Idylwild IBA is an area of mostly forest habitats extending for about 12 km along Marshyhope Creek and its tributaries in Caroline County from Federalsburg northwards to Highway 404. Idylwild Wildlife Management Area comprises the majority of the site and includes deciduous floodplain forest flanking Marshyhope Creek, extensive areas of immature pine woodland and agricultural fields managed as a demonstration area for northern bobwhite management. To the north of Idylwild WMA lie several blocks of pine plantations at Line Road and east of Noble Road, some floodplain forest in the vicinity of Smithville Lake and privately owned agricultural fields. Idylwild WMA is owned and managed by Maryland DNR. The site includes three tracts of the Chesapeake Forest (at Line Road, Bloomery Road and on the east side of Idylwild WMA), which is owned and managed by Maryland DNR, some land owned by Caroline County and private farmland and pine plantations.
The varied habitats of Idylwild are important for bird assemblages of Forest-Interior Dwelling Species (FIDS) and shrubland species as well as a number of at-risk species. 16 species of FIDS breed regularly in the floodplain forest, including the WatchListed Prothonotary Warbler. The 776-acre bobwhite management demonstration area of young pine woodland and oldfield habitats supports good numbers of shrubland birds such as Prairie Warbler, Yellow-breasted Chat and Field Sparrow as well as a bobwhite population estimated at around 100-200 individuals in fall. This site holds one of the few remaining populations of Whip-poor-will on Maryland's Eastern Shore - more than 20 calling birds have been heard here.