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Purpose:
This workplan provides specific recovery objectives for the Newell’s shearwater (Puffinus auricularis newelli) that can be met within five years. Although the nature of the threats to this species has not changed appreciably since the recovery plan was issued in 1982 (USFWS 1982), the severity of these threats (e.g., increased development) and thus the urgency of addressing them have increased as shearwater populations have declined. Therefore, the general long-term recovery strategy for this species has not changed, but identification of interim recovery objectives and actions are needed to help ensure that initial conservation efforts by different agencies or groups are focused on the same ultimate goals, that limited recovery resources are used efficiently, and to provide milestones that can be used to track and evaluate progress toward recovery. Failure to realize these milestones may indicate that additional resources are needed, or that the current recovery strategy requires modification.
Species Summary:
Newell’s shearwater or `A`o is a seabird belonging to the “Manx-type shearwater” group, a species complex that has undergone frequent taxonomic revision. Newell’s shearwater is a subspecies endemic to the Hawaiian Islands, where it is known to nest on Kaua`i, Moloka`i, and Hawai`i (Ainley et al. 1997, Reynolds and Ritchotte 1997, Day and Cooper 2002, Day et al. 2003). Newell’s shearwaters may nest on Maui (Cooper and Day 2003), and in very small numbers on O`ahu and Lehua Islet near Ni`ihau (E. VanderWerf, USFWS, pers. comm. 2003). Numbers of colonies and individuals are greatest on Kaua`i (Ainley et al. 1997). Most Newell’s shearwater colonies are found at high elevations, and this may always have been the case; subfossil remains of Newell’s shearwater in lowland midden sites are far less abundant than those of wedge-tailed shearwaters (P. pacificus) (Olson and James 1982) that commonly nests in lowland and coastal areas today. The fact that known Newell’s shearwater colonies are remote and/or occur on slopes greater than 65 degrees suggests that predation by nonnative mammals has further constrained this seabird’s breeding habitat (Ainley et al. 1997).
Colonies typically are located in areas of open native forest dominated by `ohia (Metrosideros polymorpha) with a dense understory of `uluhe fern (Dicranopteris linearis). Burrows are most commonly placed at the base of trees, where the substrate may be easier for the birds to excavate. Some colonies on Kaua`i are located in vertical cliff faces (Wood et al. 2001), where birds presumably are nesting in rock crevices rather than burrows. The Newell’s shearwater breeding season begins in April, when birds return to prospect for nest sites. A pre-laying exodus follows in late April, and highly synchronized egg-laying occurs in June. Pairs produce one egg, the average incubation period is between 53 and 54 days, and the fledging period ranges from 81 to 94 days (B. Zaun, USFWS, unpubl. data). Most fledging takes place in October and November (Table 1, Ainley et al. 1997). The Newell’s shearwater is a pelagic bird and forages over deep water east and south of Hawai`i; the species’ long incubation and fledging periods may reflect the long travel time to and from foraging areas.
Study of reproductive success in one Newell’s shearwater colony on Kaua`i documented an average annual production of 0.66 young per pair (Ainley et al. 2001), a rate comparable to other Puffinus species. First breeding occurs at approximately six years of age (Ainley et al. 1997). Compared with similar species, the rate of non-breeding is thought to be high, even among experienced adults occupying the colony during the summer breeding season (Ainley et al. 2001). No specific data exist on longevity for this species, but other shearwaters may reach 30 years of age or more (Bradley et al., 1989, del Hoyo et al. 1992). Like other seabirds of oceanic islands, this species has no natural land-based predators. This and the species’ low fecundity makes Newell’s shearwaters especially vulnerable to anthropogenic- related increases in mortality. In 1995, the population of Newell’s shearwater was estimated at 84,000 birds (95% confidence interval 57,000 – 115,000; Spear et al. 1995), with approximately 75 percent occurring on Kaua`i (Ainley et al. 1997). The breeding population is estimated at 14,600 pairs (Ainley et al., unpubl. data). Population models incorporating best estimates of breeding effort and success yielded a population decreasing at a rate of 3.2 percent annually (Ainley et al. 2001). When variables estimating the anthropogenic mortality suffered by Newell’s shearwater (e.g., predation, light attraction, and collision) were included, these models predicted an annual population decline of 6.1percent or a population decline of approximately 60 percent over 10 years (Ainley et al. 2001). Recent analysis of data trends 2 from radar surveys revealed an overall decline of roughly 50-70 percent in detection rates between 1993 and 2001, although detections for 1999, 2000, and 2001 were similar (Day et al. 2003).
