The ecology of blue-crowned manakins (Lepidothrix coronata): a comparison study of biometric sexing using discriminant analyses

Blue-crowned manakins (Lepidothrix coronata) exhibit neotenic retention of subadult monomorphic plumage in sexually mature males. Definitively plumaged adult L. coronata are dichromatic, with males displaying a black body and blue crown while females retain green colouration characteristic of Pipridae species. Male neoteny and the reliance on soft tissue colouration to identify females make mature monomorphic L. coronata indistinguishable in the field, presenting research and management difficulties. The application of biometric measurements with discriminant function analysis (DFA) offers a practical methodology to sex L. coronata. Three DFA methods were compared using L. coronata of definitive plumage and known sex to determine the best modelling methodology for future applications. A linear discriminant analysis was performed using biometric measurements and combined with a principal component analyses. Quadratic discriminant analysis was performed using biometric measurements as a comparison to linear methodologies. Linear and quadratic discriminant analyses of biometric measurements produce a 92.86 and 91.2 per cent accuracy sexing definitively plumaged L. coronata, indicating applicability of statistical modelling as a potential solution for future field applications

Lek dynamics and range-wide morphometric patterns of lesser prairie-chickens

Doctor of PhilosophyDivision of BiologyDavid A. HaukosThe lesser prairie-chicken (Tympanuchus pallidicinctus) is a lek-breeding prairie-grouse of the Southern Great Plains. The lesser prairie-chicken range spans four ecoregions with an east-west precipitation gradient and is subject to severe droughts on a 5-10 year cycle. The influence of the range-wide precipitation gradient and severe drought cycle on lesser prairie-chicken morphology is unknown and a range-wide morphometric compilation has never been assembled. The lesser prairie-chicken population booms and busts in response to drought and estimates of population trends are made from counts of displaying males on leks. Despite the conservation importance of leks, there are many untested assumptions about how leks form on the landscape and what factors determine their persistence into subsequent breeding seasons. My dissertation seeks to fill these knowledge gaps, by (1) assembling a range-wide synthesis of lesser prairie-chicken morphometrics data, (2) determining severe weather influences on morphometric traits, (3) test the hotspot hypothesis as an explanation for lek formation, (4) determine factors that influence lek persistence and (5) evaluate lek formation and persistence findings in translocated population that has no existing lek complex. I assembled a range-wide data set of (n = 2,048) lesser prairie-chicken morphometrics from the period of 1986 to 2019 and compared among ecoregions and weather conditions based on the Palmer Drought Severity Index. Lesser prairie-chicken morphometric traits are largest in the Short-Grass and Sand Shinnery Oak Prairies and smaller in in the Mixed-Grass and Sand Sagebrush Prairies. Morphometric changes following years of extreme weather are universal across ecoregions, where adult female traits remain unaffected and male sexually selected traits increase in size after extreme weather. Incredibly, lesser prairie-chicken body fat during spring lekking is tightly constrained by sex with males exhibiting 2-3% body fat, whereas females exhibited 4-8% across all weather conditions. I tested the hotspot hypothesis, which posits that leks should form in areas where males are most likely to encounter females, and anthropogenic and female movement data as determinants of lek persistence in the Short-Grass Prairie/CRP Mosaic and Mixed-Grass Prairie ecoregions of Kansas with 143 GSP-backpacked females from 2013-2016 and 53 individual leks. As a lek-breeding species, lesser prairie-chicken females are solely responsible for incubating their nest and raising broods, which creates a sexually driven difference in space and habitat use that is reflected in both the formation and persistence of leks on the landscape. I found that lesser prairie-chicken lek dynamics are driven by female habitat constraints, where increased female space use and number of nest sites starting at a 5 km scale (F₅,₇₈ = 2.50, P = 0.04) determines the number of males displaying at leks and concentrations of female spatial use determines where new leks form on the landscape. I then compared patterns of established lek complexes to the dynamics of lek formation and persistence in the translocation of lesser prairie-chickens (n = 411) to the Sand Sagebrush Prairie Ecoregion in 2016-2019. The formation and persistence of leks by translocated birds is also driven by female space utilization, where the location of newly formed leks comprised of translocated birds can be explained by female nesting attempts and space use and the persistence and stability of translocation leks can be explained by multiyear nesting efforts by females starting at a 5 km buffer (F₄,₂₁ = 6.57, P = 0.01). My research offers an explanation for the spatial-temporal dynamics of lek formation and persistence on the landscape and provides means to use morphometrics to evaluate weather stressors and resource allocation in lesser prairie-chickens

Lesser prairie‐chicken dispersal after translocation: Implications for restoration and population connectivity

Abstract Conservation translocations are frequently inhibited by extensive dispersal after release, which can expose animals to dispersal‐related mortality or Allee effects due to a lack of nearby conspecifics. However, translocation‐induced dispersals also provide opportunities to study how animals move across a novel landscape, and how their movements are influenced by landscape configuration and anthropogenic features. Translocation among populations is considered a potential conservation strategy for lesser prairie‐chickens (Tympanuchus pallidicinctus). We determined the influence of release area on dispersal frequency by translocated lesser prairie‐chickens and measured how lesser prairie‐chickens move through grassland landscapes through avoidance of anthropogenic features during their dispersal movements. We translocated 411 lesser prairie‐chickens from northwest Kansas to southeastern Colorado and southwestern Kansas in 2016–2019. We used satellite GPS transmitters to track 115 lesser prairie‐chickens throughout their post‐release dispersal movements. We found that almost all lesser prairie‐chickens that survived from their spring release date until June undergo post‐translocation dispersal, and there was little variation in dispersal frequency by release area (96% of all tracked birds, 100% in Baca County, Colorado, 94% in Morton County, Kansas, n = 55). Dispersal movements (male: 103 ± 73 km, female: 175 ± 108 km, n = 62) led to diffusion across landscapes, with 69% of birds settling >5 km from their release site. During dispersal movements, translocated lesser prairie‐chickens usually travel by a single 3.75 ± 4.95 km dispersal flight per day, selecting for steps that end far from roads and in Conservation Reserve Program (CRP) grasslands. Due to this “stepping stone” method of transit, landscape connectivity is optimized when <5 km separates grassland patches on the landscape. Future persistence of lesser prairie‐chicken populations can be aided through conservation of habitat and strategic placement of CRP to maximize habitat connectivity. Dispersal rates suggest that translocation is better suited to objectives for regional, rather than site‐specific, population augmentation for this species