REPORT TO THE U.S. FISH AND WILDLIFE SERVICE

FOR

HAWAIIAN

ENDANGERED SPECIES PERMIT: TE-25955C-1

REPORTING PERIOD JANUARY 01, 2019 – DECEMBER 31, 2019

SUBMITTED BY:

Melissa R. Price Assistant Professor University of -Manoa 1910 East-West Road Sherman Hall Rm 118 Honolulu, HI 96822

Phone: 808-956-7774 Email: [email protected]

January 31, 2020

1 2 EXECUTIVE SUMMARY 3 The (Himantopus mexicanus knudseni) is an endangered subspecies of the 4 Black-necked stilt (Himantopus mexicanus) that inhabits wetlands throughout the Hawaiian 5 Islands. Depredation of eggs and chicks by introduced predators is a major threat to Hawaiian 6 Stilt populations. Where and when a decides to nest may impact the likelihood of egg or 7 chick depredation. Nesting in close proximity to water may decrease depredation rates by 8 mammals, as water can act as a barrier to mammalian predators, does not hold scent, and 9 provides an obstacle-free escape route for chicks. Alternatively, some mammalian predators may 10 be attracted to water, and a number of aquatic species have been identified as predators of 11 Hawaiian Stilt chicks, including the American Bullfrog (Lithobates catesbeianus). Vegetation 12 height is also an important factor for egg and chick survival, as taller vegetation may help 13 conceal nests and chicks from predators, particularly aerial species. Additionally, depredation is 14 often not constant across the breeding season due to changes in parental activity, nest and chick 15 abundance, or habitat characteristics. The Hawaiian Stilt nests from February to September 16 across the Hawaiian Islands. The nesting season coincides with a seasonal decline in 17 precipitation, which may alter habitat characteristics and thus impact depredation rates. Further, 18 management tools, such as mammal-exclusion fencing, are currently in use and may greatly 19 increase egg and chick survival. The objectives of this project were to: 1) identify habitat 20 characteristics important for nest-site selection and chick habitat use; 2) identify factors that 21 impact hatching and fledging success. 22 We found that preferred to nest in shorter vegetation than what was available and 23 preferred Pickleweed (Batis maritima) rather than other available plant species. However, nest- 24 site characteristics, such as vegetation height and distance to water, did not have an impact on 25 egg depredation risk. Early nests had a higher chance of hatching than late nests. The number of 26 depredated nests peaked later in the nesting season, following a peak in nest initiation. 27 Introduced mammals were the primary egg predators and included rats (Rattus spp.), feral cats 28 (Felis catus), and Small Indian (Herpestes auropunctatus). The number of eggs laid, 29 as well as hatching success, was greater inside the mammal exclusion fence at Honouliuli 30 Wetland, compared to a nearby site without a fence, Waiawa Wetland, where mammalian 31 predators are only excluded via trapping. The average home range size for 12 tracked pre- 32 fledglings was 0.94 ± 1.42 acres, and most chicks were observed using vegetated mudflats near 33 open water. Of the 20 chicks that were tracked in this study, 7 fledged (35%), 6 had unknown 34 fates (30%), 4 died due to unknown causes (20%), 2 were depredated by a feral cat (10%), and 1 35 died due to emaciation (5%). 36 Our results suggest that management of predators, particularly mammals, is key to 37 improving stilt hatching success, as preferred nest-site characteristics do not reduce the 38 likelihood of egg depredation. Tall, invasive vegetation, such as California Grass (Brachiaria 39 mutica), should continue to be controlled, as it was rarely used for nesting. More desirable 40 vegetation, such as Pickleweed, should be made available throughout wetlands to encourage 41 larger spacing between nesting pairs, which may help to reduce egg depredation pressure. 42 Increasing mammalian predator control later in the nesting season may also increase hatching 43 success of later nesters. Alternatively, mammal-exclusion fencing may provide year-round 44 protection from mammalian predators, increasing both egg and chick survival. More data is 45 needed to form conclusions regarding home range and survival of Hawaiian Stilt chicks. 46 Improved detection methods and radio-tagging attachment styles will be used in the 2020 nesting 47 season, which will reduce uncertainties and improve statistical power of analyses.

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48 INTRODUCTION 49 This report fulfills the annual reporting requirements for the permit agreement listed below. The 50 reporting period is January 1, 2019– December 31, 2019. 51 52 Permit 53 Number: TE-25955C-2 54 Effective date: March 27, 2019 55 Expiration Date: March 26, 2024 56 57 Nesting Ecology of the Hawaiian Stilt (Himantopus mexicanus knudseni) on O‘ahu 58 59 The Hawaiian Stilt (Himantopus mexicanus knudseni) is an endangered subspecies of the 60 Black-necked Stilt (Himantopus mexicanus) that inhabits wetlands throughout the Hawaiian 61 Islands (U.S. Fish and Wildlife Service 2011). The Hawaiian Stilt nests from February to 62 September across the Hawaiian Islands. Nest depredation has been identified as a major threat to 63 Hawaiian Stilt nesting success (U.S. Fish and Wildlife Service 2011). Hawaiian Stilts have a 64 variety of potential mammalian, avian, and aquatic predators, including introduced rats (Rattus 65 spp.), feral cats (Felis catus), Small Indian Mongooses (Herpestes auropunctatus), Cattle Egrets 66 (Bubulcus ibis), Barn (Tyto alba), catfish (Order: Siluriformes), and American Bullfrogs 67 (Lithobates catesbeianus), as well as native Black-crowned Night-Herons (‘Auku‘u; Nycticorax 68 nycticorax hoactli) and Hawaiian Short-eared Owls (; Asio flammeus sandwichensis) (U.S. 69 Fish and Wildlife Service 2011). Where and when a bird decides to nest can impact the 70 likelihood of nest depredation. Nesting in close proximity to water may decrease depredation 71 rates, as water can act as a barrier to mammalian predators (Picman 1988, Hoover 2006). 72 Alternatively, some mammalian predators may be attracted to water (Bonesi and Palazon 2007). 73 Vegetation height is also an important factor for nest survival, as taller vegetation may help 74 conceal nests from predators, particularly aerial species (Kristiansen 1998, Jedlikowski et al. 75 2015). Further, nest depredation is likely not constant across the breeding season (Thyen and Exo 76 2005, Wilson et al. 2007, Polak 2016) and may vary due to changes in nest abundance 77 (Tinbergen et al. 1967, Holt 1977, Nams 1997) or parental activity (Skutch 1949, Martin et 78 al. 2000). 79 Hawaiian Stilts have a prolonged nesting season compared to Black-necked Stilts, which 80 generally nest from April to August in temperate regions (Carmona et al. 2000, Conway et al. 81 2005, Ackerman et al. 2014). Increased nesting opportunities due to a prolonged breeding season 82 suggest within-season timing of nesting may not be as important for determining nesting success 83 of Hawaiian Stilts, as is demonstrated in other waterbird species in temperate regions (Thyen and 84 Exo 2005, Cuervo 2010, Ackerman et al. 2014). However, precipitation on most islands in 85 Hawai‘i varies temporally, with the “wet season” occurring October through April, and the “dry 86 season” May through September (Price 1983). The Hawaiian Stilt nesting season begins during 87 the “wet season” and coincides with a seasonal decline in rainfall across the islands, which may 88 cause temporal changes in available nesting habitat, leading to differences in nest depredation 89 risk. 90 Habitat characteristics may also impact chick habitat use and survival, as nesting near 91 vegetation and water is important for both foraging and protection from predators. Sordahl 92 (1982) found that Black-necked Stilts that nest in close proximity to vegetation had greater 93 survival, as chicks used vegetation to hide from predators. Use of nearby water bodies was also

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94 important for decreasing chick depredation, as open water does not hold scent and has few 95 obstacles, providing a safe escape route from mammalian predators (Sordahl 1982). In order to 96 effectively guide management decisions, more research is needed that examines how habitat use 97 impacts Hawaiian Stilt chick survival. 98 Ground nesting tend to benefit most from predator removal (Lavers, Wilcox, and 99 Donlan 2010). However, targeted removal of a single predator type, such as cats, may lead to 100 predator release of rats or other mesopredators, which may increase in number and increase 101 depredation on eggs or chicks (Rayner et al. 2007). Thus, predator control approaches that target 102 multiple species or exclude entire taxonomic groups of invasive predators, such as mammal- 103 exclusion fencing, may be warranted in some cases (Smith et al. 2010; Young et al. 2013). 104 Fencing that excludes mammalian predators, often referred to as predator-proof fencing or pest- 105 proof fencing, prevents the depredation of eggs and chicks by excluding invasive mammalian 106 predators (Burns, Innes, and Day 2012). Multiple methods for invasive predator removal are 107 currently being used in protected Hawaiian Stilt nesting habitat, including traps, fences, and 108 poison baiting. For endangered species, in which depredation significantly contributes to 109 extinction risk, fencing may be the most effective option for species recovery. In contrast, in 110 species nearing population sizes that may warrant delisting, the question remains whether 111 mammal-exclusion fencing is a cost-efficient option for recovery. Resource managers use 112 changes in population through time to measure the effectiveness of management actions (Reed et 113 al. 2007); however, there may be a lag in population growth immediately following conservation 114 actions. Measures of reproductive success and mortality provide more immediate measures of 115 potential changes in population demographics. Studies of target species following the 116 implementation of a management action allows resource managers to evaluate its cost 117 effectiveness in mitigating extinction risk. In June 2018 the U.S. Fish and Wildlife Service 118 (USFWS) completed a mammal-exclusion fence around the 1,006 m perimeter of the Honouliuli 119 wetland unit within the Pearl Harbor National Wildlife Refuge (PHNWR) complex on O‘ahu. 120 This mammal-excluding fence offers the ability to compare reproductive success with the nearby 121 Waiawa wetland unit, also within the PHNWR, in which trapping, and removal of mammalian 122 predators is the main form of invasive predator removal. In both locations, avian, aquatic, and 123 amphibious predator types are not controlled. 124 The primary objective of this project was to conduct field research on the nesting ecology 125 of the Hawaiian Stilt in wetlands on O‘ahu. Specifically, we aimed to: (1) identify habitat 126 characteristics important for nest-site selection; (2) identify top predators to eggs and chicks; (3) 127 determine factors that impact hatching and fledging success; (4) compare nesting behavior and 128 nesting success inside and outside of mammal-exclusion fencing; (5) determine home-range and 129 habitat use of chicks. 130 131 METHODS 132 Study Sites 133 This study was conducted in various wetlands on the island of O‘ahu. Study sites 134 included: Kawainui Marsh and Hamakua Marsh located in Kailua; the Marine Corps Base 135 Hawai‘i-Kāne‘ohe Bay (MCBH-KB) located in Kāne‘ohe; He‘eia National Estuarine Research 136 Reserve located in He‘eia; Honouliuli Wetland located in Waipahu; Waiawa Wetland located in 137 Pearl City; and James Campbell National Wildlife Refuge located in Kahuku (Figure 1). 138 139

