Winter Raptor Research Updates From the Field – Week 1

By Jenna Schlener – Research Intern

For the past few weeks, our research team has been searching for Red-tailed Hawks throughout Addison County in preparation for trapping. While this gave us a good idea of where to look, we quickly learned that it is important to stay flexible, and most of all, patient. 

To catch the red-tails we use something called a Bal-chatri (or BC) trap. Like much of the foundational knowledge and tools we have on raptors, these types of traps originated from falconry. BC traps can be traced back to falconry in east India where horsehairs were tied as nooses around cane cages with live prey inside to lure the raptors in.

Example of a BC trap. Image from creative commons.

Modern versions of these traps substitute hardware cloth for the cane and fishing line for the horsehairs. In order to trap a raptor, live prey is placed inside the hardware cloth cage to entice the bird to come to the trap. As it attempts to snatch the prey, tiny nooses surrounding the cage entangle the raptor’s talons so it can’t fly away.

In order to maintain everyone’s health and safety, we split up into different cars and had two teams out looking for birds. When we saw a bird we wanted to try to trap, we slowly drove by, dropped the trap in view of the raptor, headed down the road to wait. More often than not the raptors ignored our attempts and we’d drive on to the next bird. After hours of searching, we finally had a taker.

An adult Red-tailed Hawk. Photo by Bryce Robinson.

Just before sunset this beautiful bird came down to our trap. For the Red-Tailed Hawk Project, they are specifically looking for adult breeders of a Red-tailed hawk subspecies called abieticola which breeds in more northern regions. This bird had some of the darker markings indicative of that subspecies. However, looking closer at the feathers, we concluded that it is only a second-year bird and so may not breed yet this year. We decided not to put a transmitter on this bird, but still gave it a color band for potential re-sighting opportunities and released it. This bird received color band Blue – OK.

View from where the first bird was captured. Photo by Jim Armbruster.

The next day temperatures were low and it seemed the birds were even more hunkered down than the day before; no luck for us. On day three our patience finally paid off. With the first drop of the trap we captured a richly marked bird and decided to deploy our first transmitter.

Adult red-tailed hawk abieticola subspecies named “Goodrich”. Photo by Bryce Robinson.
Field where Goodrich was encountered. Photo by Jim Armbruster

Using Teflon ribbon the transmitters are carefully attached to the birds like a backpack. The transmitters record GPS points and when the bird is in range of a cellphone tower, all the GPS data are downloaded. This will allow us the opportunity to see where Goodrich ﹘ the name we gave the bird for the area it was trapped in ﹘ goes both in the winter and during the breeding season. Goodrich received color band Blue – 1U.

Goodrich with a transmitter attached. Photo by Bryce Robinson.

We are still waiting for some materials to come in before our trackers are ready to go out but in the next few weeks we’ll be trapping again with the Cornell team to find one more for their project. Check back soon for more updates!


  1. pam Kerstner on January 18, 2021 at 7:12 pm

    WOW this is interesting I had no about these traps. It will so good to learn about the info that comes from these great birds and future birds.

    • Jim Armbruster on January 20, 2021 at 3:42 pm

      we are excited to see what we learn from these birds and where they go!

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