Male red-winged blackbirds (Agelaius phoeniceus) being gregarious, and causing heavy damage to corn crops in the northeast, including southern Quebec and Ontario, sterilization has been studied as a means to manage their populations. With chemosterilants (thiotepa and Ornitrol®) tested, year to year variations in reproductive success occurs. The spermatogenesis is disrupted, but the overall effect is not specific. Biosterilisation with 10.0 µg doses of GnRH-analogue hormones is more specific, and the spermatogenesis is disrupted for at least a month, but several spaced injections were required. No field trials have been done yet.