More birds added to our project thanks to the Mackinac Straits Raptor Watch

Bryce recently spent a week at the Mackinac Straits Raptor Watch in Mackinaw City, Michigan, where he and Nick Alioto deployed eleven units on migrant Red-tailed Hawks. Nick will be conducting a movement ecology study focused on migrants in the great lakes region, and we’re excited to see what insights he gains from these tagged birds. Take a look below at the excellent new birds, and stay tuned to learn where these birds breed.


Trap location: Cheboygan, Michigan

Trap date: 3 April 2021


Trap location: 2 April 2021

Trap date: 2 April 2021


Trap location: Mackinaw, Michigan

Trap date: 2 April 2021


Trap location: Mackinaw, Michigan

Trap date: 4 April 2021


Trap location: Mackinaw, Michigan

Trap date: 4 April 2021


Trap location: Mackinaw, Michigan

Trap date: 4 April 2021


Trap location: Mackinaw, Michigan

Trap date: 5 April 2021


Trap location: Mackinaw, Michigan

Trap date: 5 April 2021


Trap location: Mackinaw, Michigan

Trap date: 5 April 2021


Trap location: Mackinaw, Michigan

Trap date: 5 April 2021


Trap location: Mackinaw, Michigan

Trap date: 5 April 2021

Thanks to Nick Alioto and Ed Pike, and the Mackinac Straits Raptor Watch for their willingness to collaborate, and to Leah Rudge for her help! To learn more about their work, visit

More birds join the project in the eastern Great Plains

We’ve been busy! Over the past two weeks, we’ve been putting transmitters out on the eastern Great Plains, primarily in Kansas. We added 8 new transmitters and an additional 8 birds that are marked with color bands. Take a look at the new birds!

Apart from the generous contributions from the Kansas Ornithological Society and the Burroughs Audubon Society, these transmitters are those purchased from our fundraising efforts. Thanks again to everyone who contributed!

New birds carrying transmitters



Plo Koon






Other birds sampled and tagged with color bands

Blue – 0Y

Blue – 3F

Blue – 3A

Blue – 2A

Blue – 2B

Blue – 2T

Blue 2H

Blue – 4D

Special thanks to everyone that offered their COVID conscious help during the effort, including John Bollin, Dave Rintoul, Rene Martin, Fernando Machado, and Paul Mackenzie.

Meet Ahsoka – a light-morph harlani carrying a transmitter in Kansas

Meet Ahsoka, an after fourth-cycle harlani that wears the color band blue – 3Z!

Luke added this excellent light harlani to our growing group of birds carrying transmitters. We first found this individual last year on its wintering territory just outside of Lawrence, Kansas. We checked regularly during our trapping efforts last winter to see if it was trappable, and continued doing so this winter. It usually perches in trees that are either not accessible or are in areas that are difficult to trap, so our efforts were always thwarted. But, luck and opportunity finally came together and Luke was able to pull it over to a trap and capture it. Nice work Luke!

Meet Obi-Wan – a new bird carrying a transmitter in Vermont

Meet Obi-Wan, an after second-cycle that wears the color band blue OB. Over the weekend we were able to trap and transmitter this bird in collaboration with the Vermont Institute of Natural Science.

We also caught and color banded a few other birds. If you live in the New England or eastern Canada, keep an eye out for birds with blue color bands!

Blue OS

Blue OR

Blue OH

Meet our two new birds – a harlani from Utah, and an abieticola from Vermont


Grogu is a fourth-cycle dark morph harlani captured in Salt Lake City, Utah on 18 December 2020. The primary molt limits on this individual indicate an after third-cycle, but we actually know the age of Grogu because the bird was caught and banded at the Salt Lake International airport in 2018, when it was in second-cycle plumage. So, Grogu is in its fourth-cycle this winter.

The folks at Salt Lake International Airport capture and relocate birds in an effort to eliminate bird-airplane collisions. A collaborator at HawkWatch International, Jesse Watson, reached out to them this winter to ask them if they would be willing to cooperate to get transmitters on harlani or any other birds of interest. They agreed, and Grogu is the first from that cooperation!

Grogu was released in the desert west of Salt Lake City, and we are getting location data already! We’re excited to see where the bird ends up over the next year, and will share as we go along.


