Valchi Dol, Nature reserve in Eastern Rhodopes, Bulgaria.

Valchi Dol is a nature reserve in the Eastern Rhodopes with mixed broadleaf forests, open meadows, and rocky cliffs. The area provides different habitats that support a wide variety of wildlife.

Valchi Dol was declared a reserve on 25 November 1980 by Order No. 877 of the Committee for Environmental Protection, covering 776.24 hectares. Its purpose was to preserve Bulgaria's only griffon vulture colony at the time, discovered in 1978 on the large Kartal Kaya rock. The reserve is part of the Studen Kladenets protected area and Important Bird Area.

The reserve's name, Valchi Dol ("Wolf's Hollow"), comes from the surrounding land. The Rhodope primrose, a Balkan endemic and Tertiary relict found here, is known locally as the "Orpheus flower" after an ancient legend, and as the "phoenix" because it can survive dried out for over two years and revive when placed in suitable conditions.

Valchi Dol is the only strict reserve in the Eastern Rhodopes, so there are no marked visitor trails inside it. Access is limited to the designated feeding ground and observation building next to the reserve, where griffon vultures can be watched. The reserve lies south of the Studen Kladenets reservoir, in the lands of Studen Kladenets, Stari Chal and Boynik, Krumovgrad municipality.

On the huge Kartal Kaya cliff, the first naturally returning griffon vulture colony in Bulgaria was found in 1978. A feeding platform and an observation building stand next to the reserve, so the birds can be watched without entering the strictly protected territory.