Australian Field Ornithology 2019, 36, 124–129 http://dx.doi.org/10.20938/afo36124129

The importance of Hutt Lagoon and fossil river estuaries to shorebirds in mid Western

M.J.C. Singor¹*, Linda Giblett² and C. Heap3

¹149a Bishopsgate Street, Carlisle WA 6101, Australia ²Unit 39, 140 Teranca Road, Greenfields WA 6210, Australia 3P.O. Box 216, Byford WA 6122, Australia *Corresponding author. Email: [email protected]

Abstract. Little is known about the dynamics of the shorebird populations of the mid Western Australian coastline between Kalbarri and Geraldton, as this area is remote and sparsely populated. We surveyed shorebirds at several sites in this region, including fossil river estuaries from intermittent rivers (Hutt, Bowes and Greenough Rivers) and wetlands on the western shoreline of Hutt Lagoon and around Port Gregory. Totals of 21 migratory shorebird species and 9 Australian-breeding shorebird species were recorded from 64 visits in 2006–2010 and 87 visits in 2017–2018. The highest counts related to Banded Stilt Cladorhynchus leucocephalus (652), Red-capped Plover Charadrius ruficapillus (300) and Red-necked Stint Calidris ruficollis (300). The highest numbers of most species were recorded at Hutt Lagoon and associated semi-permanent wetlands near Port Gregory, with mean counts in 2017–2018 of 109 migratory shorebirds (mainly Red-necked Stints) and 227 Australian-breeding shorebirds (mainly Banded Stilts), from the accessible part of that wetland system. This shows the importance of such wetlands in providing shorebird habitat in the region. None of the wetlands met criteria for international importance.

Introduction

There is a large stretch of the Western Australian coastline, from Geraldton (425 km north of ) to Kalbarri (167 km north of Geraldton), for which little information on shorebirds is available. This coastal area between Kalbarri (592 km north of Perth) and Geraldton is generally dry and barren and largely devoid of suitable sites for shorebirds. Available sites are limited to some small fossil river estuaries and Hutt Lagoon (a large coastal salt lake with associated smaller wetlands). The coast itself consists of Figure 1. Port Gregory and Hutt River. Google Earth narrow sandy beaches backed by dunes or cliffs, and the beaches are generally too steep and exposed to ocean waves to provide important habitat for shorebirds (though this was not checked during the current study). Fossil estuaries are formed by inland rivers that flow to the coast only during winter or periods of heavy rainfall. They empty into the ocean for short periods and in some years not at all. The river mouth is closed by a sandbar and a small pool of water often remains during the year, attracting shorebirds, although in some years this will dry out over summer.

This paper presents results of surveys of those sites in this 167-km stretch of coast, in an endeavour to fill some of the gaps and provide baseline data for future studies. The shorebird surveys were conducted over two distinct periods (2006–2010 and 2017–2018). Figure 2. Port Gregory town drainage ponds. Photo: Linda Giblett Study area sites was conducted in 2017–2018 and was extended to In 2006–2010, the study area was the wetlands along the include the Bowes River estuary (28°24′S, 114°27′E) and causeway leading to Port Gregory (28°11′S, 114°15′E) estuary (28°51′S, 114°38′E). (Figure 1), on the western side of Hutt Lagoon. It included the town drainage ponds in Port Gregory (Figure 2), small Hutt Lagoon (Figures 4–5) is a large shallow salt lake wetlands around the township and the Hutt River estuary near the Indian Ocean coast, just north of the mouth of the (28°13′S, 114°18′E) (Figure 3). A repeat study of these Hutt River, in the mid-western region of . Shorebirds at Hutt Lagoon and fossil river estuaries, Western Australia 125

Figure 3. Hutt River estuary. Note the sandbars partially Figure 4. Hutt Lagoon wetlands, causeway and lake. Note blocking the mouth of the fossil river estuary. Photo: the large flock of shorebirds, mainly Banded Stilts and Linda Giblett some Red-necked Avocets. Photo: Linda Giblett

Figure 5. Hutt Lagoon from Port Gregory causeway. Photo: Figure 6. Bowes River estuary. Photo: Linda Giblett Linda Giblett

Figure 7. Greenough River, at low water level. Photo: Linda Figure 8. Greenough River estuary, at high water level. Giblett Photo: Linda Giblett

