The City of Portland has adopted policies for bird-friendly building design and practices as part of the City’s updated Green Building Policy #37122. These policies, adopted in April 2015, are applicable to development projects completed for the City of Portland.
I’ll cover the remainder of the green building policies in another post, but here is a summary of the background and considerations which led to the development of the bird-friendly resources. First, some fast facts on birds in the City of Portland:
The City of Portland's official bird is the Great Blue Heron
There are over 200 species that regularly call Portland their home, some of which are on watch lists for low population count
Birds are good for tourism: Over 41 billion dollars is spent on bird watching (2011 data from the US Fish and Wildlife Services report).
Bird strikes count for over 1 billion bird deaths annually in the US—one of the top three including habitat reduction and housecats. Dead birds are not often seen/found due to predators, architectural elements and vegetation.
The City of Portland was only a handful of cities to adopt an Urban Conservation Treaty for Migratory Birds (USFWS) in 2003 responding to the diversity of birds in the region and their importance within the city’s ecosystem.
The City of Portland adopted a Bird Agenda in 2011 and held a Design Summit in 2012.
The most recent effort is the development of a Resource Guide for Bird-friendly Building Design developed in partnership with the Audubon Society, US Fish and Wildlife and the American Bird Conservancy.
Buildings can be dangerous for birds: During the day, panels of unmarked glass walls create reflections of trees and sky that birds cannot recognize as walls. Other transparencies, like glass railings at corners and skybridges also trick birds. Eco-roofs do a great job of attracting birds and providing resting places, but adjacent glass walls can confuse birds. In the evening, the amount of artificial light can also affect bird migration patterns and fool birds into thinking its daylight. Bird/building collisions are especially detrimental because they affect healthy/sick, young/old and common/rare bird populations equally.
Luckily, the Resource Guide includes some innovative, bird-friendly elements for use in windows, lighting and other building features to help reduce bird strikes. Following a “2” by 4” rule for windows—marking horizontal elements at a maximum of 2” apart and vertical elements at a maximum of 4” apart can approximate bird dimensions and increase their ability to recognize the area as impassable. Recommendations also include limiting large expanses of glass, using glass frit and other materials to create safer building walls for birds. At night, external lighting can be controlled with full cut off shields to reduce light spill and maintain a night sky.
Additionally, the solutions for addressing bird-friendly design are also synergistic with energy savings and green building measures — with the use of glare control devices, window shading to reduce heat gain and even LEED Pilot credits, Credit #55, Bird Collision Deterrence. At the ground floor, patterned glass can create interesting building branding and privacy, while also keeping a sense of transparency and connection to the street.
Interestingly, the City of Portland’s Mixed Use zones project will increase the amount of required ground floor window area—for more on those proposed standards of this project, see a recent article from this Focal Point blog.
For more information and resources:
· Green Building Policy update (2015) that includes the Bird Friendly checklist used by City of Portland project managers
· City of Portland’s Green Building Program webpage and contacts
· Audubon Society’s Bird Friendly Building Design Toolkit
· Resource Guide for Bird-Friendly Building Design (July 2012)
· Bureau of Environmental Services’ Guidance on Avoiding Impacts on Nesting Birds During Construction and Revegetation Projects (2010)