Thursday, 5 November 2015

RE: [cobirds] Re: Roosting Crows

Here are some American Crow experiences that I have had over the years in Boulder County.

 

Ted Floyd holds the Boulder County eBird high count record at 925 on 10/23/13.

 

Three years ago while doing the Boulder CBC at Valmont Reservoir with John Vanderpoel, we observed a flock (murder?) of black corvids just a few minutes after 7:00 a.m. that numbered in the several hundreds.  These birds flew directly overhead at low altitude indicating that they were, perhaps coming from the nearby woods along Boulder Creek—perhaps a staging area.  The birds were of three distinctly different sizes and tail shapes.  We did not replicate this experience to the same extent in either 2013 of 2014.  Who know what next month brings?

 

I remember (almost 30) years ago heading up into the mountains toward Nederland and in the late dusk watching a seemingly endless string of American Crows fly west over Barker Reservoir.  A friend commented that it looked like a stream of Sooty Shearwaters off the California coast.  Then someone else said that the birds were heading to the Eldora Ski Area where they would roost under the night skiing lights. 

 

 

From: cobirds@googlegroups.com [mailto:cobirds@googlegroups.com] On Behalf Of David Suddjian
Sent: Thursday, November 05, 2015 2:22 PM
To: Colorado Birds
Subject: Re: [cobirds] Re: Roosting Crows

 

Crow roosts are mostly large scale affairs, and they can be hard to find because the crows often stage in varied spots, and some staging areas may not be very close to the actual roost. And crow behavior can be deceptive as the birds may remain at a staging area until well after it begins to get dark after sunset. Based on observations from some roosts I have studied (in California), the actual entry into the final roost trees usually happens in the gloaming (late dusk), when it can be hard to see exactly what is going on. Details that Nan and Jared share about their observations strike me as more related to staging spots than the actual roost. Fly outs from roosts in the morning happen under similarly dark conditions.

 

A large number of crows (1000s) roost in the Conifer area (JeffCo), but I haven't tracked down the spot. And a large number of these crows move from there early in the morning to populate the southern Denver Metro Area, and they probably go elsewhere, too. I see these birds passing over my home region early in the day, and again in the afternoon, although exact routes and numbers seem variable. But they are making long flights and going up into the mountains to spend the night.

 

There is another roost in Park County somewhere up the Deer Creek watershed, up the valley from (appropriately) Crow Hill (County Road 43). Even though that spot is a number of miles from Conifer, I think the two roost areas are related with specific roost locations shifting between these areas in some way that I have not sussed out. 

 

David Suddjian

Littleton, CO

 

On Thu, Nov 5, 2015 at 1:43 PM, 'Nan Campbell' via Colorado Birds <cobirds@googlegroups.com> wrote:

I wonder if the crows that hang around Cheesman Park scatter in smaller groups to roost in the evenings. There are a dozen or so that fly into a big tree near 13th and Steele as the sun sets every day. Could they be a family group?

Nan Campbell 

Sent from my iPod.


On Nov 5, 2015, at 1:27 PM, Jared Del Rosso <jared.delrosso@gmail.com> wrote:

Over the past week, several dozen crows have been gathering at the Governor's Mansion in central Denver at dusk, though I haven't confirmed that they roost there overnight. A small number -- fewer than a dozen -- hang around the adjacent Governor's Park during the day. On blustery afternoons, a dozen or so of them will often gather on one of the large apartment buildings east of Governor's and then launch themselves into the wind. 

 

Close to 100 often gather at Cheesman Park in the cold months. Now and then, they decide to close out the day by showing off for each other -- flying, tumbling, calling wildly -- which is a pretty spectacular event to observe as the sun sets over the mountains. Even better is when they decide, also at dusk, to mob the resident Red-tailed Hawk as it flies over the park. Even my dog stops, cranes his neck, and takes that in. 

It wasn't always like this in my neighborhood. W.H. Bergtold, a physician and ornithologist who lived near Cheesman Park in the early-1900s, reported one crow "flying over Eleventh Avenue, and Corona Street" on December 7, 1913 and another one "seen in Cheesman Park, May 1, 1917." 

 

- Jared Del Rosso

Denver, CO

 

On Thursday, November 5, 2015 at 7:20:24 AM UTC-7, Steve wrote:

Hi COBirders,
Just adding to the thread …

When I taught at Air Academy HS I used to regularly see large flights of crows leaving the canyons on the West side of the Academy, heading towards town.  Usually this was early morning, in the winter months. Never saw a roost, but hundreds of crows would fly over some mornings.

Steve Brown
Colorado Springs

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