Ornithol Sci 19: 135 – 144 (2020)

ORIGINAL ARTICLE Nocturnal migration in the Tataka Area, Yushan National Park, in autumn 2014

Chao-Chieh CHEN1,#, Jane-Chi WU2, Bruno Andreas WALTHER3 and Po-Jen CHIANG4

1 Department of Biomedical Science and Environmental Biology, Medical University, 100, Shih- chuan 1st Rd., Sanmin , Kaohsiung City, 807, Taiwan 2 Wild Bird Society of Pingtung County, 900, Taiwan 3 Department of Biological Sciences, National Sun Yat-sen University, Gushan District, Kaohsiung City, 804, Taiwan 4 Formosan Wild Sound Conservation Science Center Co., Ltd., 2F, 335, Yongmei Road, Yangmei District, Taoyuan City, 326, Taiwan

ORNITHOLOGICAL Abstract Detecting different bird species requires different and appropriate- sur veying methods. We tested a new detection method for the Tataka Area in Yushan SCIENCE National Park, Taiwan, which is an important alpine stopover site for migratory land- © The Ornithological Society birds. Numerous migrant species have previously been reported from this area during of Japan 2020 bird counts and banding operations. However, these traditional survey methods are incapable of detecting nocturnal migrants. Therefore, we applied acoustic monitoring devices to survey the flight calls of nocturnal migrants in the Tataka Area in order to identify the species and estimate their detection rate. We set up acoustic recorders at five recording stations twice a month during September, October and November, and once in December 2014. We identified 18 nocturnal migrant taxa from 801 hours of recordings. The Black-crowned Night Heron Nycticorax nycticorax was the most frequently recorded species, followed by thrushes (Turdus spp.) and the Brown Shrike Lanius cristatus. Passages of nocturnal migrants occurred during every hour of the night, but with a significantly higher detection rate during the period from 2000 to 2300. Detection rates also varied significantly among months and recording stations. Significantly higher detection rates were recorded in September and October than in November and December. The recording station on a ridge detected significantly fewer birds than the other four recording stations situated in or near valleys. This suggests that nocturnal migrants use lower-lying stream valleys in order to pass over mountain ridges at the lowest possible point. This study provides the first evidence to demonstrate that, besides landbird migrants, many shorebird species and even kingfishers migrate through alpine areas at night when they pass over Taiwan Island during autumn migration.

Key words Acoustic monitoring, Nocturnal flight call, Stopover site, Transit migrants

Nocturnal migrants are elusive and difficult to cohesion of migrating flocks of conspecifics because study. Although radar is a useful tool for detecting they usually migrate together in a widely dispersed migrating birds, it is usually unsatisfactory for iden- pattern at night (Hamilton 1962; Larkin & Szafoni tifying species (Farnsworth et al. 2004; Gagnon et al. 2008). Coordination of movements during migration 2010; Smith et al. 2014). However, some nocturnal might be another purpose of flight calls (Griffiths et migrants give flight calls while migrating at night al. 2016). Since these flight calls are species-spe- (Graber & Cochran 1959, 1960; Evans 1994). One cific, they can be used to identify nocturnal migrants presumed function of flight calls is to maintain the to species level (Graber 1968; Evans & Rosenberg 2000; Murray 2004, http://www.islandnet.com/~rpbo/ (Received 15 October 2019; Accepted 18 February 2020) acousticmonjjm.pdf; Evans 2005; Farnsworth & # Corresponding author, E-mail: [email protected] Lovette 2005). Graber and Cochran (1959, 1960) pio-

