Understanding the role diet plays in the structure of food webs is
vital, and dietary knowledge is key for conservation management success.
There is limited knowledge of the diets of woodland bird species, due
largely to difficulties in accurately identifying plant and invertebrate
taxa being consumed. Here, we show the effectiveness of multi-marker
faecal metabarcoding to provide the most in-depth dietary analysis of a
generalist passerine, the Hawfinch (Coccothraustes coccothraustes,
Linnaeus), to date. Faecal samples were obtained from 2016-2019 from
Hawfinch populations prior to and during the breeding season throughout
the UK. DNA was extracted from 263 samples and amplified using Internal
Transcribed Spacer 2 (ITS2) and cytochrome C oxidase subunit I (COI)
barcodes. Using high-throughput sequencing (HTS), we identified 49 and
97 ITS2 and COI zero radius operational taxonomic units (zOTUs)
respectively which equated to reputed dietary items. The herbivorous
element of Hawfinch diet was dominated by naturally occurring taxa such
as beech (Fagus sylvatica, Linnaeus), hornbeam (Carpinus betulus,
Linnaeus) and oak (Quercus sp., Linnaeus). The most taxon rich and
commonly recorded invertebrate taxon identified was Lepidoptera. We
found Hawfinch diet varied spatially, as well as between sexes. Hawfinch
showed broad dietary plasticity and utilised multiple resources within
their foraging environments. Our study shows the potential of
multi-marker DNA metabarcoding to reveal subtle dietary differences, but
also highlights the challenges of studying omnivorous species using
metabarcoding methods.
Using multi-marker DNA metabarcoding to reveal the diet of a scarce woodland bird
