Aleutian Tern Onychoprion aleuticus
Estimated average number of individuals by week based on eBird data, Jul 2012 to Jun 2022
Peak week Sep 10-Sep 16, Sep 17-Sep 23
Early date 20 Aug 2011
Late date 15 May 2011
A pelagic trip in Sep or Oct will be your best bet to see this species, which passes through Singapore during these months.