A studio for bird study

Tag: raptor

Rough-legged Hawk Nestlings

by Bryce W. Robinson

Rough-legged Hawk Nestlings

I was surprised the first time I saw the proximity of nesting Rough-legged Hawk and Gyrfalcon. It was my first summer in Alaska. I was along the Dalton Highway peering through a scope at an incubating white Gyrfalcon. Only 100 meters down the cliffside was an incubating Rough-legged Hawk. Now that I’ve gained an in depth experience with cliff nesting birds of the Arctic, I see why these birds tolerate one another. There simply aren’t enough locations to be choosy.

These eyes were watching me as I pulled out one of my Gyrfalcon nest cameras the other day. This is on the extreme end of Gyrfalcon – Rough-legged Hawk nest proximity. These nests are only about 10 meters apart, and given that these young Roughies are about to fledge, they will both be successful. Almost every cliff I’ve worked in this summer has had a nesting Rough-legged Hawk pair. Some cliffs have had two, along with nesting Raven and Cackling Goose (yes, they nest in cliff nests often). Real estate is limited, so all suitable sites are usually occupied given enough food in the area.

Rough-legged Hawks are a favorite. I gained a familiarity with them during past winters in Utah, and it was always a dream of mine to see them on their breeding grounds. Each time I’m around a nest, I remember my current place and business in life, something that is not to be taken for granted. I’m living a personal dream, and I’m happy.

Gyrfalcon Nest Observation

by Bryce W. Robinson

Somewhere between 45-50 days after hatching, young Gyrfalcons take a leap from their nest and fly for the first time. The clip above shows an angsty female preparing herself for that first jump. Her two siblings, both male, had already left the nest. This fact added to her anxiety as they called from outside of the nest.

Last year I put some effort into seeing a Gyrfalcon’s first flight, but was never in the right place at the right time. This year, I’m making another attempt. The clip above – as seen from a tent through our Zeiss Diascope – is as close as I’ve come to seeing a first flight. I spent hours with my field partner Ellen in a tent outside of the eyrie waiting for the bird to make the leap. The clip shows the closest she came. After this intense flapping bout, she sat down and went to sleep. We had to leave before the bird left the nest, but the time spent watching her was worthwhile.

B_Fieldnotes

First hand study is invaluable. We live in an interesting world where technology gives us so much, so fast, so often. We are able to learn at such a high pace, and research is no exception. For instance, I’m gaining insight into multiple nests using motion-sensor cameras. This provides me an in-depth exposure to Gyrfalcon nests at a higher rate than ever before . This is all due to the camera technology. But I’m missing out on a slow pace digestion of first hand observation. I’m missing out on the whole picture. To get the full perspective, and truly see what it is like in the nest, I need to watch them myself.

B_observation

While I watched, I took notes on behaviors. I also did a bit of field sketching. Field sketches force you to focus, and digest very small details that can heighten your understanding of your subject, but also enhance your observation skills. Besides all that, it is an enjoyable way to pass the time while the nestlings sleep.

Ellen_observation

Ellen and I took turns watching the nest. We were able to see two prey deliveries during our time watching. A male fledgling returned after one of the prey deliveries, hoping to get part of the meal. The female, however, would not oblige. I most enjoyed watching their behaviors. The birds interacted with one another in an endearing manner. They would pick at each other, as if preening. I wasn’t quite sure if this was curiosity, playful, or truly preening. They would also watch flies buzz around the nest, as if they were about to pounce. You could see the predator engineered mind in the way they followed the flies. They were figuring out what they needed to do to survive.

Male (R) and female (L) Gyrfalcon fledglings. Digiscoped with a Zeiss Diascope 65 T* FL

Male (L) and female (R) Gyrfalcon fledglings. Digiscoped with a Zeiss Diascope 65 T* FL

Although we missed the first flight of the female, we’ll have a few more opportunities to try with other nests. This means more hours behind the scope to watch, and more hours to learn.

To find out more about The Peregrine Fund’s Gyrfalcon Program, visit The Tundra Conservation Network and www.peregrinefund.org

Banding Nestling Gyrfalcons in Western Alaska

by Bryce W. Robinson

Gyrfalcon Nestlings

Photo 1. Gyrfalcon nestlings just after seeing their very first human being. One nestling is attempting to hide, while the other looks boldly into the eyes of the onlooking researcher.

