Metabarcoding-based dietary analysis of hen harrier (Circus cyaneus) in Great Britain using buccal swabs from chicks

Abstract

The hen harrier is a heavily persecuted bird of prey in Great Britain since its diet includes Red grouse, a game bird shot in driven and walked-up grouse shooting. Unlike walked-up shooting where shooters walk up moors and flush grouse with dogs, in driven grouse shooting the grouse are driven by beaters towards static shooters. Driven grouse moors (DGMs) are increasingly being managed to sustain high densities of Red grouse intensifying a long-standing conservation conflict between conservationists and grouse moor keepers. A metabarcoding approach was used with degenerate universal cytochrome oxidase I and cytochrome b primers along with hen harrier blocking primers. A novel sampling method was used to detect prey in buccal swab samples from chicks from broods across Great Britain from both managed and unmanaged moorland habitats. This resulted in detection of 62 species of prey across 51 broods with Meadow pipit, Red grouse, Wren, Skylark, and voles being most frequently detected. Frequency of occurrence data and species accumulation curves reveal high incidence of Red grouse and low prey species richness in the diet of hen harriers in DGMs but low incidence of Red grouse and high prey species richness in walked-up and unmanaged moors. Waders were only detected within walked-up and unmanaged moors and not within DGMs where they have been reported to occur at high densities. Regional species detected included endemic species such as the Orkney vole seen only in Orkney. This study represents the first metabarcoding-based dietary analysis in a raptor using buccal swabs.

Whose Kids Did You Eat? Genetic Identification of Species and Parents of Larval Lampreys in Fish Predator Guts

“…Recently, DNA metabarcoding of gut contents was used qualitatively to characterize species composition of the diet of Arctic Lamprey Lethenteron camtschaticum in 556 the ocean (Shink et al 2019), and this same technology could potentially be useful in detecting consumed larvae in the guts of lamprey predators. Use of DNA metabarcoding on homogenized and digested feces and/or buccal swabs has also been shown to be effective in assessing the vertebrate and invertebrate diet profiles of not only fish predators (Guillerault et al 2017;Kumari et al 2019) but also avian (Nota et al 2019;Sow et al 2020) and mammal predators (Deagle et al 2009;Gillet et al 2015). However, some challenges still remain with these molecular techniques (Amundsen and Sanchez-Hernandez 2019).…”

Strategies for sample labelling and library preparation in DNA metabarcoding studies

“…Therefore, discussions regarding labelling strategies in the present article are largely applicable to metabarcoding on these other platforms. For example, the one‐step (Schnell et al, 2018 ) and the two‐step PCR approach (Braukmann et al, 2019 ; Nota et al, 2019 ) have been used on the Ion Torrent platform, and the tagged PCR approach has been used on BGI's MGISEQ platform (Yang et al, 2020 ). Further, third generation technologies yielding long reads have been employed in metabarcoding; Pacific Biosciences (PacBio) (James et al, 2016 ; Tedersoo et al, 2018 ) and the portable Oxford Nanopore Technologies MinION sequencer (Karst et al, 2021 ).…”

Metabarcoding of fecal DNA reveals the broad and flexible diet of a globally endangered bird

“…For natural bird populations, it is challenging to accurately and efficiently characterize the complex composition of diets ( Gong et al 2017 ; Nota et al 2019 ). Owing to their elusive predatory behavior and versatile feeding habits, direct field observations of prey or food capture are not possible ( Jedlicka et al 2017 ; Trevelline et al 2018 ).…”