Laura Erickson's For the Birds

Wednesday, January 11, 2012

Ryan Brady and the oldest known Northern Shrike

This photo, taken March 17, 2006 when she was first banded, is of the Northern Shrike who is now the oldest on record. Photo courtesy of Ryan Brady. Copyright 2012 by Ryan Brady. All Rights Reserved.

My friend Ryan Brady is one of my favorite people, combining superb birding skills, depth and breadth of ornithological expertise, a commitment to conservation and education, and engaging enthusiasm. Ryan is the bird monitoring coordinator for the Wisconsin Bird Conservation Initiative. This week, I was elated to read one of his facebook posts starting, “The oldest known Northern Shrike in North America lives on!” He was reporting about a Northern Shrike that he’d banded in 2006 as part of a research project he does in conjunction with Northland College. This shrike has returned to Ashland for seven years now. She’s already on the Patuxent Wildlife Research Center Bird Banding Laboratory’s website as the longevity record holder for Northern Shrikes. Other shrikes may be older, but we can’t know without tracking banded birds.

I had to get more information about something this cool, so I called Ryan. Since 2005, he’s color-banded more than 100 Northern Shrikes, giving each a unique combination of color bands which has allowed him to keep track of individuals while they’re in his neck of the woods in winter. This project is the only study of Northern Shrikes currently taking place in the United States. Ryan told me that on March 17, 2006 he caught and banded the record-setting female, who was already an adult. It was impossible to know how old she was at that point, but she must have hatched in the summer of 2004 or earlier. Ryan put a regular US Fish and Wildlife Service aluminum band above a dark blue color band on her right leg and a white color band on her left leg.

Every year since then she’s returned to the same winter territory around the Ashland airport. Most years he finds her throughout the season in the open habitat around the airport.

The oldest Northern Shrike on record. This photo was taken on February 27, 2011. She was seen again on January 8, 2012. Photo courtesy of Ryan Brady. Copyright 2012 by Ryan Brady. All Rights Reserved.

For two winters he conducted a radio telemetry study, tracking the movements of 11 individual shrikes. He tracked this female’s movements in January and February of 2009, a year when rodent populations were very low. Ryan found her in town a lot, as much as three miles from the airport. She was presumably taking backyard birds because 2009 happened to be a banner year for siskins and crossbills. The next year, the rodent population was back up and she was back spending all her time on her territory by the airport. The 11 shrikes he tracked in that telemetry study held territories averaging about 450 hectares, which is about 1100 acres, or 1.75 square miles. The smallest territory was only about 30 hectares. This female’s territory in 2009 was by far the hugest, about 1600 hectares.

This week Ryan also had another marked bird return—an adult male bird that he’d banded in April 2009 who is now 3 and a half years old. This is older than the shrike in second place on the Patuxent longevity webpage. Shrikes show strong site fidelity, but when we see a shrike in the same place year after year, we can never be certain that it’s the same individual unless it’s banded, because the previous year’s bird may have died or for some other reason not returned, only to have the available habitat occupied by a new bird.

Ryan Brady is going to be the Friday night speaker at the Sax-Zim Bog Winter Bird Festival on February 17, talking about his shrike project and the record-breaking female. He’ll be showing up-close-and-personal photos of many of the shrikes he’s worked with as he discusses how he ages and sexes them and what he’s learned about winter site fidelity, home range size, physiology, and more. The Sax-Zim Bog Winter Bird Festival always has interesting speakers and great field trips, but this one may be the best yet.

3 comments :

  1. Can you tell me what Shrikes eat to survive in the winter?

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  2. I just witnessed a northern shrike kill a female pine grosbeak under the birdfeeder on our deck. It was quite awful. Isn't this an awfully big bird for the shrike to attack? I left for a few minutes, thinking I'd need to get a shovel to take care of the "dead" bird (there was blood coming from it's neck/spine) but when I returned it was gone. Could the shrike have carried it away? The pine grosbeak was the size of a robin...

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  3. Sorry I didn't notice these comments to respond! Shrikes eat birds (a Pine Grosbeak would be sort of extreme, but they do go for birds that size, including robins, too) and small rodents. And they can carry even heavy prey surprisingly well. They "cache" it on a barb or thorn to return to as they get hungry.

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