Primary threats:
Predation – No terrestrial mammalian predators are native to the Hawaiian Islands, and ground-nesting and fossorial bird species, including shearwaters and petrels, are especially vulnerable to predation from rats (Rattus spp.), cats (Felis silvestris), dogs (Canus domisticus), pigs (Sus scrofa), and mongooses (Herpestes spp.) (Hodges and Nagata 2001, Zino et al. 2001, Keitt et al. 2002, Smith et al. 2002, Jouventin et all. 2003, Keitt and Tershy 2003, Martinez- Gomez and Jacobsen 2004). Predation by cats on adult and juvenile Newell’s shearwaters has been documented on Kaua`i (Telfer unpubl. data), and rats are assumed to prey on shearwater eggs and chicks although at present no data exist to document this. The recent discovery of the small Indian mongoose (Herpestes auropunctatus) on Kaua`i presents an additional potential threat. The non-native barn owl (Tyto alba) also preys on adult Newell’s shearwaters (Ainley et al. 1995).
 Collision - Newell’s shearwaters frequently collide with power lines, buildings, cars, and other obstacles. Although adult shearwaters are apparently less attracted to lights, they do collide with power lines, towers, and other structures (Cooper and Day 1998, Podolsky et al. 1998). Since 1978, the Save Our Shearwaters project has banded and released more than 25,000 shearwaters picked up by Kaua`i residents and brought to stations set up around the island (T. Telfer unpubl. data, Day et al. 2003; Table 1). Although undoubtedly important for these fledglings, and a critical source of information, the effects of this rescue effort on the shearwater population are unknown – few bands from SOS-released birds have been recovered. Without continued efforts to reduce light pollution and threats from collisions with structures, increasing urbanization on Kaua`i will pose a growing threat.
Habitat Degradation and Loss – Newell’s shearwater habitat has been degraded by feral ungulates. Pigs and goats (Capra hircus) alter the vegetation structure, facilitate the invasion of nonnative plants and perhaps of predators, crush burrows, and compact the soil (Cruz and Cruz 1996, Cuthbert 2002). Invasive non-native plants, such as Albizia falcataria, Psidium spp., and Rhodomyrtus tomentosa, displace native vegetation and can completely alter vegetation structure and substrates typical of shearwater habitat. For example, the habitat at the Kaluahonu colony (southeastern Kaua`i) has been almost completely, and perhaps irreversibly transformed in just a few years, and is now dominated by nearly pure and impenetrable stands of R. tomentosa. Intensive surveys in 2003 indicate that the number of birds returning to this colony has either dramatically declined or it has been abandoned entirely (R. David, Rana Productions, Inc., pers. comm.).
Light Attraction – Newell’s shearwaters are attracted to light sources and fall to the ground exhausted after fluttering around lights for long periods of time (Ainley et al. 1997, Podolsky et al. 1998). Fledgling shearwaters are particularly vulnerable to light attraction on their first nocturnal flight from their burrow to the sea (Telfer et al. 1987, Ainley et al. 2001). Shielding lights to prevent upward radiation has been shown to reduce seabird attraction (Reed et al. 1985, Telfer et al. 1987), and in 2003, the Kauai Island Utility Cooperative (KIUC) completed shielding all of the street lights they operate on Kaua`i. However, lights at the harbor, airport, hotels, and playing fields continue to attract fledgling shearwaters.
Other – Newell’s shearwaters depend on predatory fish (e.g., tuna [Thummus spp.]) to drive prey species to the surface of the ocean. Because of over fishing, several tuna species are now imperiled. The energetic costs of the reduction in predatory fish to Newell’s shearwaters are unknown as is the effect on chick growth and fledgling production. The location and habitat conditions at colonies have prevented the systematic collection of life history data. A lack of demographic information makes determining the efficacy of management difficult. Newell’s
shearwaters are affected by natural disturbance, particularly hurricanes (see Day and Cooper 1995).
Although hurricanes are part of the species’ evolutionary history, the habitat disturbance they cause now is exacerbated by habitat degradation caused by invasive non-native plants and feral ungulates. Hurricanes occurring during the shearwater breeding season likely result in the death of some individuals, exacerbating losses due to anthropogenic factors. Furthermore, hurricane related damage to forests facilitates the spread of non-native plants (see Horvitz et al. 1998) and may increase the accessibility of nesting colonies to introduced predators.