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140 Data Collection 141 Nest-site selection. Weekly nest surveys were conducted from February to August of both 142 2018 and 2019. Surveys began with observers driving around the perimeter of the wetland to 143 identify nesting behavior, such as incubation or territorial displays, and then conducting foot 144 surveys to confirm potential nests. All nests were monitored during the incubation period and 145 were considered active if at least one egg was present. For each nest, we recorded GPS 146 coordinates, took measurements of the height of the tallest vegetation and recorded the dominant 147 vegetation species within a 1 m radius of each nest (Ackerman et al. 2014), and recorded the 148 distance from the nest to the nearest water body. The same habitat variables were recorded at 149 randomly-selected points within Hamakua Marsh, Kawainui Marsh, Honouliuli wetland unit, 150 Waiawa wetland unit, and James Campbell National Wildlife Refuge, representing available 151 nesting habitat. One random point was generated within 50 m of each nest using the Random 152 Point Generator from Google Maps (Schaming 2015). Random points that fell within open water 153 habitat were regenerated, as members of the family (stilts and avocets) are not 154 known to construct nests in open water and thus would not represent available Hawaiian Stilt 155 nesting habitat. In 2019, we additionally collected data on whether nests or paired random points 156 were located on islands, which we defined as surrounded by water in all directions. 157 Egg survival. For a subset of nests (204 out of 253), a Bushnell No-Glow Aggressor HD 158 Trophy Camera (Bushnell Corporation, Overland Park, KS, USA) was placed at least 3 m from 159 the nest, mounted on a 2” x 1” furring strip, and secured with a camera strap. Cameras were 160 programmed to take two images back-to-back immediately upon infrared motion activation. 161 Cameras were programmed to have a five second delay between each activation. One control 162 photo was taken every hour using field scan mode. Cameras were checked weekly for battery life 163 and SD card data retrieval and were removed either immediately after a nest was confirmed 164 failed or 10 days after a nest was confirmed successful. 165 Nests were considered successful if at least one egg hatched and failed if no eggs 166 hatched. Nest fate was determined by observing camera photos, and for nests without cameras, 167 by evaluating habitat conditions within the nest site, which we defined as within one meter of the 168 nest. Nests were determined flooded using the following criteria: (1) precipitation data showed a 169 correlation between a recent high intensity rainfall event and time of identified nest failure; (2) 170 the nest was found underwater and empty; (3) intact eggs were found outside of the nest 171 following an increase in water level (Bayard and Elphick 2011). Nests were considered 172 depredated using the following criteria: (1) tracks were observed in the soil near the nest site or 173 foreign feces werefound within the nest site; (2) evidence of bite marks or fragments of eggs 174 found in or around the nest site; (3) the nest was found empty prior to the expected hatch date 175 (Hoover 2006). Nests were considered abandoned if eggs were intact and present in the nest at 176 two weeks or more past the expected hatch date and parents were confirmed to be no longer 177 incubating or defending the nest either by direct observation or by camera photos (Pierce 1986). 178 Nests were considered hatched if: (1) chicks were observed inside the nest or within the nest site 179 by direct observation or camera photos; (2) the nest was found empty on or within one day of the 180 expected hatch date (Cuervo 2010, El Malki et al. 2013). This method of determining successful 181 nests accounts for eggshell removal by parents immediately after eggs hatch, as this behavior has 182 been documented for Recurvirostrids (Sordahl 1994) and was observed anecdotally during this 183 study via game cameras and direct observations. 184 Nest initiation date was identified as the approximate date that the first egg was laid and 185 was determined either by backdating from the hatch date of the oldest nestling (Polak 2016),

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186 using an incubation period of 24 days (Coleman 1981, U.S. Fish and Wildlife Service 2011), or 187 dividing in half the difference between the number of days in the Hawaiian Stilt incubation 188 period and the number of days the nest was under observation and subtracting from the date the 189 nest was found (Martin et al. 1997). If the date of failure could not be determined, we dated the 190 failure on the midpoint between the last date the nest was observed active and the date the nest 191 was found failed (Mayfield 1961). 192 Chick home-range and survival. Stilt chicks (pre-fledging) at least 10 days of age were 193 hand captured and fit with 4 bands, comprised of 3 Darvic color bands and one U.S. Geological 194 Survey (USGS) aluminum band (Photo 1). VHF radio transmitters (Holohil BD-2) were glued to 195 the backs of chicks using Loctite super glue and by trimming down and feathers in a small area 196 about 1-2 cm above the uropygial gland. Transmitters weighed no more than 3% of each 197 individual’s body weight. If transmitters were observed loose, or fallen off, transmitters were 198 resecured or reattached using the same methods. Later in the season a different glue (Torbot) was 199 used, but no difference was noted in retention times of transmitters between glue types. We also 200 tried trimming fewer feathers on pre-fledglings later in the season, and gluing transmitters to 201 trimmed feathers, with improved success compared to fully trimming the area. 202 After the release of banded and radio-tagged chicks, we relocated chicks using VHF 203 receivers or through band re-sighting every day for the first 7 days after capture. After the first 7 204 days, we relocated tagged individuals at least 3 times a week until the tagged individual fledged, 205 at which point we located the fledgling at least once a week thereafter. Causes of mortality were 206 recorded when known, otherwise all tagged individuals were tracked until VHF transmitters fell 207 off, VHF transmitter batteries ran out, or after the individual could no longer be re-sighted via 208 bands. For each observation of a chick we recorded GPS location, behavior (i.e. foraging or 209 resting), transmitter status (if applicable), and the surrounding habitat (i.e. water, mudflat, short- 210 vegetation wetland, tall-vegetation wetland, short-grass field, tall-grass field). 211 212 Data Analyses 213 Nest-site selection. All analyses were conducted in the program R 3.5.3 (R Core Team 214 2019). Pearson’s paired t-tests were used to compare distance to water and vegetation height 215 between nest sites and random points. A G-test of independence was used to compare vegetation 216 species between nest sites and random points. Further, G-tests of independence were used to 217 compare each vegetation species to the sum of all other vegetation species using a Bonferroni 218 correction of p-values. A Pearson’s chi-square test of independence was used to compare the 219 number of nests placed on islands to the number of random points located on islands. Linear 220 regression analyses were used to examine changes in nest-site characteristics over the nesting 221 season. 222 Egg survival. To determine factors that impact nest depredation a mixed-effects logistic 223 exposure model was used to predict daily survival probability of nests using the lme4 package 224 (Bates et al. 2015). Logistic exposure is equivalent to logistic regression with a custom logit link 225 function that accounts for exposure days (Shaffer 2004). Exposure days for each nest were from 226 the date the nest was found to the date the nest failed or was successful (Mayfield 1961). Only 227 nests known to have failed due to depredation or produced at least one chick were used in this 228 analysis. Dates were scaled such that day 1 was the first day a nest was found during the nesting 229 season. Fixed variables included in the models were linear and quadratic terms for nest initiation 230 date, distance to water, vegetation height, and their interactions. Study site was used as a random 231 variable in all of our models. Constant daily survival was used as the null model. We developed

