On Sun, 14 Apr 1996, Don Cecile wrote:

> wondered if this might be a 'dummy' nest since it was so close to one of the
> other nests. I am as yet uncertain though because one of the wrens was
> sitting in the flimsy nest at the time (perhaps forming its shape?).
>
> After having watched them for a while, I was curious as to whether marsh
> wrens normally make dummy nests or is this uncommon? If they do make dummy
> nests, why did I not see more nests around, and wouldn't a dummy nest remain
> unfinished? Why would a marsh wren bother to make an elaborate nest when
> something rather flimsy might serve the same purpose? (assuming that the
> purpose would be to foil predators)
>

According to "The Birder's Handbook," Elrich et al., Marsh Wrens build
their nest "attached to reeds, built in layers with entrance usu near top
(usu facing w or s), of reeds, grass, lined with fine plant materials,
feathers. Male builds, female lines."

Also, on dummy nests: "Roost in dummy nests in nonbreeding season."
Bewick's, Sedge, House, and Winter Wrens are all listed as making dummy
nests as well.

One explanation offered for dummy nest construction (but offered as an
hypothesis, not fact) involves hormones: "Since nest building requires
a lower level of hormonal stimulation than does sexual behavior, building
may begin early in the courtship cycle or continue through incubation, and
may account for some of the so-called dummy nests that are constructed and
never used (Ehrlich et al. 547)"

As for me, I'm no expert- but I did get a nice picture of a Marsh Wren
singing, so I love 'em! :-)

-Pat
scott931 at uidaho.edu
http://www.uidaho.edu/~scott931/projects/guide.html