Habitat Inventory and Search for Ivory-billed Woodpeckers in the Cache River Watershed, Illinois

Abstract

The Cache River watershed of Illinois presently contains >10,000 ha of mature bottomland forest habitat distributed among a National Wildlife Refuge (Cypress Creek NWR) and state-owned Nature Preserves and Natural Areas. Several thousand more hectares will likely be reforested in the coming years. The Cache River watershed in Illinois provides possibly the best habitat for woodpeckers in the state and is home to thousands of Pileated (Dryocopus pileatus), Red-bellied (Melanerpes carolinus), and Downy (Picoides pubescens) Woodpeckers year-round, and also hosts thousands of Red-headed Woodpeckers (Melanerpes erythrocephalus) each winter. Tens of thousands of field hours logged in the mature bottomland forests of the Cache River watershed by Avian Ecologists and their research assistants since 1993 have yielded no evidence of the presence of IBWOs. However, other individuals have made unsubstantiated reports of IBWO sightings from at least two separate locations within the watershed since the beginning of 2005. The combination of habitat, overall woodpecker densities, and recent unsubstantiated sightings of IBWOs warranted an intensification of search efforts in the Cache River watershed of Illinois. There are several natural forces that continue to occur in the Cache River watershed in Illinois that help to maintain the presence of the large dead and dying trees that are important to woodpecker populations. These forces include beavers, ice storms, violent weather (wind, lightening and tornadoes), and flooding. Taken together, it may be possible for an IBWO to exist in the Cache River watershed in Illinois, but we currently lack the unequivocal evidence necessary to confirm this possibility.