Subject: [Tweeters] Hummingbird Question
Date: Apr 15 22:27:37 2009
From: Rob Sandelin - floriferous at msn.com


Is plant nectar simply sucrose? No, it is much more complex. So while the
energy value of sugar water and nectar may be similar, the nutritional value
of all the different nutrients in nectar are unique to each plant.
Hummingbirds evolved with plants, not sugar water and their dependence upon
plant nectar micro-nutrients is not known. The long term affect of sugar
water diets on hummingbirds is unknown. If sugar water is the only diet
provided, the health effects would be assumed to be negative. However how
much sugar water is ingested, what percentage of the diet that represents is
unknown. Like all bird feeding, there is no strong data to support that it
is beneficial or harmful. We simply do not know the affects of our actions
no matter what Birds unlimited and other commercial ventures advertise.
Cornell started doing some long term feeder studies, then apparently
stopped. I would be interested to pointers to studies on bird feeders, it is
a project of one my students.

Rob Sandelin
Naturalist, Writer, Teacher
Snohomish County

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From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of russ
tkachuk
Sent: Wednesday, April 15, 2009 8:30 PM
To: William Kaufman; rnbuffle at yahoo.com; tweeters at u.washington.edu
Subject: Re: [Tweeters] Hummingbird Question


On 15/04/09 4:55 PM, "William Kaufman" <beaux at u.washington.edu> wrote:





Rolan and Tweeters:

Nutrition of flower nectar.
Sugar is the energy producing substance in biological reactions.
The liver converts ingested substances to useable molecules;
carbohydrates are converted to sugar which has a caloric value of 4 Calories
per gram.
The "standard" solution for humming bird feeders is 4/1, i.e., four
parts water and one part sugar (20%).
Flower nectar is 25% sugar, stronger than feeder nectar.
So, the nutritional value (energy) of the two nectars is very
similar.
Interestingly, the rate of energy expenditure for the humming bird
is fifty times that of man.
I was surprised to find that Google has an extensive list of
publications for "flower nectar caloric value" (nectar biology).

(Check: http//web.cortland.edu/broyles/nectar%20biology.html)

Bill Kaufman
Woodinville


Hello All:



I would like to mention that I have been using essentially saturated sucrose
solutions for feeding hummingbirds for at least 30 years in Winnipeg,
Manitoba and 14 years here in Roberts Creek, BC.

The birds have always seemed to be abundant and very healthy around my
feeders. If I lived in a hot, dry desert area, such as in Arizona, probably
20% by weight solutions would be preferable, since deserts are short on
water, the birds need to drink more water in such areas.

Reasons for using saturated sucrose (virtually 50% by weight) solutions are:
1. These solutions do not support microbiological growth.
2. One does not have to fill feeders as often.
3. Saturated sucrose solutions remain liquid even in low freezing
temperatures.

Using saturated sucrose solutions still means that one has to clean the bird
feeders, but not as often. Microbiological growth will still occur in
feeders containing even saturated sucrose solutions, but at much lower
rates. This is due to water vapour condensing on the feeder walls above the
solution surface and the attendant draining eventually lowers the sucrose
concentrations so that bugs start growing on the interior feeder walls
above the solution.

Regards,
Russ Tkachuk (a research chemist in a former life)
Roberts Creek, BC


rtkachuk at dccnet.com

On 4/8/09 6:46 PM, "Rolan Nelson" <rnbuffle at yahoo.com> wrote:



Greetings Tweets,

My wife raised a question tonight that I couldn't answer, so we thought to
turn to y'all for some help.

Is there any nutritional difference between the sugar water hummingbirds get
from feeders and the nectar they collect from flowers?

Some botanists, ornithologists, etc out there?

Peace, Rolan

Rolan Nelson
Fircrest, WA
rnbuffle at yahoo.com



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