Population productivity and late breeding habitat selection by the threatened Little Bustard: the importance of grassland management

Abstract

SummaryWe investigated population productivity and habitat selection of the Little Bustard Tetrax tetrax in the late breeding period, in grassland-dominated landscapes of south-west Iberia. Specifically, our goals were to investigate how these parameters are influenced by the management of (1) grazing and (2) hay production. We conducted bird counts from 22 June to 4 July (2012 to 2016) using low speed 4x4 car surveys. The relationship between the density of the species, population productivity and farm management (grazing and haying) was evaluated using Generalized Linear Mixed Models and Kruskal-Wallis tests. Male and female densities were significantly higher in short vegetation compared to all other types of vegetation considered, but population productivity was similar in short and medium vegetation. Hay stubbles were found to be unattractive for the species. The availability of suitable habitats depends on the timing of grazing, notably of seasonal (spring) grazing. Species density was higher in fields ungrazed during winter and with moderate to high stocking rates in spring (around 0.8 LU/ha or higher), depending, at least for males and females, on each year’s weather characteristics. We conclude that low to moderate stocking rates during winter and spring are essential to ensure successful breeding and thus population persistence. Current levels of haying in our study area are detrimental for the species’ conservation.

Biased adult sex ratios in Western Europe populations of Little BustardTetrax tetraxas a potential warning signal of unbalanced mortalities

“…Nevertheless, the small number of young individuals recorded in non-breeding flocks is consistent with the low productivity (i.e. number of fledglings per female) reported in some of our study areas (Lapiedra et al 2011, Morales et al 2008a, Tarjuelo et al 2013, Cuscó et al 2020, Faria and Morales 2018.…”

Temporal trends of land-use favourability for the strongly declining little bustard: assessing the role of protected areas

“…A 250 m buffer has been used in previous little bustard studies and represents the radius where detectability of the species is highest ( e.g. , García de la Morena et al, 2018 ; Faria & Morales, 2018 ).…”

Can current farmland landscapes feed declining steppe birds? Evaluating arthropod abundance for the endangered little bustard (Tetrax tetrax) in cereal farmland during the chick‐rearing period: Variations between habitats and localities

“…However, females are extremely shy and hardly detectable prior to hatching (García de la Morena et al., 2018). Surveys were done during the two hours following sunrise or preceding sunset, coinciding with little bustard activity peaks (see Faria & Morales, 2018; Morales et al., 2008; Tarjuelo et al., 2013 for similar methodology). The number of stops varied between the study sites according to their extension and the potential habitat for the species.…”