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232 a priori candidate models and ranked them using the Akaike’s Information Criterion corrected 233 for small sample size (AICc). Akaike’s weights (wi) were used to determine the probability that 234 each model was the best model. Model comparison results were computed using the MuMIn 235 package (Barton 2016). 236 Pearson’s t-tests were used to compare the number of eggs laid per nest, the number of 237 eggs hatched per nest, and the proportion of eggs hatched per nest between sites with and 238 without a mammal exclusion fence. 239 Chick home-range and survival. For home range analysis, 100% minimum convex 240 polygons were created for each tagged individual using relocation data prior to fledging. 241 242 RESULTS 243 Nest-Site Selection 244 We collected data on distance to water and vegetation height for 106 nests and paired 245 randomly-selected available habitat points in 2018 (n = 71) and 2019 (n = 35). Distance to water 246 was similar between nest sites (x̅ = 3.69 ± 0.38 m, n = 106) and random points (x̅ = 3.72 ± 0.43 247 m, n = 106; two-sample t-test: t105 = - 0.05, P = 0.95), but stilts nested in shorter vegetation (x̅ = 248 14.67 ± 1.41 cm, n = 106) than what was available (x̅ = 21.08 ± 3.19 cm, n = 106; two-sample t- 249 test: t105 = - 1.96, P = 0.05; Figure 2). Stilts selected nest sites with vegetation that was different 250 from what was available within the habitat (G5 = 31.74, P < 0.001), preferring Pickleweed (Batis 251 maritima; 58%; n = 61) above what was available (G1 = 14.06, P = 0.001), and utilizing 252 California grass (Brachiaria mutica, 4%, n = 4; G1 = 7.41, P = 0.03) and areas with no 253 vegetation (20%, n = 21; G1 = 14.91, P < 0.001) less often than expected based on what was 254 available (Figure 3). In 2019, the use of islands for nesting (n = 12) was similar to the number of 2 255 islands randomly available within the habitat (n = 6, ꭕ 1 = 1.86, P = 0.17). Distance to water was 256 not correlated with nest initiation date (R2 = 0.002, t = 0.26, P = 0.77). While vegetation height 257 was positively correlated with nest initiation date, there was not a strong linear trend, and 258 hatched and depredated nests were located in a wide range of vegetation heights (R2 = 0.05, t = 259 2.68, P<0.001; Figure 4). 260 Hawaiian Stilts in this study were occasionally observed utilizing “unprotected” spaces 261 for nesting, where human presence is not restricted. Three Hawaiian Stilt pairs in MCBH-KB 262 were observed building and defending nests on a wooden dock near Sag Harbor pond. Of the 263 three nests, only one was determined successful using photo analysis. Another nest, discovered 264 in the Salvage Yard of MCBH-KB, successfully produced one chick, which was radio-tagged 265 and monitored by our team through fledging. One stilt pair nested in a sludge basin in the 266 Wastewater Reclamation Facility within MCBH-KB and produced two chicks. However, the 267 pre-fledged chicks were unable to travel outside of the basin, and one chick was found dead due 268 to emaciation (see Appendix C), while the other chick was removed from the basin by our team 269 per USFWS instructions, as it was severely underweight. Upon removal, the chick was observed 270 regularly by our team and eventually fledged. Two stilt pairs nested at He‘eia NERR, one inside 271 a lo‘i patch and another in a recently cleared field of mangrove. The lo‘i nest produced three 272 fledglings, which were banded by our team, and the mangrove nest produced two fledglings, 273 which we were unable to band. 274 275 Egg Survival 276 Nests were discovered from March 13 to June 26 in 2018 and from February 26 to July 10 277 in 2019. Out of 253 total nests discovered in both years, 51% (n = 130) produced at least one

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278 chick, 18% (n = 45) failed due to depredation, 2% (n = 6) failed due to flooding, 12% (n = 29) 279 failed due to abandonment, and 17% (n = 43) had unknown fates (Table 1). Out of 158 nests that 280 were used to model nest depredation risk, 100 nests produced at least one chick, and 38 nests 281 failed due to depredation of eggs. Confirmed egg predators included Small Indian Mongooses (n 282 = 7), rats (n = 3), feral cats (n = 6), Black-crowned Night-Herons (n = 3), and a Hawaiian 283 Gallinule (n = 1). We were unable to confirm predator types for 18 depredated nests. The number 284 of depredated nests peaked later in the nesting season, following a peak in nest density (Figure 285 5). Correspondingly, the highest ranked model with the lowest AICc value and the largest weight 286 was the linear term for nest initiation date (Table 2). All models containing a temporal variable 287 had a summed Akaike weight (wi) of 0.57, suggesting a strong temporal effect on nest survival. 288 The linear date model predicted that daily nest survival was lowest for nests initiated later in the 289 nesting season (Figure 6). Models containing the terms ‘distance to water’ and ‘vegetation 290 height’ performed worse than the null model of constant daily survival. Models with the term 291 ‘vegetation height’ had a summed wi of 0.23, and models with the term ‘distance to water’ had a 292 summed wi of 0.25, providing little support for effects of nest-site characteristics on daily nest 293 survival (Table 2). 294 The number of eggs hatched per nest was greater inside the mammal-exclusion fence 295 (x̅ = 3.33 ± 0.29) than the site without fencing (x̅ = 1.29 ± 0.33; t25 = 4.71, p < 0.001; Figure 7). 296 The proportion of hatched eggs per nest was also greater insider the mammal-exclusion fence 297 (x̅ = 0.83 ± 0.07) than in the site without fencing (x̅ = 0.34 ± 0.09; t26 = 4.37, p < 0.001; Figure 298 7). There number of eggs laid per nest was also greater inside the fence (x̅ = 4.00 ± 0.00) than in 299 the site without fencing (x̅ = 3.67± 0.11; t20 = 3.16, p = 0.005; Figure 8). Inside the fence, 44.4% 300 of nests had at least one egg hatch and 55.6% of nests had the full clutch hatch. At the site 301 without mammal exclusion fencing, only 14.3% were full clutch hatches, 33.3% had at least one 302 egg hatch, 28.6% were depredated and the other 23.8% were abandoned, flooded or had 303 unknown fates (Figure 9). The time spent by chicks in the nesting area did not differ significantly 304 between sites (t = 0.59, p = 0.56; Figure 10). 305 306 Chick Home-Range and Survival 307 11 chicks (pre-fledging) were successfully captured, banded, and radio-tagged, with an 308 additional individual tracked with just band resights. We collected data for 10 stilt chicks in 309 MCBH-KB and two chicks in Kawainui Marsh. Home-range sizes varied by individual and by 310 pond (Figure 11, Figure 12, Figure 13, and Figure 14). The average home range was 0.942 ± 311 1.418 acres (Table 3). An additional eight chicks were monitored using observational surveys. Of 312 the total monitored chicks (n = 20), 7 fledged (35%), 6 had unknown fates (30%), 4 died due to 313 unknown causes (20%), 2 were depredated by a feral cat (10%), and 1 died due to emaciation 314 (5%). see Appendix C, Diagnostic Case Report – Case Number: 25659). Tracked individuals 315 were primarily observed using vegetated mudflats near water, but behaviors and habitat use 316 varied by pond (Table 4). An additional 8 sub-adults (post-fledging) were observed during 317 surveys at MCBH-KB, but our team was unable to capture and band these individuals (Table 5). 318 Two chicks found in Sag Harbor of MCBH-KB were assumed to have been depredated. 319 Transmitters of both chicks fell off prior to the disappearance of the chicks; however, on 320 06/16/19 a cat was observed in the vegetation nearby and was observed running away with an 321 unidentified bird in its mouth. The transmitter of one of the chicks was found on the ground near 322 where the cat was observed. The observation of the cat was immediately reported to MCBH-KB

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323 staff, but both chicks were not observed again, indicating that both chicks were likely depredated 324 by the cat. 325 On 5/17/19 a chick was found dead within 3-m of a nest in Pa‘akai within MCBH-KB 326 (Photo 2). The chick was found in a rut, on its side near a small puddle. Our team brought the 327 chick to USGS. On 9/24/19 we received a response from USGS, stating that the cause of death 328 could not be determined (Appendix C, Diagnostic Case Report – Case Number: 25653). We also 329 observed two featherless chicks (Photos 3 and 4) at a nest in Kaluapuhi within MCBH-KB. Per 330 camera photos, the chicks were able to move from the nest after hatching; however, no 331 observations of the chicks were recorded in subsequent surveys, indicating that the chicks likely 332 perished. 333 A chick that was being tracked but no longer had a transmitter was found dead in a basin 334 within the Water Reclamation Facility on 6/7/2019. The carcass was dropped off at USGS by the 335 field team for necropsy, and an incident report was completed. Our team suspected that this 336 chick died of dehydration or starvation because there was no obvious damage to its body, and the 337 basin in which it was enclosed had no water for about a week prior to death. The team received 338 the necropsy report from USGS on 9/24/19, and the chick indeed died from emaciation 339 (Appendix C, Diagnostic Case Report – Case Number: 25659). Discussions with MCBH-KB 340 staff, and their discussions with USFWS staff, led to the decision to remove its sibling, also in 341 the sludge basin, from the basin. The second chick was very thin when the team removed it from 342 the pond, but was tracked for another month, at which time it successfully fledged. 343 On 7/8/2019, a pair of adult stilts were observed in Sag Harbor, with one adult acting 344 strangely. It was sluggish, and clumsy, rolling its head back and forth, and would stumble when 345 it attempted to walk. The adult did not run, breathe abnormally, or generally react to human 346 intervention. It was transported to Feather and Fur where MCBH-KB staff contact info was listed 347 on the intake form. MCBH-KB staff later informed the team that the individual died at Feather 348 and Fur. 349 One pre-fledgling that previously had a transmitter was found dead at Kawainui Marsh 350 on 6/11/19. The transmitter had fallen off 4 days before the individual was found dead. The body 351 was twisted, with the bill pressed into a crack in the mudflat (Photo 6). There was blood on the 352 bill and legs, suggesting that something had attacked the individual. DOFAW staff were 353 informed, and the body was disposed of per their instructions. 354 355 ADDITIONAL FIELD WORK 356 Waterbird Surveys 357 Hawaiian Stilt surveys were performed in combination with nesting surveys at MCBH 358 and He‘eia NERR. Area surveys were conducted by driving around the perimeter of most 359 wetlands; however, in MCBH-KB, point count surveys were usually conducted, as it is not 360 possible to drive the perimeter of most ponds in this site. Refer to Appendix D for survey data. 361 362 Adult Stilt Banding 363 Two adult stilts were banded during attempts to capture sub-adults in MCBH-KB. An 364 adult male was caught on 09/09/19 in Kaluapuhi (L: Red/Red, R: Grey/Aluminum, USGS: 0944- 365 03823). The adult male is assumed to be the father of the three banded and tracked chicks in 366 Kaluapuhi (S10, S11, S12), and his assumed partner was already banded (L: Yellow/Green, R: 367 Orange/Aluminum). Both banded adults were regularly seen defending and calling when the 368 chicks were observed for home range analysis. An adult female was caught alongside Mokapu

