A studio for bird study

Tag: wader

Rock Sandpiper (Calidris ptilocnemis) – A GIF to illustrate the power of feathers for rendering shape

by Bryce W. Robinson

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I finally had the pleasure of seeing a “nominate” Rock Sandpiper (Calidris ptilocnemis ptilocnemis) during my time on the Bristol Bay coast of the Alaska Peninsula. This bird was hanging out with darker Rock Sandpipers (likely tschuktschorum) and Dunlin. These birds breed on Bering Sea Islands and mostly winter in Alaska’s Cook Inlet, farther north than any other shorebird (Gill et al. 2002).

While sifting through the many photos I took of this bird I found three taken almost simultaneously that illustrate the power of feathers for rendering a birds shape, and how much and quickly that can change for an individual bird.

After seeing the potential of putting the three photos together, I taught myself how to create a GIF (Graphic Interchangeable Format). I feel a GIF is an excellent way to show how only a few seconds and a relaxed posture can change the shape of a bird.

Referenced literature:

Gill, Robert E., Pavel S. Tomkovich and Brian J. McCaffery. (2002). Rock Sandpiper (Calidris ptilocnemis), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/rocsan

DOI: 10.2173/bna.686

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Juvenile Whimbrel (Numenius phaeopus) in Flight

by Bryce W. Robinson

I’ve included two photos of in-flight juvenile Whimbrel that I took in the first week of August 2016. I’m sharing these images for the simple reason of illustrating how a young juvenile differs from an adult. The age of these birds is told by the overall fresh, clean plumage and relatively short bill. It’s that simple in August. In a few months the bills will grow to a length comparable to the adults and determining age will become more difficult.

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Red Knot (Calidris canutus roselaari) Fieldwork in Western Alaska

by Bryce W. Robinson

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Adult Red Knot (Calidris canutus roselaari) captured on the breeding grounds in western Alaska.

On 1 July I travelled to Nome, Alaska to work on roselaari Red Knot research. I’ve spent the last month working on the project, and I’ve learned a great deal. The U.S. Fish & Wildlife Service has been conducting research on breeding Red Knots for the last seven years on ridge lines outside of Nome. They’ve focused on reproductive monitoring, marking and resighting birds, and determining the timing of arrival and departure on their breeding grounds. The effort has also provided collaboration with folks studying this population on their migratory and wintering grounds. You can read more about the connectivity study here.

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Red Knot research field station. Seward Peninsula, Alaska

I feel fortunate to have joined the work, especially considering that the collaborative study effort on this circumpolar breeding species is growing. This year a researcher from the Royal Netherlands Institute for Sea Research (NIOZ) joined the USFWS study effort in Alaska. Jan van Gils Ph.D., whose work was recently featured as the cover article in Science Magazine, joined Jim Johnson and Lucas DeCicco and the USFWS crew to investigate the potential impacts that trophic mismatch may pose on the breeding roselaari Red Knot. It was excellent spending time with Jan, as we discussed many ideas concerning climate change impacts on Red Knots and Arctic life alike.

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Jan van Gils et al. 2016 as featured on the cover of Science Magazine.

Alaska’s Red Knot population breeds on higher elevation rocky tundra. Many ridge lines on the Seward Peninsula are important breeding grounds for Red Knots. With climate change comes impacts to prey populations that the Red Knot needs for successful breeding.

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Red Knot breeding grounds in western Alaska. The low rocky ridge lines surrounding the river valleys are the preferred breeding habitat of the roselaari Red Knot.

There is then the potential that the tight timing of arrival and breeding of these birds may no longer coincide with the peak abundance of prey populations, something that has already been shown in many species that breed in the Arctic. Thus, understanding fully the timing of their breeding on the ridge is essential for understanding future climate change impacts.

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Pinpoint GPS unit attached to an adult Red Knot.

To better understand the latter portion of the timing of Red Knot breeding on the Alaskan ridges, Jim and Luke began deploying pinpoint GPS dataloggers on adults to determine when they depart the breeding grounds, the time they spend on migratory stop over sites, and the length of migration, . This year we deployed units that have already started returning data on migratory locations and duration. It will be exciting to see how the birds differ, or don’t.

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Luke checks out the placement of the pinpoint GPS unit on this adult roselaari Red Knot.

I had an excellent month on the peninsula. Apart from learning a great deal about these birds and their breeding ecology, I gained more exposure to excellent bird life in one of my favorite ecosystems. At the end of the season Luke and I shifted our focus to the coastal areas to attempt trapping of staging Juvenile Red Knots for more pinpoint deployment. I’ll highlight the rewards from the effort in my next post. In the end the Red Knot work was the cessation of an excellent summer of Alaskan bird study.

The season was successful thanks to a great field crew apart from Jim, Luke, and myself: Nick Hajdukovich who handled the lead for the first part of the season before Lucas joined in the field, Sarah Godin, Bethany, and Charlie and Linnaea Wright. 

Rock Sandpiper Short

by Bryce W. Robinson

Rock Sandpiper – Calidris ptilocnemis. As seen through the ZEISS Diascope 65 T* FL