Western Australian Bird Notes Quarterly Newsletter of the Western Australian Branch of BirdLife Australia No. 173 March 2020 birds are in our nature Members in the field World Wetlands Day bird walk Albany, p 32, photo by White-winged Fairy-wren at Mullaloo, photo by Caroline Shaun Welsh Mynott So hot for Brown-headed Honeyeater, p 42, photo Delene Osprey with catch, photo by Garry Taylor van Dyk David Budd rescuing two Eurasian Coots at Mandurah, p34 Bibra Walk, p 36, photo by Alan Watson Front cover: Red-necked Stint at Rottnest Island - photo by Clive Nealon Page 2 Western Australian Bird Notes, No. 173 March 2020 Western Australian Branch of EXECUTIVE COMMITTEE, 2020 BirdLife Australia Chair: Mr Viv Read Office: Peregrine House 167 Perry Lakes Drive, Floreat WA 6014 Vice Chair: Dr Mike Bamford Hours: Monday-Friday 9:30 am to 12.30 pm Secretary: Lou Scampoli Telephone: (08) 9383 7749 E-mail: [email protected] Treasurer: Beverly Winterton BirdLife WA web page: www.birdlife.org.au/wa Committee: Alasdair Bulloch, Mark Henryon, Andrew Hobbs, Chair: Mr Viv Read Peter Jacoby, Jennifer Sumpton and Beth Walker BirdLife Western Australia is the WA Branch of the national organisation, BirdLife Australia. We are dedicated to creating a brighter future for Australian birds. General meetings: Held at the Bold Park Eco Centre, Perry Lakes Drive, Floreat, commencing 7:30 pm on the 4th Monday of the month (except December) – see ‘Coming events’ for details. Executive meetings: Held at Peregrine House on the 2nd Monday of the month. Communicate any matters for consideration to the Chair. Western Australian Bird Notes Print ISSN 1445-3983 Online ISSN 2206-8716 Joint WABN Editors: Allan Burbidge Tel: (08) 9405 5109 (w) Tel/Fax: (08) 9306 1642 (h) Fax: (08) 9306 1641 (w) E-mail: [email protected] Suzanne Mather Tel: (08) 9389 6416 E-mail: [email protected] Production: Michelle Crow Printing and distribution: Daniels Printing Craftsmen Tel: (08) 9204 6800 danielspc.com.au Notes for Contributors Common Noddy, photo by Garry Taylor The Editors request contributors to note: • WABN publishes material of interest to the WA Branch; • contributions should be written or typed with double spacing—a copy on disk or emailed would assist, especially if in MS Word as a document without styles; do not embed C o n t e n t s pictures or graphics in MS Word; • contributions to be sent direct to the Editors, either at the 4. Summer Migrants - 20 30. Notices. office or by email: Years of Monitoring Trans- 30. New members. Sue Mather: [email protected] Equatorial Bird Species on Allan Burbidge: [email protected] Rottnest Island by BirdLife 37. Regional Groups. • WABN uses BirdLife Australia recommended English names; Western Australia. 35. Excursion reports. • except for Observations, contributions will be published unless the contributor is informed to the contrary; 10. From the editor 41. Observatory reports. • Full Editorial Policy is in WABN 74:10-12; 11. Observations 46. Coming events. • WABN is not peer reviewed. 11. Crossword 49. Crossword answers. 14. Obituary. 50. Calendar of events. • Printing Deadlines (at BirdLife WA Office) 16. BirdLife WA reports. 18. WA Branch reports June 2020 issue: 1 May September 2020 issue: 1 August 21 Across the Nullarbor: December 2020 issue: 18 October news from National March 2021 issue: 1 February Office. 22. Members’ contributions. Western Australian Bird Notes, No. 173 March 2020 Page 3 Summer Migrants - 20 Years of Monitoring Trans-Equatorial Bird Species on Rottnest Island by BirdLife Western Australia Understanding the role of Rottnest Island is important All records were entered into the BirdLife 2020 database as while the island is an A Class Reserve under the and included in the Rottnest Island BirdLife report on the administration of the Western Australian Government, it is annual surveys. Species presence, abundance and richness also a tourist resort under the appointed Rottnest Island were evaluated for each site. Seven wader species, Grey Authority. While recognising that natural assets such Plover, Whimbrel, Bar-tailed Godwit, Ruddy Turnstone, as birds on the salt lakes are part of the attraction, the Curlew Sandpiper, Red-necked Stint, and Sanderling, were stated purpose of the island is to ‘grow visitor numbers by recorded regularly on the island. The census figures from providing best-in-class tourism products’ (Rottnest Island 20 years of bi-annual surveys (1998-2018) showed that Authority Annual Report 2017/2018). The potential for abundance estimates varied between 806 (1998) and 2280 conflict is thus considerable. (2014) (Table 1). However, in 1998 ‘complete coverage of the island was not possible’ (Davis 1998) and this Rottnest Island provides an important habitat for non- could explain the low count for that year. The coverage in breeding populations of trans-equatorial migratory subsequent years has been complete with more volunteers shorebirds, referred to