If it's big enough and leafy enough the birds will come

A new study from the Cornell Lab of Ornithology highlights specific features of urban green spaces that support the greatest diversity of bird species. The findings were published today in the journal Landscape and Urban Planning.

The study focuses specifically on parks in New York City. It uses observations submitted to the eBird citizen-science database from 2002 through 2019 to estimate the variety of species found on an annual and seasonal basis.

Bottom line: the more green space available, the greater the diversity of birds. Models show that Increasing the area of green space by 50% would result in an 11.5% increase in annual and an 8.2% increase in seasonal species diversity.

Trees are also important, particularly for migratory species during spring when models show a 50% increase in canopy cover would result in a 23.3% increase in species diversity.

"Our findings emphasize the broad importance of area and the value of tree canopy cover for spring migrants," said lead author Frank La Sorte at the Cornell Lab. "It also shows that ecological data from citizen scientists can be useful in urban planning and management."