It is ~14 km long, ~2.3 km wide, and runs parallel with the ~7 km south of Port Gregory and is generally closed by a coast. In this study, it is taken to cover the wetlands on both sandbar. The Hutt River estuary (Figure 3) contains pools sides of the causeway leading into Port Gregory as well as of water even over summer, possibly derived from springs, the samphire Halosarcia sp. shoreline extending from the and the water is generally brackish (Brearley 2005). causeway out to the spit in a north-westerly direction. A small lake south of the causeway was created when the Bowes River is situated south of the township of road closed off part of the inlet. Water pipes run through Horrocks. When in flood, this small river flows into the Indian this lake to supply seawater to the evaporation ponds in Ocean. A large estuary lagoon forms behind the sandbar Hutt Lagoon. When in operation, seawater leaks out of (Figure 6), and there are pockets of samphire along the the pipes and into the lake, thereby maintaining a viable riverbanks and a small floodplain on the southern side of shorebird habitat over summer. The Hutt River is located the river mouth. 126 Australian Field Ornithology M.J.C. Singor et al.

The Greenough River estuary (Figures 7–8), the 2017: a nest with four eggs (4 September), another clutch largest estuary surveyed, enters the Indian Ocean at (21 October) that failed, and an adult with three juveniles Cape Burney just south of Geraldton, and extends for a (21 October). Black-winged Stilts used a large exposed considerable distance inland. Its mouth is usually closed mudflat, ~1 km upstream on the northern side, ofthe by a sandbar and accumulations of seagrass. Composition Bowes River estuary to roost and feed. of beachwrack is variable, depending on the material available in the offshore environment but here generally Discussion contains the genera Amphibolis, Posidonia and Halophila (Wells 2002). The wetlands around the Port Gregory causeway (Hutt Lagoon) and the drainage ponds in Port Gregory were the Methods sites most valuable to shorebirds as they contained water throughout summer. These sites combined had the highest Shorebird surveys were conducted over two distinct number and diversity of species. Hutt Lagoon is a very periods. The first surveys were conducted mainly during shallow ephemeral salt lake that dries out over summer, February and March in 2006–2010 and covered the and any variation in the volume of water entering it will wetlands at Hutt Lagoon, shorebird sites around the Port impact on shorebird habitat. This was evident when the Gregory township and the Hutt River estuary (Heap 2008, remnants of tropical cyclone Joyce caused heavy rainfall 2009). Surveys from June 2017 to June 2018 covered at Port Gregory over the weekend 13–14 January 2018: these same sites and, in addition, the Bowes River and Hutt Lagoon filled quickly and flooded the samphire fringe, Greenough River estuaries. All sites were covered on foot. and triggered heightened shorebird feeding activity along Estuaries were surveyed by walking along the riverbanks the edge of the lagoon. Large sections of Hutt Lagoon have on both sides, including the sandbars. Access to the tracks never been surveyed and this site potentially supports a along each river depended on water levels. Surveys were much larger shorebird population. conducted from one to five times a month. Two types of brine shrimps live in Hutt Lagoon and feed on the microscopic green alga Dunaliella salina. The native Results brine shrimps Parartemia, which prefer less-saline water, are often abundant in pools around the fringing marshes Numbers of shorebirds counted are summarised in after rain. The other type of brine shrimp Artemia, an Table 1 (maximum and mean counts of each species introduced species, is more salt tolerant (Brearley 2005). at each site; all scientific names are listed in Table 1) Brine shrimps are a known food source for Banded Stilts and Table 2 (monthly counts at four of these sites in (Marchant & Higgins 1993; Pedler 2017). 2017–2018). More shorebirds were counted at Hutt It is evident that Hutt Lagoon is a minor coastal refuge Lagoon than at other sites, with maximum counts of ~1600 for the Banded Stilt. The maximum number of this species (sum of maxima for all species for years 2017–2018 at Hutt recorded there in this study was 652, though their numbers Lagoon) compared with <300 at any of the three fossil river might have been higher as large sections of the lagoon estuaries. Up to 1121 Australian-breeding shorebirds and were not surveyed. Numbers of Banded Stilts fluctuated 466 transcontinental migratory shorebirds were counted from year to year, with counts >100 in 2006, 2007, 2010, at Hutt Lagoon, compared with 158 and 125, respectively, 2017 and 2018. The juveniles sighted at Hutt Lagoon In at the Greenough River estuary and fewer elsewhere September 2017 had probably originated from the breeding (Table 1). Transcontinental migratory shorebirds formed event of January 2017 in the western desert from the ~25% of the overall mean counts of shorebirds. The most Eastern across the border to the Northern Territory. numerous Australian-breeding species were Banded Stilt, Red-capped Plover, Black-winged Stilt and Red-necked The smaller fossil river estuaries (Hutt and Bowes Rivers) supported low numbers of migratory shorebirds. The larger Avocet (Table 1). The most numerous transcontinental Greenough River estuary supported higher numbers migrants were Red-necked Stint, Ruddy Turnstone, of both migratory and Australian-breeding shorebirds. Common Greenshank and Common Sandpiper (Table 1). During the austral summer, the mean populations for the Australian-breeding shorebirds were found nesting at Greenough River estuary were: Common Greenshank (8), Hutt Lagoon (causeway), drainage pond wetlands in Port Common Sandpiper (4), Grey Plover (4) and Red-necked Gregory and at the Bowes River estuary. Red-capped Stint (22). Plovers were breeding (nest with two eggs) at the Port Hutt Lagoon supports moderate numbers of migratory Gregory causeway on 31 October 2017, and on 2 February shorebirds during the austral summer, with mean 2018 a nest with two eggs was located on a peninsula populations of 30 Ruddy Turnstones, 131 Red-necked north-west of the Port Gregory causeway. Two pairs of Stints and 26 Sharp-tailed Sandpipers during 2017–2018. Black-winged Stilts were breeding at the Port Gregory Some migratory shorebirds, such as Red-necked Stint causeway on 4 September 2017, each nest having four and Ruddy Turnstone, can be found nearly all year at eggs. Hutt Lagoon, as can the Australian-breeding Banded and At wetlands to the north of Port Gregory, Red-capped Black-winged Stilts, Red-capped Plover and Red-necked Plovers were breeding on 13 December 2017. Four pairs Avocet. Vegetated, brackish drainage ponds in Port of Black-winged Stilts were breeding at the drainage Gregory were attractive to the Wood Sandpiper. It is at the ponds in the Port Gregory town centre on 4 September town’s drainage ponds that some of the rarer shorebirds, 2017. At Bowes River estuary, a Red-capped Plover was such as Ruff and Long-toed Stint, have been sighted. Hutt seen with two chicks on 8 November 2017. Black-winged Lagoon and associated wetlands clearly supported more Stilts were recorded breeding there in September–October birds than the other areas examined in the present study, Shorebirds at Hutt Lagoon and fossil river estuaries, Western Australia 127

