spread tail

plural spread tails

1. The tail of a bird (or likeness thereof) when the tailfeathers are held tautly outward in a fan-like arrangement.

   There is evidence which seems to show that a spread tail is more aggressive than a folded one and that cocking the tail up is more aggressive than pointing the tail downwards.

   1964, G. J. Broekhuysen, “A Description and Discussion of Threat- and Anxiety-Behaviour of Burhinus Capensis (Lichtenstein) During Incubation”, in Feestbundel H. Boschma, page 244

   3 more examples

   Moreover, for slight deflections of the vane from the wind direction a spread tail presents a greater extent of surface to the wind than a straight-tail vane of the same dimensions.

   1893, Charles Frederick Marvin, Anemometry, page 16

   Now, as we understand all this the Brahma tail most admired is the full spread tail that almost forms a half circle to build out the saddle and make it possible for the saddle to make the concave sweep to the coverts.

   1901 June, “The Brahma Fowl”, in American Poultry Journal, volume 32, number 6, page 497

   Birds with long forked tails, such as some swifts, swallows, terns, frigate birds, and the fork-tailed falcon (Elanoides furcatus), use the spread tail as a long flap on each side to help deflect air over the main wing surface and keep the flow attached at higher angles of attack than otherwise would be possible.

   2012, Ulla M. Norberg, Vertebrate Flight, page 236