Recovery Strategy:
The recovery strategy for the Newell’s shearwater includes five components to reduce mortality, maintain or increase suitable nesting habitat, and to fill in gaps in our knowledge of the species:
(1) minimize adult/breeder mortality and maximize fledgling production by developing and implementing effective predator control methods in colonies;
(2) reduce the potential for collisions with power lines, towers, and other structures;
(3) protect existing colonies from degradation due to invasive plants and pigs;
(4) reduce fallout associated with lights; and (5) improve monitoring methods, initiate studies to determine the effects of the tuna fishery on Newell’s shearwater populations, and collect needed demographic data.
Interim Recovery Objectives:
In order to meet the long-range recovery goals for the Newell’s shearwater, the following short-term objectives should be accomplished first.
1. Implement predator control in at least two colonies and install ungulate fencing around at least two colonies.
2. Determine or estimate the number of adults that collide with power lines and structures.
3. Collaborate with the Kauai Invasive Species Committee to identify priority areas where invasive alien plants are a problem and help develop effective techniques for their control and interdiction.
4. Encourage Kauai County to adopt a light pollution ordinance, and shield all remaining lights around hotels, playing fields, shopping centers, and other areas determined to be a hazard to shearwaters.
5. Develop and implement effective monitoring techniques in at least two colonies that would facilitate the estimation of the effects of recovery actions.
6. Continue broad-scale monitoring to assess population-wide trends throughout Hawaii to better understand threats and guide recovery efforts.
7. Develop studies to address fishery-related questions and collect demographic data.
If these objectives are met within five years, then new interim recovery objectives will be identified to continue to guide progress toward full recovery. If these objectives are not met within five years, then the causes for failure should be identified and rectified if possible. If it is not possible to correct the causes for failure and the current strategy is deemed ineffective, then a new strategy will be developed and new actions identified.
Five-year Recovery Actions:
The following actions are needed to realize the interim recovery objectives described above. Because of the logistical difficulties and uncertainties surrounding implementation of many recovery actions, the efficacy of these actions will be evaluated annually based on the results from the previous field season and modified as necessary. Because of the remote location and sensitive habitat structure of most known Newell’s shearwater colonies, the relative impacts of the numerous threats to any given colony and the success of efforts to mitigate these threats may be difficult quantify. Development of techniques to monitor the results of recovery actions is a major challenge in the recovery of this species.
1. Predator control:
Although cats, rats, owls, and to a lesser degree pigs all likely prey on adult and young Newell’s shearwater the feasibility of implementing predator control is complicated by access to nesting areas, sensitivity to human disturbance, and creation of access routes for predators (although see Ainley et al. 2001). To date, only two sites have been identified as suitable to begin some predator control. Presently funded by DOFAW/FWS/Tesoro and conducted by KEBRT staff. The upcoming EPA registration of rodenticides for aerial broadcast in Hawaii will likely benefit Newell’s shearwaters.
1.1. Continue removal of cats at the Kalaheo colony. Include placement of traps in lower areas of the colony, assuming access can be gained with acceptably low levels of disturbance.
1.2. Begin removal of barn owls and cats at the Moalepe colony.
1.3. Examine the feasibility of conducting an experimental aerial application of rodenticide in a Newell’s shearwater colony on Kaua`i.
1.4. Examine stomach contents of predators captured to document diet or implement stable isotope analysis studies to identify prey signatures in predator tissue or scat (Keitt et al. 2002).
1.5. Document home ranges of predators using tracking devices. For barn owls, roosts can be located by radio tracking, and pellets at the roost can be used to identify prey. For cats, radio tracking can be used to estimate home range size and estimate extent of use of nesting areas for hunting and determine the correct spatial scale for trapping effort or other control methods. The methods and models developed by Keitt et
al. (2002) may provide a useful starting point in estimating the impact of predators on Newell’s shearwater nesting colonies.
1.6. Continue monitoring and trapping for mongoose (funded and implemented by DOFAW/KISC).
2. Light attraction and collision:
Light attraction and collisions are responsible for hundreds of strandings annually and may be a major source of mortality. Greater public understanding of the causes of fallout is needed to increase support for, and voluntary participation in, mitigating this threat.
2.1. Hire a public outreach coordinator to develop partnerships with private landowners and businesses to assist with efforts to reduce mortality sources. Presently funded and implemented by DOFAW/FWS.
2.2. Institute public outreach program on Kaua`i to decrease lighting during shearwater fledging period. Presently funded and implemented by DOFAW/FWS/KIUC.
