[Bluebird-babble] 2007 nestbox summary

Wed Aug 15 00:35:30 EDT 2007

2007 nestbox summaryCheryl, 

Bluebirds are particularly tolerant of people, and as long as you know approximately when the young hatched, you can open the box and check the nest up to 14 or 15 days after hatching. Anything beyond that could result in premature fledging and the young would most likely die. 

I moved here from California last year, where I had a bluebird run for several years (14 to 18 boxes), and part of our record keeping was counting the eggs, counting young, and then determining the number that fledged. A number of times I'd encounter the female sitting on the eggs, and she remained there during the closing and opening of the box. Bluebirds seem to vary from box to box, and some were pretty aggressive--diving and chirping--when their box was approached, but none ever contacted me in all those years of weekly next inspections during the bluebird nesting season (March thru early August in California).

Those were Western Bluebirds, but we encountered the same thing this past season with Mountain Bluebirds here in Parker. One pair of bluebirds adopted a decorative birdhouse in our front yard, and another pair adopted a California-style box (modified for fence mounting) in our back yard. Each nest had 4 eggs which hatched and all 8 young fledged. The only way we could inspect the nest in the decorative house was by peeking into the entry hole, sometimes using a mirror. The backyard box has a front-opening door and we were able to count the eggs, then the young, and clean out the box after they fledged. Hopefully they all bonded on the boxes, and will return next spring. The decorative box has since been modified so we can easily lift off the roof.

Joe Lapoint
  ----- Original Message ----- 
  From: Maryl B.<mailto:marylb at infionline.net> 
  To: Listserv of the Colorado Bluebird Project<mailto:bluebird-babble at denveraudubon.org> 
  Sent: Tuesday, August 14, 2007 9:41 PM
  Subject: Re: [Bluebird-babble] 2007 nestbox summary

    ----- Original Message ----- 
    From: Cheryl<mailto:cearnest1606 at msn.com> 
    To: 'Listserv of the Colorado Bluebird Project'<mailto:bluebird-babble at denveraudubon.org> 
    Sent: Tuesday, August 14, 2007 3:27 PM
    Subject: Re: [Bluebird-babble] 2007 nestbox summary

    We have 14 acres between Hartsel and Buena Vista and I purchased two blue bird boxes to put out this year along the entry to our land. That's how I ended up on the mailing list. We had blue bird nests in both boxes and the birds were flying in and out with food so I can only assume there were babies in there but I was afraid to open the box and disturb them. Can someone please give me some basic information as to what the birds will "allow" you to do? I'd love to look in next year and see the eggs, babies, etc. Also, I'd like to put out more boxes but I always thought they should be along the road since that's where we see the blue birds all the time. Is it worthwhile to put boxes in other spots? Thanks for any info.

    Cheryl Earnest

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    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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