Histrionicus histrionicus (Harlequin Duck)
- Describes the food habits, behavior, range, and conservation status of this species.
- http://animaldiversity.ummz.umich.edu/site/accounts/information/Histrionicus_histrionicus.html

Harlequin Duck
- Appearance, range, migration cycle, feeding habits, and conservation status of Histrionicus histrionicus.
- http://www.hww.ca/hww2.asp?pid=1&cid=7&id=47

Harlequin Duck (Histrionicus histrionicus linnaeus)
- Illustration, description, range, and status in Nova Scotia.
- http://museum.gov.ns.ca/mnh/nature/nsbirds/bns0070.htm

Harlequin Duck (Histrionicus histrionicus)
- Winter range map, photos, identification tips, and taxonomy chart.
- http://www.mbr-pwrc.usgs.gov/id/framlst/i1550id.html