Goodrich is an after third-cycle, relatively lightly marked abieticola (or perhaps intermediate between abieticola and borealis) captured in Addison County, Vermont on 20 December 2020. We’re not exactly sure what to expect out of this bird, so in this way this individual will help us understand the connection between the more heavily marked abieticola, and these lighter, or more intermediate birds. This bird could breed quite far north, or it simply could breed more locally in northern Vermont, or southern Quebec. We will see!

Bryce had the privilege of spending a few days in western Vermont, working with folks from the Vermont Institute for Natural Sciences (VINS) to get out a transmitter for a collaboration with the Red-tailed Hawk Project on a winter home range study they are conducting. We’re excited to see where Goodrich ends up to breed, and will share as the data comes in.

Blue 1W is our First color banded bird of the project – A gorgeous juvenile Krider’s in eastern Kansas!

Yesterday, 10 November 2020, Luke caught this stunning juvenile near Lawrence, Kansas (nice work Luke!). Unfortunately, we are not putting out telemetry units on juveniles, but Luke still took the necessary samples, and put a color band on the bird. This bird is now carrying a blue 1W on its left leg, so keep an eye out for it!

We tentatively identify this individual as the subspecies kriderii, given the overall paleness of the bird as well as the rusty tones throughout the body plumage, especially the primary coverts. We also expect a juvenile harlani to lack these warm tones and have more globular streaking in the belly, patagials, etc. The regularity of the barring in the tail, and the fineness in the wings, also supports kriderii. Juvenile harlani and kriderii can be quite difficult to distinguish, which is why this bird carrying a color band is so exciting. Even more, it’s important to note that these two subspecies come into contact, so the characteristics of some individuals may blend together and we may be ‘splitting hairs’ if we try to name it one or the other. If we can resight this bird in its definitive plumage, we’ll have a direct comparison between juvenile and adult plumage, which will strengthen our ability to identify it. We also now have the ability to genetically assess where this individual may group with others, further strengthening our understanding of how to name these odd plumages.

We need your help to resight our color banded birds! We hope to put out a large number of color bands this winter. The coming breeding season, we hope our efforts pay off and we get some breeding locations from relighting color bands at nest sites. Please pay attention to your local Red-tailed Hawks this summer, and see if you can find a color band! If you do, take a photo and let us know!

We’re raising money for transmitters – Support the Red-tailed Hawk Project!

This fundraising campaign ends on 15 November, 2020. Make a contribution today!

Make a one-time contribution of any amount

Help us purchase additional GPS transmitters! To make a contribution* of any amount, select the number in dollars below (e.g. selecting 70 will equal a $70 contribution). This one-time contribution* will be put towards the purchase of additional tracking devices, which cost $790 per transmitter.

1.00 $

Or, select a support level and get one, or all of the following items if you contribute!

Why are we asking for your support?

As you may know, we currently have two birds that are transmitting data to achieve two objectives: connect their phenotype and genotype to a breeding location and resolve the status of polymorphism in the subspecies abieticola. At this point we need to get many more transmitters out, because two birds is not enough to understand to what population these types belong. We also want to add more birds carrying transmitters as a strategy for obtaining breeding locations for population genomics work, while developing a growing dataset to answer questions including, but not limited to, the timing of movements, differential movements between and within populations, and to better understand plumage type as an indicator of geographic origin.

We need your help to do this! Our strategy is costly, because it requires a great deal of money and time on our part. Despite these costs, this strategy is the most efficient and effective method for achieving our research goals, because by approaching the sampling with transmitters we will avoid the challenge of international permitting, and the cost of travel to difficult areas to access such as the remote forests of boreal Canada. In other words, by tackling this research in this way, we will save both time and money!

The Plan

We plan to begin an ambitious effort for deploying transmitters starting this coming winter. Below is a detail of our plan, and how the money contributed by you will make this happen:

  • We plan to use the money from this campaign to purchase at least 10 tracking units to deploy this coming winter in the northeastern U.S., and the Great Plains. Even if COVID 19 limits this effort, we will be able to at least deploy units in New York and Kansas. 
  • We will make the money you contribute go the farthest it can. To do this, we will target wintering subspecies that breed in regions that are logistically difficult and expensive to access, such as Boreal Canada and Alaska. These include B. j. harlaniabieticola, and a dark non-harlani (potentially abieticola) type that winters in the Great Plains, and on occasion parts of the east.
  • If we deploy these ten units this year, and obtain photographs and blood samples from each bird, we will have a solid start to the sampling for the evolutionary research, as well as for building an extensive dataset of full cycle movements for these enigmatic subspecies. 

