Subject: Re: Feeder Ratio and Water for Hummers
>Date: Thu, 16 Sep 1999 09:02:26
-0700
>From: "T. Wood/S. Williamson" <otter@PRIMENET.COM>
>Subject: Re: Feeder Ratio and Water for Hummers
>Hi, Cathy and all:
>
>A 3:1 ratio is within often quoted "acceptable"
range (3:1 to 5:1), but I
>don't generally recommend a stronger solution than 4:1 except
for
>overwintering birds. Especially for desert hummingbirds, nectar
is an
>important source of water, and if they have no less concentrated
nectar to
>drink (as may be the case in urban settings) there's a chance
they may not
>get enough water over the long term. Though desert hummingbirds
at least do
>occasionally drink water, this may put them at risk of disease
if they're
>sharing a bird bath or fountain with larger species.
>
>I'm a little more concerned about your softened water. Bill
Calder,
>
>I'm a little more concerned about your softened water. Bill
Calder,
>longtime hummingbird researcher, found higher than normal
levels of sodium
>in the urine of urban hummingbirds in Tucson, where many people
use
>chemical water softeners. The typical softener system replaces
the calcium
>ions in the water with sodium, in the form of ordinary salt.
This, too, is
>probably not good for the birds in the long run. Natural nectar
contains a
>variety of electrolyte salts providing a balance of sodium,
potassium and
>other ions, so to bring your nectar substitute closer to the
real thing you
>might use untreated tap water or bottled drinking water. If
and when you
>get your reverse osmosis purifier, you shouldn't use that
water for the
>feeder solution, either, because it will be completely salt-free.
The salts
>found in nectar are apparently physiologically important to
the birds, and
>a deficit or imbalance might cause the birds to seek out alternate
and
>potentially dangerous mineral sources (especially females
prior to
>nesting).
>
>Sheri Williamson
>Southeastern Arizona Bird Observatory
>PO Box 5521, Bisbee, Arizona 85603-5521
>Web Site: http://www.sabo.org
>Business E-mail: sabo@sabo.org
>Personal E-mail: otter@primenet.com
++++++++++++++++++++++++++++++++++++++++++++++++
>Date: Thu, 16 Sep 1999 16:35:56
-0500
>From: "Maurice Duvic Sr." <jsb8@WEBTV.NET>
>Subject: Re: Feeder Ratio and Water for Hummers
>Cathy: I've often wondered
how the direction to boil the water to be
>used for hummer feeders got started. Maybe it was written,
>originally, by a boozer who knew he mixed equal parts of sugar
and water
>and boiled for five minutes to get simple syrup for his sweet
drinks -
>Old Fashioned, Collins, Julep, etc. Or, maybe, it was by a
candy-making
>mama who mixed 2 cups sugar to l l/2 cups of boiling water
to make her
>fondants
>
>In both of these cases the ratio of sugar to water is considerably
>different than l to 4. There can be two reasons for using
boiling water:
>to kill bacteria in the water or to facilitate dissolving.
If humans
>are safely drinking the water there are not many harmful bacteria
>present. And, at room temperature, one part sugar dissolves
with a few
>stirs in four parts of water.
>
>AND, these birds have survived for a long, long time drinking
what we
>would consider highly contaminated water. (Dead fish and other
animals
>, excrement, decayed vegetable matter , etc.) AND, from what
I have
>read, birds have an immune system that is much more effective
than that
>of humans
>
>As for the mineral content of human drinking water: Nature
has equipped
>its creatures with systems that balance the negatively and
postively
>charged elements in their bodies. If the system acquires too
much of
>one element it is excreted. Your ion-exchange system removes
calcium
>(Ca. produces "hardness" in water) and substitutes
sodium. (Table
>salt, NaCl) To avoid the possibility of over-loading the ability
of the
>birds' systems to excrete any excess sodium you might draw
their water
>before it goes through the ion exchange.
>
>Humans consume a lot of sodium and get rid of a lot through
sweating
>(notice how salty sweat is?) urination and solid excretion.
