvenile and the latter, a female (Riley & Wardill 2001).

Taxonomy

The first specimen of caerulean paradiseflycatcher was collected by Meyer in 1873. The species has always been placed in the Monarchidiae family, but within three different genera. When described in 1878, Meyer placed the species in the genus Zeocephus; later it was placed in the genus Hypothymis (Riley & Wardill 2001; Whitten et al. 1987). In 1939, it was placed into the monotypic genus Eutrichomyias, also of the Monarchidae family, and distinguished from Hypothymis by its abundant rictal bristles (Riley & Wardill 2001). Riley and Wardill (2001) suggest that the species may be more related to Hypothermis, but insufficient information impedes a conclusive decision. Therefore, we accept the species as Eutrichomyias rowleyi, which follows the Integrated Taxonomic Information System (ITIS 2007).

Habitat and Life History

The caerulean paradiseflycatcher was known only from its type specimen until 1998. Current knowledge of its ecology and behavior are based on 33 sightings between 1998 and 1999 (Riley & Wardill 2001; Whitten et al. 1987). Riley and Wardill (2001) point out that the basic lack of ecological information on this species impedes its conservation. Information about the species' range, behavior, reproduction, and population size is quite limited.

The species has been observed mostly in the steepsloped, closed canopies of lowelevation broadleaf primary forest, between 1,394 and 2,133 ft (425 and 650 m). A few birds were observed foraging on a scrub forest ridge top or in secondary forest, but only when those areas were bordered by primary forest. The caerulean paradiseflycatcher prefers primary forest habitat, but can forag

FOR FURTHER INFORMATION CONTACT Dr. Patricia De Angelis, at the above address; by fax to 7033582276; by email to
ScientificAuthority@fws.gov; or by telephone, 7033581708.