What We Need & What You Get

To get the sampling started to achieve all of our research objectives, we need to purchase transmitters. Below is a summary of how much these transmitters cost, and how the money you contribute will be applied.

  • Cost of transmitters –  One unit =  $790 ($500 per unit, plus $100 for insurance, $120 for yearly data fees, and $70 for shipping from the company in Europe). We would very much like to deploy at least ten of these units this winter, so we hope to raise as much as $10,000! 
  • A contribution from you is not just generosity. There is a perk! You can choose to make a contribution of any amount, or you can choose support levels that include perks the following perks: $20 – Red-tailed Hawk Stickers; $30 – Dark Morph Red-tailed Hawk Tee; $60 – a limited archival giclee print of a Western Red-tailed Hawk plate, illustrated by Bryce W. Robinson; and for $100 you receive all three! To claim these perks, click on the photos above! All orders will be filled after the campaign ends on 15 November, so you will receive your order sometime before December.
  • We’ll regularly post updates on the birds that are carrying transmitters purchased by this campaign. These updates will be on the project website, as well as our Facebook page. If you choose to contribute, please let us know where you heard about the campaign so that we can be sure you will see these updates.

The Impact

We are creating a research program that will grow, enabling an increased understanding of this widespread and beloved species. But the data we gather from our effort will also go beyond understanding the Red-tailed Hawk alone. Here are a few examples of the impact we think our program will have:

  • At the most fundamental level, our work will provide insight into Red-tailed Hawk subspecies that have been an enigma for so long. By attaching genetic samples to the breeding locations we obtain with the transmitters, we will be able to put genetic context to subspecies concepts, which might help us understand why harlani appears to be so different, and if subspecies such as abieticola truly are a distinct population.
  • Our work will also help us understand the evolutionary history of this species, which will be extremely informative for understanding the diversity we see in the species today, as well as providing yet another perspective on how geologic history can shape the process of speciation.
  • Connecting year round movement patterns to plumage and genetics will strengthen our ability to monitor Red-tailed Hawks, and enact conservation efforts if these are ever necessary. Even more, by doing so in Red-tailed Hawks, we can continue to refine this technique for use in other species. 
  • We also hope that by crowdfunding for transmitters, we can involve the community in this research, and expand our collective understanding of this beloved raptor. Through this, we also hope that anyone involved will gain a greater understanding and appreciation for how this type of research is conducted. 

Risks & Challenges

Transmitters can fail, birds can die for many reasons, natural and human caused. It is possible that some of the transmitters we deploy will not provide movement data, or a breeding location. But, we have a plan in case this happens!

  • We plan to purchase insurance on the transmitters, so that in the event that a unit stops working for any reason, they will be replaced and we can try again. 
  • If a bird dies, we can follow the signal of the unit to its location and assess the cause of death. Many studies use this technique to track hawks, and birds alike. Deaths from transmitters are extremely rare, so the likelihood of the transmitter harming a bird is very small. But birds still die from natural causes, or they get shot, hit by a car, or a wind turbine. We’ll know if this happens, and we’ll learn a lot if it does.

Other Ways You Can Help

We understand that you may have a keen interest in this work, but can’t donate any money. Some people just can’t contribute, but that doesn’t mean they can’t help:

  • Regardless of whether or not you contribute money, please follow us on Facebook, and share the project with your friends. Please encourage others to follow along, and to help us out!
  • Make sure to regularly check in on the website to follow along on our progress on the blog. We’ll post regular updates here, as well as discussions on subspecies identification, and more.

Thank you so much for your help! We’re excited to have you along!

*It’s important to note that unfortunately, a contribution to our effort is not at this time tax deductible. If this impacts your decision to contribute in any way, please contact us!

We have breeding locations!