2 0.11 0.14 1.48 0.03 0.07 0.03 0.03 0.66 0.33 3.14 4.25 0.14 11.74 11.25 Mean 12.03 2017–2018

3 1 8 1 1 1 1 7 7 3 18 27 10 65 73 13 71 283 Max. Greenough River estuary 2017–2018

0.4 0.4 3.4 1.48 0.48 0.14 0.07 0.07 0.07 0.03 2.51 1.44 2.88 1.22 15.2 2.48 Mean 25.88 2017–2018

2 1 1 3 1 1 8 4 9 8 11 11 11 15 27 13 47 55 201 Bowes River estuary Max. 2017–2018

1.44 0.22 0.44 1.33 3.66 0.55 Mean 2017–2018

9 6 2 2 5 8 2 Hutt River estuary 25 Max. 2017–2018

0.5 0.33 1.29 1.04 0.04 0.83 0.29 0.87 0.08 0.08 0.12 2.08 0.12 0.16 27.2 18.5 1.45 45.5 0.16 11.54 Mean 73.75 16.04 134.7 2017–2018 Hutt Lagoon

1 7 1 3 6 4 7 2 1 1 8 1 2 8 2 11 56 61 94 24 59 300 652 300 Max. 1587 2017–2018

0.08 0.08 1.12 0.41 0.08 2.16 1.45 0.08 0.25 3.66 2.29 0.08 8.12 0.54 Mean 2006–2010

1 1 6 3 1 4 2 2 8 5 2 6 85 24 21 23 Hutt River estuary Max. 2006–2010

1.6 0.8 1.4 11.4 0.55 0.02 3.05 0.05 1.27 0.05 0.07 0.02 0.15 0.27 0.02 1.87 0.77 63.5 0.05 0.05 Mean 24.42 90.77 19.02 2006–2010 Hutt Lagoon

5 1 1 8 2 1 1 3 4 1 5 8 2 2 11 40 19 18 48 35 126 536 150 244 Max. 1231 2006–2010

