Pesky crows

ORRINGTON – A regular visitor, a knowledgeable and enthusiastic hawk-watcher, came into the Fields Pond Audubon Center this week and said he heard a lot of crows nearby. He stopped to see what the crow ruckus was about. It was a red-tailed hawk!

The same day, another crow riot was heard from the center. Their “caws” were fast and sounded like they were about something urgent. We ran outside and saw about 50 crows chasing two eagles!

A neighbor heard another crow ruckus the next day. Crows were all cawing toward a dense pine tree. The source of their excitement could not be seen amongst the pine branches. But a great horned owl had been hooting every night from 3 to 5 a.m. We surmise the crow riot was about the owl because eagles and red-tailed hawks don’t usually hide inside pine trees during the day.

Why risk it?

Rarely, a great horned owl has been seen grabbing a crow with its talons in the midst of a crow riot. Why do crows take the risk? It may alert other crows of the danger, reducing the element of surprise that predators usually rely on. Or it may teach young crows who the dangerous predators are.

This past summer, Bangor ornithologist Jessica Yorzinski showed children in our nature camp a demonstration of “mobbing,” the term used for this behavior. Children helped her set up a stuffed owl in the field. They walked out together and returned under a dark sheet so birds wouldn’t see that the owl was set up by people. Not only crows but also tree swallows and red-winged blackbirds mobbed the owl, quite a sight. Children learned how to record this behavior. Yorzinski will publish results of her study of mobbing in a biology periodical.

Smart crows

This week, at last we had our fields mowed. We always mow late to avoid harming nesting birds like bobolinks and savannah sparrows and butterflies like monarchs and our rare (in Maine) Baltimores. But not this late! The wet ground this fall put it off even longer than usual.

The mowing drew in a flock of crows. We wondered what food they were finding in the newly mowed field. A quick survey turned up cranberries in the wet areas, and meadow mice nests and tunnels in the drier areas – not a bad diet for the crows, with protein, carbs, and vitamin C!

Send sightings, comments, or questions to fieldspond@maineaudubon.org