For the second year in a row, killdeer are nesting on the ecoroof atop the Walmart store at Delta Park.

Killdeer are a relatively common native bird species and have been observed using several ecoroofs in Portland. They are a ground-nesting shorebird that prefer wide-open spaces. The young birds can run before they can fly, so they need nearby water sources to survive – something that isn’t typically available on rooftops in the summer. 

Walmart’s ecoroof, completed in 2013, is the largest ecoroof in Portland. The roof measures 37,000 square feet and manages stormwater before it hits the ground and turns into runoff to the Columbia Slough.    

Besides reducing stormwater runoff, the roof was created with ground-nesting birds like killdeer in mind. It includes habitat elements like permanent water features that collect condensate from air conditioners, and patches of woody debris and rock piles that increase the diversity of insects and simulate more natural ground-level habitats.

Environmental Services monitors stormwater runoff from this roof to learn how ecoroofs on warehouse-type buildings perform compared to the smaller ecoroofs that we’ve traditionally monitored. Portland State University also monitors this unique roof for research about ecoroof design and pollution retention, air quality and other issues.

Photo credit T. Liptan