If there is
>a possibility of upsetting the "balance" by too
much loss of the
>electrolyte sodium, "salt pills" are administered
- at least in the "Old
>Army."
>
>I don't know if the lack of minerals in your proposed osmosis
system
>would be deleterious. And I don't know what part of the hummingbirds'
>electrolyte needs are dependent on nectar compared to that
provided by
>the variety of insects they consume. Can you imagine the research
>project necessary to determine this? The salt content of h'bird
feces
>can be determined rather easily. If it is high it might indicate
that
>the bird's innards are functioning properly - getting rid
of exlcess
>
>Good luck!
>
> Vic
>Maurice V. Duvic, Sr.
> Jackson, MS 392ll
================================================
Date: Sun, 6 Jan 2002 00:18:14
EST
From: Stacy Peterson <SJPeterson@AOL.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: [HUMNET-L] Rufous hummer sucrose preferences
HUMNET,
Was perusing the technical literature
this evening and came across this
reference. My apologies if it has been posted to Humnet before.
Thought it
might of particular interest to some given our fascination with
refractometers this fall!
Blem, C. R., et al. 2000. Rufous Hummingbird sucrose preference: Precision of selection varies with concentration. Condor 102: 235--238.
"When offered sucrose solutions
varying in concentration by 10% increments,
Selasphorus rufus preferred 50% concentrations. At concentrations
approximating those of hummingbird-pollinated flowers, birds could
distinguish solutions differing by only 1%."
Best,
--Stacy
^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^
Stacy Jon Peterson
4442 Sijan St. Apt. A
Mtn Home AFB, ID 83648
=================================================
Date: Sun, 6 Jan 2002 02:57:48
EST
From: Stacy Peterson <SJPeterson@AOL.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] Rufous hummer sucrose preferences
In a message dated 1/5/2002 10:57:23
PM Mountain Standard Time,
lanny@HUMMINGBIRDS.NET writes:
> >"When offered sucrose
solutions varying in concentration by 10% increments,
> >Selasphorus rufus preferred 50% concentrations.
>
> Sure they do. And children prefer candy to vegetables, too.
I think the most important issue
is whether or not hummingbirds _in nature_
get anything near the concentration of sucrose used in the experiment.
If
not, then in my opinion the results of the study as cited in the
mini-abstract loss their appeal. And then I agree with your follow-up
issue
-- namely, too many laypeople are of the "more is better"
persuasion, and
that could be a problem if they hear these results.
But if sucrose concentrations
for preferred hummer flowers are "off the
chart" on Dennis' refractometer, then perhaps hummers in
the wild are getting
sucrose concentrations higher than we originally thought.
I'll agree that the birds seem
to be doing fine with feeder sucrose at 1:4.
So why mess with success. Better to be safe than sorry, and all
that. But the
findings of the study cited, the work of Hainsworth and Wolf,
the work of our
very own "sugar daddy" Dennis, and the apparent absence
of peer-reviewed
research stating the ill-effects of high sucrose solution on hummingbirds
(please correct me if I'm wrong here; I haven't been able to find
anything),
raise some interesting questions nonetheless.
Best,
--Stacy
^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^
Stacy Jon Peterson
==================================================
Date: Sun, 6 Jan 2002 06:38:39
EST
From: Bob Sargent <RubyThroat@AOL.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeas
t
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] Rufous hummer sucrose preferences
Stacy and Humnetters
In wild free flying birds, my less than scientific experiments
indicated the
opposite. Those Rufous (and Ruby-throated) that attempted to feed
on 50%
sucrose solutions mostly ignored it. Even when placed in feeders
at the
"preferred" locations, it was still mostly ignored.
Also noted were the long
episodes of bill-cleaning and tongue-extending by individual birds
after
feeding on this thicker syrupy solutions. I strongly suspect that
the
micro-grooving in the tongue would have much difficulty with this
very thick
viscosity fluid.
As I have often stated on Humnet,
I am not a big fan of the tendency to feed
stronger and stronger solutions. The great work done my our own
Dennis-The-Menace has shown that there are many flowers in our
gardens that
contain solutions of stronger than 4 to 1 ratio. What we do not
know for
sure is whether the hummers make a point of choosing those blossoms
containing the stronger solutions.
