What is an American Goshawk? Our Role in the Rising Interest in the Species

By Rob Miller, IBO Research Biologist, GIS Specialist

We would like to introduce you to North America’s newest bird species… the American Goshawk (Accipiter atricapillus)!

an extreme closeup of a goshawk's face shows the black and gray patterned face, and fine details including the small feathers around the bird's eyes, the intense bright red eye, strong brow bone, and even some blood around the mouth from his most recent meal. The background shows lodgepole pine forest with an open grassy understory — Five-year-old adult male American Goshawk “Purple BW” (color and code from applied band). This male was originally banded as a nestling in 2018 ~6km away. This year, along with his mate, he successfully fledged 3 young. Sawtooth National Forest, 2023. Photo Credit: Robert Miller

Wait…what? Yes, sort of…

The Taxonomic Split and its Evidence

In July of this year, the American Ornithological Society decided to go along with the overwhelming evidence that most goshawks in North America are not closely related to most goshawks in Europe and Asia, voting to split the Northern Goshawk into the American Goshawk and the Eurasian Goshawk (Accipiter gentilis). The evidence includes plumage, vocalizations, behaviors, and most convincing of all, high resolution genetics.

It was long past time to make the split.

The genetic evidence includes such observations as the Black Goshawk (Accipiter melanoleucus) being more closely related to the American Goshawk than is the Eurasian Goshawk. Also more closely related, three other goshawk species. The three goshawk subspecies in North America have all been moved under the American Goshawk (A. a. atricapillus [most of NA], A. a. apache [AZ and NM], and A. a. laingi [British Columbia]).

Our Role in the Rising Interest

Unrelated to the taxonomic split, IBO’s goshawk programs have been seeing a growth spurt. We have worked with goshawks off and on for 30 years, but more consistently over the past 13 years. We have maintained our core work in the Minidoka Ranger District of the Sawtooth National Forest, but have extended our consulting efforts on the species out to the full Intermountain Region of the Forest Service.

a very large adult female goshawk perched on a branch with a forested background. Her mouth is open, aggressively calling — Advancing the core science for the species, focusing on the breeding and post-breeding ecology. Adult female American Goshawk on territory, South Hills, Idaho. Photo Credit: Robert Miller

In each of the past few years we have extended our habitat modeling expertise out to new forests including the Targhee NF and the Uinta-Wasatch Cache NF. We have just signed a new agreement with the Caribou NF, and are close to adding three more forests in the Pacific Region. This last year we added a fieldwork component in the Uinta-Wasatch-Cache NF and next year we expect to add a few more field projects into the mix.

Leading Research Team

With our Research Lead, two graduate students, and up to eight technicians next year, we have cemented ourselves as a leading research team on the species in western North America.

a view from the ground looks up toward the dizzying height at the top of some very tall and sparsely branched conifer trees. the biologist wearing helmet and climbing gear looks tiny at the top of the tree! — Field technician (Phil S.) accessing an American Goshawk nest, 75 feet above the ground, to band and genetically sample the young. Uinta-Wasatch-Cache National Forest, 2023. Photo Credit: Robert Miller

Goshawks as Ecosystem Health Indicators

So why the renewed interest in goshawks? They continue to be the best indicator of ecosystem health in most of our forests. With an increase in forest health issues (pine beetle outbreak, spruce beetle outbreak, higher than expected tussock moth mortality, sudden aspen death syndrome), increase in fire severity, climate change (amplifies all issues), and greater Forest Service investment in reducing fuels, the Forest Service needs a champion for the ecosystem functions that the goshawks provide. We are happy to engage with them in this role. #kakkakkak

a messy nest of twigs and conifer needles host two awkward young hawks. They have a disheveled mix of baby down and new brown feathers growing in. One is perched on a thin branch hanging out over the edge of the nest. Both look toward the camera with grumpy expressions. The background is a full canopy of conifer trees with a few aspen trunks — Two American Goshawk nestlings. The bird on the right didn’t want to play and stayed out beyond our reach. The bird on the left donated some genetic material and received some nice “bling” as a reward! Uinta-Wasatch-Cache National Forest, 2023. Photo Credit: Phil Stollsteimer

You Can Help Make an Impact on Goshawk Conservation

We need your help to continue our American Goshawk research! Check out our latest fundraiser by heading over to IBO’s Bonfire shop, where you will see our newest (and currently most popular!) T-shirt design: “The American Goshawk Project”! It features artwork by the very talented Emma Regnier (@falcofous on Instagram).

Proceeds from this fundraiser will help offset the significant costs of field equipment like transmitters and thermologgers. Learn how this important scientific equipment will be utilized next season by Jessy Wilson, Boise State M.S. Raptor Biology student, in her newsletter article below.

The American Goshawk Project T-shirt design, created by Emma Regnier. Available in different styles and colors in IBO’s Bonfire store!

