[Bluebird-babble] 2007 nestbox summary

Mon Aug 13 21:07:02 EDT 2007

Thanks for the kind words.  Property with a stream running through it in CB--yum!  I guess a price you pay for the wonder of the stream is Tree Swallows (is that what you're referring to?).  Our closest water (not counting the recirculating pump in the bird bath) is the Arkansas River, about 1.5 miles away.  And even there, we didn't see any Tree Swallows breeding.  (We're doing a priority block for the Breeding Bird Atlas that includes our property and part of the river--so we're exceptionally aware of the breeders of the area this summer.)  The Violet-greens are the last breeders to arrive in our area, so there's very little competition between them and other nesters.  In fact, they seemed to wait politely for the 2 nests of White-breasted Nuthatches to fledge before taking over.  I actually thought initially that the nuthatches were doing a second brood, the transition was that seamless (and the eggs are that similar).  

And you guessed it--I'm a research psychologist.  I love numbers and statistics.  Summarizing numbers is my biz.

Tina Mitchell
Christina.Mitchell at UCHSC.edu

________________________________

From: bluebird-babble-bounces at denveraudubon.org on behalf of Gerald B Smith
Sent: Mon 8/13/2007 5:22 PM
To: 'Listserv of the Colorado Bluebird Project'
Subject: Re: [Bluebird-babble] 2007 nestbox summary

Tina,

VERY nice [and scientific] report ... most envious of your number of boxes ... and species ... ALL we get for last two years in our two boxes on ½ acre with stream running through [yes, IN town] ...are swallows ... and, purple they are ... maybe Bluebirds NEXT year ... but doubt it because the swallows arrive about two weeks earlier at this valley / altitude of 9K ft.?

Good job ... wondering where your science education came from?

Jerry & Mary Alice Smith

Crested Butte, CO 81224

PS  Have you ever seen a dozen male swallows court and then feed one female ... she kept all of them on the "the string" well past fledgling by playing, "with child" again and again ... what a life!

________________________________

From: bluebird-babble-bounces at denveraudubon.org [mailto:bluebird-babble-bounces at denveraudubon.org] On Behalf Of Christina.Mitchell at UCHSC.edu
Sent: Monday, August 13, 2007 5:05 PM
To: Bluebird-Babble at denveraudubon.org
Subject: [Bluebird-babble] 2007 nestbox summary

Hi, all--

Sadly, but inevitably, our breeding season has come to an end.  We have 71 nestboxes on 39+ acres in central Colorado--pinyon/juniper/scrub oak habitat at about 7200' in the rain shadow (eastern flank) of the northern Sangres. We've had nestboxes up for 7 years, but this is the first year I've monitored them during the breeding season.  (In the past, we've simply cleaned out the boxes at the end of the season and guessed at what might have used them.)  This summer, we had 7 different species using the nestboxes; 23 boxes were used by birds (and lots by mice and chipmunks) and 2 boxes by 2 different species (Violet-green Swallows moved in right after White-breasted Nuthatches fledged).  The big species surprise was one pair of Western Bluebirds; we've never had them summer in our habitat before.  

Here's the summary.  

Mountain Bluebird:  26 eggs; 14 fledged; 53.8% success. (We had 2 very late nests--total of 10 eggs--that never hatched and probably never had a chance.  If I adjust for those, the rate was 87.5%.  I like that better, although 53.8% is better science.) 

Western Bluebird:  6 eggs; 6 fledged; 100%  

Non-bluebird species-

White-breasted Nuthatch:  14 eggs; 14 fledged; 100% 

Violet-green Swallow:  37 eggs; 29 fledged; 78.4% 

Mountain Chickadee:  18 eggs; 18 fledged; 100% 

Juniper Titmouse:  11 eggs; 5 fledged; 45.5% 

Ash-throated Flycatcher:  9 eggs; 8 fledged; 88.9% 

Total:  121 eggs; 94 fledged; 77.7%  

The juniper titmice either were the unluckiest or made the worst choices.  Only 1 of 3 nests raised any young at all; eggs were removed early on by some critter (snake? chipmunk?) in the other 2.  The Violet-green Swallows had the highest (and only, actually) mortality among the nestlings--5 dead in 2 boxes, no apparent sign of predators, unknown cause of death.  

It was a very fun undertaking.  We have 30 more nestboxes that were unmonitorable this year (placed too high or built so that the bottom opened--great for cleaning, but not for monitoring). My husband's going to reposition or and/or revamp those over the winter, so I'll have even more next year.  Thanks to Kevin and the CBP for providing the encouragement and support to get me motivated to give it a try!

Tina Mitchell

Coaldale, CO

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