heads up, Golden: cranes coming over (Boulder County)

[Linda Andes-Georges]

Hi folks--

Cranes passing over every day now. 165 on the wing over Boulder right now, headed south with sounds of cheer.

Linda

[Sean Walters]

Hello All,

I saw a flock of cranes fly over Colorado State University at 12:30 today. I had made rough estimate of 175 birds. Maybe the same birds?

Sean Walters
Fort Collins, CO

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[Christian Nunes]

At 2:36, City of Boulder Ranger Dave Gustafson called to report a flock of about 200 cranes going over Valmont Reservoir. Linda, if you send me you location we can do the rough math on their pace.

Christian Nunes
Boulder

Sent from my iPhone

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[Christian Nunes]

I caught up with a flock of ~156 as they headed out over US 36 south of Boulder at 3:03. Scattered groups followed, summing to 244 over the course of 15 minutes. 

I did some calculations based on Sean, Linda, Dave, and I seeing the same flock of ~156-165. The results of which can be seen here:

https://www.google.com/maps/d/edit?mid=zG5lCtrQ39_0.kXlDSQcDzYR0&usp=sharing

At least one of these birds was a small, dark, Lesser Sandhill Crane. It really stood out. Assuming it came from the breeding grounds in Siberia, I calculate that it took it 25 days to cover the ~3,500 mi to Colorado if it maintained a pace of 17 mph and spent at least 8 hours a day on the wing. Not too bad. 

I found a source that says they can travel from 15-50 mph, depending on the wind. Most of my calculations based on Sean, Linda, and others' reports put these birds at 17-35 mph depending on the segment of their journey. They made it from Table Mountain to Valmont Reservoir pretty quickly, 14 minutes at 35 mph. I presume Linda saw them thermal up and up, and then when they did their straight shot glide they were probably moving at a good clip until they caught their next thermal near the Legion Park Overlook. 

Lots of people at my office on Cherryvale Rd got to enjoy the spectacle. Thanks for the heads up! 

Christian Nunes

Boulder, CO

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