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hummingbirds, bees, and colors; romantic mockers; mute swans
Added Chipping Sparrow to the yard list, as two perched near the feeders
but didn't eat much. A Gray Catbird is a new regular at the suet feeder,
and meowed at me from there while I sat on the ground six feet below
digging up weeds (Star-of-Bethlehem, yuck!). And lately, two mockingbirds
have been sharing the suet in a scene that looks more appropriate to
Valentine's Day than Easter or Passover... Yellow-rumps are into their
breeding plumage, and singing lustily, but so far no vireos or other
warblers migrating through Old North Durham. Hopefully they'll all show up
for the Durham Spring Bird Count next Sunday...
Some clarifications on the hummers-insects-flower color discussion: *some*
insects can see the color red, especially butterflies. The main difference
between butterfly- and hummingbird-pollinated flowers tends to be shape,
not color; and the two groups do overlap. Where the red color becomes
significant is in relation specifically to BEES. Bees' vision is shifted
to the short wavelengths; it allows them to see into the ultraviolet, but
in compensation reds appear black to them. So flowers which "want" to
deposit their pollen on birds have red flowers; those which are
specialized for bees usually have blue or purple flowers, or are yellow to
our eyes, but have patterns in ultraviolet that unaided vertebrate eyes
cannot see. The research Gary referred to showed that hummingbirds can be
trained to visit any flower color, but since bees flock most heavily to
blues, purples, and yellows, the hummers find less nectar there, and more
stinger-armed competition, and so spend most of their time visiting reds.
Back to invasive exotic species:
On Fri, 18 Apr 2003, Ritch Lilly wrote:
> On an unrelated note, the number of Mute Swans in our area is either getting
> better or worse depending on your point of view. I had a total of 25
> yesterday as I was out and about. Can someone tell me the status of that
> bird here locally?
> Are they protected? Should
> they be removed? When is such a species determined to be established?
Can't speak to their status; the only population I hear much about in the
Carolinas is down there in the Conway/Myrtle Beach/Georgetown zone of SC.
I don't think they're protected in their own right, but in some places
they are protected in order to avoid people without hunting permits
shooting Tundra or Trumpeter Swans thinking that they are Mutes.
They definitely should be removed, although down here in the Carolinas,
they're less of a menace; up north they run other waterfowl out of nesting
habitat, but down here our only common nesters in most places are Wood
Ducks that don't use the same habitat. Their prodigious wastes have caused
clam beds to be closed up north, and could lead to closings of oyster beds
down here; they might also cause serious damage to aquatic vegetation if
they get common enough. The big question is how? Animal-rights groups get
their panties bunched up over swans getting shot, and addling eggs can
only get you so far. In the Chesapeake Bay, where Muties are a major
problem, they have all kinds of proposals and counter-proposals. Not sure
which one they're using.
As for being established, if they are fledging young Muties faster than
the adult birds are dying off as roadkill or whatever it is that kills
them, that works for me...
On Fri, 18 Apr 2003, Paula Jeannet Mangiafico wrote:
> I wonder what effect the various hurricanes and ice storms in the last ten
> years have had on populations of woodpeckers and other birds that depend on
> dead or downed timber?
I actually tend to see the most woodpeckers around the various waterfowl
impoundments like Horton's Pond and in many of the gamelands, and along
the edges of artificial lakes like Jordan, Falls, etc. While the
hurricanes and ice storms tend to produce *fallen* trees, the impoundments
and dams flood forests and kill trees but leave them standing, more to the
Joshua S. Rose
Department of Biology (Zoology, R.I.P.)