After months of waiting, our birds Kansas 01 and 02 have started their fall migration back to their wintering areas in Kansas. We now know where each bird breeds, and we can tell a bit about each just from this knowledge.

Surprisingly, both birds breed in an area of northern British Columbia, in a glacial valley on the western side of the front range. To me, this is perhaps the most surprising part of the story. Both birds follow a very east/west migration path that includes a flight over the mountains, rather than tracing ridge lines in a more north/south direction. Very peculiar, but enlightening!

The birds appeared to have nested, and it looks like our birds are one male and one female. Check out the image below that indicates that within reason, both did indeed breed, because of the central orientation of the movements. For both images, I filtered the dates for the locations to include 6 June to 6 July, and cropped each at the same dimensions and altitude, so they represent approximately the same coverage of geographic area. Focus on the dots, and ignore the lines and you can tell the clustering is quite different for the two during this time period.

These clusters suggest that KAHA 01 (red) is likely a male, while KAHA 02 (purple) is likely a female. From the distribution of the spread during particular times, we can tell that KAHA 02 was probably incubating, and the breadth of the movements of KAHA 01 suggest it was making foraging movements quite regularly throughout the summer. We do have blood samples from each so we have the ability to check for certain if these are a male and a female.

What subspecies are these birds? Does this answer the question of whether or not the subspecies abieticola has a dark morph? The short answer is that it is complicated, and at the moment it does not answer the question of polymorphism in abieticola. This is for two reasons – the first being that this region is a contact zone between as many as four taxa – calurus, harlani, abieticola, and borealis. Thus, the genetic work will be crucial for figuring out where these two birds fit in these categories, if they fit at all!

To solve the subspecies question, we need to put out more transmitters!

Special thanks to the organizations that made this work possible: Burroughs Audubon Society, Kansas Ornithological Society, and the Hawk Migration Association of North America (HMANA).

Are there B. j. calurus that winter in the great plains?

The question of whether or not Western Red-tailed Hawks winter on the great plains has been debated for years. Below I detail an anecdote that shows that at least one bird does…

We were surprised to catch the bird below in eastern Kansas last winter. It’s a rufous bird that as far as I can tell, is a Western Red-tailed Hawk (ssp. calurus). Take a look, and compare the bird to the photos of a bird I caught near Boise, Idaho, in July.

Eastern Kansas – February 2020

Southwestern Idaho – July 2020

Westerns, or nearly pure Westerns, do breed east of the rockies in New Mexico, Colorado, Wyoming, etc. The hybrid zone from calurus into borealis hasn’t been properly characterized, but through eBird and the Macaulay Library we are beginning to get a broad picture of this cline. Consider the pattern at the Colorado contact zone. We know that borealis breed to the front range in Colorado (with influence likely entering the range in some areas), and interbreed with calurus throughout the region. One the other end, Kansas is yet to have a clearly documented breeding calurus in the state, although Luke may change that, but that is his story. The point is, calurus influence largely fades out before the border between Colorado and Kansas.

Could the rufous bird we caught come from an area like the Colorado contact zone? Could it have originated from intermountain region? Or could it come from further north within the distribution of calurus in British Columbia?

At the moment, we don’t have the answers for these questions, but we can find out by scaling up our transmitter effort!

A Potential Intergrade harlani X abieticola

In February 2020, we trapped a very interesting dark bird north of Atchison, Kansas. We were targeting dark non-harlani for our transmitter effort to track these birds to their breeding grounds as a first step for understanding if the subspecies abieticola is polymorphic.

At first pass this bird looked like our target, but when we extracted it we immediately saw the multiple harlani traits throughout the birds plumage. After later successfully trapping our targets, I came back to photos of this bird for comparison and recognized the similarities in traits, which led me to the conclusion that this interesting dark bird is likely an intergrade between harlani and the dark birds that we outfitted with transmitters (we are calling these abieticola, which might be an oversimplification, but we’re working on it!)

Below I’ve included a figure that compares a dark harlani (top) that I trapped with Neil Paprocki, Caitlin Davis, and Johnna Eilers in Northern Idaho in November 2019, the interesting intergrade (middle), and one of our transmitter birds (bottom). I also included photos of the tails of each to allow more detailed comparison between the three.