I've visited the traditional nest site of yellow-crowned night-herons in
east Columbus a number of times this year, and heard reports from any
number of other observers, including local residents. It was quite
obvious that beginning on 6 April when they first appeared that only
three adults were present, and so it has remained, apparently. A pair
promptly nested in one of the existing nests, and the third bird hung
out at the other one. The nests were in the same large sycamore.
        The active nest, SE of the other one and over the east curb at #211,
produced a nestful of young [this colony of two pairs usually produces
4-5/nest] during May; leaf cover and viewing angles made it hard to
tell, but it seemed at least four young were hatched. None had been
noted earlier at the other nest, over the middle of Preston Rd. Recently
some observers have reported that this neglected nest was newly active.
Some speculated that the disappointed adult was a female who was
eventually impregnated by the male from the other nest, because in
recent weeks both nests have had young in them. Based on the apparent
ages of the young, I doubt this hypothesis.
        I don't know, but today we went to the site and saw three or more young
birds--at least one in the 'new' nest and two in the 'old' one. It was
hard to tell how many were there in all, but they all appeared to be of
a similar size and age. Only one adult was present, at the 'new nest,"
but the other adult(s?) could easily have been away foraging for food.
        In past years, the young night-herons have quickly grown enough to fly
shortly after the fourth of July, and these birds looked pretty much
fully fledged and of the right size. It looked to me as if one or more
of the four or more young in the first nest had moved to the second one;
this certainly would have given them more room. Perhaps all three adults
remained to feed them. The previously unused nest was smaller but in a
lot better shape than the old one, which was sagging and seemingly
falling apart. All of this poses questions:
        --how cooperative are YCNH at communal nest sites? Will odd unmated
pairs/individuals feed the young of mated ones? [in past years, year-old
immature birds have arrived with the adults and seemed to act as
helpers, but not this year]. Will they cede territory in an unused nest
to allow successful pairs to use them?
        --will unmated YCNH remain at a nest site through the breeding season
if a mate does not appear? Will an unmated female accept impregnation
from a male from a nearby existing pair? How might they be distributed
over two nests?
        --has anyone seen four adults at the Preston Road site this year? Has
anyone seen more than five young there this year?
        Our situation here, with two pairs showing up year after year after
year, provides a unique opportunity to answer these questions. It would
be very interesting to know the answers, and careful observations are
requested.
Bill Whan
Columbus
p.s. yellow-throated warblers were singing lustily at this site today.

______________________________________________________________________

Ohio-birds mailing list, a service of the Ohio Ornithological Society.
Our thanks to Miami University for hosting this mailing list.
Additional discussions can be found in our forums, at www.ohiobirds.org/forum/.

You can join or leave the list, or change your options, at:
http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
Send questions or comments about the list to: [log in to unmask]