Vale Gierzwaluw

Apus pallidus  ·  Pallid Swift

id 69342
datum 12 november 2022
gemeente Schouwen-Duiveland (ZL)
locatie Westenschouwen
coördinaten N 51.66702  O 3.7154
aantal, kleed 1
soort waarneming veldwaarneming
status Aanvaard, gepubliceerd in jaarverslag CDNA
waarnemer(s) M Sluijter
opmerkingen photographed. Before the 2020 influx there were 29 records; the first record was in 2006 and the second as recent as 2013 (Groenendijk & van der Laan 2020; figure 3). After the 2020 influx with 14 records (21 individuals), this year’s invasion was astonishing with a total of 84 records involving 159 individuals. The first appeared on 15 October and the final two were recorded on 12 November. All others were photographed in the short window between 22 October and 4 November (plus one on 10 November). Due to the large number, the huge turnover and the presence of groups of up to seven, assessing the total number of individuals involved was complicated. Because of this high turnover we have assumed that birds seen on a subsequent day on more or less the same location involved newly arrived individuals. In October, only three certain Common Swifts A apus were photographed, on 1, 4 and 7 October. The first Pallid Swift turned up a week later. Due to this gap, the committee decided it should be safe to implement a more pragmatic approach. For a record to be acceptable, we required to have at least one photograph of each individual which at least strongly suggested Pallid, through characters like the facemask, upperwing-coverts, overall colour, pale vent and contrast between coverts and flight feathers of the upperparts. To acquire a reliable overview of this influx, the committee has asked local experts per region (eg, a Wadden Sea island) to summarise the stream of reports. They were asked to submit and also assess the photographs uploaded on, eg, www.waarneming.nl and, when relevant, to combine sightings which might concern the same individual(s). In addition to the records in the above-mentioned period, several 10s of undocumented observations of unidentified Common or Pallid were registered on www.trektellen.nl and www.waarneming.nl.


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