135 C.-C. CHEN et al. neered the study of flight calls of nocturnal migrants. important stopover site in Taiwan for autumn Later on, Evans (1994) used more advanced acousti- migrants from northern regions, such as Japan, cal devices to monitor the migration patterns of noc- Korea, northeastern China, and Siberia (Sar 1989; turnal migrants in North America. Nevertheless, it Hsieh 1995; Chen et al. 2009, 2010). Sar (1989) first was time consuming to transcribe the recorded data noticed that significant numbers of Grey-faced Buz- (Evans & Rosenberg 2000). Recently, the automatic zard-Eagle Butastur indicus, Chinese Sparrowhawk classification of flight calls for bioacoustics monitor- Accipiter soloensis, Brown Shrike Lanius cristatus, ing has been developed (Stowell & Plumbley 2014; and migratory warblers (especially Locustellidae) Salamon et al. 2016), and its application will promote passed through this alpine stopover site in autumn. the study of flight calls in the future. He also reported the spectacular nightly experience Since 2009, scientists have tried to compile a com- of a huge number of migrating Brown Shrikes fly- plete bird list for the Yushan National Park (YNP) ing into a lodge at Shihshan Station (Fig. 1). Later in central Taiwan. They showed that YNP contains on, Hsieh (1995) carried out banding operations all of Taiwan’s 29 endemic bird species as well as from 1992 to 1994 in nearby Zizhong (Fig. 1) and almost all resident bird species except those which captured more than 20 different species of transit occur exclusively in the lowland plains (Chen et migrants. In recent years, Chen et al. (2009, 2010) al. 2009, 2010, 2018; Chen & Liu 2011). However, and Chen and Liu (2011) conducted a 3-year survey it has been very difficult to determine the number of autumn migration and found 12 additional migrant of migrant species that actually appear in the park. species in the Tataka Area. Shorebirds were occa- After conducting ground surveys and banding opera- sionally heard calling overhead during the night, but tions, we realized that these traditional methods were have never been caught in mist nets (see Chen et al. applicable only for diurnal landbird migrants, but 2009, 2010). The aim of this study was to identify were ineffective for nocturnal migrants. Therefore, nocturnal migrants through acoustic monitoring and we applied acoustic monitoring to identify nocturnal to quantify their relative abundance during autumn migrants by their flight calls in 2014. migration in the Tataka Area. This is the first acoustic The Tataka Area (Fig. 1) is well known as an monitoring study designed for migrants in Taiwan,

Fig. 1. Map of the Tataka Area and the location of our five recording stations. The double black line indicates the only major road in the area, while the thin black line represents the county border (which for most of the map traces the highest part of the east-west ridge). Yushan National Park is indicated in green. The insert shows the location of our study site within Taiwan.

136 Nocturnal migrants in Taiwan and is possibly the first of its kind in eastern Asia. net websites such as Macaulay Library (2014, https:// www.macaulaylibrary.org/) and Xeno-canto (2014, https://www.xeno-canto.org/). After all the recorded MATERIALS AND METHODS files had been transcribed into an EXCEL worksheet, The study area is located along the New Central we tallied the number of species recorded per hour Cross-Island Highway between Zizhong (23°29′02″N, for all sampling periods. The number of migrant 120°49′49″E, 2310 m, a.s.l.) and the Tataka Saddle species (or species richness) detected per hour was (23°28′32″N, 120°54′00″E, 2600 m, a.s.l; Fig. 1). then defined as the detection rate. For later statistical The Tataka Area is located on the west flank of the analysis (see ANOVA below), we further categorized highest peak in Taiwan, Yushan (or Mount Jade, 3,952 the night into four periods: early night (1700–2000); m a.s.l.) and is the logistical base (2,620 m a.s.l.) for late night (2000–2300); midnight (2300–0200); and climbing its peak. We selected five recording stations before dawn (0200–0600). The local times for sunset along the east-west highway at approximately equi- and sunrise were 1806–1715 and 0543–0633 dur- distant locations (mean straight line distance=1,988 ing the study period (11 September to 16 Decem- m) within the Tataka Area. This array was chosen ber; Central Weather Bureau of Taiwan 2014, https:// in the hope of avoiding double counting of migrants www.cwb.gov.tw/V8/C/K/astronomy_day.html). that mainly pass over in a north-south direction. We tested three hypotheses concerning the spa- Four out of the five recording stations were “near- tiotemporal distribution of nocturnal migrants, with saddle” locations, associated with a nearby saddle; detection rate as the response variable. The first null the remaining station was near a ridge at a “non- hypothesis was that the detection rate would be the saddle” location (Fig. 1). Migrants are more likely to same for the four different months of autumn migra- pass over saddle locations, thus we considered such tion. The second null hypothesis was that the detec- locations as “treatment sites.” In contrast, mountain tion rate would be the same for the four different ridges are more likely to present barriers to migrants, nighttime periods. The third null hypothesis was that therefore we considered the non-saddle location to be the detection rate would be the same for the five a “control site” (see further details in Discussion). different recording stations. To test these hypothe- We conducted seven field trips during the autumn ses together, we conducted a Three-way Repeated migration of 2014, two per month during Septem- Measures ANOVA with “hour” as the sampling unit ber, October and November, and one in the middle (SAS software, version 9.4; SAS Institute Inc., Cary, of December. At each station, we set up one digital North Carolina). recorder (Sony, M10) before dusk and operated it throughout the night (recordings usually lasted from RESULTS 1700 until 0600). Each recorder was attached to a tree trunk or a roadside facility (e.g., traffic sign- We examined recordings from 14 nights at five post) at approximately 1.5 m in height. The micro- stations for migrant flight calls, and identified 18 phone of the recorder was oriented towards the north taxa of nocturnal migrants during 801 hours (Fig. and leveled 45 degrees above the horizon. The next 2, Supplementary Material 1). Nine of the 18 spe- morning, we removed the recorders and downloaded cies were shorebirds, five were landbird migrants, the recordings into a portable hard drive. Recordings and four were waterbirds. In 28 cases, flight calls were made over two consecutive nights during each were difficult to identify and were therefore classi- field trip, providing us with 14 nights of recording for fied as “unknown.” The Black-crowned Night Heron each station and a total of 70 overnight recordings for Nycticorax nycticorax was the most common noc- the entire study. turnal migrant, followed by thrushes (Turdus spp.) In the laboratory, we carefully examined the and the Brown Shrike. Brown Shrikes appeared quite recordings for migrant flight calls. We used one hour early in September, and decreased sharply in October as a sampling period and noted each species when its (Table 1). Shorebirds, including plovers and sandpip- flight call was detected within the hour. The distinc- ers, had the greatest detection rate in late September, tive flight calls of common migrants were known to and then decreased as time progressed. The Black- us beforehand, and for unfamiliar calls we consulted crowned Night Heron reached its peak in late Octo- with experienced birdwatchers or compared our ber, and declined rapidly in November. Thrushes as recordings with flight call templates found on inter- a group arrived later than other migrants. They were

