Coarse‐Scale Online Data Reveal Habitat Similarities but Weak Cross‐Taxa Congruence Between Insectivorous Bats and Birds in the Eastern United States

ABSTRACT Aim Prudent use of cross‐taxa congruence can aid biodiversity conservation by quantitatively evaluating possible indicator taxa. However, highly variable results among spatial extents and study regions present challenges to its practical application. We aim to evaluate insectivorous birds as possible surrogate taxa for bats. Bats are cryptic, understudied, and imperilled animals that may greatly benefit from conservation actions targeted at more easily observable surrogate taxa, should strong congruence exist. Location Temperate and northern forests of the eastern United States. Methods We used 6 years of data from eBird and the North American Bat Monitoring Program (NABat) to explore cross‐taxa congruence and broad‐scale habitat associations between insectivorous birds and bats in eastern North America. We used spatial linear models to evaluate cross‐taxa congruence and community responses to coarse‐scale habitat features. Results Our results indicated weak positive congruence for species richness of bats and birds. We revealed similar strong community responses to forest structure. Birds were more responsive to the distribution of forested habitat in the landscape and forest type. Additional principal component analysis revealed high overlap between cavity‐nesting birds and snag‐roosting bats. Main Conclusions Our results discourage the general use of birds as surrogates for bats in eastern and northern temperate forests. Our eclectically sourced dataset yielded habitat associations that align well with known trends in bat and bird biodiversity, which suggest potential utility of mass‐aggregated online resources for answering broad‐scale ecological questions.