[Tweeters] Dark-eyed Junco presumed nest abandonment

[Steve Hampton]

Josh,

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
study.

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.
1996
<https://birdsoftheworld-org.proxy.birdsoftheworld.org/bow/species/daejun/cur/references#REF56026>).
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

> 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

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>



-- 
​Steve Hampton​
Port Townsend, WA  (qatáy)
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