Hi Sandy,
My sense is that the issues with the rufous are probably complex. Anna’s
thriving likely plays a role. I recall when I first came to Oregon 33 years
ago that I had to take my ornithology classes up to the trails around the zoo
to get them Anna’s. That compares to this past summer when I conducted my
entrie field research season focusing on Anna’s here on campus and in my
backyard (all my other field sites were closed due to Covid) with ample numbers
of birds. Rufous used to be a regular visitor to my yard but this year I had
one female amongst all the Anna’s. Even then she was around when mostly
juveniles were hanging around the feeder. It is not just at my house. I
regularly walk at Champoeg State Park where I always encountered rufous. This
year I THOUGHT I might have heard a male a time or two. There have been
multiple published reports suggesting their populations are declining, but the
way populations are tracked it could also involve shifts in migratory routes.
------------
Donald R. Powers, Ph.D.
Professor of Biology
Department of Biological & Molecular Sciences
George Fox University
414 N. Meridian St. #6107
Newberg, OR 97132
(503) 554-2705
dpowers@xxxxxxxxxxxxx
http://www.dpowerslab.com
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<https://experiment.com/projects/how-do-hovering-hummingbirds-survive-hot-days>
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On Dec 29, 2021, at 9:21 AM, Sandy Leaptrott <sandyleapt@xxxxxxxxxxx> wrote:
Hi Dan,
It would seem that there is a lot of unpublished information about
hummingbirds.
So, it would seem the combination of flowers and feeders in my garden is
working for the hummingbirds right now because they are not visiting the
feeders at their usual approximately 15 minute intervals, so maybe I will
just do what I am doing unless I notice birds in distress.
I wonder if the sugar nectar ratio in my garden flowers explains why I have
fewer Rufous Hummingbirds. I had it in my mind that the non migratory and
territorial nature of Anna's might be the reason I see fewer Rufous
Hummingbirds. I removed a couple of types of perennials from my garden these
past years that the Rufous Hummingbirds favored. These particular plants
self-seed so vigorously and thrive without care I fear their escape into
nearby wetlands.
As my garden has matured it has gotten so much easier to look after the
birds, especially through spring and summer, because the birds find their own
food. It is kind of hard on my fragile butterfly population, the rest of the
pollinators seem to be thriving.
Sandy Leaptrott
NE Portland
Sent from my iPad
On Dec 28, 2021, at 9:31 PM, Dan Gleason <dan-gleason@xxxxxxxxxxx> wrote:
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
<mailto: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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