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369 Rd. in between Kaluapuhi and ʻEkolu on 09/12/2019 and was banded by the team 370 (L:Yellow/Yellow, R: Grey/Aluminum, USGS: 0944-03825). 371 372 373 374 375 DISCUSSION 376 Nest-Site Selection and Egg Survival 377 Hawaiian Stilts in this study preferred to nest in low-lying vegetation. On average, stilts 378 nested in vegetation of a height similar to those found in other studies of Hawaiian Stilts 379 (Coleman 1981), as well as global populations of Black-necked Stilts (Hamilton 1975, Sordahl 380 1996, Ackerman et al. 2014). While stilts selected nest-sites in shorter vegetation, vegetation 381 height did not have a strong impact on depredation risk. In this study, 80% of identified predators 382 were introduced mammals, which primarily rely on olfactory senses for hunting prey; thus, taller 383 vegetation would not likely decrease the chance of nest discovery by mammalian predators. 384 Parental activity may also have affected nest conspicuousness and thus, nest depredation 385 pressure (Martin et al. 2000, Schmidt and Whelan 2005). Parents, which were frequently 386 observed using anti-predator behavior (broken wing displays) and aggressive flight (“dive- 387 bombing”), may have altered their behavior to compensate for the increased risk (Cresswell 388 1997), masking the significance of certain habitat variables. Further, if important habitat features 389 for nesting success are limited, we would expect the impacts of nest-site characteristics on nest 390 survival to be apparent; however, the Hawaiian Stilt population may not be at carrying capacity, 391 and competition for suitable nesting habitat may be minimal. Although vegetation height at nests 392 in this study increased as the nesting season progressed, there was considerable variation among 393 early and late nests, suggesting that preferred vegetation was likely available throughout the 394 nesting season. Proximity to water was also variable among early and late nests and did not 395 impact nest depredation. In fact, nests located on islands, which were surrounded by water, were 396 just as likely to be depredated as nests not placed on islands. Indeed, depredation by mongooses 397 was confirmed for nests located on small islands within wetlands and mongooses were observed 398 swimming to nesting areas on several occasions. 399 Nest survival was higher for nests initiated early in the nesting season, as has been found 400 in other waterbird species in temperate regions (Thyen and Exo 2005, Cuervo 2010, Ackerman et 401 al. 2014) and a waterbird species in the tropics (Ramos 2001). Indeed, the number of depredated 402 nests peaked later in the nesting season in both 2018 and 2019. This could have been associated 403 with an increase in nest density in the middle of the nesting season in both years, as has been 404 observed in other studies (Elmberg et al. 2009). Even though nest density decreased at the end of 405 the season, predators may have improved their recognition of nests (Nams 1997) or increased 406 their search intensity in areas where nests had previously been found (Tinbergen et al. 1967). 407 Predator abundance may also have increased later in the season or alternative prey items of 408 potential predators may have decreased, as these factors were not measured by our study. 409 Alternatively, early nesters may have been of better phenotypic quality (Price et al. 1988, 410 Verhulst and Tinbergen 1991). 411 The results from this study suggest that mammal-exclusion fencing results in greater 412 nesting success than trapping mammalian predators alone. Although trapping is continuous, there 413 may be some delay before mammalian predators are removed allowing opportunity for 414 prior to removal. The trapping and removal of waterbird predators from sites may allow for 415 predator-release (Rayner et al. 2007) if predators from adjacent habitats readily recolonize the

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416 site. The loss in trapping effectiveness may be greater still in systems near urban development 417 that have a ready source of rats, feral cats, and dogs to fill the void. Reed et al. (1998) conducted 418 a sensitivity analysis and found parameters such as catastrophic stochastic events, maximum age 419 and density dependent reproduction had “little effect” on the Hawaiian Stilt projections. 420 However, the likelihood of stilts persisting more than 200 years dropped notably when clutch 421 failure rate or first-year mortality rate increased above 70%. Surprisingly, clutch sizes laid by 422 breeding pairs within the mammal-exclusion fencing were significantly greater than those 423 without an enclosure. Perceived depredation risk has been shown to invoke a physiological 424 response that can negatively impact clutch size and adult fitness (Zanette et al. 2011; Thomson et 425 al. 2010). 426 In our study, potential avian and amphibious predators were confronted by adult stilts and 427 typically met with mobbing while perceived mammalian predators, including humans, received 428 weaker responses such as circling and dive bombing. Our research was unable to quantify a 429 varied response to predator types but would have likely been consistent with North American 430 literature (Sordahl 2004). However, in the absence of mammalian predators, non-native avian, 431 aquatic and amphibious predators may experience predator-release inside mammal-exclusion 432 fences and could be present in higher numbers inside of mammal-exclusion fences. Regardless, 433 we would still expect some nest failures from avian, aquatic or amphibious predators, nest 434 abandonment, and/or flooding. Thus, we expected the number of eggs laid versus hatched within 435 a site to differ greatly. In Waiawa, without mammal exclusion fencing, fewer eggs hatched than 436 were laid, as expected. Surprisingly, our results for Honouliuli, inside the fence, indicated a 437 barely significant difference between the number of eggs laid versus hatched. This may be due to 438 stilts’ potential to respond to avian and amphibious predators. 439 Nearly as many nests were determined abandoned as were determined depredated. Cause 440 of abandonment is often difficult to determine, as there are several potential causes: 441 presence/harassment from predators, competition between stilts, poor egg development, 442 undetected flooding, and human disturbance. Photo analysis indicated that our presence was 443 likely not the cause of nest abandonment, as adults returned to the nest immediately after the 444 camera was placed and then abandoned the nest days or weeks later, or adults were never 445 observed near the nest or in the camera frame. More research is needed to assess causes of nest 446 abandonment. 447 Hawaiian Stilts in this study were occasionally observed utilizing “unprotected” spaces 448 for nesting, where human presence is not restricted, several of which successfully hatched. Use 449 of “unprotected” spaces for nesting may increase as protected areas are reduced due to 450 anthropogenic causes (i.e. sea level rise); further research is needed to determine the potential for 451 unprotected areas to provide suitable nesting habitat for Hawaiian waterbirds.

452 453 Chick Home-Range and Survival 454 Home range size varied greatly, potentially due to variations in number of GPS locations 455 for each individual, or possibly due to variability in habitat characteristics or community 456 dynamics. A second year of home range and habitat characteristic data are needed to understand 457 these dynamics. Chicks tended to utilize vegetation when feeling threatened (Photo 5). Chicks in 458 MCBH-KB often used the shallow ruts created by Amphibious Assault Vehicles (AAVs), 459 limiting our team’s ability to see chicks from a distance. To combat these limitations, the team 460 identified new methods to assist with chick detection including spotlighting, thermal technology, 461 and following adult behavior(in order of most to least effective). Additionally, our team

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462 identified that using Loctite super glue to attach transmitters to trimmed feathers (not bare skin) 463 is the best method for increasing retention times of transmitters. These methods will be used for 464 the next nesting season to improve sample sizes. Improved methods for detecting chicks and 465 experience with the site will allow the team to reduce uncertainties for the 2020 nesting season 466 and improve statistical power of analyses. 467 468 MANAGEMENT RECOMMENDATIONS 469 Tall, invasive vegetation, such as California grass, should continue to be controlled, as it 470 was rarely used for nesting by stilts. More desirable vegetation, such as Pickleweed, should be 471 made available throughout wetlands to encourage larger spacing between nesting pairs, which 472 may help to reduce depredation pressure. Our results suggest that Water hyssop was not selected 473 for more than what was available; however, this native low-lying plant species likely also 474 provides desirable nesting habitat for Hawaiian Stilts and should be made available throughout 475 Hawaiian Stilt nesting sites. While we were able to determine some vegetation preferences of 476 stilts for nesting, longer studies are needed to confirm the impact of vegetation characteristics on 477 Hawaiian Stilt nest survival. Manipulation of water levels is an important component of 478 waterbird management globally and has been directly linked to nest survival in subtropical 479 wading bird species (Lorenz 2014). Proximity to water did not change over the nesting season, as 480 we had originally predicted, which may have been due to the manipulation of water levels at 481 some sites during our study period. Although we did not find a correlation between proximity to 482 water and nest depredation, proximity to water likely impacts the probability of nest flooding. 483 Additionally, proximity to water may have changed at nests throughout the nesting season, 484 further complicating our ability to detect a correlation between water and depredation. Future 485 studies should examine these relationships to inform additional management actions. 486 While our study identified seasonality in nest depredation of the Hawaiian Stilt, our 487 results did not indicate that nest depredation was linked to nest-site characteristics. Rather, it is 488 likely that differences in traits or behavior of parents, changes in predator activity, or a 489 combination of the two, are responsible for the temporal differences observed in this study. Our 490 study is the first to examine seasonality in nest survival of the Hawaiian Stilt, and as such, our 491 results have important implications for the timing of management actions. Land managers likely 492 need to increase predator control, particularly for introduced mammalian predators, as the stilt 493 nesting season progresses. Land managers should also consider increasing mammalian trapping 494 in high density nesting areas. Our results suggest that management of predators, particularly 495 mammals, is key to improving stilt nest survival, as preferred nest-site characteristics do not 496 reduce the likelihood of nest depredation. Further, mammal-exclusion fencing may be a useful 497 tool to help recover endangered waterbirds, by increasing nesting success. For other Endangered 498 waterbird species that breed year-round inside the enclosure, the recruitment potential could be 499 substantial. Our study, though limited in sample size inside the fence, also suggests stress may be 500 lower in birds inside the mammal-exclusion fence, potentially increasing clutch size. A banded 501 population is essential for estimating recruitment inside and outside the mammal-exclusion 502 fences. Future research into chick mortality and causes of death in and out of the fence would 503 lend another metric to bring context to invasive biology in the Hawaiian Islands. As complete 504 island-wide eradication of mammalian predators is not feasible at this time, Hawai‘i's 505 Endangered waterbirds are conservation reliant and predator management must be sustained for 506 waterbirds to persist. Continuous monitoring of waterbird populations over time is necessary for 507 adaptive management.

