Port Stephens shorebirds & waterbirds 2004-2020 The Whistler 14 (2020): 54-69 Port Stephens shorebird and waterbird surveys 2004-2020 Alan Stuart 81 Queens Road, New Lambton NSW 2305, Australia. [email protected] Received 25 October 2020; accepted 9 November 2020; published on-line 19 November 2020. Shorebird and waterbird populations in the Port Stephens estuary in New South Wales have been monitored regularly since 2004, using teams in boats to survey sub-sections of the estuary simultaneously. Overall, 23 shorebird species and 31 waterbird species have been recorded in the surveys, which were carried out twice-yearly in most years, as one summer survey and one winter survey. Sixteen migratory shorebirds were recorded, including 13 species which had regular records. The most abundant shorebird species in Port Stephens was Bar-tailed Godwit Limosa lapponica, followed by Far Eastern Curlew Numenius madagascariensis and Whimbrel N. phaeopus. The numbers of visiting shorebirds have decreased, with average declines of around 2.5% per year having occurred for the above three species since 2004. There were several records in summer of more than 1% of the total world population of Far Eastern Curlew; Port Stephens is an internationally significant site for that species. In winter, many immature (non-breeding) curlews stay in Port Stephens, with an average winter count of 66 birds and a peak count of 223 birds in 2009. More than 1% of the total population of the Australian Pied Oystercatcher Haematopus longirostris was regularly recorded in Port Stephens, in both the summer and winter surveys and with a peak count of 192 birds. The numbers of Sooty Oystercatcher H. fuliginosus increased, such that since 2013 more than 1% of the total population of subspecies H. f. fuliginosus has often been present, particularly in summer. The most abundant waterbirds were Australian Pelican Pelecanus conspicillatus, Little Pied Cormorant Microcarbo melanoleucos, Little Black Cormorant Phalacrocorax sulcirostris, Great Pied Cormorant P. varius, Silver Gull Chroicocephalus novaehollandiae and Greater Crested Tern Thalasseus bergii, all of them having average counts of more than 100 birds in both the summer and winter surveys. The Little Tern Sternula albifrons was only recorded in low numbers each summer until 2016. From then, their numbers increased, to a peak count of 304 birds in 2018 and breeding colonies have re-established. Several waterbird species were present in larger numbers in the winter surveys than in summer. Examples included Little Pied Cormorant, Great Cormorant P. carbo, Great Pied Cormorant and Caspian Tern Hydroprogne caspia. Conversely, species such as Black Swan Cygnus atratus, Silver Gull, and Greater Crested Tern were more abundant in summer than in winter. There was some evidence to suggest that rainfall patterns (El Niño and La Niña events)) affected waterbird numbers. INTRODUCTION roosting habitat for shorebirds and various waterbirds. This includes two nature reserves – The Port Stephens estuary (Figure 1), situated Gir-um-bit National Park (the southern part of the approximately 200 km north of Sydney, is a reserve is centred at 32º 42ꞌS, 151º 58ꞌE) and popular tourist and recreational area. The area Corrie Island Nature Reserve (32º 40ꞌS, ꞌ152º around the south-eastern section of the estuary has 08ꞌE). Also, there are several islands (see Figure experienced substantial development as has the 1) that offer foraging or roosting habitat. At low north-eastern section to some extent. However, tides, many mudflats and sand banks around the many parts of Port Stephens are relatively Port, and oyster racks, become exposed; these all undisturbed. All the Port Stephens waters, to the offer opportunities for shorebirds and some high-tide shoreline, are part of the Port Stephens- waterbirds to forage. Many other waterbird species Great Lakes Marine Park. can utilise the extensive areas of open water found in Port Stephens. A substantial portion of the less-disturbed parts of Port Stephens provides suitable foraging or 54 Port Stephens shorebirds & waterbirds 2004-2020 The Whistler 14 (2020): 54-69 Karuah Tea Carrington Gardens Hawks Nest Pindimar Little Swan Bay Winda Woppa NSW Corrie Island Swan Bay PORT STEPHENS Soldiers Pt Gir-um-bit NP Nelson Bay Shoal Bay Tanilba Lemon Tree Salamander Bay Bay Passage Oyster Cove Cromarty Bay Tilligerry Creek 1 km N Figure 1. Port Stephens in New South Wales, showing the main towns and topographic features. Prior to 2004, Port Stephens was sometimes simultaneously surveyed sub-areas (sectors) of Port surveyed for shorebirds, particularly in the 1980s, Stephens, following pre-defined standard routes every and its importance for certain species was time. Due to human activity, shorebirds only recognised (Lane 1987; Smith 1991; Bamford et occasionally use the south-eastern section of the Port al. 