Bob Sargent
Trussville, Alabama
===================================================
Date: Mon, 7 Jan 2002 09:56:38
-0600
From: MiriamLDavey <athena@INTERSURF.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] rufous hummer sucrose preferences
Lanny, Bob,
Sorry to be so late in posting
to this thread, but just now opened a
backlog of email.
Lanny, Bob, y'all are advoacting
Humnet promote the use of 4:1 sugar water?
I beg to differ. Y'all do realize 4:1 is the equivalent of just
20% sugar,
don't you?
Am I wrong in remembering that
a great many of Dennis' nectar measurements
were significantly higher in sugar % than that? Or do those higher
measurements just stick in my mind because they also just happened
to be
measurements of nectar in humplants which some of us have real
data showing
hummers visiting them (a hard indication of preference) more often
than
other garden plants?
There is also another study I've
heard of but can't cite----showing Rocky
Mtn hummers' preference for a 40-something percent sugar solution,
with at
least some locally native hum-visited plants measuring out at
40-something
percent nectar. The study was done at the biological station at
Crested
Butte, CO, if I'm not mistatken.
That's the equivalent of somewhere between 1:2 and 1:1, a far cry from 1:4.
The longtime birder-ornithological-humgardeners-core
Humnetters from this
area seem to agree (and I presume to speak for them/us) that at
least the
hummers around here prefer a stronger solution.
In summer, I use 1:3, or 25%.
In winter, I use 1:2, or 33.333... %
In winter in freezing weather, I use 1:1, or 50%
Higher solutions also lower freeze-up
temps, as was pointed out in previous
posts.
I would be careful in generalizing
Homo sapiens' tendency to overindulge in
substances such as refined sugar, to other species. A few points
off the
top of my head----Homo spapiens is one of the few with a complex
social
system, which tends to channel natural urges and drives, such
as hunger, in
strange directions. In case anyone hasn't noticed it, we are also
in or
near the apex of a population explosion, which I suspect has perverting
effects, via overcrowding and epidemic disease, on normal biological
drives
like those of hunger, eating, and satiation. And lastly, unlike
hummers, our species did not evolve by heavily utilizing food
with an
extremely high sugar content as more than an occasional part of
our diets.
Cakes, candy, soft drinks, and even highly refined carbohydrates
which get
converted quickly by the body to sugar are recent things (last
few
thousand, or really hundred years). Honey would have been about
the
closest thing to our modern sugary foods and white carbs, but
I don't think
it was more than a rare treat except for a few of the wealthiest
in a
handful of human cultures.
In other words, we are all -
- - - ed up, and assuming other species have
identical urges and problems leads to mistaken conclusions.
MiriamLDavey
BatonRougeLA
===================================================
Date: Mon, 7 Jan 2002 10:41:51
-0600
From: Dennis K Demcheck <ddemchec@USGS.GOV>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] Rufous hummer sugar preferences
I'm currently consolidating my
sugar content results from June-December
2001. I'm going to try to get it in a readable form for LOS news
or
something. Lately, I've been playing around with standards to
get a better
feel for the gizmo's tolerances.
But cutting to the chase, here are a few general conclusions:
1. The sugar content of plants
in hummer-fanatic gardens, as Stacy &
Miriam have mentioned, is way up there. They average around 27%-30%.
That translates as higher than 1:3 (25%) and some Salvias such
as S.
madrensis and S. guaranitica have percentages greater than my
instrument's
maximum reading of 32% (1:2).
2. Although I have reported "Greater
than 32%" in an effort to report
facts, not opinions, I'm fairly sure that in general, the sugar
content is
not a lot greater than 32%. I have been testing out a digital
refractometer that goes to 45%. I got my hands on one right before
the
freeze. I got a S. madrensis reading of 33.4%.
3. A huge generalization with
many exceptions is that non-Salvia &
non-Justicia nectar-producing plants do have lower percentages,
closer to
20% and the classic 1:4 ratio. I think Humgardeners have selected
for
higher sugar percentages by word-of-mouth.