137 C.-C. CHEN et al.

160

140

120

100

80

60 Frequency

40

20 Common Greenshan k Thrushe s Long-toed WagtailGray Pacific Red-necked Olive-backed Bunting Co mm on S Marsh Kentish Common K Brown Shrike Gray Heron As h y M inivet Black-bellied W Nigh t 0 Unknown ood Heron Sandpipe r Sandpipe r Golden-Plove r Plove r Stin t ingfisher andpiper Stin t Plove r Pipi t

Species

Fig. 2. The frequency of hours during which nocturnal migrants were detected from 801 hours of recordings in the Tataka Area, Yushan National Park, Taiwan, September–December 2014.

Table 1. Number of hours during which four main migrant taxa were detected in the Tataka Area, Yushan National Park, Taiwan, September–December 2014 (dates are given as month/days).

Date Taxa 9/10–11 9/29–30 10/12–13 10/29–30 11/12–13 11/21–22 12/16–17 Total Brown Shrike 22 35 3 ––––60 Shorebirds 1 18 5 2 15– 32 Black-crowned Night Heron 10 37 43 59 1 4 – 154 Thrushes –21 2 11 41 19 76 Others* – 17 17 10221 49 All migrants 33 109 69 73 15 52 20 371 No. hours 75 114 119 126 119 120 128 801 Detection rate# 0.44 0.96 0.58 0.58 0.13 0.43 0.16 0.46

*The complete species list is given in the Supplementary Material 1. #Detection rate=No. of taxa/hr. first recorded in late September, and their numbers December (0.16). Detection of migrants increased increased slowly and reached a peak in late Novem- rapidly during the night until it reached a plateau dur- ber and continued passing in medium numbers into ing the late night period (2000–2300; Fig. 3); after mid-December (Table 1). that, detection decreased gradually until the last hour On average, 0.46 taxa were detected each hour before dawn, when a second peak was detected. (Table 1). The highest detection rates occurred in In the Three-way Repeated Measures ANOVA, late September (0.96) and October (0.58), and the significant differences were found in detection rate lowest rates occurred in early November (0.13) and among the four months (F3, 25=30.63, P<0.0001; Table

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0.80

0.70

0.60

0.50

0.40

0.30 Detection rate 0.20

0.10

0.00 17 18 19 20 21 22 23 00 01 02 03 04 05 06 Time

Fig. 3. Detection rates (taxa/hr) of nocturnal migrants during each hour in the Tataka Area, Yushan National Park, Taiwan, September–December 2014.

