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Tracking the long-term decline and recovery of an isolated populationWESTEMEIER, R. L; BRAWN, J. D; SIMPSON, S. A et al.Science (Washington, D.C.). 1998, Vol 282, Num 5394, pp 1695-1698, issn 0036-8075Article

Nocturnal singing in grassland birdsWALK, J. W; KERSHNER, E. L; WARNER, R. E et al.The Wilson bulletin (Wilson Ornithological Society). 2000, Vol 112, Num 2, pp 289-292, issn 0043-5643Article

Continuous nesting of Barn Owls in IllinoisWALK, J. W; ESKER, T. L; SIMPSON, S. A et al.The Wilson bulletin (Wilson Ornithological Society). 1999, Vol 111, Num 4, pp 572-573, issn 0043-5643Article