Andersson Widowbirds

Charlies Darwin postulated that males’ ornamentation will bear some cost on survival, attracting predators or reduce mobility, but this loss of fitness will be regained by increased mate success. These traits are used in direct male-male conflict or are preferred by females. Andersson Widowbird (Euplectes progne) is classic case demonstrating a trait that reduces survival, but increase mate success in 

Male Widow bird in flight
sourced:www.biodiversityexplorer.org

Andersson figure
 showing results of experimental alteration

             Widowbirds are highly sexually dimorphic females are a plain brown camouflage; whereas male are black with red marking and have extremely long trails. The tail of male Widowbird is so long that it disrupts its ability to fly making the easy targets for predation. In Andersson experiment, looked male-male interactions and females mate choice. He found that a male, regardless of trail size, could hold equal amount of territory; this meant female selection must be driving the process. By experimentally altering male tail lengths, adding extensions or cut feathers, he showed that females were selecting for longer tails and therefore maintaining the trait. The is a classic paper of evidence for sexual selection and mate choice

References  

Andersson, M. 1982, "Female choice selects for extreme tail length in a widowbird", Nature, vol. 299, no. 5886, pp. 818-820.