First-time use of metal construction for mounting artificial nests on trees for Saker Falcons <i>(Falco cherrug)</i> in Bulgaria

Abstract Artificial nests offer a promising solution to nest shortage, stemming from decreased breeding habitat for raptor populations. In Bulgaria, an area with declined raptor populations and increasing habitat loss, artificial nests offer an opportunity to re-establish breeding pairs of Saker Falcons (Falco cherrug) . As a part of the nonprofit Green Balkans’ captive breeding and release programme for Saker Falcons, 20 artificial nests were installed in the Stara Zagora region from 2020–2021. Nests were made from a steel metal frame filled with dried sticks and vegetation and installed in old-growth trees. Each nest site was evaluated for characteristics such as habitat type and prey availability. None of the 20 artificial nests have been used by Saker Falcons yet, but they have been regularly monitored for activity since their installation. As Saker reintroduction efforts continue, ongoing monitoring of artificial nests will be essential in determining their effectiveness for future reintroduction projects. The specifications of construction and placement of artificial nests in this project can be used to inform other raptor reintroduction projects, considering location differences and individual species needs.