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Age‐Specific Survival and Probable Causes of Mortality in Female Lesser Prairie‐Chickens
Author(s) -
HAGEN CHRISTIAN A.,
PITMAN JAMES C.,
SANDERCOCK BRETT K.,
ROBEL ROBERT J.,
APPLEGATE ROGER D.
Publication year - 2007
Publication title -
the journal of wildlife management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.94
H-Index - 111
eISSN - 1937-2817
pISSN - 0022-541X
DOI - 10.2193/2005-778
Subject(s) - brood , demography , population , biology , ecology , sociology
ABSTRACT Long‐term population declines and habitat reductions have increased concern over the status of the lesser prairie‐chicken ( Tympanuchus pallidicinctus ). Robust estimates of demographic parameters are essential for identifying population declines and planning effective management. We evaluated the effects of age and season on the survival of female lesser prairie‐chickens at 2 sites in southwestern Kansas, USA. Using telemetry data from a 7‐year field study (from 1997 to 2003), we estimated seasonal (Apr—Sep) and annual (Apr—Mar) survival. We also examined daily survival rates of females attending nests during the 26‐day incubation period and young during the 14‐day early brood‐rearing period. We evaluated the probable mortality causes of radiomarked birds by examining evidence at recovery sites. We captured 227 female lesser prairie‐chickens (87 yearlings, 117 ad, and 23 age undetermined) and fitted them with radiotransmitters. Estimates of 12‐month survival were lower among yearlings (Ŝ 12 = 0.429, SE = 0.117) and adults at site I (Ŝ 12 > = 0.302, SE = 0.080) than among yearlings (Ŝ 12 = 0.588, SE = 0.100) and adults at site II (Ŝ 12 > = 0.438, SE = 0.083). The patterns in timing of mortality and age‐specific 6‐month survival were consistent with those of 12‐month estimates at site I from 1998 to 2002, with a peak in mortality during May and June. Females tending to nests or to prefledged chicks had lower daily survival ( DŜR tend = 0.993, SE = 0.001) than females not involved in these activities ( DŜR failedbreeder = 0.997, SE = 0.002). We recorded 92 mortalities from April 1997 to March 2003, and 59% and 11% were attributed to predation by mammals and raptors, respectively. Our research suggests that predation during the nesting season can have a major impact on lesser prairie‐chicken demography, and conservation efforts should focus on enhancing female survival during the nesting and brood‐rearing seasons.