Speculum feathers
A male mallard. The speculum feathers are bright blue with white edges
The speculum is a patch, often distinctly coloured, on the secondary wing feathers, or remiges, of some birds.
Examples of the colour(s) of the speculum in a number of ducks are:
Common teal and green-winged teal: Iridescent green edged with buff.[1]
Blue-winged teal: Iridescent green.[2] The species' common name comes from the sky-blue wing coverts.
Crested duck and bronze-winged duck: Iridescent purple-bronze, edged white.[3]
Pacific black duck: Iridescent green, edged light buff.[3]
Mallard: Iridescent purple-blue with white edges.[1]
American black duck: Iridescent violet bordered in black and may have a thin white trailing edge.[1]
Northern pintail: Iridescent green in male and brown in female, both are white on trailing edge.[2]
Gadwall: Both sexes have white inner secondaries.[1]
Yellow-billed duck: Iridescent green or blue, bordered white.[4]
Bright wing speculums are also known from a number of other birds; among them are several parrots from the genus Amazona with red or orange speculums,[5] though in this case the colors are pigmentary and non-iridiscent.
References
 | Wikimedia Commons has media related to Speculum feathers. |
^ abcd Dunn, Jon L. & Alderfer, Jonathan (2006). National Geographic Guide to the Birds of North America. National Geographic Society. ISBN 1-4262-0072-2..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"""""""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ ab Bellrose, Frank C. & The Audubon Society (1983). The Audubon Society Master Guide to Birding. National Geographic Society. ISBN 1-4262-0072-2.
^ ab Madge, Steve; Burn, Hilary (1988). Waterfowl: an Identification Guide to the Ducks, Geese, and Swans of the World. Boston: Houghton Mifflin. ISBN 0-395-46727-6.
^ Zimmerman, Dale A.; Turner, Donald A.; Pearson, David J. (1999). Birds of Kenya and Northern Tanzania. Princeton University Press. ISBN 0-691-01022-6.
^ Robert S. Ridgely & John A. Gwynne, Jr. (1989). Birds of Panama with Costa Rica, Nicaragua, and Honduras. Princeton University Press. ISBN 0-691-08529-3.
