[Tweeters] Dark-eyed Junco presumed nest abandonment
stevechampton at gmail.com
Sun Aug 7 20:41:22 PDT 2022
Sorry to hear about the nest failure. Given how late it is -- and the fact
that there are lots of junco juvies about -- this may have been their
second clutch of the summer. In these cases with my nest boxes, I generally
toss the nest and eggs into the bushes, leaving them scavengers or insects.
Birds of the World (BOTW) species account does have some numbers from a
Of 170 nests on territories of 93 males (1989–1993), 29.4% failed before
hatching, additional 15.9% between hatching and fledging (Ketterson et al.
Mean clutch size was 3.57 eggs ± 0.72 SE; mean number of nestlings in nests
in which eggs hatched (hatching success) was 3.36 ± 0.094 SE. In nests that
produced ≥1 fledgling, number of fledglings was 3.08 ± 0.112 SE. Of broods
followed until independence (2 wk after fledging), mean number of brood
members still alive was 2.34 ± 0.156 SE.
To maintain their population, of course, they need only replace themselves
once in their lifetime with another breeding offspring, so there's a lot of
attrition along the way for eggs, chicks, fledges, juveniles, etc.
On Sun, Aug 7, 2022 at 8:05 PM Josh DeSilvey <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
> 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
> Tweeters mailing list
> Tweeters at u.washington.edu
Port Townsend, WA (qatáy)
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