Causes of mortality and temporal patterns in breeding season survival of lesser prairie‐chickens in shinnery oak prairies

Abstract

Baseline survival and mortality data for lesser prairie-chickens (Tympanuchus pallidicinctus) are lacking for shinnery oak (Quercus havardii) prairies. An understanding of the causes and timing of mortalities and breeding season survival in this ecoregion is important because shinnery oak prairies have hotter and drier environmental conditions, as well as different predator communities compared with the northern distribution of the species. The need for this information has become more pressing given the recent listing of the species as threatened under the U.S. Endangered Species Act. We investigated causes of mortality and survival of lesser prairie-chickens during the 6-month breeding season (1 Mar-31 Aug) of 2008-2011 on the Texas Southern High Plains, USA. We recorded 42 deaths of radiotagged individuals, and our results indicated female mortalities were proportionate among avian and mammalian predation and other causes of mortality but survival was constant throughout the 6-month breeding season. Male mortalities were constant across avian and mammalian predation and other causes, but more mortalities occurred in June compared with other months. Male survival also varied by month, and survival probabilities were lower in June-August. We found predation on leks was rare, mortalities from fence collisions were rare, female survival did not decrease during incubation or brood-rearing, and survival was influenced by drought. Our study corroborated recent studies that suggested lesser prairie-chickens are living at the edge of their physiological tolerances to environmental conditions in shinnery oak prairies. As such, lesser prairie-chickens in our study experienced different patterns of mortality and survival that we attributed to hot, dry conditions during the breeding season. Specifically, and converse to other studies on lesser prairie-chicken survival and mortality, drought positively influenced female survival because females did not incubate eggs during drought conditions; the incubation period is when females are most vulnerable to predation. Male mortalities and survival were negatively influenced by drought later in the breeding season, which we attributed to rigorous lekking activities through late May combined with lack of food and cover as the breeding season progressed into summer. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Long-term lesser prairie-chicken nest ecology in response to grassland management

“…This trade‐off between cover and escape from predators is demonstrated by Haukos and Smith () who reported females in shinnery oak habitats in Texas selected nest sites with 50% overhead cover. Further, cover at the nest bowl may change through the nesting season as predation threat shifts from raptors (Behney et al , ) to mammals (Hagen et al , Wolfe et al , Grisham and Boal ).…”

Temporal Variation in Breeding Season Survival and Cause-Specific Mortality of Lesser Prairie-Chickens

“…Nest success, brood survival, and adult female survival are often cited as the most important vital rates when considering the persistence of bird populations with a high reproductive capacity (i.e., large clutch sizes; Saether and Bakke 2000;Hoekman et al 2002;Moynahan et al 2007;Hagen et al 2009). Only a small number of studies have estimated survival rates of lesser prairie-chickens in eastern New Mexico and West Texas (Haukos et al 1989;Patten et al 2005;Wolfe et al 2007;Leonard 2008;Pirius 2011;Grisham and Boal 2015). In the time between these studies, this region experienced an extended period (4 y; 2009-2013) of drought that began to subside in 2014 (Grisham and Boal 2015;Strong 2016).…”

“…Only a small number of studies have estimated survival rates of lesser prairie-chickens in eastern New Mexico and West Texas (Haukos et al 1989;Patten et al 2005;Wolfe et al 2007;Leonard 2008;Pirius 2011;Grisham and Boal 2015). In the time between these studies, this region experienced an extended period (4 y; 2009-2013) of drought that began to subside in 2014 (Grisham and Boal 2015;Strong 2016). This drought contributed to continued declines of lesser prairiechicken populations in the region (Grisham and Boal 2015;McDonald et al 2016).…”

The relative contribution of climate to changes in lesser prairie‐chicken abundance

“…Additionally, weather conditions in the Great Plains can cause decreases in important population demographic parameters such as reproduction (Grisham et al. , Grisham and Boal ) or juvenile (Pitman et al. ) and adult survival (Plumb ).…”

“…The effects of climate may be intensified through agricultural practices in the region (Stohlgren et al 1998), which are projected to increase in the future (Sohl et al 2012). Additionally, weather conditions in the Great Plains can cause decreases in important population demographic parameters such as reproduction (Grisham et al 2013, Grisham andBoal 2015) or juvenile (Pitman et al 2006) and adult survival (Plumb 2015). Many avian species endemic to the Great Plains region are decreasing in response to changes in climate (Peterson 2003), which may be affected by a decoupling of food availability (e.g., insect abundance) and brood rearing (Pitman et al 2006).…”