Murder on the Move: UW Bothell Crow Roost Taking Flight

Crow flock at sunset | Win Yuu | Canva

This article was originally published in the print version of the Fall 2024 issue of EarthCare Northwest. Special thanks to Dr. Douglas Wacker, UW Bothell Associate Professor, for his insights on local crow behavior.

by Carol Roll

If you glimpse skyward an hour before dusk, like clockwork, you will start to see clusters and sometimes even steady streams of American Crows all flying in the same direction. Our area is home to one of the nation’s largest flocks (also known as a murder) of crows. The North Creek Wetland, part of the UW Bothell campus,
hosts as many as 16,000 individual crows each night. Renton also hosts a large nightly roost and there may be a third large flock joining the list of local crow hot-spots.

Roosts, or groups of birds all sleeping together at night, provide birds with safety including physical safety from predators and warning communications if there is a disturbance. Late fall and winter are the best seasons to see our murders in all their cawing and squawking glory. First, the cottonwood and willow trees they perch in lose their leaves, making the sheer number of crows more visible. Second, the number of birds flocking together is significantly bigger in the fall and winter. Many crows spend spring and early summer away from their flocks to build individual nests and care for their young.

Despite their nighly routine, there is one curious change in the roosting behavior of the UW Bothell flock of late. A portion seems to be moving, sparking the interest of many crow fans and corvid researchers in the area. Last winter, as part of the annual Audubon Christimas Bird Count, as many as 8,000 crows werewitnessed flying past their usual Bothell roost to a newly restored wetland at Sixty Acres in Redmond. Scientists believe that this is a natural occurrence, but there is no scientific record of a similar roost move, so much remains to observe and speculate about. Some potential reasons include recent construction on the UW Bothell campus, overcrowding among the crows themselves, or the influx of large numbers of Cackling Geese now sharing the wetland. Another theory is the trees have grown taller and may no longer be the crow’s “ideal” habitat in comparison to the smaller trees from more recent restoration work at the Redmond site. One can only guess at the reasons why these highly intelligent and social birds have started to explore a new roost for their nightly meet up, but it will be interesting to see what behaviors emerge next.

More on Crows

Visit the Birds Connect Seattle calendar for upcoming opportunities to visit the Bothell or Renton crow roosts or other crow-related classes and events. 

To learn more abou the UW Bothell crow roost visit: https://www.uwb.edu/about/crows