There is a wide range of sugar concentrations in flowers and a wide range of
preferences in the many species of all hummingbirds. However, nectar in flowers
most attended by Anna’s Hummingbirds are on average in the range of very
slightly higher than 1: 5 ratio of sugar to water. Rufous like sweeter flowers,
1:4 or slightly above. If given a choice, Rufous will come to 1:3 in preference
to 1:4 even though that’s a bit sweeter than their average flower nectar. So
Rufous tolerates 1:3 better than Anna’s but 1:3 will not cause great harm to
Anna’s. The higher sugar does,however, slightly dehydrate the tissues and thus
the birds come to the feeder more often to drink more to relieve some thirst. A
1:4 mixture supplies ample sugar to met the needs of Anna’s even in these cold
temperatures. Since Rufous, which tolerates 1:3 better, is not here in the
winter and Anna’s, which prefers slightly lower sugar, is here in winter, why
supply the higher sugar? It increases its metabolic needs which it is trying to
conserve. It adds some additional stress. It can handle that but why cause it
unnecessarily? In winter, Anna’s are most attentive to feeders upon awakening
from the night’s torpor and again late in the day when they are consuming
enough sugar to convert to fat to use for energy to survive the night. During
the day they still feed but often sit fluffed up nearby a feeder so as to not
expend excess energy searching for food. Of course they still need to glean
insects from plant surfaces to obtain their needed protein. On very cold days
they will go into torpor for periods of time during the day as well as through
the night as an additional way to reduce energy use. I stay with 1:4 since that
meets their metabolic needs and Rufous that likes sweeter is not here.
Dan Gleason
Owner, Wild Birds Unlimited of Eugene
Ornithology Instructor, retired, University of Oregon
dan-gleason@xxxxxxxxxxx
On Dec 28, 2021, at 8:21 PM, larspernorgren <larspernorgren@xxxxxxxxx> wrote:
I read on Obol over ten years ago that Rufous Hummingbirds tolerate 3:1 syrup
but that more than 4:1 was unhealthy for other species. No references or
explanation how this was determined. Everyone seemed to accept it as fact.
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------
From: Christine Maack <cmaackster@xxxxxxxxx>
Date: 12/28/21 7:32 PM (GMT-08:00)
To: Sandy Leaptrott <sandyleapt@xxxxxxxxxxx>
Cc: Obol <obol@xxxxxxxxxxxxx>
Subject: [obol] Re: Hummingbird nectar ratios
Do you know if those plants are the ones with a higher sugar content?
Chris
On Tue, Dec 28, 2021 at 7:12 PM Sandy Leaptrott <sandyleapt@xxxxxxxxxxx>
wrote:
Hello All,
Somehow I missed the nectar ratio discussion the first time around. Maybe
this explains why, even in this cold weather, my Anna's favor blooming
plants over the feeders. They use the feeders first thing in the morning
but once they get warmed up and moving around they head for the Viburnum
bodnantense, winter blooming heathers, and a winter blooming jasmine in my
garden and a neighbor's Strawberry Tree (an Arbutus of some sort).
My winter blooming plants seem to be blooming about a month early this
winter.
Sandy Leaptrott
NE Portland
Sent from my iPad
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