Cooperative Fish and Wildlife Research Units Program: Arkansas
Education, Research and Technical Assistance for Managing Our Natural Resources

Darrah, A. J., and D. G. Krementz. 2011. Habitat Use of Nesting and Brood-rearing King Rails in the Illinois and Upper Mississippi River Valleys. Waterbirds 34: 160-167.


Most studies of the King Rail (Rallus elegans) have investigated habitat use during the nesting season, while few comparisons have been made between the nesting and brood-rearing seasons. King Rails were located during the nesting season in Missouri using repeated surveys with call playback, and systematic searches for broods were conducted during the brood-rearing season. King Rail adults were located at 12 survey points in 2006 and 14 points in 2007, and five King Rail broods were located each year. Water depth was measured and dominant cover type was determined for randomly sampled 5-m plots within used and unused habitats. Logistic regression models were fit to the data and top models were selected from the candidate set using AICc. Nesting adults occurred more often in areas dominated by short (≤1 m) emergent vegetation (β ̂ = 0.77±0.27) and deeper water ((β ) ̂= 0.05±0.02). Broods occurred more often in areas dominated by short emergent vegetation (β ̂ = 1.19±0.37) and shallow water (β ̂ = – 0.17±0.06), and less often in areas dominated by tall (>1 m) emergent vegetation (β ̂ = – 1.15±0.45). A modified catch-curve analysis was used to estimate chick daily survival rates during selected 7-day periods for each year. Daily survival rate ranged from 0.92±0.008 in late June 2007 to 0.96±0.005 in late July 2006. Management plans for King Rails should include the different habitat types needed during the nesting and brood-rearing stages. Additional studies on the sources of brood mortality are needed to provide further wetland management improvements.