Pluvialis squatarola Numenius minutus Numenius madagascarensis Limosa lapponica Arenaria interpres Calidris acuminata Calidris subminuta Calidris ruficollis Xenus cinereus Actitis hypoleucos stagnatilis Tringa Haematopus longirostris Haematopus fuliginosus Cladorhynchus leucocephalus Erythrogonys cinctus Himantopus leucocephalus Calidris tenuirostris Numenius phaeopus Charadrius leschanaultii Philomachus pugnax Calidris ferruginea nebularia Tringa Calidris melanotos Recurvirostra novaehollandiae Calidris alba Heteroscelus brevipes Charadrius ruficapillus Tringa glareola Tringa Elseyornis melanops Vanellus tricolor Vanellus Years Years Locati on Grey Plover Little Curlew Eastern Curlew Bar-tailed Godwit Ruddy Turnstone Sharp-tailed Sandpiper Long-toed Stint Red-necked Stint Sandpiper Terek Common Sandpiper Marsh Sandpiper Australian-breeding shorebirds Australian Pied Oystercatcher Sooty Oystercatcher Banded Stilt Red-kneed Dotterel Total Number of surveys Black-winged Stilt Great Knot Transcontinental migrants Transcontinental Whimbrel Greater Sand Plover Ruff Curlew Sandpiper Common Greenshank Pectoral Sandpiper Red-necked Avocet Sanderling Grey-tailed Tattler Red-capped Plover Wood Sandpiper Wood Black-fronted Dotterel Banded Lapwing Maximum and mean counts of shorebirds at four sites (Hutt Lagoon, and estuaries of the Hutt, Bowes and Greenough Rivers) in mid-western Western Australia for the for Australia Western in mid-western Rivers) and Greenough of the Hutt, Bowes (Hutt Lagoon, and estuaries sites four at of shorebirds 1. Maximum and mean counts Table and 2017–2018. periods 2006–2010 128 Australian Field Ornithology M.J.C. Singor et al. 9 24 27 27 Totals 0 0 0 0 0 0 0 0 0 1 0 6 0 0 0 1 Jul. 2 1 1 1 7 2 1 2 0 5 0 0 0 1 16 542 Jun. 1 3 2 4 5 0 2 0 0 3 0 3 2 43 40 202 May 1 3 2 4 4 1 2 6 0 6 1 4 1 36 71 364 Apr. 1 6 3 4 4 1 1 2 5 1 2 1 50 18 71 218 Mar. 3 4 4 3 2 2 2 4 2 1 2 10 69 14 59 307 Feb. 4 9 6 4 1 3 7 1 7 1 4 4 12 66 549 145 Jan. 3 7 5 5 0 5 0 0 6 0 4 5 11 91 61 371 Dec. 3 6 6 5 0 3 0 0 5 0 2 5 10 70 28 339 Nov. 3 8 7 4 4 2 3 3 8 2 3 1 2 3 81 14 Oct. 3 7 2 4 2 1 2 2 5 1 2 1 0 3 16 207 Sep. 0 3 0 0 3 0 0 1 0 1 0 1 0 0 0 Aug. 1 n/c Monthly shorebird data for Port Gregory, and the Hutt, Bowes and Greenough River estuaries in mid-western Western Australia from August 2017 to July 2018; n/c = not n/c July 2018; to 2017 August from Australia Western in mid-western estuaries River and Greenough and the Hutt, Bowes Gregory, Port for data Monthly shorebird Port Gregory No. surveys Months 2017-2018 Average monthly count Average No. migratory species Average monthly count Average No. migratory species No. Aust.-breeding species No. Aust.-breeding species Hutt River estuary No. surveys Greenough River estuary No. surveys Average monthly count Average Average monthly count Average No. migratory species No. migratory species No. Aust.-breeding species No. Aust.-breeding species Bowes River estuary No. surveys Table 2. Table counted. counted. Shorebirds at Hutt Lagoon and fossil river estuaries, Western Australia 129

and casual observations by various people have shown Brearley, A. (2005). Ernest Hodgkin’s Swanland: Estuaries and that they can attract a large range of shorebird species Coastal Lagoons of South-Western Australia, pp. 272–284. University of Western Australia Press, Perth. 9 27 24 27 (e.g. Red-necked Phalarope Phalaropus lobatus: Singor

