Cooperative Fish and Wildlife Research Units Program: Vermont
Education, Research and Technical Assistance for Managing Our Natural Resources

Bonter, D. N., T. M. Donovan, E. Brooks. 2008. What are we missing with ground-level mist nets? Using elevated nets at a migration stopover site. Journal of Field Ornithology 79:314-320.


Mist nets deployed in a standard ground-level fashion capture birds approximately 0.5–2.6 m above the ground. In habitats where the vegetation extends above this height, standard mist net deployment may inadequately sample the targeted avian community and age- and sex-classes within species. Such sampling biases may raise questions regarding studies based on data from mist-net captures. To determine if birds were equally likely to be captured by mist nets at different heights, we constructed a series of paired ground-level and elevated mist nets (hereafter "net rigs") at a research station in western New York State. Net rigs were operated during 14 migration seasons from 2000 to 2006 (spring and fall each year), and 19,735 birds of 118 species were captured. Capture rates were significantly higher in ground-level nets, but 12 species were only captured in elevated nets. Of 44 species with at least 50 captures, 25 species were more likely to be captured in the ground-level nets and two species in the elevated nets. For four of 18 species, more birds were captured in the elevated nets during fall migration than during spring migration. We conclude that standard ground-level net placement was more efficient in capturing birds in the secondary growth habitats that we sampled. However, ground-level nets may not adequately sample the entire targeted community or all age- or sex-classes within species.