The Downtown Portland Crow Roost
For more than a decade, crows have been gathering to roost in downtown Portland. This roost has been gradually growing over time to the point where today it can exceed 10,000 birds. Scientists believe that crows form winter roosts because there is safety in numbers, the large number of birds provides warmth during the harsher winter months and it allows for exchange of information among the crows. Roosts can occur on both urban and rural landscapes. A variety of factors may attract crows to urban landscapes for roosting including warmer ambient temperatures, food subsidies provided by garbage cans and other accessible food sources, lighting, and reduced predator populations such as Great Horned Owls.
The crows begin roosting in the fall and continue until the late winter. In spring and summer, crows will disperse out across the landscape in smaller family groups to nest and raise young. People are treated to a remarkable wildlife event as crows converge on downtown Portland from all directions in the late afternoon. They will typically congregate in a variety of locations in raucous groups. In certain areas, virtually every tree and ledge can be covered in crows. As darken falls, they will settle into downtown trees for the night. They will typically depart to forage across the landscape before sunrise.
For many years, there have been concerns raised about the large amounts of fecal matter that accumulates in certain areas of downtown, especially high human activity areas such as the transit mall. Portland Audubon generally encourages the community to be tolerant of the wildlife that shares our urban landscape, but where significant conflicts are occurring we work with the community to find humane, ecologically responsible solutions.
Downtown Clean and Safe which is responsible for keeping the downtown core area clean has worked for many years to address challenges associated with accumulation of crow feces in high human traffic areas in an ecologically responsible and humane manner. Initially they focused on cleaning strategies including purchase of the “Poopmaster 6000,” a Zamboni-like device to clean streets and sidewalks. In 2016, they shifted to contracting licensed falconers to haze the birds as they congregate in the evening. We appreciate Downtown Clean and Safe for explicitly stating their commitment to finding humane, non-lethal, ecologically responsible solutions to address the conflicts that are occurring. Notably, Downtown Clean and Safe testified in support of a City of Portland ban on the use of bird poisons that have been used to kill crows in various locations in Portland and elsewhere.
While tolerance and coexistence with wildlife is our preferred strategy, we also recognize in some cases, conflicts do need to be addressed. Part of the reason Portland has become a national leader in urban wildlife conservation is its combination of aggressive programs to protect and promote wildlife and wild habitat and its innovative strategies to proactively resolve wildlife conflicts.
Portland Audubon has endorsed Downtown Clean and Safe’s approach to resolving its concerns. Christmas Bird Count data indicates that American Crow populations have been increasing significantly at a continental, statewide and local scale over recent decades. In Portland they have been increasing at a rate of 2.9% per year over the past 50 years. The Harris Hawks used for hazing have no direct contact with the crows. The hazing is likely to only move the crows a short distance and many crows are likely to remain within the hazing area. They are also likely to return if the hazing is discontinued. The objective is simply to cause enough displacement to alleviate the most intense concentrations of crow feces in downtown areas with the highest levels of human activity. There will still be thousands of crows roosting in downtown Portland and there will still ample opportunity for people to enjoy watching the crows. These type of non-lethal approaches to conflict resolution involving crows are recommended not only by Portland Audubon but also Humane Society of the United States and the US Fish and Wildlife Service.