Announcing the American Goshawk Project!

By Jessy Wilson, Boise State M.S. Raptor Biology student

Hi! I am so excited to be joining IBO’s Team Goshawk as a new graduate student! I will be studying the newly renamed American Goshawk, with a special focus on the ecology of breeding goshawks. Goshawks in the IBO study area (southern ID, northern UT) have been reflecting trends of population declines as well as declining rates of occupancy and productivity. Additionally, the rate of breeding territory turnover has increased and is above the long-term average.

This suggests the goshawks in these areas are experiencing abnormal population changes.

a fluffy nestling has mostly cottonball down, with just a few brown feathers beginning to peek through. Its large pale yellow feet grasp awkwardly on the nest and it can't quite stand on its own yet. It has a silver aluminum band on one leg, and a purple colored metal band on the other. The purple band has two white letters stamped into it. — American Goshawk nestling, returned to its nest 65 feet above the ground, after receiving metal and color bands. Sawtooth National Forest, 2023. Photo Credit: Jessy Wilson

Even with IBO’s research on American Goshawks over the past several years, we still don’t know where goshawks travel when they leave a previously occupied territory (i.e., territory turnover event), how their breeding success compares in new locations, and how the habitat and landscape characteristics compare between known and unknown sites.

As a new Master’s student in Boise State’s Raptor Biology Program, I will be addressing these research questions and more with Jay Carlisle, Rob Miller, and the Intermountain Bird Observatory.

a small brown rectangular transmitter. The brown neoprene straps are worn and frayed after use. The transmitter is dusty from laying on the ground. a sticker on the side is partly legible and reads: "if found please contact found.ctt.com" and lists a phone number — An older, previously-used cellular transmitter, approximately the size that would fit a goshawk. The solar panel is seated at the top of the unit and a cushioned neoprene pad is affixed to the bottom where it will rest on the bird’s back. Photo Credit: Jessy Wilson

Utilizing GPS transmitter data, I plan to examine the movement of American Goshawks throughout their yearly cycle.

This will include where they choose to occupy breeding territories, where dispersing adults are moving, and what this means for current forest management and goshawk conservation in the Great Basin.

a dark blackish gray goshawk is held in a biologists outstretched hand. The goshawk is looking downward and to the side with intense orange eyes. Behind is a burned forest scene with darkened tree trunks, orange dead conifer needles, and mostly bare understory — An unusually dark plumaged adult female American Goshawk, captured for the purpose of applying color bands and USGS bands. This female can now be re-sighted in the future and identified as the same bird. Sawtooth National Forest, 2023. Photo Credit: Jessy Wilson

In addition to studying adult goshawk movement ecology, I also plan to study the microclimate conditions that goshawks experience at the level of the nest by placing thermologgers to remotely record data like temperature and relative humidity.

Nest data on this scale has never been collected before in this study area.

This will give us insight into questions such as – how warm does it actually get in the canopy where goshawks nest? What sun exposure do goshawk nestlings experience as canopy cover changes? How does this nest microclimate data influence goshawk nest success, likelihood of future occupancy, and long-term breeding trends in goshawk territories?

2 young hawks with white fuzzy down in stick nest in pine tree — Two young American Goshawk nestlings keep close watch on biologists as they approach the nest. Photo Credit: Robert Miller

Collecting data with thermologgers would allow us to make more informed explanations about what mechanisms might be driving nest failures and decreased occupancy/productivity rates.

Support Our Goshawk Conservation Efforts

Transmitters and thermologgers needed for this project are a significant expense, and our research team has put together a fundraiser to help cover the costs. T-shirts and sweatshirts are available for purchase in IBO’s Bonfire shop, with artwork designed by a fellow Lucky Peak alum, Emma Regnier (@falcofous on Instagram).

The American Goshawk Project T-shirt design, created by Emma Regnier. Available in different styles and colors in IBO’s Bonfire store!

Research like this is not possible without your help, and we’d like to invite you to invest in this great project! Beyond the Bonfire fundraiser, we are also seeking any individuals or organizations who may be interested in sponsoring a goshawk by covering the costs of one transmitter. Depending on the specific unit, cellular or satellite units range $800-$1200 per unit plus annual data fees. By sponsoring a goshawk, donors can symbolically “name” a bird, receive special updates on that specific bird…

…and have the opportunity to join us for a day in the field!

an adult female goshawk with striking gray, black, and white plumage and intense red eye sits quietly on a twig nest, peering out through pine branches. — American Goshawk on a nest. Photo Credit: Robert Miller

Stay Informed and Support the Project

You can stay up to date on the American Goshawk Project through Facebook (IBO Team Goshawk), and on Instagram (@americangoshawk)! Thank you for your interest and support!

This article is part of our 2023 end of the year newsletter! View the full newsletter here, or click “older posts” below to read the next article.

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