2.3. Develop guidelines for mitigating fallout from light attraction. Examples include assessment of the feasibility of seasonal “black-outs” and modification of county lighting ordinances for Newell’s shearwaters.
2.4. Investigate attraction to lights of different color and flashing pattern to determine guidelines for communications tower construction.
2.5. Identify “hot spots” of fallout in areas with and without lighting influences and assess feasibility of burying powerlines. In progress by KIUC.
3. Invasive Plants and Pigs:
Although the effect of invasive plants on the reproductive success of Newell’s shearwaters has not been studied, some plant species alter the habitat to such a degree that there is little doubt that nesting would be affected. Pigs have been documented destroying fossorial seabird nesting habitat often resulting in the abandonment of colonies (Cruz and Cruz 1996, Cuthbert 2002).
3.1. Develop and coordinate monitoring and mitigation work with Hawai’i Invasive Species Council (HISC).
4. SOS:
Presently, the SOS program is staffed and overseen by DOFAW and has a long-standing history of successful community involvement to support recovery of downed birds. The work is presently funded by DOFAW/KIUC and conducted by DOFAW staff and community volunteers. The following additional needs have been identified by the working group. However, neither DOFAW or KEBRT presently have staff or funds
to implement these additional actions, and work will be needed to secure the funds and staff to appropriately integrate these into the current program.
4.1. Continue the present SOS program.
4.2. Evaluate the current program, develop written protocols, and implement modifications as needed to improve the scope and effectiveness of the program.
4.3. Incorporate rehabilitation procedures as necessary before birds are released. Technical advice from an avian veterinarian or qualified wildlife rehabilitator will be necessary, possibly from IBRRC or DOFAW. Develop protocols as appropriate.
4.4. Explore methods to evaluate survival rates of released birds, possibly using tracking devices. Implement experimental test of alternative rehabilitation protocols if determined to be necessary.
5. Monitoring:
Radar surveys and other forms of monitoring are needed to determine distribution, abundance, population trends, geographic variability in threats, and to investigate the efficacy of various management actions. Partially funded by DOFAW/USFWS and implemented by the Kauai Endangered Bird Recovery Team (KEBRT).
5.1. Continue radar surveys in June to replicate previous surveys in 1993 and 1999-2001 to: 1) confirm geographic variation in detections, 2) determine whether declines in detections (1993 – 2001) are continuing, and 3) better understand the apparent stability in detections between 1999 and 2001. Adding additional sites (e.g., the Na Pali coast) may help to clarify the above trends.
5.2. Evaluate present survey design for statistical power and make changes as appropriate. In terms of power, a trade-off exists between the number of sites sampled and the number replicates at each site. The goal is to survey the maximum number of sites with the minimum number
of replications to provide sufficient power to detect the changes of interest.
5.3. Document the species’ distribution and colony locations using radar and audio surveys. Knowledge of the species’ distribution is limited by a lack of information at a regional scale. Systematic surveys by observers at remote sites in key areas would likely identify additional colonies.
5.4. Investigate usefulness of conducting surveys later in the season, possibly October, as a means of measuring fledging success and reducing variability in survey results caused by presence of non-breeding birds.
5.5. Investigate flight altitude and usefulness of vertical radar to assess threat from collision with towers.
5.6. Compile a database and GIS for all existing published and unpublished information, including radar data, colony locations, survey sites, flyways, fall-out levels, and threats.
5.6.1. Conduct analyses to document links between shearwater population size, movements, urbanization, and fallout.
5.6.2. Complete structured ranking of known colonies for restoration work (predator control, ungulate control, invasive plants control), based on feasibility and estimated probability of successfully increasing productivity.
5.7. Develop new (e.g., data loggers, acoustic monitoring [www.serdp.org/research/CS/CS-1185.pdf], stable isotope analysis [Keitt et al. 2002]) and refine existing (e.g., radar, night vision) monitoring techniques at the appropriate scale to examine the efficacy of management actions designed to mitigate threats at specific colonies.
References:
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Bradley, J.S., R. D. Wooller, I.J. Skira and D.L. Serventy. 1989. Age-dependent survival of breeding short-tailed shearwaters Puffinus tenuirostris. Journal of Animal Ecology 58:175-188
Cooper, B.A. and R.H. Day. 1998. Summer behavior of dark-rumped petrels and Newell’s shearwaters at power lines on Kauai. Colonial Waterbirds 21:11-19.
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