Relative use of municipal street trees by birds during summer in state college, Pennsylvania

Relationships between street-tree characteristics, including habitat features, and use by urban birds were investigated from May to July 1980 in State College, Pennsylvania. Bird presence or absence was sampled in 1278 individual street trees of 24 species. Log-linear analysis of tree species, height class and bird occurence determined that pin oak (Quercus palustris), American elm (Ulmus americana) and honeylocust (Gleditsia triacanthos var. inermis) were used more frequently by birds (P<0.05), and there was a linear relationship between height class and bird occurrence. Relative use of tree species by a group of three exotic bird species was highly correlated with that of the remaining native bird species (P<0.01). Logistic-regression analyses of bird occurrence on 10 habitat variables and tree characteristics showed that tall street trees located in areas with little other deciduous tree cover were more attractive to both the native and exotic bird groups (P<0.05). In addition, native birds were observed more often in trees planted in residential areas with little vehicular traffic, whereas exotic birds were more frequent in business areas with greater traffic volume. Because of the interest in bird watching among urban residents, municipal arborists should be aware that street trees may differin their attractiveness to birds.