Table 2. Results of Three-way Repeated Measures ANOVA on detection rates of nocturnal migrants in the Tataka Area, Yushan National Park, Taiwan, September–December 2014.

Source Type III SS df MS F P Hour (Period) 7.31 9 0.81 1.98 0.0392 Month 36.17 3 12.06 30.63 <0.0001 Error 1 (Month×Hour (Period)) 9.84 25 0.39 Station 13.88 4 3.47 10.19 <0.0001 Error 2 (Station×Hour (Period)) 12.25 36 0.34 Month×Station 15.26 12 1.27 3.10 0.0003 Period 16.02 3 5.34 6.57 0.0120 Month×Period 22.44 9 2.49 6.07 <0.0001 Station×Period 3.41 12 0.28 0.69 0.7606 Error 3 282.08 689 0.41 Total 431.01 800

2), with September and October having a higher rate tion terms of Month×Period and Month×Station also than November and December (Tukey’s test; Table reached a significant level (F9, 689=6.07, P<0.0001; 3). The four nighttime periods also differed signifi- F12, 689 =3.10, P<0.001; Table 2; Figs. 4-5). The cantly (F3, 689=6.57, P<0.05; Table 2), with the late peculiar migration pattern of thrushes occurring night period having a significantly higher detection mostly within the dawn period during November rate than all the other periods (Tukey’s test; Table 3). and December and at Zizhong accounted for a great Moreover, there was a significant difference among amount of the variation in the interaction terms. the five recording stations (F4, 36=10.19, P<0.0001; Table 2). Tukey’s test revealed that New Peak Gate DISCUSSION had a significantly higher detection rate than 103.5 K and Shihshan Station, and both Tataka Saddle and Using Repeated Measures ANOVA, we found that Zizhong had a significantly higher detection rate than the detection rates of nocturnal migrants were sig- Shihshan Station (Tukey’s test; Table 3). The interac- nificantly different for the three main effects (month,

139 C.-C. CHEN et al. night period, and station). The results support the These results are in accordance with the main trend three hypotheses and show that nocturnal migra- of autumn migration in the northern hemisphere (e.g., tion is very dynamic, both spatially and temporally. Van Doren et al. 2015; La Sorte et al. 2016). The First, detection rates were higher in September and overall migration is naturally composed of numerous October than in November and December, and high- discrete passages for all the migrant species, and the est of all in late September (0.96) when they were timing of movement of the dominant migrant spe- more than twice the level of early September (0.44). cies therefore greatly influences the overall trend. In addition, differences in diets and breeding grounds of migrant species can affect their migration schedule Table 3. Multiple comparisons among levels of the three and their passage time at stopover sites. main effects on detection rates in the Tataka Area, Yushan Second, detection was highest during the late night National Park, Taiwan, September–December 2014. period (2000–2300). This result is consistent with the trends detected during several banding and moon- Variable Level Grouping* Average No. hours watching studies conducted in previous years (Chen Month September A 0.75 189 et al. 2009, 2010) and also agrees with moon-watch- October A 0.58 245 ing studies (Newman 1956) and radar studies (Graber November B 0.28 239 1968; Farnsworth et al. 2004) from North America. December B 0.14 128 Nocturnal migrants usually take off around half hour Station New Peak Gate A 0.67 155 after sunset (Gauthreaux 1971; Kerlinger & Moore Tataka Saddle BA 0.51 146 1989). If we assume that the migrants in our study Zizhong BA 0.50 165 (1) take off during this time period, (2) fly at a speed 103.5 K BC 0.36 167 of approximately 40–60 km/hour (Kerlinger 1995), Shihshan Station C 0.28 168 and (3) mostly fly directly south, then most migrants Period Late night A 0.73 204 detected during the first half of the night took off Early night B 0.42 163 in central and northern Taiwan, which may explain Midnight B 0.41 198 the peak during 2000–2300. Migrants detected later Before dawn B 0.30 236 during the night may include migrants which took off from areas north of Taiwan, e.g., the Japanese *Different letters indicate significant differences between averages by Tukey’s tests. Ryukyu Islands, which may explain the lower detec-

1.40

1.20 Early night Late night 1.00 Midnight Before dawn 0.80

0.60 Dection rate 0.40

0.20

0.00 September October November December Month

Fig. 4. Comparison of detection rates of nocturnal migrants among four months and nighttime periods (early night: 1700–2000; late night: 2000–2300; midnight: 2300–0200; and before dawn: 0200–0600) in the Tataka Area, Yushan National Park, Taiwan, September–December 2014.