as waders. BirdLife Australia’s participating in the survey. Therefore to establish the Western Australian Branch has conducted bi-annual population trend of the waders the 1998 results have been Rottnest Island shorebird counts since 1998. The data from omitted. Figure 1 trend line shows a decline in the overall this work add to the national BirdLife Australia database population. The intervals between the significantly lower and to the Rottnest Island Authority (RIA) records. Results records, 2005, 2010 and 2017 are five and seven years from the bi-annual censuses on the island suggest its respectively. The years that the population was noticeably protected environments act as a refuge for migratory above the trend line were in 2001, 2011, 2012, 2013, shorebirds when compared with declining mainland sites. 2014 and 2018. The continued environmental management of the island has secured this habitat by limiting and controlling tourist activity in the species’ habitats and through monitoring the water quality in the lakes. Continued 2500 Population trend of trans-equatorial waders 1999-2018 census helps researchers understand what are the important habitats for this suite of birds and the Rottnest Island administration shows how tourism 2000 and shorebird protection can co-exist. A request from the Australian Wader Studies Group 1500 resulted in a part island survey in 1997, but in 1998 this was formalised into a non-breeding season shorebird survey of the entire island, lakes and 1000 beaches (Davis 1998). Since 1998 the biannual count has been extended to include seabirds such 500 as terns under the protocol of the BirdLife Australia Shorebird 2020 initiative. However this article 0 addresses specifically the trans-equatorial migratory waders on the island. 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 The wader habitats on the island are the 12 salt lakes and some of the coastal shoreline. The reef system Figure 1. Population trend of trans-equatorial waders on off the coastline is exposed at low tide and has been Rottnest Island, 1999- 2018 shown to support foraging waders. The food for trans- The population decline was also reflected in a decline equatorial waders, 43 invertebrate taxa, was recorded in in species richness from 1998 to 2018, mirroring the a study on the salinity and temperature levels and the population decline overall (Figures 1 and 2). However fauna dependent on the lakes (Edwards 1983). Wader the species richness trend, ranging from eight (2013) to species favouring the coastal habitat are dependent for 16 (2000, 2005) species does not correspond with the food on invertebrates found along the reef and shoreline. population trend results in that there is no consistent The invertebrates in the coastal habitat, particularly on correlation between the years of species richness and the intertidal zone, were resurveyed in 2007, showing 45 population abundance. mollusc species. Previous work in 1982 had shown that there were twice as many marine molluscs on Radar Reef The Rottnest trans-equatorial migratory species have been and four times as many on Cape Vlamingh than on the categorized as regular migrants, uncommon migrants adjacent mainland (Irvine et al. 2008). It's not surprising and vagrant migrants. Of the 20 wader species recorded then, that Rottnest is an important area for waders, and historically, seven were considered regular migrants to this area is now a marine protected zone. the island on the basis of the 100% presence, except Bar-tailed Godwit (95%) and Whimbrel (85%) in the In order to obtain realistic and repeatable estimates 19 surveys. Species that were considered uncommon, of wader numbers, the whole island was surveyed in a occurred in >20% of surveys and those species that could two to three hour period in the early morning. This has be seen as vagrant migrants occurred occasionally (Table involved between 12 and 18 volunteers and represents 2). Two uncommon species are of interest as they could be approximately 540 volunteer hours per survey. The lakes seen as vagrant and occurred in small numbers but Pacific and coastline were surveyed by teams of two experienced Golden Plover has been recorded in 30% of sightings and volunteers allocated to each lake or length of shoreline Red-necked Phalarope in 40%. known to be utilised by waders. Page 4 Western Australian Bird Notes, No. 173 March 2020 Summer Migrants - 20 Years of Monitoring Trans-Equatorial Bird Species on Rottnest Island by BirdLife Western Australia, ctd 2009 to 181 in 2018. But this is a decline from the 2001 record of 430 and reflects the 1973- Species richness trend of trans-equatorial waders 1999-2018 2014 records showing a 3.17%/per annum 18 decline nationally (Clemens et al. 2016). This 16 species moves on the island between the coast and lake habitats, dissimilar to other south- 14 west locations where it has not been recorded 12 in summer Shorebird 2020 counts (Birdata).