Notes From Minneapolis

From Twin Cities Naturalist,

Crows coming into cities to roost in massive numbers in the winter is a relatively new phenomenon that started in the 1960s and increased each decade. There are now many massive crow roosts around the country with populations in the tens of thousands each. Crows have always roosted together at night but it is presumed that as cities expanded, they overtook the historical roost sites that were outside the city. Crows historically avoided people but some of these birds learned that there are advantages to being in the city at night and have learned new behaviors. Crows are amongst the most intelligent birds. There’s also some evolutionary selective pressure going on here. The crows that overcame their fear of humans have prospered and multiplied because of the advantages of roosting in the city while those more timid crows have not been as successful and thus not passed on their timid genes.

Loring Park on the edge of downtown Minneapolis is a great example of why these roosts are successful and advantageous. First off, the park is well lit. The biggest enemy to roosting crows is the Great Horned Owl. The owls will come into a roost at night and pluck the sleeping birds out of the trees. Owls are less common in urban areas. No matter where birds roost there is safety in numbers but there is also safety in lighting. The park is lit up at night for human’s safety but it makes the crows safer as well as they can see Great Horned Owls better.  (Read more.)