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1.20 103.5K 1.00 Tataka Saddle Shihshan Zizhong 0.80 New Peak Gate

0.60

Detection rate 0.40

0.20

0.00 September October November December Month

Fig. 5. Comparison of detection rates of nocturnal migrants among four months and five recording stations in the Tataka Area, Yushan National Park, Taiwan, September–December 2014. tion rates. Van Doren et al. (2015) also found a two- for the most western portion) and likely represents peak pattern of flight calls of nocturnal migrants in a barrier for migrants. Nevertheless, this ridge has the eastern United States, with the first peak appear- several saddles (lower-lying points or depressions) ing right after midnight, and the second peak in the which are the starting points for small streams flow- hour immediately before dawn. They showed that ing in a northerly direction. We assume that migrant the second peak was mainly attributed to thrushes, as birds flying south in autumn use these lower-lying diagnosed by their low frequency calls. In our study, stream valleys to guide them so that they then end the second peak near dawn was also mostly due to up crossing the ridge at low-lying saddles. The dis- migrating thrushes (>95%). Farnsworth and Russell crepancy in detection rates at different topographic (2007) proposed that frequent calls by thrushes near locations suggests that nocturnal migrants are more dawn might function to form groups (Hamilton likely to fly along valleys when they migrate through 1962). The second detection peak near dawn also mountainous terrain. This interesting result should contributed greatly to the significant interaction of be followed up with further studies, e.g., increas- Month×Period because thrushes passed mainly dur- ing the number of comparisons between non-sad- ing the late migration season. dle (ridge) and near-saddle (or valley) stations, and Third, as expected from its location, we found that perhaps using a combination of radar and acoustic the “non-saddle” Shihshan Station had a significantly monitoring. The preference by nocturnal migrants for lower detection rate than the four other “near-saddle” certain geographical features suggests that they may recording stations. Shihshan Station was taken as a use visual clues to navigate through the mountains “control site” because it is situated on the hillside at night. of a ridge that extends northwards whereas the other One of the objectives of this study was to apply four stations are located at stream sources or near acoustic monitoring to detect species that are seldom saddles on the main ridge running roughly in an east- or never encountered through bird count or banding west direction. Our results support our assumption operations. This study added seven new species to that whereas ridges are avoided by migrants, because the bird list of Yushan National Park, including Grey they represent a barrier, saddles provide preferred Heron Ardea cinerea, Pacific Golden Plover Pluvia- migration routes because they represent funnels lis fulva, Grey Plover Pluvialis squatarola, Kentish along which migrants fly over mountains. The main Plover Charadrius alexandrinus, Red-necked Stint ridge in the Tataka Area runs in an east-west direc- Calidris ruficollis, Long-toed Stint Calidris sub- tion (shown by the thin black line in Fig. 1, except minuta, and Marsh Sandpiper Tringa stagnatilis.