2008). However, the surveys in general were Stephens coastline and only in small numbers (AS pers. obs.). Hence that area was not included in the surveys. infrequent, and they were land-based. Being The teams collectively covered the remainder of the limited to land-accessible locations meant that not Port Stephens shoreline including all of the contained all of the now-known roost sites for shorebirds islands. were able to be surveyed, because some of them are only accessible by boat (Stuart 2011). In 2004 I Each survey commenced approximately 90 minutes began organising regular boat-based surveys of before the predicted time for high tide at Soldiers Point Port Stephens, with all shorebirds, waterbirds and in Port Stephens. The surveys of each sector took c. 3 birds of prey utilising the marine and estuarine hours to complete, meaning that all the surveys were habitats of the Port being recorded. For 2004-2007, carried out in high-water conditions when shorebirds a survey was carried out every summer, and there usually are congregated at their roost sites (Finn 2007). Port Stephens is often subjected to strong afternoon sea have been both summer and winter surveys in most breezes, hence days with early high tides were chosen years since 2008. for the surveys. Some of the results from the post-2004 surveys Every vessel had a dedicated skipper and 1-2 observers, have been presented elsewhere, namely: the at least one of whom was an experienced birdwatcher. interim findings from the first three years of After the initial set of surveys in 2004, teams were summer surveys (Stuart 2005, 2007); information assigned such that at least one of the observers and/or about the Australian Pied Oystercatcher in Port the skipper had surveyed the sector previously and was Stephens (Stuart 2010; Fraser 2019); data for familiar with the route and its subtleties. Each team shorebirds from the 2004-2011 surveys and recorded the numbers of all shorebird species observed and of all other waterbirds, as well as birds of prey. comparison with pre-2004 shorebird records (Stuart 2011); data for some shorebirds from the A de-briefing session for participants was held after 2004-2015 surveys (Roderick & Stuart 2016); and every survey. That session provided the opportunity to information about the birds of prey in Port eliminate any possible instances of double-counting Stephens (Stuart 2016). In this report I present and because of movements of birds out of a sector mid- discuss the findings for all shorebird species and survey. Such instances were found to be rare. the main waterbird species from the 2004-2020 surveys. Data management The records for each sector were entered into Birdata as individual Shorebirds 2020 surveys. For each summer METHODS and winter overall survey, the aggregated counts for each species from all six sectors were collated in a The general methodology for the surveys has been Microsoft Excel file, from which graphs (annual results described previously (Stuart 2011). Four to six teams and trends, summer/winter comparisons) were generated (for most of the surveys, six teams) in boats using standard Excel software tools. Regression 55 Port Stephens shorebirds & waterbirds 2004-2020 The Whistler 14 (2020): 54-69 analyses were carried out using Excel’s Data Analysis The Coefficients of Variation (CV), (which is the Add-in software. ratio of the Standard Deviation (SD) to the Mean) for the results from all surveys have ranged between 7% and 35% (Tables 2 and 3). RESULTS Table 2. Results from summer surveys in Port Stephens Surveys (number of species of shorebirds and waterbirds, total counts of shorebirds and waterbirds, and the overall The summer surveys, spanning 2004-2020, were results). carried out in February, except in 2005 when the Shorebirds Waterbirds Overall originally scheduled date had to be postponed to Year Spp Birds Spp Birds Spp Birds early March. There were some operational issues 2004 13 2053 23 2387 36 4440 during the 2005 survey and only 80-90% of the 2005 11 689 13 688 24 1377 targeted area was able to be surveyed. The winter 2006 18 1527 18 1473 36 3000 surveys have spanned 2008-2020 and all of them 2007 14 1750 25 1796 39 3546 were done on a July date, if done at all. In 2016, 2008 13 1695 21 982 34 2677 2009 14 1554 16 2235 30 3789 owing to deteriorating weather conditions during 2010 15 1812 22 2280 37 4092 the scheduled survey, not all areas were able to be 2011 11 1431 19 1072 30 2503 visited by boat on the chosen date. All the main 2012 13 1479 19 967 32 2446 roost sites that were missed that day were able to 2013 10 1147 18 1580 28 2727 be surveyed from land-based visits over the 2014 11 1230 21 1740 32 2970 following two days. Extended periods of poor 2015 13 1327 18 1406 31 2733 2016 13 1419 18 1216 31 2635 weather conditions prevented the winter surveys in 2017 8 937 16 1510 24 2447 2015 and 2017 from occurring.