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508 LITERATURE CITED 509 Ackerman, J. T., M. P. Herzog, J. Y. Takekawa, and C. A. Hartman (2014). Comparative 510 reproductive biology of sympatric species: Nest and chick survival of American avocets 511 and black-necked stilts. Journal of Avian Biology 45(6): 609-623. 512 Baker. J. K. and C. A. Russell (1979). predation on a nesting nene. Elepaio 40: 51–52. 513 Barton, K. (2016). MuMIn: Multi-model inference. R package ´ version 1.43.10. https://cran.r- 514 project.org/web/packages/MuMIn/index.html. 515 Bates, D., M. Machler, B. M. Bolker, and S. C. Walker (2015). Fitting ¨ linear mixed-effects 516 models using lme4. Journal of Statistical Software 67:1–48. 517 Bayard, T. S. and C. S. Elphick (2011). Planning for sea-level rise: Quantifying patterns of 518 saltmarsh sparrow (Ammodramus caudacutus) nest flooding under current sea-level 519 conditions. The Auk 128(2): 393–403. 520 Bonesi, L. and S. Palazón (2007). The American Mink in Europe: Status, impacts, and control. 521 Biological Conservation 134: 470-483. 522 Burns, B., J. Innes, and T. Day (2012). The Use and Potential of Pest-Proof Fencing for 523 Ecosystem Restoration and Fauna Conservation in New Zealand. In Fencing for 524 Conservation: Restriction of Evolutionary Potential Or a Riposte to Threatening Processes?, 525 65–90. 526 Carmona, R., C. Carmona, A. Castillo-Guerrero, and E. M. Zamora-Orozco (2000). Nesting 527 records of and Black-necked Stilt in Baja California Sur, Mexico. The 528 Southern Naturalist 45(4): 523-536. 529 Cheke, A. (1987). An ecological history of Mauritius. In Studies of Mascarene Island Birds (A. 530 W. Diamond, editor). Cambridge University Press, Cambridge, UK. 531 Clunie, F. and P. Morse (1984). Birds of the Fiji bush. Fiji Museum, Suva, Fiji. 532 Coleman, R. A. (1981). The reproductive biology of the Hawaiian subspecies of the black- 533 necked stilt, Himantopus mexicanus knudseni. Ph.D. dissertation, Pennsylvania State 534 University, State College, PA, USA. 535 Conway, W., L. M. Smith, and J. D. Ray (2005). Shorebird habitat use and nest-site selection in 536 the Playa Lakes Region. Journal of Wildlife Management 69(1): 174-184. 537 Cresswell, W. (1997). Nest predation: The relative effects of nest characteristics, clutch size and 538 parental behavior. Behavior 53: 93–103. 539 Cuervo, J. J. (2010). Hatching success in Avocet Recurvirostra avosetta and Black-winged Stilt 540 Himantopus himantopus. Bird Study 52(2): 166-172. 541 El Malki, S., S. Hanane, L. Joulami, and R. El Hamoumi (2013). Nesting performance of the 542 Black-winged Stilt and Collared Pratincole on a Moroccan coastal wetland: A 543 comparison between natural and artificial habitats. Wader Study Group Bulletin 120(1): 544 47–52. 545 Elmberg, J., K. Folkesson, M. Guillemain, and G. Gunnarsson (2009). Putting density 546 dependence in perspective: Nest density, nesting phenology, and biome, all matter to 547 survival of simulated mallard Anas platyrhynchos nests. Journal of Avian Biology 548 40:317-326. 549 Gorman, M. L. (1975). The diet of feral Herpestes auropunctatus (Carnivora: Viverridae) in the 550 Fijian Islands. Journal of Zoology 175: 273-278. 551 Hamilton, R. B. (1975). Comparative behavior of the American Avocet and the Blacknecked 552 Stilt (Recurvirostridae). Ornithological Monographs No. 17.

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553 Holt, R. D. (1977). Predation, apparent competition, and the structure of prey communities. 554 Theoretical Population Biology 12:197–229. 555 Hoover, J. P. (2006). Water depth influences nest predation for a wetland–dependent bird in 556 fragmented bottomland forests. Biological Conservation 127:37–45. 557 Jedlikowski J., M. Brzeziski, and P. Chibowski (2015). Habitat variables affecting nest predation 558 rates at small ponds: A case study of the Little Crake Porzana parva and Water Rail 559 Rallus aquaticus. Bird Study 62: 190-210. 560 Kristiansen, J. N. (1998). Egg predation in reedbed nesting Greylag Geese Anser anser in 561 Vejlerne, Denmark. Ardea 86: 137-145. 562 Lavers, J. L., C. Wilcox, and C. J. Donlan (2010). Bird Demographic Responses to Predator 563 Removal Programs. Biological Invasions 12 (11): 3839–59. 564 Lorenz, J. J. (2014). The relationship between water level, prey availability, and reproductive 565 success in Roseate Spoonbills foraging in a seasonally-flooded wetland while nesting in 566 Florida Bay. Wetlands 34 (1): 201. 567 Martin, T. E., C. Paine, C. J. Conway, W. M. Hochachka, P. Allen, and W. Jenkins (1997). 568 Breeding biology research and monitoring database (BBIRD) field protocol. Montana 569 Cooperative Wildlife Research Unit, Missoula, MT, USA. 570 Martin, T.E., J. Scott, and C. Menge (2000). Nest predation increases with parental activity: 571 Separating nest site and parental activity effects. Proceedings of the Royal Society of 572 London B-Biological Sciences 267: 2287–2293. 573 Mayfield, H. (1961). Nesting success calculated from exposure. Wilson Bulletin 73: 255-261. 574 Mercer, R. (1967). A field guide to Fiji Birds. 2nd edition. Fiji Museum, Suva, Fiji. 575 Nams, V. O. (1997). Density-dependent predation by skunks using olfactory search images. 576 Oecologia 110:440–448. 577 Picman, J. (1988). Experimental study of predation on eggs of ground-nesting birds: Effects of 578 habitat and nest distribution. The Condor 90: 124-131. 579 Pierce, R. (1986). Differences in susceptibility to predation during nesting season between Pied 580 and Black stilts (Himantopus spp.). The Auk 103: 273-280. 581 Polak, M. and Z. Kasprzykowski (2013). The effect of weather conditions on the breeding 582 biology of the Eurasian Bittern Botaurus stellaris in eastern Poland. Ethology Ecology 583 and Evolution. 25: 243–252. 584 Price T., M. Kirkpatrick, and S. J. Arnold (1988). Directional selection and the evolution of 585 breeding date in birds. Science 240(4853): 798–799. 586 Price, S. (1983). Atlas of Hawai‘i. Second Addition. University of Hawai‘i Press, Honolulu, HI, 587 USA. 588 Ramos, J. A. (2001). Seasonal variation in reproductive measures of tropical Roseate Terns 589 Sterna dougalli previously undescribed breeding patterns in a seabird. Ibis 143: 83-91. 590 Rayner, M. J., M. E. Hauber, M. J. Imber, R. K. Stamp, and M. N. Clout (2007). Spatial 591 Heterogeneity of Mesopredator Release within an Oceanic Island System. PNAS 104 (52). 592 R Core Development Team (2019). R: A language and environment for statistical computing. R 593 Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org. 594 Reed, J. M., C. S. Elphick, and L. W. Oring (1998). Life-history and viability analysis of the 595 endangered Hawaiian Stilt. Biological Conservation 84(1): 35-45. 596 Reed, J. M., C. S. Elphick, A. F. Zuur, E. N. Ieno, and G. M. Smith (2007). Time Series Analysis 597 of Hawaiian Waterbirds. In Analysing Ecological Data, 615–31.