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These species normally appear along coastal wet- cies have similar calling rates and loudness). lands and beaches but are rarely detected at inland sites. This is the first study to demonstrate that many ACKNOWLEDGMENTS shorebird species and even the Common Kingfisher Alcedo atthis migrate through an alpine stopover site We are grateful to the Yushan National Park Head- during autumn migration in Taiwan. The supposi- quarters of Taiwan for providing grants for this study. tion that they really only fly across this mountainous We thank L-M Yin and W-L Tsai for their assistance region and never land is supported by the results at the Tataka Tourist Center. We are also grateful to of a banding operation conducted in the same study T-T Liu and Y-W Hsu for their assistance in the field. area for two consecutive years (Chen et al. 2009, 2010), during which 150 individuals of 14 migrant species were captured, all of which belonged to land- REFERENCES bird migrants except for Cattle Egret Bubulcus ibis Central Weather Bureau of Taiwan (2014) Daily astron- (3 individuals). Furthermore, Hsieh’s (1995) banding omy. Available at https://www.cwb.gov.tw/V8/C/K/ study of 1992–1994 also showed that no shorebird astronomy_day.html (accessed on 2 September 2014). was captured, and herons only occupied a very small Chen C-C & Liu T-T (2011) A planning for hawk- portion of the nocturnal migrants captured (3 out of watching season and the extension of bird resources 209 birds). Therefore, it is highly likely that migrat- conservation in Yushan National Park. Yushan National ing shorebirds never land in forested and mountain- Park Headquarters, Nantuo. (in Chinese with English ous areas, except perhaps during extreme weather summary). events (Elkins 2004). Chen C-C, Tsai C-M, Chen H-L & Wang S-H (2009) Of course, detection rates based on acoustic The bird resource census and planning of population monitoring depend on two factors: the calling rate monitoring system and establishment of database in of the migrant species and the loudness (or acous- Yushan National Park. Yushan National Park Head- tic pressure) of the calls; both factors are affected quarters, Nantuo. (in Chinese with English summary). by atmospheric conditions such as wind speed and Chen C-C, Tsai C-M, Chen H-L, Wu J-C & Liu T-T cloud cover (Smith et al. 2014). The calls of many (2010) The bird resource monitoring and planning shorebirds are considerably louder than those of pas- and establishment of database and website in Yushan serine species. For example, the Lanceolated Warbler National Park. Yushan National Park Headquarters, Locustella lanceolata, which was the second most Nantuo. (In Chinese with English summary). abundant species in the banding studies conducted Chen C-C, Chen H-L, Ou Yang C-W, Wu J-C, Liu T-T by Chen et al. (2009, 2010), was totally absent from & Liao L-L (2018) Bird inventory in Yushan National our acoustic recordings. This is likely due to its weak Park. J National Park 28(2): 28–43. (in Chinese with calls although it may also simply rarely or never call English summary). during flight. Therefore, different surveying methods Elkins N (2004) Weather and bird behaviour. 3rd ed. T are essential to compile a complete list of migrants & A D Poyser, London. transiting an area or region. Evans WR (1994) Nocturnal flight call of Bicknell’s Thrush. Wilson Bull 106: 55–61. The average detection rate of 0.46 species per Evans WR (2005) Monitoring avian night flight hour may appear to be low, but it should be noted calls—The new century ahead. Passenger Pigeon that we used presence data instead of total counts of 67: 15–24. flight calls in our analysis because it was impossible Evans WR & Rosenberg KV (2000) Acoustic monitor- to determine if individual flight calls were uttered ing of night-migrating birds: a progress report. In: by the same or different individuals (but see Evans Bonney R, Pashley DN, Cooper RJ, Niles L (eds) & Rosenberg 2000). Therefore, we used hours as Strategies for bird conservation: The Partners in our sampling units and tallied the number of species Flight planning process. pp 151–159. Proceedings recorded within each hour to provide a relative fre- RMRS-P-16: U.S. Department of Agriculture, Forest quency of occurrence or detection rate. As a result, Service, Rocky Mountain Research Station, Ogden. the numbers presented in this study should not be Farnsworth A (2005) Flight calls and their value for used to represent the total number of migrants pass- future ornithological studies and conservation ing through the study area, although they may be research. Auk 122: 733–746. indicative of relative abundance (assuming that spe- Farnsworth A & Lovette IJ (2005) Evolution of noctur-

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Supplementary Material 1. Numbers of hours during which nocturnal migrants were detected in the Tataka Area, Yushan National Park, Taiwan, September–December 2014 (dates are given as month/days).

Date Taxa 9/10–11 9/29–30 10/12–13 10/29–30 11/12–13 11/21–22 12/16–17 Total Black-crowned Night Heron 10 37 43 59 1 4 – 154 Thrushes –2 1 2 11 41 19 76 Brown Shrike 22 35 3 ––––60 Unknown 0 13 8 5 0 2 0 28 Grey Heron 02240008 Ashy Minivet 00 6 1 0007 Grey Plover 00 1 005 06 Wood Sandpiper 04200006 Common Sandpiper 0 3120006 Kentish Plover 04000004 Marsh Sandpiper 04000004 Common Greenshank 00 1 0 1 0 02 Long-toed Stint 02000002 Common Kingfisher 02000002 Grey Wagtail 00 1 0 1 0 02 Pacific Golden Plover 1 0000001 Red-necked Stint 0 1 000001 Olive-backed Pipit 00 0 0 1 001 Bunting 00000011 All migrants 33 109 69 73 15 52 20 371 No. hours 75 114 119 126 119 120 128 801 Taxa/hr 0.44 0.96 0.58 0.58 0.13 0.43 0.16 0.46

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