Rare birds in the Netherlands in 2018 Gerjon Gelling, Vincent van der Spek, James Lidster & CDNA his is the 39th annual report on rare birds in the colum bianus was removed. With these changes, TNetherlands to be published in Dutch Birding. the Dutch list still numbers 521 species. Further­ A few adjustments have been made in comparison more a retrospective ‘eastern yellow wag tail’ with previous reports, in order to improve the Mota cilla tschutschensis/macronyx/taivana from readability. Most records are from 2018 but there 2008 was a new ‘superspecies’. Other highlights are also belated and reconsidered records dating include the second Black­headed Wagtail M fel- back to 1964. These have been assessed by the degg, third Great Knot Calidris tenuirostris, fourth Dutch rarities committee (Commis sie Dwaalgasten Hooded Merganser Lophodytes cucullatus and Nederlandse Avifauna; CDNA), a joint committee Eastern Black­eared Wheatear Oenanthe melano- of the Dutch Birding Association (DBA) and the leuca, fifth Eastern Bonelli’s Warbler Phylloscopus Nederlandse Ornitho logische Unie (NOU). Rec­ orientalis, sixth White­throated Wagtail M cinereo- ords are assessed digitally by eight voting members. capilla, seventh and eighth Cirl Bunting Emberiza This report contains 235 reviewed reports, resulting cirlus and ninth Red­eyed Vireo Vireo olivaceus. in 155 accepted records. Records of all taxa From 2016, a Dusky Thrush Turdus eunomus accepted up to and including 2018, as well as (third) and, from 2017, a White­throated Wagtail pending reports, can be found on the online (fifth) were also accepted. database www.dutchavifauna.nl. Please note that In addition, 2018 was a record year for Pallid some reports from 2018 and earlier are still under Swift Apus pallidus (14), Baltic Gull Larus fuscus review or awaiting submission and are therefore fuscus (six), Lesser Grey Shrike Lanius minor (five), not included. Blyth’s Reed Warbler Acrocephalus dumetorum (11), Iberian Chiffchaff P ibericus (six, equalling Remarkable records in 2018 2010) and Pied Wheatear O pleschanka (three, With at least 374 species recorded in 2018, it was equalling 1999). an average year for species diversity. With a few reports still pending, this number may rise. The Additional committee work in 2018 average over the last 10 years is 373 (figure 1). There were two committee meetings, one in Grey­cheeked Thrush Catharus minimus was new January and one in August. The August ‘meeting’ to the Dutch list, whereas Whistling Swan Cygnus was unusual in the sense that we did not physically [Dutch Birding 41: 375-400, 2019] 375 Rare birds in the Netherlands in 2018 388 tische Kommision (DAK) to demonstrate our digital voting system and to explore possibilities for future 380 377 377 international collaboration. 374 374 370 Members The following CDNA members voted on records in 364 365 361 this report: Garry Bakker, Christian Brinkman (secretary until early 2019), Thijs Fijen, Diederik Kok, James Lidster (treasurer since 2019), Eddy Nieuwstraten (chairman), Hans Schekkerman (new member since 2019), Vincent van der Spek 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 (secre tary since 2019) and Rik Winters (treasurer; FIGURE 1 Number of species recorded in the Netherlands depart ing member after two terms (eight years) in per year in 2009­18 (average 373) / aantal vastgestelde 2019). Gerjon Gelling (archivist) and August van soorten per jaar in Nederland in 2009­18 (gemiddeld Rijn (assistant) supported the committee as non­ 373) voting members by submitting many reports published on national and regional websites. At the start of 2018, Marcel Haas, the former archivist, meet up but instead digitally decided on several was thank ed for the huge amount of work he had issues. An interesting experiment but we now done since January 2013. know a face­to­face meeting has our preference. Recent decisions with consequences for this report Glossary include: 1 The criteria for re­introduced species Details included for each record in this report are, that occur as vagrants have been updated. if available: date(s); location and/or municipality Populations have to be self­sustaining in order to (municipal divisions as of 1 January 2018); prov­ qualify for potential acceptance. For example, ince; number of birds if more than one, plumage Bearded Vulture Gypaetus barbatus is currently and sex; type of record if ringed, photographed, not acceptable as a wild vagrant, since the CDNA sound­recorded, videoed or found dead (and considers all observed individuals to originate where specimen is stored, if known); names of up from (not yet fully self­sustaining) re­introduction to three observers involved in finding, identifying programs in the Alps. 2 The criteria for species that and recording, and relevant references in the require proof that they do not show any signs of literature, which normally include (inter)national captivity (‘omgekeerde bewijslast’) in order to get but not regional journals, and published photo­ accepted, were updated. Marbled Duck Marma- graphs. Records from 2017 lasting into 2018 that ronetta angustirostris was added to the list. In already have been published in the 2017 report specific cases it is now possible to demand addi­ (Gelling et al 2018) are repeated here without tional evidence for any record submitted when the reference. Observations not (yet) submitted but committee decides this is necessary (in theory, a mentioned in the 2017 report are not repeated in Harlequin Duck Histrionicus histrionicus at sea this report. The sequence of the records in the could be treated differently from one on a pond in species accounts is from the current year back­ an inland town). The committee also has the wards, with records within one year presented per freedom to treat any potential new species accord­ province (starting with the province with the first ing to these criteria. Finally, the state of a bird’s record of the year), and then chronologically plumage and its behaviour now weigh more heavi­ within each province. Numbers after each (sub) ly in the assessment. 3 A strategy was developed species’ name refer to the total number of for species that were ‘on hold’ awaiting expected individuals 1 from 1 January 1800 to 31 December new identification insights, or DNA information. 1979, 2 since 1 January 1980 but excluding, and This resulted in the rejection of all Tundra Peregrine 3 the current year. Taxa marked with an asterisk * Falcons Falco peregrinus calidus and all field sight­ are new to the Dutch list. For the sake of com­ ings (without DNA analysis) of eastern ‘lesser pleteness, date extensions are presented in this white throat’ Sylvia curruca/althaea taxa. If new report. identification insights are published in the future, Used abbreviations for provinces are: DR records can be resubmitted. Drenthe, FL Flevoland, FR Friesland, GE Gelder­ Chairman Eddy Nieuwstraten was invited by our land, GR Groningen, LI Limburg, NB Noord­ German colleagues from the Deutsche Avi faunis­ Brabant, NH Noord­Holland, OV Overijssel, UT 376 Rare birds in the Netherlands in 2018 Utrecht, ZL Zeeland, and ZH Zuid­Holland. For to 4 April, adult male, photographed, videoed (M Jonker ageing, calendar­year is abbreviated to cy prefixed et al; Dutch Birding 40: 133, plate 182, 2018). with 1, 2, 3 or 4 to indicate first, second, third or A returning individual first seen on 11 February 2017. fourth. The symbol # indicates corrections or ex­ Lesser Scaup / Kleine Topper tensions of date(s), location(s) or other details con­ Aythya affinis0,19,0 cerning a record. NOORD­HOLLAND Dijkwielen, Hollands Kroon, 7­8 and Decisions regarding taxonomy have been dele­ 27­28 April, adult male, photographed (F Visscher). gated to the Dutch committee for avian systemat­ A returning individual first seen on 26 February 2017. ics (Commissie Systematiek Nederlandse Avifauna; CSNA) and are not under the responsibility of the Bufflehead / Buffelkopeend CDNA. Bucephala albeola 0,7,1 ZUID­HOLLAND Gaatkensplas and surroundings, Baren- Submitting a report drecht, 20 September 2017 to 13 May, also seen at Spaarbekken Petrusplaat, Brabantse Biesbosch, Drim- Reports can be submitted through the electronic melen NB, 4 June to 27 August, adult male, photographed, form on www.dutchavifauna.nl or by using the videoed (G Duijf et al). link on www.waarneming.nl. NOORD­HOLLAND Den Oever and IJsselmeer, Hollands Kroon, 13 October 2017 to 20 March, and 9 October to Accepted records 13 February 2019, adult male, photographed, videoed. UTRECHT Nedereindse Plas, IJsselstein, Utrecht, 6­8 Whistling Swan / Fluitzwaan March, photographed (E Schuller et al). Cygnus columbianus 0,0,0 The records from Noord­Holland and from Noord­ Based on newly described identification features other Brabant/Zuid­Holland concern long­staying and return­ than the amount of black on the bill (Visscher & van ing individuals, the latter already since November 2004. Duivendijk 2015), all five records were reassessed. After 14 years, this bird did not return to Barendrecht in According to Evans & Sladen (1980), only a small minor­ the winter of 2018/19. ity (4.3%) show more than 10% yellow on the bill. This minority type however seems to be over­represented in Hooded Merganser / Kokardezaagbek Dutch records. This was, eg, the case for a widely Lophodytes cucullatus 0,3,1 twitched bird in Drenthe, Friesland and Groningen in the UTRECHT Haarrijnse Plas, Vleuten, Utrecht, 5­6 Novem­ winters of 1997/98 and 1998/99. ‘Hybrigades’ with ber, 2cy male, photographed, videoed (B Kasius, E Schul­ Bewick’s Swan C bewickii are a realistic option, and ler et al). Bewick’s with aberrant bills are not unheard of (Evans & Sladen 1980). Identification based on a single feature is Blue-winged Teal / Blauwvleugeltaling therefore tricky, especially in birds with a relatively large Spatula discors 6,35,2 amount of yellow on the bill. The presence of the new DRENTHE Vloeivelden Zuidzijde, Nieuw Buinen, Borger- features could not be determined in the records.