[cobirds] Re: Swallow departures from northern Front Range in 2013

I've been thinking about this a lot of late.

First, I swear...About 6 weeks ago I was going to post to COBirds a prediction that a Barn Swallow would be seen this year on a Colorado Christmas Bird Count. Probably John Martin. Well, I'll make the prediction now. Okay, I've just jinxed that particular outcome. Somewhere out there, Duane Nelson is poking voodoo needles in an effigy of me.

Large numbers of Barn Swallows remained last year into mid-October, with a few lingering into the first few days of November.

And there was something of a tardy departure, too, in 2011.

This is wild conjecture, but I think something big is going down with Barn Swallows in our region. Across the Northern Hemisphere, swallows are engaged in some dramatic range shifts. Like flocks of Northern Rough-winged Swallows wintering in Philadelphia. And think about the whole Cave Swallow phenomenon; that species wasn't on any Eastern birder's radar screen 25 years ago, and now it's annual in the hundreds.

Back to Colorado Barn Swallows. (Sorry, Hannah and Andrew's macaroni is boiling over as I type, and the cat won't leave me alone.) I've seen dependent young into the 2nd week of September the past 3 years, and on 2 visits this month to the Wyoming Hereford Ranch, I saw dependent young. Plus, there was that monster September roost (thousands of birds) in 2009-2011 in Boulder County.

Again, and to wrap up a rambling note, my speculation is that we're seeing some longer-term behavioral and range shift with Barn Swallows in our region. Let's pay attention, let's diligently eBird all our Barn Swallows for the rest of 2013, and, if one does waft down the Arkansas River on the John Martin CBC, you heard it here first.

Ted Floyd

Lafayette, Boulder County, Colo.

On Thursday, September 26, 2013 10:29:57 AM UTC-6, Dave Leatherman wrote:

So, is it just me or does it seem like Barn Swallows have been the last swallow species standing for much longer this late summer-autumn than usual? 

In the way of example, in the northwest corner of Grandview Cemetery in Fort Collins there is a bridge over a ditch that hosts nesting by both Cliff and Barn Swallows.  It appears to me the Cliff Swallows were single-brooded this year and the Barns did their normal double nesting.  Last Cliff was seen there, or anywhere else for that matter, on 4 August.  Birder's Handbook by Erlich et al says Cliff Swallows "usually have 1 brood, sometimes 2-3."  I guess the weather this year, particularly the late spring storms and a resultant late start to nesting, determined 2013 as a single brood year for the Cliffs.  I just don't recall a year when for essentially all of August and September if one sees a swallow, one could assume the overwhelming possibility was Barn.  Given the explosion of aerial insects of late, it seems ironic that a major group (excepting Barn) of insect-eaters is no where to be seen.  The analogy that comes to mind are sports fans who leave the game early, only to hear during their drive home that the home team pulled off a record-setting comeback.  Just what is the environmental clue that dominates the decision of a species to refrain from, or go for, an additional brood?  Ditto for migration south.  Is it day-length, nighttime temps, an assessment of available food resources now and into the near future, something else?

I'd be interested in the observations of others about Cliff, or any other swallow species for that matter, departing earlier this year compared to a "normal" year, if there is such a thing in CO? 

Dave Leatherman
Fort Collins  

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