Totals 2018). Heap, C. (2008). Hutt River waders, summer 2008. Western Australian Bird Notes 126, 24–26. The three fossil river estuaries surveyed in this study Heap, C. (2009). Hutt Lagoon and River, summer 2009. Western Australian Bird Notes , 11–12. have several factors in common. They all contained 130 0 0 0 0 0 0 0 0 1 0 6 0 0 0 1 0 Marchant, S. & Higgins, P.J. (Eds) (1993). Handbook of Australian, Jul. extensive samphire fringes, had an estuary lagoon and a New Zealand & Antarctic Birds, Volume 2: Raptors to Lapwings. sandbar across the river mouth. The mudflats that fringe Oxford University Press, Melbourne. the rivers have a substrate of limestone, are shallow and Pedler, R.D. (2017). Banded Stilt Movement and Breeding Ecology seem to provide poor feeding grounds. The mudflats in Arid Australia. PhD thesis. Deakin University, Melbourne. 2 1 1 2 7 2 1 5 0 0 0 1 0 1

16 along the shorelines of the fossil rivers progressively Pedler, R.D., Ribot, R.F.H. & Bennett, A.T.D. (2014). Extreme 542 Jun. dry out over summer, reducing feeding sites. The sites nomadism in desert waterbirds: Flights of the banded stilt. investigated support modest numbers of shorebirds Biology Letters 10 (10), 1–5. and provide a locally available stopover, contributing to Pedler, R.D., Ribot, R. & Bennett, A.T.D. (2017). Long-distance flights and high-risk breeding by nomadic waterbirds on desert 1 2 3 5 4 2 0 0 3 0 3 0 2 regional biodiversity. They did not attract the vast numbers 43 40 202

May salt lakes. Conservation Biology 32 (1), 216–228. of shorebirds found on gently sloping mudflats in the far Pedler, R.D., Weston, M.A. & Bennett, A.T.D. (2015). Long north-west of Western Australia (e.g. 80-mile Beach and incubation bouts and biparental incubation in the nomadic Roebuck Bay: Rogers et al. 2011) and they did not meet Banded Stilt. Emu 11, 75–80. the criteria of an internationally significant site (Bamford Rogers, D.I., Hassell, C.J., Boyle, A., Gosbell, K., 1 2 3 4 4 2 1 6 6 0 4 1 1 36 71 364 Apr. 2008). Minton, C., Rogers, K.G. & Clarke, R.M. (2011). Shorebirds of the Kimberley Coast – Populations, key sites, trends and threats. Journal of the Royal Society of Western Australia 94, Acknowledgements 377–391. 1 3 6 4 4 1 1 5 2 2 1 1 Singor, M. (2018). The Red-necked Phalarope in Western 50 71 18 218

Mar. We thank Dr Mike Bamford, Dr Roz Jessop and Richard Loyn, Australia. Western Australian Bird Notes 167, 15–17. whose contributions greatly enhanced the manuscript. Wells, F.E. (2002). Seasonality of beachwrack at Oakajee in the mid-west region of Western Australia. Records of the Western Australian Museum 21, 269–275. 3 4 3 4 2 2 4 2 1 2 2 References 69 10 59 14 307 Feb. Bamford, M., Watkins, D., Bancroft, W., Tischler, G. & Wahl, J. (2008). Migratory Shorebirds of the East Asian-Australasian Flyway: Population Estimates and Internationally Important Received 27 June 2018, accepted 24 April 2019, Sites. Wetlands International-Oceania, Canberra. published online 30 August 2019 4 9 4 6 3 1 7 7 1 4 1 4 66 12 549 145 Jan. 3 7 5 5 5 0 0 6 0 4 0 5 11 91 61 371 Dec. 3 6 5 6 3 0 0 5 0 2 0 5 70 10 28 339 Nov. 3 7 8 4 4 3 2 8 3 3 2 2 1 3 14 81 Oct. 3 2 7 2 4 2 1 5 2 2 1 0 1 3 16 207 Sep. 0 0 0 3 0 3 1 0 1 0 1 0 0 0 0 Aug. 1 n/c Port Gregory No. surveys Months 2017-2018 Average monthly count Average No. migratory species Average monthly count Average No. migratory species No. Aust.-breeding species No. Aust.-breeding species Greenough River estuary No. surveys Hutt River estuary No. surveys Average monthly count Average Average monthly count Average No. migratory species No. migratory species No. Aust.-breeding species No. Aust.-breeding species Bowes River estuary No. surveys