Counting Crows: Documenting Portland's Urban Roost
Start Date
3-17-2025 10:20 AM
End Date
3-17-2025 10:29 AM
Abstract
Communal roosting by American Crows has been documented since the early 1800s with naturalists of the day describing winter roosts numbering in the hundreds of thousands. Roosts large enough to draw the attention of urban residents were rarely described until the 1970s but are now common across North America. The natural history of Portland’s urban crow roost began in early 2013 with the first eBird and media reports. We began documenting Portland's winter roost in November 2017. Since that time we have recorded over 120 detailed censuses and documented a four-fold increase in the number of roosting crows peaking at over 22,000 in January 2024. A paper documenting our methods, data, and findings was published in the Oregon Birding Association's Fall 2023 journal.
Since the beginning of the roost in Portland there have been perceived conflicts between crows and some residents and businesses, with the primary concern being the quantity of droppings produced. To date the human response has been to attempt to force roosting crows away from "high conflict" areas, but our data indicates that these efforts have only short term localized impacts. Understanding why crows prefer specific areas could inform strategies for attracting crows to lower conflict areas. The arrival of crows in downtown Portland each winter night is arguably the single largest urban wildlife phenomenon in the city. Our goal is to prompt a broader research effort to eventually shift from a strategy of blunt force to one of informed enticement.
Subjects
Animal ecology, Environmental policy, Wildlife biology
Persistent Identifier
https://archives.pdx.edu/ds/psu/43075
Creative Commons License
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License.
Counting Crows: Documenting Portland's Urban Roost
Communal roosting by American Crows has been documented since the early 1800s with naturalists of the day describing winter roosts numbering in the hundreds of thousands. Roosts large enough to draw the attention of urban residents were rarely described until the 1970s but are now common across North America. The natural history of Portland’s urban crow roost began in early 2013 with the first eBird and media reports. We began documenting Portland's winter roost in November 2017. Since that time we have recorded over 120 detailed censuses and documented a four-fold increase in the number of roosting crows peaking at over 22,000 in January 2024. A paper documenting our methods, data, and findings was published in the Oregon Birding Association's Fall 2023 journal.
Since the beginning of the roost in Portland there have been perceived conflicts between crows and some residents and businesses, with the primary concern being the quantity of droppings produced. To date the human response has been to attempt to force roosting crows away from "high conflict" areas, but our data indicates that these efforts have only short term localized impacts. Understanding why crows prefer specific areas could inform strategies for attracting crows to lower conflict areas. The arrival of crows in downtown Portland each winter night is arguably the single largest urban wildlife phenomenon in the city. Our goal is to prompt a broader research effort to eventually shift from a strategy of blunt force to one of informed enticement.