Clearly, not only do hummers
prefer 1:3 and 1:2 sugar solutions, but that
is what we are offering them in our specialized gardens even without
feeders.
However, what bothers me when I sample a Lobelia cardinalis (native
Cardinal flower) that is only 17% sugar, is "What percentages
have they
have evolved with?" It's like what Lanny mentioned with candy
vs.
vegetables. I'm comfortable with offering higher sugar percentages
in
winter and I don't believe there is any acute harm.
Sometimes I wonder and worry if we are being smarter than nature
by
offering very high percentages, and in the long run maybe that
isn't so
smart.
Dennis Demcheck
Baton Rouge
==============================================
Date: Mon, 7 Jan 2002 11:32:17
-0700
From: "Christopher N. Lotz" <Lotz@UWYO.EDU>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] rufous hummer sucrose preferences
Hi all
It is very puzzling because nectars
produced by hummingbird-pollinated
flowers in nature tend to be markedly more dilute than seems best
for
the birds physiologically, and markedly more dilute than what
hummingbirds prefer when offered choices in the lab. Pyke and
Waser
(1982) reported an average concentration of 25 % (weight of sugar
over
total volume of solution), for a sample of 202 species of
hummingbird-pollinated flowers. The range was 7 % to 67 %.
William Calder (back in 1979)
showed that hummingbirds must generally be
forced to consume large water excesses that need to be excreted,
because
of their watery diet. Even at ambient temperatures of 90 oF, Calder
predicted that hummingbirds would not need to drink free water
as long
as nectar was about 30 % (about 70 % water!) or less. At mild
ambient
temperatures (60 oF), Calder predicted that hummingbirds would
always
get excess water from their food, even if nectar was saturated
with
sugar. At fairly low ambient temperatures (50 oF), hummingbirds
would
always have a huge water excess. Field experiments using labeled
water
have shown that hummingbirds and other nectar-feeding birds in
the wild
do indeed have huge water excesses that they have to excrete.
Carol
Beachat, Calder and Braun (1990) likened nectar-feeding birds
to
freshwater fish rather than typical terrestrial birds because
they have
the problem of having to constantly rid themselves of water. In
fish,
the water enters through the skin and needs to be excreted; in
hummingbirds it is consumed in the food.
It is bizarre that hummingbird
nectars seem to be so dilute. There
appear to be many physiological disadvantages of feeding on such
dilute
nectar:
1) the kidneys have to consume huge volumes of water every day;
2) it is difficult to conserve minerals when excreting such large
volumes;
3) nectar has to be warmed to body temperature. It takes 20 %
more
energy to warm 5 % sucrose from 40 oF to body temperature (102
oF). When
feeding on 15 % sucrose, it takes 10 % or so more energy. When
feeding
on 35 % sucrose, it takes almost no extra energy to warm the food
to
body temperature. This is because very little water has to be
ingested
when feeding on 35 % sucrose, and so there is very little volume
to warm
up.
etc.
An African sunbird species has
been found to have a higher metabolic
rate when feeding on dilute sucrose compared to more concentrated
sucrose. There is definitely an energetic cost involved in feeding
on
dilute nectar.
For a hummingbird even at a moderate
ambient temperature, and especially
for ones in the cold (such as the poor ones in NY, Minneapolis,
etc.,
this winter), I think that the chances of survival would be greatly
increased by offering them concentrated food. Then at least they
wouldn't have to expend even more energy than they are already
(to keep
warm, and to support their very active lifestyles). It would help
to
warm the food, but this is impractical and largely unnecessary
anyway if
the birds are being fed concentrated food.
Hummingbirds in the lab definitely
do prefer higher sugar concentrations
than what they get in the field. What they prefer seems to be
physiologically advantageous. But why then do flowers produce
dilute
nectars? Is it to deter insects, many of which are even poorer
at coping
with dilute nectar than birds?
I suspect that my e-mail will
be controversial. I look forward to
further debate.
