The Northern Goshawk

While driving home from work today, a bird flew across the Wolf Ridge driveway. It's coloration and flight pattern were unfamiliar to me (and I've become pretty familiar with our resident, winter birds). Based on size and wing flaps, I quickly hypothesized that this was a Norther goshawk. There have been a few potential goshawk sightings in the past month, which is what motivated my theory. It's pretty fitting because tomorrow, I'll be assisting with our first round of goshawk surveys, an annual survey that takes place all across Northern Minnesota. Wolf Ridge has participated in various capacities over the years, but the DNR is especially encouraging wide-spread participation this year because of fear of a declining population.

A Northern goshawk in flight.

The Northern goshawk is the largest of the North American accipiters, a family of hawks that are best identified by their distinctive flight pattern: flap-flap-flap-glide. Other accipiters include the cooper's hawk and the sharp-shinned hawk. The name "goshawk" originated as a shortening of its colloquial name, the "goose hawk" (or sometimes "grouse hawk"). When used in falconry, goshawks were famous for their ability to hunt larger birds, sometimes as big as cranes.

The first part of the goshawk survey involves simply identifying if goshawks are present at Wolf Ridge. Tomorrow, Tom and I will hike an area where sightings have happened in the past with a megaphone connected to an ipod in hand. We'll project a goshawk call through the woods to see if we can get the attention of any resident goshawks. If we do identify the presence of goshawks, we will then be searching for a nest, a task for which we will don helmets to protect ourselves from attacking raptors, as goshawks are known for their fierce protection of nests. If a nest is identified, we will closely monitor the nest while keeping a respectful distance so as not to disturb the birds.

A juvenile Northern goshawk (left) with brown plumage next to an adult (right) in gray.

We'll be able to identify adult Northern goshawks by their silver-gray back, fine-gray barring on the front, and distinctive stripe of white just above the eye. As an accipiter, it has short, broad wings, which help it to maneuver through dense woodlands when ambushing prey, typically large birds, squirrels, rabbits, and hares. Minnesota goshawks rely primarily on ruffed grouse and snowshoe hare for food. Northern goshawks are known to be quite persistent when it comes to hunting prey: there is an account of one goshawk following a snowshoe hare for more than 45 minutes before the hare finally came out into a clearing where it was immediately grabbed by its pursuant.

In the 19th century, goshawks in the United Kingdom and Ireland were almost entirely wiped out, having been targeted by gamekeepers. Thanks to a concerted effort, the European populations have since bounced back. Goshawk populations don't seem to be as affected negatively by chemical pesticide poisoning as other bird species. Today, the biggest threat to goshawk populations, both locally and internationally, is habitat loss. They rely on forests and woodlands for hunting and nesting, a habitat we humans are continuously destroying. There have been multiple efforts in the past to get the US Fish and Wildlife Service to list this bird as "endangered" or "threatened" because of damage to nesting territory, old growth and mature forests. While not successful, these efforts motivated the implementation of a number of goshawk surveys nationwide, including the one that I will be partaking in this spring.