The best part of working on a project focused on nesting Gyrfalcons is interacting with the nestlings. I can’t help but spend a moment or two to admire them each time I get one in my hands. They are young, yet full of personality and intelligence. I lose the ability to articulate the experience of dropping into a nest, and being the first human these nestlings have ever seen. Their response is remarkable, as they recognize me as an intruder and prepare to fight. There is, however, a certain degree of curiosity in their eyes. What impresses me most is their confidence, seen in their posture and stare.

Female Gyrfalcon Nestling

Photo 2. A tenacious young female Gyrfalcon, age 25 days. She is full of fight and intelligence. This attitude will serve her well after she leaves the nest and needs to learn to hunt and kill to survive.

We schedule our second round of nest entries when the nestlings are 25 days old. At this point their legs have fully developed, so we can outfit them with aluminum USGS leg bands. These bands give them a unique identification number, so that if the bird is caught or found researchers can tell where the bird came from, and where it went.

Banding Gyrfalcon Nestlings

Photo 3. Crimping the “lock-on” band. Most Gyrfalcons take band size 7B. We put bands on the right leg, and crimp a metal fold-over to ensure this piece of leg jewelry stays with the bird for its entire life.

As the nestlings grow, they begin to realize the tools that evolution has provided them to hunt, kill, and defend themselves. When we enter the nests to band, the nestlings have developed into fighters. They bite, rip, and use their talons to lash at intruding researchers. Because of this newly developed tenacity, working with them takes its toll.

Part of the Work

Photo 4. A hand weathered by tenacious Gyrfalcon nestlings. This is part of the work. The young are held in a way that they are unable to bite the hands of the researcher, but they are intelligent and talented. Often, they figure a way to make us pay for the important data we collect.

It’s great to see youngsters that have so much fight. This aggressiveness will translate into behaviors necessary for their survival. Although the most aggressive young are not the most enjoyable to handle, it means the birds have what it takes to be a large falcon in the Arctic.

weight

Photo 5. Weighing a young Gyrfalcon. We weigh the nestlings to help calculate a general age, if unknown. Weight also helps us determine the health of the nestling.

Apart from banding, we have a number of other tasks to complete while handling the young. We take DNA samples, weights, wing and tail measurements to estimate age, and check for parasites. After each nestling receives its treatment, we switch out batteries and memory card in the nest camera. We will not come back to the nest until the young have left, so it’s important to make sure the camera continues taking data until the end.

So far, we’ve been to three of our twelve nests. Our hands have a lot more abuse ahead of them, but we are excited to continue nonetheless. More pictures and stories to come.

Thanks to Ellen Whittle for the photos of the work

Notes on Gyrfalcon Molt

by Bryce W. Robinson

Adult Male Gyrfalcon - Falco rusticolus

Photo 1. Adult Male Gyrfalcon – Falco rusticolus

I like to pay attention to molt in birds. There are many aspects of a birds life history that can be reflected by their strategy for feather replacement. A great example is something I’ve been watching with the nesting Gyrfalcons I’ve been working with lately.

Last summer, I noticed something about the molt between male and female Gyrfalcons. While I was entering nests to install cameras in the early nesting period (mostly during incubation), I noticed that males were behind females in their molt progression. Following my initial observation, I started paying closer attention to each bird. I continue to take notes on this, and wanted to share the molt of a pair from a nest I visited recently.

Adult Female Gyrfalcon - Falco rusticolus

Photo 2. Adult Female Gyrfalcon – Falco rusticolus

You can see that the male (photo 1) has just dropped his fifth primary. Falcons generally begin their primary molt at P 4&5 and progress in two directions. The female (photo 2) has dropped her third, fourth, fifth, and sixth primaries. You can see P 4&5 are growing in already.

This illustrates a few simple things in the life of a Gyrfalcon. One, that energetics govern the ability to molt. Two, that male and female Gyrfalcons have different energetic roles and energy budgets during incubation and early brood rearing. They have different roles in the process. These are illustrated by the fact that they differ in the progression of their molt.

Later, the rates even out as both adults need to provision for their growing brood. I hope to get photos of this pair on my next visit to the nest in a few weeks.