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598 Schaming, T. D. (2015). Population-wide failure to breed in the Clark’s Nutcracker (Nucifraga 599 Columbiana). PLoS One 10(5): e0123917. 600 Schmidt, K. A. and C. J. Whelan (2005). Quantifying male Wood Thrush nest-attendance and its 601 relationship to nest success. The Condor 107: 138–144. 602 Seaman, G. A. (1952). The mongoose and Caribbean wildlife. Seventeenth North American 603 Wildlife Conference 188–196. 604 Seaman, G. A., and J. E. Randall (1962). The mongoose as a predator in the Virgin 605 Islands. Journal of Mammalogy 43: 544–546. 606 Shaffer, T. L. (2004). A unified approach to analyzing nest success. The Auk 121: 526-540. 607 Skutch, A. F. (1949). Do tropical birds rear as many young as they can nourish? Ibis 91:430– 608 455. 609 Smith, R. K., A. S. Pullin, G. B. Stewart, and W. J. Sutherland (2010). Effectiveness of Predator 610 Removal for Enhancing Bird Populations. Conservation Biology 24 (3): 820–29. 611 Sordahl, T. A. (1982). Antipredator behavior of American Avocet and Black-necked Stilt chicks. 612 Journal of Field Ornithology 53(4): 315-325. 613 Sordahl, T. A. (1994). Eggshell removal behavior of American Avocets and Black-Necked Stilts. 614 Journal of Field Ornithology 65 (4): 461-465. 615 Sordahl, T. A. (1996). Breeding biology of the American Avocet and Black-Necked Stilt in 616 Northern Utah. The Southwestern Naturalist 41(4): 348-354. 617 Sordahl, T. A. (2004). Field Evidence of Predator Discrimination Abilities in American Avocets 618 and Black-Necked Stilts. Journal of Field Ornithology 75 (3): 223–31. 619 Thomson, R. L., G. Tomás, J. T. Forsman, J. Broggi, and M. Mönkkönen (2010). Predator 620 Proximity as a Stressor in Breeding Flycatchers: Mass Loss, Stress Protein Induction, and 621 Elevated Provisioning. Ecology 91 (6): 1832–40. 622 Thyen, S. and K. M. Exo (2005). Interactive effects of time and vegetation on reproduction of 623 redshanks (Tringa totanus) breeding in Wadden Sea salt marshes. Journal of Field 624 Ornithology 146: 215–225. 625 Tinbergen, N., M. Impekoven, and D. Franck (1967). An experiment on spacing-out as a defense 626 against predation. Behaviour 28:307– 321. 627 U.S. Fish and Wildlife Service (2011). Recovery plan for Hawaiian waterbirds, second revision. 628 U.S. Fish and Wildlife Service, Portland, OR, USA. 629 Verhulst, S. and J. M. Tinbergen (1991). Experimental evidence for a causal relationship 630 between timing and success of reproduction in the Great Tit Parus m. major. Journal of 631 Animal Ecology 60(1): 269–282. 632 Wilson S., K. Martin, and S. J. Hannon (2007). Nest survival patterns in Willow Ptarmigan: 633 Influence of time, nesting stage, and female characteristics. The Condor 109: 377-388. 634 Young, L. C., E. A. VanderWerf, M. T. Lohr, C. J. Miller, A. J. Titmus, D. Peters, and L. Wilson 635 (2013). Multi-Species Predator Eradication within a Predator-Proof Fence at Ka’ena 636 Point, Hawai’i. Biological Invasions 15 (12): 2627–38. 637 Zanette, L. Y., A. F. White, M. C. Allen, and M. Clinchy (2011). Perceived Predation Risk 638 Reduces the Number of Offspring Songbirds Produce per Year. Science 334 (6061): 1398– 639 1401. 640 641 642 643

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644 APPENDIX A. FIGURES AND PHOTOS 645 646 Figure 1. Study sites on the island of O‘ahu, Hawai‘i, USA ...... A-2 647 Figure 2. Barplot comparing vegetation height at nest sites and random points ...... A-2 648 Figure 3. Pie charts comparing vegetation species at nest sites and random points ...... A-3 649 Figure 4. Linear regression of vegetation height at nests over 2018 and 2019 nesting seasons 650 combined ...... A-3 651 Figure 5. Kernel density estimates of active nests and depredated nests throughout the 2018 and 652 2019 nesting seasons combined ...... A-4 653 Figure 6. Mixed-effects logistic exposure model showing impact of nest initiation date on nest 654 survival ...... A-4 655 Figure 7. Comparison of eggs hatched inside and outside fencing ...... A-5 656 Figure 8. Comparison of eggs laid inside and outside fencing ...... A-5 657 Figure 9. Comparison of nest fates inside and outside fencing ...... A-6 658 Figure 10. Comparison of time spent in nesting area inside and outside fencing ...... A-6 659 Figure 11. Stilt home ranges in Kaluapuhi ...... A-7 660 Figure 12. Stilt home ranges in Sag Harbor ...... A-7 661 Figure 13. Stilt home ranges in Water Reclamation Facility and Salvage Yard ...... A-8 662 Figure 14. Stilt home ranges in Kawainui Marsh ...... A-8 663 Photo 1. Typical band and transmitter arrangement on pre-fledglings...... A-9 664 Photo 2. Pre-fledged chick found dead near nest MC11 in Paʻakai on 05/17/19 ...... A-9 665 Photo 3. Three chicks caught on camera in Kaluapuhi in MCBH-KB, two of which are 666 featherless ...... A-10 667 Photo 4. Close up of one of the two featherless chicks hatched in Kaluapuhi ...... A-10 668 Photo 5. Typical posture pre-fledglings are found with when tracking tagged individuals .... A-11 669 Photo 6. Hawaiian Stilt chick found dead in Kawainui Marsh ...... A-11 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685

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686 Figure 1. Island of O‘ahu, Hawai‘i, USA. Shaded circles indicate wetlands where nesting 687 surveys were conducted. 688

689 Figure 2. Barplot comparing average (± SE) vegetation height at nest sites and random points. 690 Stilts nested in significantly shorter vegetation (x̅ =14.67 cm ± 1.41 cm, n=106) than what was 691 randomly available (x̅ =21.08 cm ± 3.19 cm, n=106, t105= - 1.96, P=0.05). 692 693

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*P-value ≤ 0.05 694 695 Figure 3. The greatest percentage of stilt nests were located in Pickleweed (Batis maritima; 696 58%; n = 61), Water hyssop (‘Ae‘ae - Bacopa monnieri, 13%, n = 14), or no vegetation (20%, n 697 = 21), and less frequently located in California grass (Brachiaria mutica, 4%, n = 4), Cattail 698 (Typha latifolia, 4%, n = 4), or other vegetation (2%, n = 2). Vegetation species was significantly 699 different between nest sites and random points (G5 = 31.74, P<0.001). Pickleweed (G1 = 14.06, P 700 = 0.001) was selected for more than what was randomly available, while California grass (G1 = 701 7.41, P = 0.03) and no vegetation (G1 = 14.91, P< 0.001) were selected for less than what was 702 randomly available. Stilts did not disproportionately select for Water hyssop (G1 = 1.22, P = 703 1.00), Cattails (G1 = 5.62, P = 0.10), or other vegetation (G1 = 0.34, P = 1.00). 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721

722 Figure 4. Linear regression of vegetation height at nests over 2018 and 2019 nesting seasons 723 combined. Nest initiation date was positively correlated with vegetation height at nests but did 724 not exhibit a strong linear trend (R2 = 0.05, t = 2.68, P <0.001). 725

A-3

726 727 728 729

730 Figure 5. Kernel density estimates of active nests and depredated nests throughout the 2018 and 731 2019 nesting seasons combined. Stilt nest density peaked in the middle of the nesting season, 732 while the number of depredated nests peaked later in the nesting season. 733

734 Figure 6. Mixed-effects logistic exposure model showing impact of nest initiation date on nest 735 survival. The solid line represents daily survival probability estimated using parameters from the 736 best fit model. Dotted lines represent upper and lower 95% confidence intervals for the estimated 737 daily survival probability. 738 739 740

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741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 Figure 7. Bar plots depicting the numbers of eggs hatched and the proportion of eggs hatched 759 per nest at each site for 2019. 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 Figure 8: Bar plot of the number of eggs laid per nest by site. 782 783 784 785 786

A-5

787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 Figure 9: A stacked bar chart indicating the fates of the nests at each site (n = 30). 813

814 815 Figure 10: A histogram and bar plot comparing the hours spent in the nesting area for each site. 816 (x̅ = 57.16; range = 24.5-118.66) 817

A-6

818 Figure 11. Home ranges depicted as 100% minimum convex polygons of of chicks in Kaluaphui 819 and Paʻakai.

820 Figure 12. Home ranges depicted as minimum convex polygons of 100% of pre-fledge GPS 821 locations recorded for S7, S8, and S9 at Sag Harbor. 822

A-7

823 824 825 826 827 828 829 830 831 832 833 834 835

836 Figure 13. Home ranges depicted as minimum convex polygons of 100% of pre-fledge GPS 837 locations recorded for S1, S2, and S8 in Water Reclamation Facility 4 and Salvage Yard. 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 Figure 14. Home ranges depicted as minimum convex polygons of 100% of pre-fledge GPS 859 locations recorded for S3 and S5 in pond 11 of Kawainui Marsh. 860 861 862

A-8

863 Photo 1. Typical band and transmitter arrangement on chicks. This chick (S13) was found in 864 Kaluapuhi on 09/12/19. 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 Photo 2. Stilt chick found dead near nest in Paʻakai within MCBH-KB on 05/17/19. Carcass was 889 brought to USGS for necropsy, of which Diagnostic summarized that the cause of death was 890 unknown (see Appendix C, Case Number: 25653). 891

A-9

892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 Photo 3. Three chicks caught on camera in nest MC07, two of which are featherless. The team 912 found one chick in the nest when visiting the nest to change camera batteries, but no chicks were 913 seen in the area in subsequent surveys. 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 Photo 4. Close up of one of the two featherless chicks hatched from MC07 in Kaluapuhi. 933 934 935 936

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937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 Photo 5. Typical posture pre-fledglings are found with when tracking tagged individuals. Once 960 pre-fledglings are about 3-4 weeks old, they hide less in the vegetation and can be spotted from a 961 greater distance inducing less disturbance to the fledgling. 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 Photo 6. Dead stilt chick (S3) found in pond 11 in Kawainui Marsh.