Chris
===========================================
Date: Mon, 7 Jan 2002 14:23:52
-0600
From: Van Remsen <najames@unix1.sncc.lsu.edu>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: Re: [HUMNET-L] rufous hummer sucrose preferences
HUMNET: on sugar concentrations
... given that (1) the range of natural
sugar concentration in flowers is huge, (2) the hummers wintering
at
feeders in general do not appear to be visibly suffering, and
we don't see
lots of dead and dying hummers around our yards, (3) the rate
of returns
of wintering hummers is amazingly high, and (4) the longevity
of many
individual hummers known to have used feeders for many months
each year is
remarkable ... then, it seems to me, that we don't have much of
a problem
as far as exact concentration of sugar in feeders, as long as
it's in the
10-30% range found in most hummer-polinated flowers.
==============
Date: Tue, 8 Jan 2002 04:19:08
EST
From: Stacy Peterson <SJPeterson@AOL.COM>
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@listserv.lsu.edu>
To: HUMNET-L@listserv.lsu.edu
Subject: [HUMNET-L] Selected flower / nectar references
HUMNET:
I found a few technical references
for those interested in pursuing the
flower-nectar thing a bit more. Might be fun to read these someday
(when I
can catch a stagecoach to the nearest good university library).
Here are three papers that sound "on-topic" by title.
Feinsinger, P. 1983. Variable
nectar secretion in a Heliconia species
pollinated by hermit hummingbirds. Biotropica 15:48-52
Bolten, A. B., P. Feinsinger,
H. G. Baker, and I. Baker. 1979. On the
calculation of sugar concentration in flower nectar. Oecologia
41:301-304
Bolten, A. B., and P. Feinsinger.
1978. Why do hummingbird-pollinated flowers
secrete dilute nectar? Biotropica 10:307-309
Best,
--Stacy
^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^...^v^
Stacy Jon Peterson
============================
X-Priority: 3 (Normal)
Importance: Normal
Date: Sat, 3 Aug 2002 23:17:07 -0500
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
From: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
Subject: [HUMNET-L] Sugar Concentrations
Pursuant to a lot of earlier
discussions about the relative merits of
stronger or more dilute sugar concentrations in winter hummingbird
feeders,
I thought you might find the conclusions of a short note in a
recent
edition of the "The Condor" interesting. On pages 672-675
of Vol 104 # 3, August 2002, Chris N. Lotz and Sue W. Nicolson
report in their note "Nectar
Dilution Increases Metabolic Rates in the Lesser Double-Collared
Sunbird"
that when they measured the metabolic rate of sunbirds fed two
different
concentrations of sucrose--0.2M and 1.2M--that the birds fed the
lower
solution consistently raised their meatobolism to compensate,
and
vice-versa. They further found that the increase in metabolism
was exactly
the increase predicted by the calculation of the metabolic cost
of raising
the temperature of the higher volume of nectar verses the lower
volume to
body temperature.
The implications for wintering
hummingbirds are obvious--cold dilute
solutions are metabolically costly, compared to cold concentrated
solutions. That means that all other things being equal--hummingbirds
in winter fed stronger solutions have an easier time fulfilling
their energy
requirements, and surviving, than hummingbirds fed weaker solutions.
"Based on these equations,
the daily energy expenditures of sunbirds must
increase by 16% and 2%, respectively, to warm 0.2M and 1.2M sucrose
by
22degreesC."
The authors actually mention
the situation for Rufous Hummingbirds, even
though the note is about sunbirds. "We have now directly
tested theoretical
food-warming costs in Rufous Hummingbirds (Lotz et al. unpubl.
data). When
the perch is placed close enough to the feeder to preclude hovering,
hummingbird metabolic rate changes exactly as predicted by our
food warming
model with changes in both nectar temperature and concentration.
We are
also
currently exploring other factors, in addition to food-warming
costs, that
may contribute to increases in metabolic rate with dietary dilution,
such
as
increases in foraging (specifically hovering) costs, and increased
kidney
work associated with larger ingested water volumes."
