Ornithologi

A studio for bird study

Category: Illustrations

Illustrating the Harpy Eagle

by Bryce W. Robinson

Untitled-3-01.jpgOver the past few years I’ve had the opportunity to illustrate the Harpy Eagle (Harpia harpyja), with the cover art for the Raptor Research Foundation‘s Journal of Raptor Research, and private commission work. Recently, I’ve focused again on the Harpy for a large and exciting project I’ve started with The Peregrine Fund (Stay tuned for details), and I’ll soon be returning to the species for Costa Rica focused work that I’ve also undertaken. I hope you enjoy the products of these upcoming endeavors as much as I’ll enjoy creating them.

Prints highlighting some of these Harpy Eagle images can be found in the shop.

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Differentiating Adult and Juvenile Gyrfalcon (Falco rusticolus)

by Bryce W. Robinson

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Given that much of my career has been focused on the world’s largest falcon, the Gyrfalcon, I often get questions about their life history and Identification. A recurring question is the age of individuals that are observed in winter. Most often, folks ask about juvenile vs. adult, so I decided to make available a simple illustration with annotations as a reference for those with these questions.

What I’ve realized is that fleshy parts confuse a lot of people, since an adult should have yellow legs and cere, whereas a juvenile should have blue. However, it takes female birds much longer to change (well into their second year), and the coloration is also influenced by individual quality and hormones. Some adults, particularly females, tend to be quite dull in the winter (compare this with observations of gull legs in winter, e.g. California Gull). Adults that are likely three years or older (given presence of retained feathers in the upper wing, etc.) can have surprisingly dull legs that may appear blue under certain conditions. The key then is to take a step back and focus on the plumage, since in most cases it is quite straight forward.

The illustration above aims to highlight the key points for aging a Gyrfalcon between adult and juvenile. Eventually I’d like to visually describe more micro-aging factors, but for now I think this will be a helpful resource for those more unfamiliar with this species.

Please, feel free to send me feedback and suggestions. Constructive criticism is always welcome.

High Numbers of Swamp Sparrow documented at Ted Trueblood WMA, Southwest Idaho

by Bryce W. Robinson

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My friends Jay Carlisle, Heidi Ware Carlisle, and I had a Melospiza morning at Ted Trueblood WMA, helping Boise State grad student Kate Owens and her fiance Ben trap Song Sparrows for Kate’s Master’s work. The highlight was catching 27 Melospiza sparrows at once, including 10 Swamp Sparrows (M. georgiana), 5 Lincoln’s Sparrows (M. Lincolnii), and 12 Song Sparrows (M. melodia). The incredible number of Swamp Sparrows left us reeling, since we had visited the area twice already this fall for Southwestern Idaho Birder’s Association and Golden Eagle Audubon Society field trips. Our first visit yielded no Swamp Sparrows, and a week ago we detected only 4 individuals (a high count for the site at the time). While processing our 10 Swamps, two remained in the reeds nearby calling, providing us a total of 12 Swamp Sparrow’s for the site! All Swamp Sparrows were young of the year, likely indicative of a productive breeding season for the species. Also notable, all birds had good fat and muscle scores which is indicative of good health, and upon release flew away with vigor.

Ted Trueblood WMA has been very generous to us in the past, hosting two of the three Idaho state records for Le Conte’s Sparrow. It continues to be a state sparrow mecca with this incredible high number for Swamp Sparrow, and who knows what will turn up in the future.

I’ve included here some photos of our morning, including a photo of four Swamp Sparrows at once, and a photo of all three members of Melospiza aside a painting I illustrated of the genus (by the way these prints are available in the shop). You can also see our numbers for the site and other species we documented, including a conservative estimate of American Tree Sparrow (Spizelloides arborea) on our eBird list:

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Photo: Heidi Ware Carlisle

 

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