A-11

983 APPENDIX B. TABLES 984 985 Table 1. Hawaiian Stilt nest fates for 2018 and 2019 ...... B-2 986 Table 2. Model selection of Hawaiian Stilt nest survival ...... B-3 987 Table 3 Pre-fledged chick home ranges and habitat characteristics ...... B-4 988 Table 4. Chick detections during surveys ...... B-5 989 Table 5. Sub-adult detections during surveys ...... B-6 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028

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1029 Table 1. Hawaiian Stilt nest fates and hatching success for the 2018 and 2019 nesting seasons. Kawainui Marsh No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success 2018 5 4 0 0 1 0 20%

2019 12 3 0 2 6 1 50% Hamakua Marsh No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success 2018 17 0 0 5 8 4 47%

2019 19 1 3 1 13 1 68% Waiawa Wetland No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success 2018 27 5 0 3 15 4 56% 2019 37 8 0 5 12 12 32% Honouliuli Wetland No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success 2018 26 10 1 3 9 3 35%

2019 18 1 0 0 16 1 89% James Campbell NWR No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success 2018 10 2 0 0 7 1 70%

2019 22 2 0 2 10 8 45% MCBH-KB No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success

2018 N/A N/A N/A N/A N/A N/A N/A

2019 58 9 2 8 31 8 53% He‘eia NERR No. observed nests Predated Flooded Abandoned Hatched Unknown Hatching Success

2018 N/A N/A N/A N/A N/A N/A N/A

2019 2 0 0 0 2 0 100% 1030 1031

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1032 Table 2. Model selection of Hawaiian Stilt (Himantopus mexicanus knudseni) nest survival in 1033 wetlands on O‘ahu, Hawai‘i. Models were ranked using Akaike’s Information Criterion 1034 corrected for small sample sizes (AICc). All models included study site (random effect). Only 1035 nests known to be depredated or hatched were included in analysis. K is number of model 1036 parameters, ΔAIC is the difference in AICc value from the top model, and wi is Akaike model 1037 weight.

Model K ΔAIC wi

Date 3 0.00 a 0.26

Null 2 0.48 0.20

Distance to water 3 1.41 0.13

Date2 4 1.61 0.11

Vegetation height 3 1.91 0.10

Date*Vegetation height 5 2.25 0.08

Date*Distance to water 5 2.63 0.07

Date + Date2 + Vegetation height + Distance to water 6 3.14 0.05

a The AICc value of the top-ranked model = 331.51

1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055

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1056 Table 3. Pre-fledge home range and habitat characteristics collected for all twelve tracked chicks 1057 at MCBH-KB and Kawainui Marsh.

No. HR GPS Size ID Pond USGS Band Color Band Fate Locations (acre) Ground Surface Composition Water Reclamation Dead via Sludge basin, mix of floating matter, vegetation, S1 Facility 0944-03803 ZA:-- emaciation 16 0.126 and sometimes standing water Water Reclamation Sludge basin, mix of floating matter, vegetation, S2 Facility 0944-03804 ZA:OO Fledged 38 0.431 and sometimes standing water Possibly attacked by something- blood on bill and legs, body twisted, fairly fresh upon finding it. S3 KA Pond 11 0944-03806 OA:-- Dead 10 0.481 Found on 6/11/19. No transmitter - Did not see again 4 days after S5 KA Pond 11 0944-03807 OA:-- Unknown 5 0.011 banding Pond that varies in size and depth with rainfall, S6 Sag Harbor 0944-03812 ZA:ZZ Predated 11 0.006 surrounded by thick vegetation and some mudflat Pond that varies in size and depth with rainfall, S7 Sag Harbor 0944-03813 ZA:OZ Predated 7 0.015 surrounded by thick vegetation and some mudflat Tidal pond with patches of thick vegetation Salvage (primarily pickleweed), gravelly mudflats available S8 Yard 0944-03814 AZ:ZO Fledged 50 4.673 at low tide Pond that varies in size and depth with rainfall S9 Sag Harbor 0944-03819 AZ:OO Fledged 65 0.186 surrounded by thick vegetation and some mudflat AAV-turned terrain with small permanent ponds and ruts that fluctuate in water depth with variable rain. S10 Kaluapuhi 0944-03820 ZA:ZK Fledged 29 2.204 Pickleweed on top of soil ridges between ruts. AAV-turned terrain with small permanent ponds and ruts that fluctuate in water depth with variable rain. S11 Kaluapuhi 0944-03821 ZA:ZB Fledged 37 2.288 Pickleweed on top of soil ridges between ruts. AAV-turned terrain with small permanent ponds and ruts that fluctuate in water depth with variable rain. S12 Kaluapuhi 0944-03822 ZA:ZR Fledged 34 0.399 Pickleweed on top of soil ridges between ruts. Flat mudflat area that connects Pa‘akai and S13 Kaluapuhi 0944-03824 ZA:YZ Fledged 18 0.484 Kaluaphui, with patches of pickleweed nearby. Avg 26.667 0.942 1058 1059 1060

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1061 Table 4. Summary of all chicks detected during the 2019 nesting seaso Date Detected Pond No. Chicks Transmitter Fate Circumstances 4/12/2019 TLF 2 No Unknown Found chicks when we first located nest. Featherless chick found in nest, too small to band. Not found again on subsequent surveys. Likely depredated. Unknown - No sub-adults observed in the area later in the season, Possibly and no defensive adult behavior observed after the first 5/10/2019 Kaluapuhi 1 No Dead observation of the chick. Water Bands and transmitters attached to one chick on 5/14/19. Reclamation Dead - Chick found dead on 6/7/19, necropsy report from USGS 5/14/2019 Facility 1 Yes Emaciation stated cause of death as emaciation. Water Bands and transmitters attached 5/14/19. Chick removed Reclamation from sludge basin on 6/11/19, and its transmitter fell off 5/14/2019 Facility 1 Yes Fledged 6/27/19. Observed fledged 7/5/19. Dead - Found dead near nest, body fresh and brought to USGS. Unknown Necropsy report noted no abnormalities, possibly 5/17/2019 Pa'akai 1 No Cause drowning COD. Dead - Found dead in nest, adult primary feathers found nearby. Unknown Team witnessed hatching of first of 4 eggs 1 week prior. 5/24/2019 ʻEkolu 1 No Cause Too torn up to collect. Likely depredated. Dead- Unknown One chick found dead on 06/11/2019. Unknown cause of 05/31/2019 Kawainui 2 Yes Cause death, possibly attacked. Second chick not seen again. Chicks may have come from dock near Sag Harbor, or an undetected nest within Sag Harbor ponds. Bands/transmitters attached 6/11/19. Suspect both depredated, due to observed cat on 6/16/19, and absence 6/4/2019 Sag Harbor 2 Yes Predated of chicks thereafter.

06/11/2019 Kawainui 1 No Unknown No transmitter - Did not see again 4 days after banding Too small to band. Not found again on subsequent surveys. No sub-adults observed in the area later in the season, and no defensive adult behavior was observed 6/25/2019 ʻEkolu 1 No Unknown after the first observation of the chick. Salvage Bands and transmitter attached on 7/2/19. Transmitter 6/25/2019 Yard 1 Yes Fledged found detached on 8/15/19, with no observation of chick. Chick may have come from dock near Sag Harbor or hazed from airfield. Band and transmitter attached 7/8/2019 Sag Harbor 1 Yes Fledged 09/23/19. Dead - Unknown Found dead near nest, fairly decomposed so did not 7/16/2019 Pa'akai 1 No Cause remove or bring in for necropsy.

8/1/2019 Kaluapuhi 3 Yes Fledged Bands and transmitters attached 8/2/19. 9/12/2019 Kaluapuhi 1 Yes Fledged Bands and transmitter attached 09/12/19.

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1062 Table 5. Date, pond location, and observations/circumstances for sub-adults detected during the 1063 2019 nesting season.

Date Detected Pond No. Sub-adults Circumstances Capture and Marking Team not present, not found in subsequent 6/18/2019 Pa‘akai 1 surveys Capture and Marking Team not present, not found in subsequent 7/2/2019 ‘Eha 1 surveys Capture and Marking Team not present, not found in subsequent 8/1/2019 Kaluapuhi 1 surveys Attempted to catch on 9/12/19 alongside Mokapu Rd. in-between Kaluapuhi and ʻEkolu, and in ‘Ekolu. Unsuccessful for sub-adult, but 9/7/2019 Kaluapuhi/‘Ekolu 1 did catch and band an adult. Capture and Marking Team not present, not found in subsequent 9/12/2019 Kaluapuhi 2 surveys Attempt to catch the sub-adult on 9/27/19 with mist nests but was 9/19/2019 Kaluapuhi 1 unsuccessful. Suspected there was a chick in the area when MC44 hatched, however no chicks were observed during multiple surveys around the area. There 10/12/2019 was also no adult behavior indicating chicks were in the area. Found the ‘Ekahi 1 individual as a sub -adult too late in the season. 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082

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1083 1084 APPENDIX C. DIAGNOSTIC CASE REPORTS 1085 1086 Diagnostic case report – Case Number: 25659 ...... C-2 1087 Diagnostic case report – Case Number: 25653 ...... C-4 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121

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1122 DIAGNOSTIC CASE REPORT 1123 U. S. GEOLOGICAL SURVEY-BIOLOGICAL RESOURCES DIVISION 1124 NATIONAL WILDLIFE HEALTH CENTER-HONOLULU FIELD STATION 1125 P. O. BOX 50167, 300 ALA MOANA BLVD., Rm. 8-132 1126 HONOLULU, HAWAII 96850 1127 Tel: 808-792-9520, Fax: 792-9596, Email: [email protected] Case Number: 25659 Submitter Name: Species submitted (n): Mr. Dain Christiansen Stilt: Hawaiian (1) University of Hawaii 1910 East-West Road Honolulu, Hawaii 96822 United States

Location: Kanehoe MCBH DateCollected: 6/07/2019 Area: Honolulu DateSubmitted: 6/7/2019 State: Hawaii DateReceived: 6/7/2019 Country: United States DateExamined: 6/7/2019