They go on to conclude, "stray
hummingbirds that survive for weeks around
artificial feeders during snowy winters in Minnesota and New York
must
strongly benefit when they are provided with relatively concentrated
sugar
solutions."
I'll leave it to Dennis or Vic
to tell us how 0.2M or 1.2M solutions
translate to 4:1 vs. 2:1 water sugar solutions. All I know is
that one is
six times stronger than the other...
David Muth
New Orleans
===================
Date: Tue, 6 Aug 2002 01:25:12
-0400
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
From: BB for Hummingbirds and Gardening for them in the Southeast
David and HUMNET,
Nobody has replied to this, so
I thought I would give it a shot. I think
that 0.2M is about 20 cups water to 1 cup sugar, and 1.2M is about
2:1.
For
excessive technical detail on how I arrived at these estimates,
please see
below.
John Sevenair
New Orleans
Technical detail: Sucrose (table
sugar) has a molecular formula of
C12H22O11 and a molecular weight of 342. A 0.2M solution therefore
contains
(0.2)(342)=68 grams of sugar per liter of solution, and a 1.2M
solution
contains (1.2)(342) or 410 grams of sugar per liter of solution.
Now comes the approximate part.
The density of sugar is 1.5 grams per mL,
but that's a solid block and not the sugar in your cup, which
has air holes
among the granules. (I could take some sugar to work and get a
number, and
I will if anybody is really, really desperate to know). So let's
say that
you take about 50 mL of sugar granules and mix them with about
950 mL of water
to make your 1 liter (1000 mL) of solution. That's about 20:1.
(Lovers of
technical detail will know that there's another approximation
here, but
never mind.)
A solid block containing 410
g of sugar would have a volume of 273 mL, but
let's say it's a little over 300 mL. Then about 330 mL of sugar
granules
plus about 670 mL of water gives you about a liter of solution.
That's
about 2:1 (water to sugar, as HUMNETters usually express it).
Is anybody still reading this? I didn't think so.
John Sevenair
========================
Date: Wed, 7 Aug 2002 06:46:27
-0400
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
David and Humnetters
I have great respect for Chris and Ms. Nicolson and their work
with
sunbirds. I am however, a bit reluctant to accept the direct
application
of these findings to Rufous hummingbirds in winter. My greatest
fear is
that the "limits" of sugar concentrations may cause
damage in birds that
feed only at this nectar source in winter. I base that on
personal
observations of problems with Rufous that have "wintered
on strong sugar
mixes". My gut feeling is that the natural progression
will be if a little
is good, then stronger is better (without any limits).
I strongly suspect that a thicker,
more dense fluid is not as easily
"lapped from a feeder" by the very specialized tongue
of a hummingbird.
The tiny grooves (tubes) in the tongue of hummers, in my opinion,
would
have more difficult being emptied than with a thinner, less concentrated
solution.
I have not found that ANY Rufous
hummingbirds have difficulty surviving on
a 4 to 1 water/sugar concentration. I do believe that if
a hummer needs
more sugar it will feed more often. I have seen many instances
in which
bloated hummers with what appears to be fluid filled tissue, DO
OCCUR where
the hummer hosts are feeding 2 to 1 or 1 to 1 solutions.
As for birds in the colder areas
like New York. I ABSOLUTELY TO BELIEVE
that extended periods of below freezing weather will kill some
hummingbirds. I just as strongly believe that most hummingbirds
will flee
such areas for warmer and more food-rich surroundings when they
are
threatened.
I am personally of the opinion
that the routine capture and relocating of
winter hummers is a mistake. In retrospect, when we all
knew very little
about their survival chances in winter, such actions appear to
have been
justified on humane grounds. I do not think that we should
make it our
lifes mission to "save the wild hummers" by extraordinary
rescue missions
that take away the opportunity of these hummers to make their
own decisions
about when they depart from colder climates. There will
always be
exceptions to this "rule", but once started it becomes
that "slippery
slope" that was the standing policy of many rehabbers and
individuals in
the past. If any of you have a wintering hummer and you
fear the prospects
of making such decisions, YOU MAY END ALL OF THE WORRY BY
SIMPLY REMOVING YOUR FEEDERS WHEN IT FIRST ARRIVES IN YOUR YARD.
