[obol] Heron Rivalry---with Photos

[Steve McDonald]

      At Alton Baker Park in Eugene on Sunday, two male Gr. Blue Herons
put on quite a show.  They swooped and croaked around for awhile, then
one lit on a power tower and the other settled on a pine tree.  The one
in the tree stretched his head down low, raised his crest and clacked
his beak once, loudly.  Then he raised his body, neck and bill so they
were pointing straight up.  He repeated this several times, then flew a
tight circle around his rival's perch and returned to the tree.  There
are some photos of this on my Flickr album.

    I've also added some more shots of the bird I think may be a
swan/goose hybrid.  I observed the bird closely today at this park and
saw more swan-like postures, as well as some that were more like those
of a domestic Chinese Goose.  Now, I have a more complete theory about
its ancestry.  This is just one possible scenario, but it's my best
speculation: 

     I propose that a Snow Goose mated with a domestic Chinese Goose
(wild swangoose derivative) that had both white and dark-colored
varieties in its heritage.  Since they are both in the Anser Genus,
fertile offspring is a possibility, although not necessarily so.
Anyway, if that couldn't happen, then my whole theory is shot.
Possibly, there could also have been some domestic Greylag ancestry
mixed in.  I figure that a Snow Goose would have been integral to this
mix, as the source of the black wing feathers. 

     Then, one of the offspring of this first pair mated with a Tundra
Swan and produced the "swoose" that is at the park.  Crosses between
geese and swans would be sterile, so no further generations of this
hybrid line would occur.  If it weren't genetically impossible, I'd
think that it looked more like just 1/4 swan than half and half.  

     You'll notice that the body of the "swoose" is the same shade of
greyish-white you'd see on a juvenal swan.  In addition to the several
black wing feathers, it has some greyish-brown feathers on its back.
The purely yellow-orange feet go against the swan-hybrid theory, as
black is a dominant inherited characteristic. But, many odd colors show
on hybrids that are visible on neither parent.  There is just a hint of
a knob on its head, which would come from a Chinese Goose ancestor.  The
furrowed feather texture on its neck is found on both Snow and Greylag
Geese.

     The bird was vocalizing a lot and it sounded just like you'd expect
from a swan/goose hybrid.  There was definitely something extra in its
voice beyond any type of goose I've heard.  The bird seems settled-in at
the park pond near the Ferry St. Bridge and is there for all to visit
and evaluate.  It's very tame and responds well to offers of bread.

Steve McDonald


http://www.flickr.com/photos/22121562@N00/