Many large building projects in Portland will now have to comply with design requirements intended to prevent bird collisions.
Under an ordinance passed this week, new developments or additions of more than 10,000 square feet will need to meet such "bird-friendly" requirements.
Advocates say the changes will help to reduce bird strikes and mortality throughout the city. Christine Maher, a biology professor at the University of Southern Maine, said a group of volunteers has monitored for dead and stunned birds along a loop in the city's Old Port over the past four years. Maher said the strikes were largely clustered near a small number of buildings.
"And those buildings all share key features. They have a lot of glass. They have proximity to habitat that attracts birds. And proximity to the waterfront, which birds are likely following on their migration," Maher said. "So using published data, our data, and the square footage of buildings of various types in the city, we estimated that 40,000 to 50,000 birds strike buildings every year, just in Portland."
Parts of a building's façade, as well as select other architectural features, such as skywalks or glass railings, now must be constructed of bird friendly materials, defined as materials or assemblies that have a "maximum threat factor of 30" according to certain groups, such as the American Bird Conservancy. Proponents said some of those design measures could include screening, avoiding reflective surfaces and using many smaller windows instead of single large panes.
Austin Smith, a principal at Simons Architects, said that there are several ways to make a building and its windows "bird-friendly."
"There are many ways to achieve this. It doesn't have to be all with glazing," Smith said. "Creative uses of screens, louvres, second facades, also accomplish this. And often you can achieve a higher energy performance with these measures, as well."
But Eamonn Dundon, with the Greater Portland Chamber of Commerce, questioned some of the advocates' data around bird strikes, and says the rules would add even more expenses for developers.
"Because it makes Portland a more expensive place to do business. And more importantly, it is not founded in the science that some of the proponents claim make such a requirement necessary," Dundon said.
Large, existing buildings will also have to follow the requirements, if they replace at least half of their exterior glazing over three years. Residential buildings are exempted.