Finally, let me make it clear
that in my experience extremely cold weather
will kill hummingbirds! It will kill them Louisiana, Alabama
or New York.
Such deaths are a part of the natural order of things and have
served these
species well since long before man starting mixing sugar water
solutions to
feed them. I would suggest that we give much thought to
how we interpret
data from caged sunbirds and apply it to free flying Rufous hummingbirds.
I give you my opinion because many of our guys on Humnet may be
tempted to
go off the deep end in mixing their sugar water.
Respectfully
Bob Sargent, President
The Hummer/Bird Study Group, Inc.
==========================
Date: Fri, 9 Aug 2002 10:53:27
-0500
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
From: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
Subject: [HUMNET-L] Minerals and other stuff in nectar
Searching the web for information
on the composition of nectar I found the
following review in PDF format at:
www.biol.vt.edu/faculty/Adler/Oikos00.pdf
You will need Adobe acrobat reader
to open it
(http://www.adobe.com/products/acrobat/readstep.html)
This is what it says:
Adler, L. S. 2001. The ecological
significance of toxic nectar. - Oikos 91:
409-420.
Nectar is about 90% sugar by
dry weight (Luttge 1977); the other 10%
consists of a myriad of compounds, including amino acids, lipids,
antioxidants, mineral ions, and secondary compounds (Luttge and
Schnepf 1976,
Baker 1977). The chemical composition of nectar varies widely
between
species, and even between different types of nectaries within
the same plant species (Davis et al. 1998). Nectars are characterized
by their ratio of sucrose:(glucose+fructose), which is consistent
within species but varies
widely between species. Amino acids are virtually ubiquitous in
nectar, and their composition ranges widely between species but
is generally consistent within a species (Baker and Baker 1982).
Pollinator taxa have been correlated
with both sugar ratios and amino acid composition across species,
suggesting
that there is selection for a characteristic ''taste'' that is
recognizable to specific pollinators (Baker and Baker 1982). Some
nectars
fluoresce under UV illumination while others do not; the color
and intensity
of fluorescence vary between more than within species, suggesting
species-specific differences in compounds responsible for fluorescence
(Thorp et al. 1975). Finally, many types of secondary compounds
have been
found in nectar from different plant species in small but consistent
amounts (reviewed below).
The species-specific differences
in nectar composition could be explained
in two ways that are not mutually exclusive: (1) the secretory
process in nectaries controls chemical composition and varies
between species or (2) the constituents of nectar reflect the
chemical composition of phloem, and phloem composition varies
between species. Researchers differ in their emphasis on these
possibilities; in his review of secretory tissues, Fahn (1988)
states that ''nectaries secrete unmodified or only slightly modified
substances supplied directly or indirectly by the vascular tissues'',
while Luttge and Schnepf (1976) emphasize the role of active transport,
rather than passive diffusion, in moving sugars against concentration
gradients. The latter opinion is focused on the transport of sugars
rather than other nectar constituents; Luttge (1977) mentions
that compounds other than sugars may move through nectaries by
passive diffusion rather than active transport. Many secondary
compounds, including alkaloids, iridoid glycosides, glucosinolates,
cardenolides, and phenolics, are transported between plant tissues
via the phloem (Baker and Baker 1982, Treutter et al. 1985, Mullin
1986, Montllor 1989, Molyneux et al. 1990, Wink 1992, Gowan et
al. 1995, Merritt 1996). Therefore differences in non-sugar nectar
composition, including secondary chemistry, may be caused by differences
in
phloem compounds that diffuseinto nectar.
[not signed]
====================
Date: Fri, 7 Feb 2003 06:42:53
-0500
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
From: BB for Hummingbirds and Gardening for them in the Southeast
Subject: Re: [HUMNET-L] keeping feeders clean (now sugar solutions)
Humnetters
Just for the record, ONE MORE TIME, I still recommend the standard
4 to 1
solution. With all due respect to my good friend and Sumo
Wrestling
Champion Miriam and others, I am not a member of the Humnet Ornithologist's
Association's Sugar Committee mentioned in her post. I DO
NOT think that
these 1 to 1 solutions are a good idea. Since I have a great
deal of
contact (and some small influence) with the public, I wanted to
express my
opinion again on this sweet subject.