SPECIMENS SUBMITTED: Carcass-Chilled 1128 History: This chick was found dead in the Water Reclamation Facility at 1129 Kaneohe Marine Corps Base on 7 June 2019. Identification - left leg: gray 1130 band over FWS band 0944-03803. 1131 Findings: Accession 1-hawaiian stilt immature unknown sex in poor body 1132 condition. 1133 Grossly, there was marked atrophy of breast muscles. 1134 1135 Final diagnosis: Accession 1-Emaciation. 1136 Comments: Gross and microscopic lesions pointed to starvation as cause of 1137 death. 1138 Management: Report Date (mm/dd/yyyy): 9/24/2019 Necropy report: Enclosed Copies of this report sent to: Mr. Keith Swindle (USFWS) Mr. Gregory Koob (USFWS) 1139 1140 If you have questions regarding this case, contact Thierry M.Work MS, 1141 DVM, MPVM at 808-792-9520. Include above Case Number. Diagnostic 1142 findings may not be used for publication without the pathologist's 1143 knowledge and consent. 1144 NOTE: Information in this report supersedes any information from previous reports regarding this 1145 case 1146 N A T I O N A L W I L D L I F E H E A L T H C E N T E R N 1147 E C R O P S Y R E P O R T 1148 1149 Submitter Name:

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Mr. Dain Christiansen Case: 25659 University of Hawaii Accession: 1 1910 East-West Road Date Collected: 6/07/2019 Honolulu, Hawaii 96822 Date Examined: 6/7/2019 United States Prosector: R. A. Rameyer Pathologist: T. M. Work 1150 1151 Signalment-Morphometrics-History 1152 CONDITION:(Poor) POSTMORTEM:(Fair) EUTHANASIA:(Not 1153 euthanized) TAG TYPE:(USFWS band) TAG NO.:(0944-03803) 1154 SPECIES:(Stilt: Hawaiian) AGE:(Immature) 1155 SEX:(Unknown) MORPHOMETRICS: Weight carcass (42 g). 1156 COLLECTION-SITE:(Kanehoe MCBH) AREA:(Honolulu) STATE:(Hawaii) COUNTRY:(United 1157 States) 1158 HISTORY: This chick was found dead in the Water Reclamation Facility at 1159 Kaneohe Marine Corps Base on 7 June 2019. Identification - left leg: gray 1160 band over FWS band 0944-03803. 1161 1162 External/Internal 1163 EXTERNAL: Feathers over the synsacrum are missing. 1164 INTERNAL: There is atrophy of breast muscles. The liver is brown. The heart 1165 is pinkbrown. The lungs are wet and tan-brown. The lungs float in formalin. 1166 The kidney is tan-black. There is a small red-blotchy area on the skull, but 1167 the brain appears normal. The ventriculus is empty except for a few small 1168 pebbles. The intestines are autolyzed. 1169 PRELIMINARY DIAGNOSIS: Emaciation. 1170 1171 Samples SECIMENS RECEIVED: Carcass-Chilled. 1172 1173 Laboratory Results 1174 1175 COMMENTS:Gross and microscopic lesions pointed to starvation as cause of 1176 death. 1177 1178 Final Diagnosis (in order of importance) 1179 Diagnosis Topog Morpho Etiol Funct Dis 1180 Link 1181 1. Emaciation ( )( )( )( )(D10140 1182 )( ) Diagnostic findings may not be published without the knowledge and 1183 consent of the pathologist. 1184 Milt Code: (Emaciation) 1185 1186 1187 1188 1189 1190 1191

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1192 1193 DIAGNOSTIC CASE REPORT 1194 U. S. GEOLOGICAL SURVEY-BIOLOGICAL RESOURCES DIVISION 1195 NATIONAL WILDLIFE HEALTH CENTER-HONOLULU FIELD STATION 1196 P. O. BOX 50167, 300 ALA MOANA BLVD., Rm. 8-132 1197 HONOLULU, HAWAII 96850 1198 Tel: 808-792-9520, Fax: 792-9596, Email: [email protected] Case Number: 25653 Submitter Name: Species submitted (n): Mr. Dain Christiansen Stilt: Hawaiian (1) University of Hawaii 1910 East-West Road Honolulu, Hawaii 96822 United States

Location: Kanehoe MCBH DateCollected: 5/17/2019 Area: Honolulu DateSubmitted: 5/17/2019 State: Hawaii DateReceived: 5/17/2019 Country: United States DateExamined: 5/17/2019

SPECIMENS SUBMITTED: Carcass-Chilled 1199 History: This chick was found dead at the Kaneohe Marine Corps Base on 17 May 1200 2019. 1201 Findings: Accession 1-hawaiian stilt immature female in good body condition. 1202 No lesions seen externally, internally, or on microscopy. 1203 1204 Final diagnosis: Accession 1-Undetermined. 1205 Comments: No lesions indicative of cause of death were seen. 1206 Management: Report Date (mm/dd/yyyy): 9/24/2019 Necropy report: Enclosed Copies of this report sent to: Mr. Keith Swindle (USFWS) Mr. Gregory Koob (USFWS) 1207 1208 If you have questions regarding this case, contact Thierry M.Work MS, 1209 DVM, MPVM at 808-792-9520. Include above Case Number. Diagnostic 1210 findings may not be used for publication without the pathologist's 1211 knowledge and consent. 1212 NOTE: Information in this report supersedes any information from previous reports regarding this 1213 case 1214 N A T I O N A L W I L D L I F E H E A L T H C E N T E R N E 1215 C R O P S Y R E P O R T 1216 1217 Submitter Name: Mr. Dain Christiansen Case: 25653 University of Hawaii Accession: 1 1910 East-West Road Date Collected: 5/17/2019 Honolulu, Hawaii 96822 Date Examined: 5/17/2019 United States Prosector: R. L. Breeden Pathologist: T. M. Work

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1218 1219 Signalment-Morphometrics-History 1220 CONDITION:(Good) POSTMORTEM:(Good) EUTHANASIA:(Not 1221 euthanized) TAG TYPE:() TAG NO.:() 1222 SPECIES:(Stilt: Hawaiian) AGE:(Immature) 1223 SEX:(Female) MORPHOMETRICS: Weight carcass (14 g). 1224 COLLECTION-SITE:(Kanehoe MCBH) AREA:(Honolulu) STATE:(Hawaii) COUNTRY:(United 1225 States) HISTORY: This chick was found dead at the Kaneohe Marine Corps Base 1226 on 17 May 2019. 1227 1228 External/Internal 1229 EXTERNAL: The head is wet with water and mud in the nares. 1230 INTERNAL: 1231 PRELIMINARY DIAGNOSIS: Drowning. 1232 1233 Samples SECIMENS RECEIVED: Carcass-Chilled. 1234 HISTO: Cerebrum, Cerebellum, Ventriculus, Intestine small (A); Liver, Kidney, 1235 Oviduct, Lung (B). 1236 1237 Laboratory Results 1238 HISTOPATHOLOGY 1239 All organs: No remarkable lesions are seen. 1240 1241 COMMENTS:No lesions indicative of cause of death were seen. 1242 1243 Final Diagnosis (in order of importance) 1244 Diagnosis Topog Morpho Etiol Funct Dis 1245 Link 1246 1. Undetermined (T00010 )( )(E00040 )(FY3500 )( 1247 )( ) Diagnostic findings may not be published without the knowledge and 1248 consent of the pathologist. 1249 Milt Code: (Open) 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268

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1269 APPENDIX D. HAWAIIAN STILT COUNTS 1270 1271 WB-Table 1. Hawaiian Stilt counts in MCBH ...... D-2 1272 WB-Table 2. Hawaiian Stilt counts in He‘eia ...... D-3 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314

D-1

1315 WB-Table 1. Hawaiian Stilt counts during the 2019 Stilt nesting season in MCBH.

Pond/Date

Kaluapuhi 19 24 N/A 21 29 11 19 N/A 10 N/A 15 17 6 14 12 9 18

Pa‘akai 15 N/A 14 12 32 9 16 N/A 14 N/A 11 10 11 N/A 5 5 8 Nu‘upia 2 N/A 4 4 5 5 7 8 N/A 3 N/A N/A N/A N/A N/A N/A N/A ‘Ekahi Halekou 2 N/A 11 5 1 6 6 4 N/A 3 N/A N/A N/A N/A N/A N/A N/A Wai Puna 7 0 N/A 2 7 3 6 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Salvage Yard N/A 3 N/A 5 3 4 5 N/A 6 N/A 3 N/A N/A N/A N/A N/A N/A Nu‘upia N/A 0 N/A 6 8 3 7 N/A 1 N/A 3 N/A N/A N/A N/A N/A N/A ‘Ekolu Nu‘upia ‘Eha 6 0 N/A 3 8 4 5 N/A 0 N/A 0 N/A N/A N/A N/A N/A N/A Sag Harbor N/A 4 N/A N/A 2 N/A 0 N/A 2 N/A 1 N/A N/A 3 3 2 0 Hale Koa N/A N/A N/A N/A 0 N/A 2 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A TLF 0 N/A N/A 2 2 0 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Heleloa 2 N/A 0 1 0 0 0 0 N/A 0 N/A N/A N/A N/A N/A N/A N/A Nu‘upia 2 N/A 0 0 0 0 0 0 N/A 0 N/A N/A N/A N/A N/A N/A N/A ‘Elua Nu‘upia 0 N/A 0 0 0 0 0 0 N/A 0 N/A N/A N/A N/A N/A N/A N/A Hema Sum

1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328

D-2

1329 WB-Table 2. Hawaiian Stilt counts during the 2019 Stilt nesting season in He‘eia NERR. 1330 5- 12- 18- 26- 16- 13- 27- 3- 9- 20- 6- 12- 24- Date Jul Jul Jul Jul Aug Sep Sep Oct Oct Oct Dec Dec Dec Stilt (Adult) 2 2 2 2 2 1 2 2 2 2 2 2 2 Stilt (Juvenile) 3 3 0 3 3 0 3 3 3 3 3 3 3

D-3