[Tweeters] Dark-eyed Junco presumed nest abandonment

HAL MICHAEL ucd880 at comcast.net
Mon Aug 8 06:53:57 PDT 2022

Studying nest success and failure rates in birds is difficult at best. First you have to actually find the nest which, as others have noted, may allow a Corvid to prey on that nest as they watch you.

I have run a line of nest boxes for twenty-some years and that does offer an opportunity to look at success/failure which I am trying to do. A few observations (no quantification yet) is that some boxes fail more than others. Also, some species fail more than others but tis may be because they are nesting in a marginal site for them.

I think we also need to remember that what is important for a species is the annual success/failure and that an individual (which may be young/old/chose a bad site/etc.) result is not all that critical.

Hal Michael
Board of Directors, Ecologists Without Borders http://ecowb.org/
Olympia WA
360-791-7702 (C)
ucd880 at comcast.net

> On 08/07/2022 9:57 PM Robert O'Brien <baro at pdx.edu> wrote:



> On the subject of Juncos. We had a single Junco feeding a flying young cowbird at our feeder a week ago First time in 50 years. I believe it nested right next to our house where we had seen it earlier. I haven't seen or heard any cowbirds here in months. They are sneaky.

> Bob OBrien Portland


> On Sun, Aug 7, 2022 at 8:05 PM Josh DeSilvey <jmdesilvey at gmail.com mailto:jmdesilvey at gmail.com > wrote:


> > > Hi all - This past weekend we witnessed the culmination of a slowly unfolding tragedy as a female Junco abandoned her nest and three eggs that never hatched. She nested for almost three weeks. We were cautious observers of her activity as she built the nest in a wine-barrel planter located on the deck in our backyard. When we realized this Junco chose this planter, we were excited to see what would unfold, even attentively counting down to when the eggs should have hatched. But then that period passed.

> >

> > We grew concerned when she did not return to the nest Saturday evening, though we did see her come and go throughout the day. This morning (Sunday) confirmed our fears when we did not spy her sitting on the nest. Looking up Junco nesting behaviour on Birds Of The World (BOTW; Thanks WOS!!) confirmed that her eggs should have hatched by Wednesday of this past week (8/3). Although the conclusion is still sad, we suspected it was inevitable. In part this post is one of mourning for our Junco (we named her June) and her loss, and not being cautious, careful witnesses to June raising her nestlings. It is also one of inquiry and I wanted to bring it to the Tweeters list for advice.

> >

> > So we have a nest and three Junco eggs. What should we do with it now? Are there agencies (glancing in the Burkes direction) in the Seattle metro area that would want these for research or teaching?

> >

> > Should we leave it as is and let what scavengers are around claim it for their benefit? Or when it starts to stink, remove it to the compost bin or green belt behind our home?

> >

> > Also, I was curious to find that BOTW does not report failure rates for broods, whether first or subsequent. In general for birds, what are failure rates for broods? What are some causes? Are second or third broods more likely to fail, then earlier ones?

> >

> > Thanks for your thoughts and answers. I look forward to reading them.

> >

> > Josh DeSilvey

> > Mountlake Terrace

> > jmdesiley at gmail.com mailto:jmdesiley at gmail.com

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