Albert (Ab) C. Perdeck died in a tragic traffic accident on the 21 May 2009. For many decades, Ab was head of the Dutch ringing centre (Vogeltrekstation) and he made many important contributions to bird ringing in The Netherlands and in Europe. Also after his retirement, Ab stayed active in research. He was keen on doing analyses of complex datasets, using state of the art statistical methods. He wrote, and contributed to, a large number of publications in the period after his retirement and his last paper only just came out, 59 years after his first paper.
Ab achieved his Biology degree in Leiden where he did his research project under the supervision of Niko Tinbergen, working on the function of the red spot on the bill of Herring Gulls (Tinbergen & Perdeck 1950). This classic ethological study is still being cited and has recently even been followed up by Leiden students under the supervision of Carel ten Cate. From 1950 onwards, Ab was appointed Head of the ringing centre (Vogeltrekstation) and when the Vogeltrekstation moved from the National Museum for Natural History in Leiden to the Institute for Ecological Research (IOO) in 1958 Ab became a researcher at the IOO in Arnhem (now part of the Netherlands Institute of Ecology — NIOO-KNAW). He remained head of the Vogeltrekstation until his retirement in 1988.
Ab's classical work on bird migration is his experiment on the orientation during migration in Starlings. For this study, 11 000 Starlings were caught on trapping stations (“vinkenbanen”) when they were passing through The Netherlands on autumn migration. The adult and juvenile birds were ringed and then brought to Switzerland by plane were they were released. Of these, 354 birds were recovered, either in the same year or in later years. The remarkable result was (see Figure) that the juveniles retained their original migration direction and thus ended up wintering in France and Spain rather than in England, where these birds were heading for when caught in The Netherlands. The adult Starlings however changed direction and did migrate towards England after being released in Switzerland (Perdeck 1958).
The work on bird migration is by its nature internationally oriented and Ab was very much aware of this. He initiated the founding of ‘The European Union for Bird Ringing’ EURING, in 1963, with the aim to standardize the coding of ringing data to make it possible to link the various national ringing databases in Europe. For his effort to initiate EURING Ab received a royal distinction. Also in organisations like the IWRB, he advocated the improvements of the ringing office practice and standardization of data coding.
After his retirement, Ab stayed on as a guest researcher at the NIOO-KNAW for another 21 years. He was closely involved in a project on seasonal timing in the Coot, together with Jan Visser, Ton Cavé and Martin Brinkhof. After this project was successfully completed with the thesis defence of Martin, Ab got involved in the work on the Great Tits. Together with Hans van Balen and myself, he worked on the fluctuation in population numbers and the effect of winter food (Perdeck et al. 2000). Ab's scientific passion was to analyse large data sets. As it turns out, his last project involved a return to the database of the Vogeltrekstation. We analysed all winter recoveries of Dutch breeding birds and showed that due to climate change, birds migrate less far nowadays (Visser et al. 2009). It was a privilege to work with him on a dataset for which he developed the coding himself and for which he had been responsible for decades.
 For (almost) all publications of Ab Perdeck: http://www.nioo.knaw.nl/content/publicaties-en-proefschriftenvan-het-nioo-knaw, which links to a RefShare data base, searching for ‘Perdeck’ gives 48 publications.