Mixing stronger sugar solutions
in order to retard the growth of mold seems
a strange reason to recommend it. It would seem to me that
keeping clean
feeders is the best way to avoid a problem with mold. Mr.
Dennis
Demcheck's fine work on sugar concentrations clearly shows that
strong
sugar solutions exist in the wild and in our gardens, but most
of the
plants tested are probably non-native nectar producers and have
little
overall influence on the daily lives of wild bird populations.
I view this
whole fiasco like feeding candy to children. Give them one
bar of candy
and they will eat it. Give them a bowl of sugar and and
spoon and they
will also eat it, whether it is good for them or not.
Of the several dozen wintering
hummers that survived the bitter cold of
this winter (-2 to 4 degrees near my home in the Birmingham area)
ALL WERE
BEING FED THE STANDARD AND WIDELY ACCEPTED 4 TO 1 SOLUTION.
None died,
none starved, none froze to death and none begged for stronger
drink. This
facination of feeding stonger and stronger solutions seems to
be more a
product of what humans want than what hummingbirds need.
Does the phrase
"if it ain't broke don't fix it" ring a bell with anyone?
Is cold weather and the death
of some hummingbirds the driving force? If
so, I suggest that cold weather will kill weak and less than perfect
hummers in Louisiana, Alabama, Ohio or wherever cold winters find
them.
This is a natural process not likely to be solved by thickening
the sugar
solution.
It would be interesting to know
what experiments were done by the
strong-syrup advocates that prompted their decision to thicken
up the
juice. My personal experiments with stronger solutions with
Ruby-throated
showed most hits occurred on the feeders with the 4 to1 and even
5 to 1
mix. Admittedly, these were simple non-controlled field
preference
experiments and did not include caged birds (I don't want to go
there again
either).
I think that I am getting another
headache caused by this "dead-horse"
issue. Two asprins will probably cure my headache, but if
two is good then
4 is probably better. I think that I will feed me 4 asprins
instead. You
can call me in the morning.
Bob Sargent
Trussville, Alabama
=====================================
Date: Sun, 12 Jan 2003 13:44:05
-0800
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
Subject: Re: [HUMNET-L] Nocturnal feeding by Rufous Hummingbirds
on 1/12/03 11:55 AM, Allen Chartier at amazilia1@COMCAST.NET wrote:
> Another sugar alternative
she asked me about was Stevia. I'd never heard
of
> this before. I told her that in the absence of any research,
I would
> definitely avoid it...stick to 4:1 with white sugar. Just
in case any of
you
> get asked about Stevia, this is what I found on an internet
search for
sugar
> substitutes:
>
> Stevia is derived from a South American shrub. Though it
can impart a
sweet
> taste to foods, it cannot be sold as a sweetener because
FDA considers it
an
> unapproved food additive. "The safety of Stevia has
been questioned by
> published studies," says Martha Peiperl, a consumer
safety officer in
FDA's
> Office of Premarket Approval. "And no one has ever provided
FDA with
adequate
> evidence that the substance is safe." Under provisions
of 1994
legislation,
> however, Stevia can be sold as a "dietary supplement,"
though it cannot
be
> promoted as a sweetener.
>
Allen,
Stevia contains no sugar; i.e.,
no food value). All it does is chemically
stimulate the taste buds and trick them into thinking they are
tasting
something sweet. For this reason, it has been tried by diabetics
and
others
as a sugar substitute. I have grown it, but I discarded it because
it
tasted far too sweet for me. I am not sure what might make it
unsafe for
human consumption, but if fed to a hummingbird, the bird would
very
probably
starve to death (but, of course, I think any self-respecting hummer
would
would know better than to give it a second taste).
I am wondering what motivates
everyone to try other things when plain
refined sugar has been proven to be the ideal hummingbird food?
John C. MacGregor IV